Limbic network function.

As seen in this outline, the M (memory, motivation) depicts the drive component of the limbic network. Before learning, an individual must be motivated to learn, to try to succeed at the task, to solve the problem, or to benefit from the environment. Without motivation the brain will not orient itself to the problem and learn. Motivation drives both our cortical structures to develop higher cognitive associations and the motor system to develop procedures or motor programs that will enable us to perform movement with the least energy expenditure and the most efficient patterns available. Once motivated, the individual must be able to pay attention and process the sequential and simultaneous nature of the component parts to be learned, as well as the whole. Thus there is an interlocking dependence among somatosensory mapping of the functional skills¹²⁴ (cognitive), attention (limbic) necessary for any type of learning, and the sequential, multiple, and simultaneous programming of functional movement (motor). The limbic amygdala and hippocampal structures and their intricate circuitries play a key role in the declarative aspect of memory.^125–128 Once this syntactical, intellectual memory is learned and taken out of short-term memory by passing through limbic nuclei, the information is stored in cortical areas and can be retrieved at a later time without limbic involvement.¹²⁹

The O refers to olfaction, or the incoming sense of smell, which exerts a strong influence on alertness and drive. This is clearly illustrated by the billions of dollars spent annually on perfumes, deodorants, mouthwashes, and soap as well as scents used in stores to increase customers’ desires to purchase. This input tract can be used effectively by therapists who have clients with CNS lesions such as internal capsule and thalamic involvement. The olfactory system synapses within the olfactory bulb and then with the limbic structures and then may go directly to the cerebral cortex without synapsing in the thalamus. Although collaterals do project to the thalamus, unlike all other sensory information, olfaction does not need to use the thalamus as a necessary relay center to access the cortical structures, although many collaterals also project there.^56,130 Other senses may not be reaching the cortical levels, and the client may have a sensory-deprived environment. Olfactory sensations, which enter the limbic network, may be used to calm or arouse the client. The specific olfactory input may determine whether the person remains calm or emotionally aroused.^131,132 Pleasant odors would be preferable to most people. With the limbic network’s influence on tone production through brain stem modulation, this is one reason aromatherapy causes relaxation and is used by many massage therapists.

A comatose, seemingly nonresponsive client may respond to or be highly sensitive to odor.¹³³ The therapist needs to be acutely aware of the responses of these patients because these responses may be autonomic instead of somatomotor and may be reflected in a higher heart rate or an increase in blood pressure. Using noxious stimuli to try to “wake up” a patient in a vegetative state has the possibility of causing negative arousal, fear, withdrawal, or anxiety and an increase in base tone within the motor generators.¹³² Using this type of input places the patient at level 2 in a “protective state of survival.” Using a pleasant and personal desirable smell will more likely place a client at level 2 “safety.” The former can lead to strong emotions such as anger, whereas the latter often leads to bonding and motivation to learn. Research has shown that retrieval processing and retrieval of memory have a distinctive emotionality when they are linked to odor-evoked memories.^134–136

The V represents visceral or autonomic drives. As noted earlier, the hypothalamus is nestled within the limbic network. Thus, regulation of sympathetic and parasympathetic reactions, both of the internal organ systems and the periphery, reflects continuing limbic activity. Obviously, drives such as thirst, hunger, temperature regulation, and sexuality are controlled by this system. Clients demonstrating total lack of inhibitory control over eating or drinking or manifesting very unstable body temperature regulation may be exhibiting signs of hypothalamic-pituitary involvement or direct pathways from hypothalamus to midbrain structures.⁵⁶ Today, this interaction of the hypothalamus with motor neurons that change or support movement has clearly been established.¹³⁷

Less obvious autonomic responses that may reflect limbic imbalances often go unnoticed by therapists. When the stress of an activity is becoming overwhelming to a client, she or he may react with severe sweating of the palms or an increase in dysreflexic activity in the mouth rather than with heightened motor activity. A therapist must continually monitor this aspect of the client’s response behaviors to ascertain that the behaviors observed reflect motor control and not limbic influences over that motor system.

If the sensory input to the client is excessive whether through internal or external feedback, the limbic network may go into an alert, protective mode and will not function at the optimal level, and learning will diminish. The client may withdraw physically or mentally, lose focus or attention, decrease motivation, and become frustrated or even angry. The overload on the reticular system may be the reason for the shutdown of the limbic network and not the limbic network itself. Both are part of the same neuroloop circuitry. All these behaviors may be expressed within the hypothalamic-autonomic system as motor output, no matter where in the loop the dysfunction occurs. Having a functional understanding of the neuroanatomy and their relationships with each other helps therapists unravel some of the mysteries patients present after CNS insult.^138,139 The evaluation of this system seems even more critical when a client’s motor control system is locked, with no volitional movement present. Therapists often try to increase motor activity through sensory input; however, they must cautiously avoid indiscriminately bombarding the sensory systems. The limbic network may demonstrate overload while at the same time the spinal motor generators reflect inadequate activation. How a therapist might assess this overload would be to closely monitor the ANS’s responses such as blood pressure, heart rate, internal temperature, and sweating versus observing or measuring muscle tone. Although the somatosensory system and the ANS are different, they are intricately connected. The concept of massively bombarding one system while ignoring the other does not make sense in any learning paradigm, especially from a systems model in which consensus creates the observed behavior. To illustrate this concept, think of an orchestra leader conducting a symphony. It would make no sense for the conductor to ask the string section to play louder if half the brass section got sick. Instead, the conductor would need to quiet the string section and all other sections to allow the brass component to be heard.

E relates to emotions, the feelings, attitudes, and beliefs that are unique to that individual. These beliefs include psychosocial attitudes and prejudices, ethnic upbringing, cultural experiences, religious convictions, and concepts of spirituality.¹²⁰ All these aspects of emotions link especially to the amygdaloid complex of the limbic network and orbitofrontal activity within the frontal lobe.^140–142 This is a primary emotional center, and it regulates not only our self-concept but our attitudes and opinions toward our external environment and the people within it.

To appreciate the sensory system’s influential interaction with the limbic network directly, the reader need only look at the literature on music and how it interacts with emotions.^143,144 Most people can give examples of instances where music has elicited immediate and compelling emotional responses of various types. Pleasant and unpleasant musical stimuli have been found to increase or decrease limbic activity and influence both cognitive and motor responses. Although the neurological mechanisms are not yet well understood, the limbic network seems to be implicated in both “positive” and “negative” emotions in response to musical stimuli.^145–148 The clinical implications are huge. Excessive noise, loudspeaker announcements, piped in music, and all the therapists’ voices can affect the CNS of a client. These responses can be highly emotional, cause changes in visceral behavior, and affect striated motor expression. Level of musical consonance or dissonance is just one element of the auditory stimulus that is subjectively experienced by the listener as pleasant or unpleasant. The implications not only that listening to music affects limbic emotional states but that the influence may direct the hypothalamus in regulation of blood flow within the CNS have also been shown.¹⁴⁸ With music or sound being just one input system, the therapist must realize that sensory influence from smell, taste, touch, proprioception, and vestibular and organ system dysfunction can lead to potential limbic involvement in all aspects of CNS function and directly affect the emotional stability of the patient.

Another very important concept linked to the emotional system is the emotional aspect of body image or the concept of SELF. For example, assume that one morning I look in the mirror and say, “The poor world, I will not subject it to me today.” I then go back to bed and eat nothing for the rest of the day. The next day I get up and look in the same mirror and say, “What a change, I look trim and beautiful. Look out world, here I come!” In reality, my physical body has not been altered drastically, if at all, but my attitude toward that body has changed. That is, the emotional component of my body image has perceptually changed.

A second self-concept deals with my attitude about my worth or value to society and the world and my role within it.¹⁴⁹ Again, this attitude can change with mood, but more often it seems to change with experience. This aspect of client-therapist interaction can be critical to the success of a therapeutic environment. The two following examples illustrate this point, with the focus of bringing perceived roles into the therapeutic setting:

Preconceived attitudes, social behaviors, and opinions have been learned by filtering the input through the limbic network. If new attitudes and behaviors need to be learned after a neurological insult, the status of the amygdaloid pathways seems crucial. Damage to these limbic structures may prevent learning¹⁵⁴; thus, socially maladaptive behavior may persist, making the individual less likely to adapt to the social environment. It is often harder to change learned social behaviors than any other type of learning.^155–158 Because our feelings, attitudes, values, and beliefs drive our behaviors through both attention and motor responses, the emotional aspect of the limbic network has great impact on our learning and motor control. If a patient is not motivated and places little value on a motor output, then complacency results and little learning will occur.^159–161 On the other hand, if a therapist places an extremely high value on a motor output as a pure expression of motor control without interlocking that control with the patient’s limbic influence, the behavioral response may lead to inconsistency, lack of compliance, and thus lack of motor learning and carryover.¹⁵⁹ Similarly, it can cause extreme stress, which even the general public knows causes disease.¹⁶²

Motivation and reward.

Moore¹²³ considers motivation and memory as part of the MOVE system. Esch and Stefano¹⁶³ link motivation with reward and help, illustrating how the limbic network learns through repetition and reward. They state that the concept of motivation includes drive and satiation, goal-directed behavior, and incentive. They recognize that these behaviors maintain homeostasis and ensure the survival of the individual and the species. Although the frontal lobe region appears to play an important role in self-control and execution activities, these functions seem to require a close interlocking neuronetwork between cognitive representation within the frontal regions and motivational control provided by limbic and subcortical structures.^140,164 An important aspect of motivated behavior is linked to patient- and family-centered therapy.* “The most powerful force in rehabilitation is motivation.”¹⁶⁷ These words are strong and reflect the importance of the limbic network in rehabilitation.

Motivated behavior is geared toward reinforcement and reward, which are based on both internal and external feedback systems. Repeated experience of reinforcement and reward leads to learning, changed expectancy, changed behavior, and maintained performance.¹⁶⁸ Emotional learning, which certainly involves the limbic network, is very hard to unlearn once the behavior has been reinforced over and over.^169,170 For that reason, motor behavior that is strongly linked to a negative emotional response might be a very difficult behavior to unlearn. For example, a patient who is willing to stand up and practice transfers just to get the therapist off his back is eliciting a movement sequence that is based on frustration or anger. When that same patient gets home and his spouse asks him to perform the same motor behavior, he may not be able to be successful. The spouse may say, “The therapist said you could.” The patient may respond, “I never did like him!” Thus repetition of motor performance with either the feeling of emotional neutrality or the feeling of success (positive reinforcement) is a critical element in the therapeutic setting. Consistently making the motor task more difficult just when the client feels ready to succeed will tend to decrease positive reinforcement or reward, lessen the client’s motivation to try, and decrease the probability of true independence once the patient leaves the clinical setting. When pressure is placed on therapists to produce changes quickly, repetition and thus long-term learning are often jeopardized, which may have a dramatic effect on the quality of the client’s life and the long-term treatment effects once he or she leaves the medical facility. Motor control theory (see Chapter 4) coincides with limbic research regarding reinforcement. Inherent feedback within a variety of environmental contexts allowing for error with correction leads to greater retention.¹⁷¹ Repetition or the opportunity to practice a task (motor or cognitive) in which the individual desires to succeed will lead to long-term learning.¹⁷² Without practice or motivation the chance of successful motor learning is minimal to nonexistent.

Positive emotional states may create a limbic environment in which the therapist can link reward and pleasure associations to new motor sequences. Although it is well known that appropriate selections of music can stimulate states of highly pleasant positive affects and physical relaxation, the neurological mechanisms for these effects are not well understood. In an early study by Goldstein^173a subjects reported pleasant physical sensations of tingling or “thrills” in response to music listening. After subjects were injected with naloxone, which blocks opiate receptors, thrill scores and tingling sensations were attenuated in some subjects. Although responses to music are highly individualized and this study has not been replicated, it suggests that endorphins may be released under certain music listening conditions that elicit pleasant physical sensations. In a positron emission tomography (PET) study of cerebral blood flow (CBF) changes measured during highly pleasurable “shivers or chills” in response to subject-selected music, Blood and colleagues¹⁴⁷ found that as the intensity of the chills increased, CBF increases occurred in the left ventral striatum, dorsomedial midbrain, bilateral insula, right orbitofrontal cortex, thalamus, anterior cingulate cortex, supplementary motor area, and bilateral cerebellum. As the intensity of chills increased, significant CBF decreases were also observed in the right amygdala, left hippocampus and amygdala, and ventral medial prefrontal cortex. The increases found in brain structures associated with reward or pleasant emotions and decreases in areas associated with negative emotional states suggest that music (1) must be carefully selected according to individual preferences and responses, in order to reliably elicit such highly pleasurable experiences as “shivers down the spine” and (2) might be used therapeutically to positively affect limbic activity.

Other studies provide additional support for the notion that music may activate limbic and paralimbic areas associated with reward or pleasurable emotions. Brown and colleagues¹⁴⁵ conducted a PET study of 10 nonmusicians who listened passively to unfamiliar music, which they later reported had elicited strongly pleasant feelings. Unlike previous studies of music, emotion, and limbic activity, this research design called for subjects to listen passively without engaging in any task such as evaluating affective components during the music. The authors noted that the music stimuli used was musically complex and strongly liked by the subjects. When the CBF during the music was compared with silent rest conditions in the same subjects, activations were seen, as expected, in areas presumed to represent perceptual and cognitive responses to music (primary auditory cortex, auditory association cortex, superior temporal sulcus bilaterally, temporal gyrus of the right hemisphere, in the right superior temporal pole, and adjacent insula). In addition, responses were found in limbic and paralimbic areas, which included the left subcallosal cingulate, the anterior cingulate, left retrosplenial cortex and right hippocampus, and the left nucleus accumbens and cerebellum. The researchers compared these results with those from the earlier studies by members of the same team^147,148 and suggest that areas such as the subcallosal cingulate are related to the direct experience of occurrent emotions rather than discriminate processing for emotion and that different areas are specifically activated during the pleasant physical responses known as “chills.” They go on to propose that the superior temporal pole and adjacent insula may serve as a point of bifurcation in neural circuitry for processing music. They also suggest that neurons from that region project to limbic and paralimbic areas involved in emotional processing and to premotor areas possibly involved in discrimination and structural processing of music. Although research has increased our appreciation of the complexity of brain activation by music, much more study is needed to validate a model of limbic network activity in human emotional responses to musical stimuli. Clinically, music can be used to improve mood and increase patient motivation to participate in rehabilitation treatment. Case studies^174,175 suggest that music can be used to decrease crying by infants and toddlers during physical therapy treatment. West has participated in both developmental and rehabilitation settings as a music therapist in co-treatment with physical and occupational therapists. The music therapist first does a thorough assessment of the individual’s preferences and responses to music, then provides music selected or composed specifically to provide motivating energy, pleasant associations, and positive affective states to accompany the motor activity. This individualized, live-music approach allows the music therapist to modify the musical elements as needed in the moment, working in a real-time limbic partnership with both the client and the physical or occupational therapist. Music or pleasure sounds can be used to help neutralize or balance the limbic influence on motor expression. Obtaining a limbic-neutral impact is critical before evaluating functional movement in order to accurately determine true motor system involvement.

Many types of emotions create motivation, such as pleasure, reward processes, emotions associated with addiction, appreciation of financial benefits, amusement, sadness, humor, happiness, and depression.^{163,173b,176–179} Some emotions tend to drive learning, whereas others may discourage learning, whether that learning be cognitive or motor.

The client’s internal system influences observable behavior.

At least once a year almost any local newspaper will carry a story that generally reads as follows: “Seventy-nine-year-old, 109-pound arthritic grandmother picks up car by bumper to free trapped 3-year-old grandson.”

We read these articles and at first doubt their validity, questioning the sensationalism used by the reporter. But we know that these events are real. That elderly lady picked up the car out of fear of severe injury to her grandchild. Emotions can create tremendously high tonal responses, either in a postural pattern such as in a temper tantrum or during a movement strategy such as picking up a car. Conversely, fear can immobilize a person and make it impossible to create enough tone to run a motor program or actually move. Evaluating muscle power or tone production in relation to emotional state (versus a pure reflection of motor control) is an aspect of evaluation often overlooked.

F²arv (fear and frustration, anger, rage, and violence or withdrawal) continuum.

One sequence of behaviors used to describe the emotional circuitry of the limbic network through the amygdala is the F²ARV continuum^157,203,204 (Figure 5-5). This continuum begins with fear or frustration. This fear can lead to avoidance behavior.²⁰⁵ If the event inducing the fear or frustration continues to heighten, avoidance behaviors can continue to develop.²⁰⁵ In a simple example, we recall or have seen these behaviors in our teens and as young adults, when the challenges faced in high school can lead to avoidance of activities. Alternately, extreme fear and frustration can also lead to anger. Anger is a neurochemical response that is perceived and defined cognitively (at the cortical level) as anger. If the neurochemical response continues to build or is prolonged, the anger displayed by the person may advance to rage (internal chaos) and finally into violence (strong motor response). A common societal example is in the case of domestic discord and violence. Women who attain the level of rage may become withdrawn and thus become victimized by a partner who is also in rage or inflicting physical or emotional violence.²⁰⁶ Another current example is posttraumatic stress disorder (PTSD), in which the prolonged stress of deployment and unique challenges of warfare lead to limited adaptive reserves in warriors and returning veterans. Suicide and domestic violence have become a more common occurrence between deployments, necessitating a dramatic shift in mental health policy in the last 5 years.^207–210

How quickly and completely any individual will progress from fear to violence is dependent on several factors. First, the genetic neurochemical predisposition (initial wiring) will influence behavioral responses.²⁰⁴ Second, “soft-wired” or conditioned responses resulting from experiences and reinforced patterns will influence output. For example, it is commonly known that abusive parents were usually abused children^203,211; they learned that anger quickly leads to violence and that the behavior of violence was somehow acceptable. Last, the quality and intensity of the stimulus initiating the continuum will influence the level of response.

The neurochemistry within an individual’s CNS, whether inherently active or altered through drugs or injury, will have great influence on the plasticity of the existing wiring.^40,212 Repetitive or prolonged exposure to negative environmental stimuli may also lead to a chronically imbalanced neurochemical state that results in a lowered threshold or tolerance to a given stimulus. Chemistry or wiring can become imbalanced from damage, environmental stress, learning, or other potentially altering situations, changing an individual’s control over this continuum.^{56,106–108,213,214} When neurochemical imbalance exists, these behaviors will persist, and balance may be restored only through natural neurochemical activity (e.g., sleep, exercise, diet, spirituality) or medication support (chemical replacement).

Therapists need to be acutely aware of this continuum in clients who have diffuse axonal shearing within the limbic complex. Diffuse axonal shearing is most commonly seen and reported in research on individuals with head trauma^215,216 (see Chapter 24). Resulting lesions within the limbic structures may cause an individual to progress down this continuum at a rapid speed. This point cannot be overemphasized. Patients with an accelerated F²ARV continuum may physically strike out at a clinician or caregiver out of simple frustration during care. Knowing the social history of the client and the causation of the injury often can help the therapist gain insight into how an individual patient might progress down this continuum. Not all head-injured patients had prior difficulty with the F²ARV continuum; however, it is important to note that many individuals received their head injuries in violent confrontational situations or in wartime conflict. Some individuals, primarily females, when confronted with stress, anger, and potential violence from another, will withdraw and become depressed. This behavior, similar to violence, will change the structure of the limbic network.⁵⁵

Gas (general adaptation syndrome).

The autonomic responses to stress also follow a specific sequence of behavioral changes and are referred to as the general adaptation syndrome.217–223 The sequential stages of GAS are a direct result of limbic imbalance and can play a dramatic role in determining client progress.

Stress can be caused by many internal or external factors, often unique to the individual. Examples include pain, acute or chronic illness or the ramification of illness, confusion, sensory overload, and a large variety of other potential sources. The initial reaction to a stressor is a neurochemical change or “alarm” that triggers a strong sympathetic nervous system reaction. Heart rate, blood pressure, respiration, metabolism, and muscle tonus will increase. It is at this stage that the grandmother lifts the car off the child as in our previous example. If the overstimulation or stress does not diminish, the body will protect itself from self-destruction and trigger a subsequent parasympathetic response. At this time, all the symptoms reverse and the client exhibits a decrease in heart rate, blood pressure, and muscle tonus. The bronchi become constricted, and the patient may hyperventilate and become dizzy, confused, and less alert. As the blood flow returns to the periphery, the face may flush and the skin may become hot. The patient will have no energy to move, will withdraw, and again will exhibit decreased postural tone and increased flexion.

This stress or overstimulation syndrome is characterized by common symptoms as described earlier.^{140,224–231} If the acute symptoms are not eliminated, they will become chronic and the behavior patterns much more resistant to change.

GAS is often seen in the elderly, with various precipitating health crises,²²¹ and also in neonatal high-risk infants (see Chapter 11), victims of head trauma, and other clients with neurological conditions. The initial alarm can be precipitated by moderate to maximal internal instability with less intensive external stress, or by minimal internal instability with severe external sensory bombardment. For instance, in the elderly, stresses such as change of environment, loss of loved ones, failing health, and fears of financial problems can each cause the client’s system to react as if overloaded.²²³ As another example, individuals with head trauma (Chapter 24), vestibular dysfunction (Chapter 22B), inflammatory CNS problems (Chapter 26), and brain tumors (Chapter 25) often possess hypersensitivity to external input such as visual environments, noise, touch, or light. In these individuals, typical clinical environments and therapeutic activities may create a sensory overload and trigger a GAS response.

Stress, no matter what the specific precipitating incident (confusion, fear, anxiety, grief, or pain), has the potential to trigger the first steps in the sequence of this syndrome.224–229^,232 The clinician’s sensitivity to the client’s emotional system will be the therapeutic technique that best controls and reverses the acute condition.

Similarly, patients with dizziness and instability, particularly within visually stimulating environments, can develop feelings of panic, which can evolve into full attacks and agoraphobic responses.²³³ These individuals avoid participating in activities that put them within visually overstimulating environments in an effort to control the dizziness and prevent the associated autonomic reactions. Similar types of reactions have been documented, such as space-motion discomfort (SMD),²³⁴ postural phobic vertigo,²³³ visual vertigo,²³⁵ and dizziness of “psychogenic” origin. Often these individuals are referred first to psychology or psychiatry. However, there is an underlying physiologic explanation for these symptoms. In a majority of individuals with SMD, there is a documented increase in vestibular sensitivity (increased vestibulo-ocular reflex [VOR] gain) and an impairment in velocity storage (shorter VOR time constant).²³⁶ In addition, the dorsal raphe nucleus (DRN of the midbrain and rostral pons) is the largest serotonin-containing nucleus in the brain and directly modulates the firing activity of the superior and medial vestibular nuclei. It is this interaction between serotonin and vestibular function that helps to explain the link between vestibular and anxiety disorders. It can also help explain how patients with sleep disorders or other serotonin-depleting disorders develop vestibular-like symptoms and anxiety.^237,238

Although there are physiological reasons underlying the vestibular system disorder in a majority of these cases, the symptoms triggered are part of a spectrum of limbic responses to aberrant vestibular, cerebellar, and brain stem interactions. Normal clinic activity or typically appropriate therapeutic activity may trigger an autonomic cascade versus the desired somatomotor response. The rehabilitation of the resultant visual and postural movement dysfunction is typically more complicated in the absence of limbic network management. The clinician’s strategic prescription (or “dosing”) of therapeutic activities with careful monitoring of the client’s emotional system and physiological response will be one of the therapeutic techniques that best controls the aberrant responses and allows vestibular adaptation and compensation to occur. This must be done to manage limbic network activity for successful motor learning to occur.

The F²ARV and GAS continua are often interrelated in individuals who have direct or indirect limbic network involvement. The therapist needs to be aware that a patient may overrespond to stress, frustration, or fear of failure in both cognitive and motor activities. The initial response may be an escalation of the F²ARV continuum with what then seems like a rapid withdrawal or a heightened state of anger (GAS). There are many ways to help the patient balance these autonomic reactions and continue to learn within the therapeutic setting. The Bonny Method of Guided Imagery and Music is a music-centered psychotherapy method that has been used extensively with individuals recovering from various types of trauma.239–242 In reviewing specific Bonny Method treatment approaches used with trauma patients, Körlin²⁴² describes a cyclical process whereby an important initial treatment period emphasizes the mobilization of inner resources, alleviating vulnerability and increasing the patient’s self-confidence. This phase uses carefully selected music that elicits positive limbic states and “bodily manifestations with qualities of warmth, energy, strength, movement, nourishing, and healing, all belonging to the implicit realm of positive vitality affects and mental models” (p. 398). The individual is then better equipped to face a period of confrontation with painful or traumatic material or the challenges faced within a therapeutic rehabilitation environment. Successful confrontation of difficult realities is then followed by a new phase of resource mobilization and consolidation of healthier behaviors that begin to replace dysfunctional defenses such as avoidance, behavioral extremes, or substance abuse.

This process continues in repeated cycles of rest-resourcing and working-confronting. The clinical success of this approach suggests that for some patients it may be advantageous to purposefully facilitate positive or pleasant physical and affective experiences before engaging in more challenging work. Although it may be impractical to provide appropriate music selections on the basis of individual assessment in the therapeutic environment (e.g., physical, occupational, music), other modalities such as heat, massage, or ultrasound treatment may also elicit relaxed, receptive physical states. The treating professional can also become aware during assessments or treatments of environmental auditory input that may trigger stress responses in patients who have limbic network involvement or who may have experienced traumatic physical or emotional injuries. These triggers can be something as simple as the therapist’s tone of the voice in a sentence to the patient or as complex as the multiple-noise environment of a busy rehabilitation setting. Some patients may need to be scheduled for early morning, during lunchtime, or in the late afternoon to provide a decrease in the auditory environment.

Decreasing stimulation versus increasing facilitation may lead to attention, calmness, and receptiveness to therapy. When the client feels that control over her or his life has been returned, or at least the individual is consulted regarding decisions (informed consent, forced choices), resistance to therapy or movement is often released and stress is reduced. Even clients in a semicomatose state can participate to some extent. As a clinician begins to move a minimally responsive client, resistance may be encountered. If slight changes are made in rotation or trajectory of the movement pattern, the resistance is often lessened. If the clinician initially feels the resistance and overpowers it, total control has been taken from the client. Instead, if the clinician moves the patient in ways her or his body is willing to be moved, respect has been shown and overstimulation potentially avoided.

No single input causes these limbic responses, nor does one treatment counteract their progression. Being aware of clinical signs is critical. In a time when therapists are often rushed by the realities of a full schedule or stressed by third-party or short discharge demands, a clinician may inadvertently miss key signs and opportunities to treat. In addition, he or she may actually create a less optimal environment by physically moving faster than the pace best tolerated by the patient, who may need more time to process stimuli or to practice a target skill. The challenge for both the therapist and the patient is to find harmony within the given environment to allow for optimal outcomes.

Developing limbic network assessment tools (or repurposing existing tools) for their ability to screen or identify the presence of direct or indirect limbic involvement is of critical value. In addition, the ability to discriminate the type of limbic involvement (decreased responsiveness and withdrawal from increased responsiveness or overresponsiveness) is important to treatment planning. Treatment techniques will be discussed later in the chapter. However, the specific techniques appropriate for treating these syndromes are tools all therapists possess. These tools range from simple variations in approach (e.g., lighting, sound, smell) to more formal therapeutic techniques, such as the Feldenkrais approach, or The Bonny Method of Guided Imagery and Music.²³⁹ How each clinician uses those tools is a critical link to success or failure in clinical interaction.

Specific limbic influences on motor system output.

Throughout the existence of humankind, emotions have been identified in all cultures. A child knows when a parent is angry without a word being spoken. A stranger can recognize a person who is sad or depressed. People walk to the other side of the road to avoid being close to someone who seems enraged. Emotions are easily recognizable as they are expressed through motor output of the face and body. Emotions similarly have an impact on functional motor control. The effect and intensity of emotions and limbic influence on motor control are an important part of the therapy evaluation. Table 5-1 helps differentiate the level of limbic activity with observed behavioral states cross-referenced with various medical conditions.

Fear.

Fear is often associated with pain, be it somatic or emotional. To the individual in pain, pain is just pain. Figure 5-6, A illustrates two people who are on a rollercoaster which could create automatic responses of fear. The boy looks scared and obviously exhibits fear. The woman could be expressing joy or fear given her motor responses. Her eyes seem fixed, which might lead to the assumption that she is truly in fear. She may not have control over her facial responses and could be exhibiting an extreme reaction to fear. If that were the case, this would be a limbic motor reaction, which could be semiautomatic. This extension pattern, if limbic, could trigger hyperextension of the neck, causing opening of the mouth. In Figure 5-6, B, the rollercoaster has stopped, and she still has the same expression. In fact, it took over a minute before she was able to relax her face and regain the feeling that she had some control over her emotional reaction. Her next reaction to occur was crying and observable frustration in her inability to control her initial response. The amygdala nuclei plays a critical role in regulation of facial responses to fear, pain, and other incoming stimuli.²⁴³ This is often observed in healthy normal individuals such as seen in Figure 5-6 and similarly can be seen in patients who are extremely fearful, no matter the cause.

Fear of falling is a common problem with the elderly, especially the elderly who have various neurological diagnoses.^244,245 Therapists working with individuals who have a fear of falling need to first acknowledge that the fear is normal and then make sure that when the individual moves, he or she does not fall. Trust will be discussed later in the chapter, but fear often precedes the development of trust. Fear is an emotional response and thus is initiated and controlled by the limbic network.

Fear of pain is another emotional response housed within the limbic network that drives many individuals’ motor responses. Whether individuals have fear of movement after a musculoskeletal injury,²⁴³ fear of going to the dentist after a dental procedure,²⁴⁶ fear of pain intensity after a chronic pain problem,²⁴⁷ or fear of falling,²⁴⁸ fear will drive motor responses, and that fear will often lead to a lower quality of life.²⁴⁴ For that reason alone, therapists need to differentiate the limbic system’s and the motor system’s summated responses when observing the movement patterns of the individual in therapy.

Anger.

Anger itself creates muscle tone through the amygdala’s influence over the basal ganglia and the sensory and motor cortices and their influence over the motor control system. This is clearly exhibited in a child throwing a temper tantrum (Figure 5-7) or an adult putting his fist through a wall. How far a client or a friend will progress through the F²ARV continuum (discussed in the previous section) depends on a large number of variables. When a client loses control, the therapist must first determine whether the intervention forced the client beyond her or his ability to control. If so, changes within the therapeutic environment need to be made to allow the client opportunities to develop control and modulation over that continuum.

Creating opportunities to confront frustration and fear or even anger in real situations while the client practices modulation will lead to independence or self-empowerment. The client simultaneously needs to practice self-directed motor programming without these emotional overlays. Thus, true motor learning can result. In time, practicing the same motor control over functional programs when confronted with a large variety of emotional situations should lead to independence in life activities and thus meet a therapeutic goal.

Similarly, being unaware of a client’s anger may lead the therapist to the false assumption that that individual has adequate inherent postural tone to perform activities such as independent transfers. If the client is angry with the therapist and performs the transfer only to get the therapist “off my case,” when the client is sent home she or he may be unable to create enough postural extension to perform the transfer. Thus this transfer skill was never functionally independent because the test measurements were based on limbic or frontal influence over the extensor component of the motor system. The client needs to learn how to do the activity without the emotional overlay. When a therapist is unwilling, unaware, or unable to attend to these variables, the reliability or accuracy of functional test results becomes questionable.

For example, West was asked to consult with a rehabilitation team to devise a treatment program to address violent rage episodes in a 40-year-old man with moderate physical and severe cognitive functioning deficits resulting from a brain aneurysm. He would escalate very rapidly along the F²ARV continuum when presented with environmental challenges such as passing another patient with his wheelchair in the hallway. Although his physical rehabilitation had progressed well and he had regained much independence in mobility, because his assaultive outbursts posed risks to other patients as well as to caregivers, this patient appeared to be heading for placement in a locked facility, a more restrictive environment than he would need considering his level of physical limitation. Although this unfortunate man had no short-term memory function and no insight about his behaviors, West found during her assessment that he was highly responsive to calming music and was able to access some intact long-term memories that could be used to elicit a relaxation response. A highly positive limbic state of deep relaxation was thus elicited, and simple verbal cues were then presented to develop a conditioned response that any staff member could then call forth with the verbal cue alone. The entire rehabilitation team was briefed on the use of this intervention and reported success using this approach in the milieu as well as during physical therapy and occupational therapy treatments when the patient would become resistant and angry in response to therapist instructions. The patient was trained to self-regulate by giving himself the same verbal cue when confronted with challenging situations. This treatment supported the patient’s ability to regain emotional controls and allowed him the opportunity to be placed in a less-restrictive community environment. West observed this individual maintaining his progress in positive behavioral adaptation in a group home environment more than a year after the intensive inpatient rehabilitation treatment protocol had been completed. The patient never recalled a previous music therapy treatment session and asked each time to have the purpose of the treatment explained to him. But his body remembered the set of behavioral experiences, and he quickly complied with the relaxation procedure. The success of this approach demonstrates that even in the absence of short-term memory and other cognitive functions usually considered essential for new learning, the skillful engagement of positive limbic states and intact areas of patient functioning (strengths) can support development of new adaptive skills, which can be generalized to new environments.

Grief, depression, or pain.

Emotions such as grief or depression can be expressed by the motor system.^56,249 The behavioral responses are usually withdrawal, decreased postural extension, and often a feeling of tiredness and exhaustion (Figure 5-8). Sensory overload, especially in the elderly, can create low muscle tone and excessive flexion. Again, because of the strong emotional factor, these motor responses are considered to be the result of the limbic network’s influence over motor control.¹¹⁰ Learned helplessness is another problem that therapists need to avoid.²⁵⁰ When patients are encouraged to become dependent, their chances of benefiting from services and regaining motor function are drastically reduced.^251,252

Pain is a complex phenomenon, and the more it is understood, the more complex it becomes253–257 (see Chapter 32). The concept of pain and pain management is discussed in detail in both Chapters 18 and 32. Hippocampal volume has been identified as a variable in pain ratings in the elderly.²⁵⁸ Whether the pain is peripherally induced or centrally induced because of trauma or emotional overload, often the same motor responses will exist. A withdrawn flexor pattern from pain makes postural activities exhausting because of the work it takes to override the existing central pattern generators. Thus, daily living activities, which constantly require postural extension against gravity, may be perceived as overwhelming and just not worth the effort. The therapist needs to learn to differentiate between peripheral physical pain and central or emotional pain and between mixed peripheral and central induced pain. To the patient, “pain is pain!”^259–266

Client-therapist bonding.

Bonding projects relaxation, whereas lack of bonding reflects isolation. Because of the potency of the limbic network’s connections into the motor system, a therapist’s sensitivity to the client’s emotional state would obviously be a key factor in understanding the motor responses observed during therapy. This requires that a therapist first understand her or his own feelings, emotional responses, and communication styles that are being used within any given clinical or social environment.267–274

In Figure 5-9 an entire spectrum of motor responses can be observed in four statues. A client who feels safe can relax and participate in learning without strong emotional reactions. The woman being held in Figure 5-9, A is safe and relaxed. The man and woman are interacting through touch with the warmth and compassion that are often observed in the client-therapist interaction of an experienced or master clinician. In Figure 5-9, B, the client and clinician seem to flow together during the treatment as if they shared one motor system. When looking at the therapist and client or looking at the man and woman in the statue, it becomes obvious that the two figures seem to flow together. In the statue, those two figures make one piece of art.

With clinical emphasis on clients generating and self-correcting motor programming, it would perhaps seem reasonable for a therapist to conclude that he or she need not, or should not, touch the patient. This conclusion may be accurate when considering the motor system in isolation and assuming that patients can self-correct errors in motor programs. When correction by the therapist is through words rather than touch, external feedback through the auditory system has replaced internal feedback from the somatosensory system. The voice, as well as touch, can be soothing and instill confidence.²⁷⁵ Yet language in and of itself will not replace the trust and safety felt both physically and emotionally through the deep pressure of touch as illustrated in Figure 5-9. Bonding and trust occur much more often through touch than through conversation.²⁷⁶ Recall, also, that verbal instructions require intact auditory processing and translation from declarative to procedural information, a cognitive ability that the client may not possess.

Referring again to Figure 5-9, A, the two men in the statue on the left demonstrate a lack of bonding. In fact, if the artist could have brought them closer together, they might just have rejected or repelled each other with greater intensity. If one of the men were the therapist and one the patient, little interaction would be occurring, and thus an assumption that learning is occurring is probably false. The therapist could do nothing to the other person (and vice versa) without that person perceiving the act as invasive, negative, or even disrespectful, with little consideration of the person’s individual values. The therapist’s responsibility is to open the patient’s receptiveness to learning, not to close it.^277,278

These pictures clearly illustrate two types of therapist-client interactions. If an artist can clearly depict the tonal characteristics of emotion, certainly the therapist should be able to recognize those behaviors in the client.²⁷⁹ If a client is frustrated or angry and simultaneously has rigidity, spasticity, or general high tone, then a therapist might spend the entire session trying to decrease the motor response. If the client could be helped to deal with the anger or frustration during the therapy session and neutralize the emotion and achieve a limbic neutral state, then the specific problems could be treated effectively. Differentiating the limbic network component from the motor control system when establishing treatment protocols has not typically been within the spectrum of a therapist’s skills. It is a skill that must be developed and practiced, as it is clear that the influence of an overactive or overloaded (limbic high) or underactive (limbic low) limbic network state may drastically alter the consistent responses of the motor systems and thus dampen the procedural learning and limit the success of the therapeutic setting. Carryover of procedural learning (Chapter 4) into adaptive motor responses needs to be practiced with consistency.⁵⁶

Many factors in an interactive setting, such as therapy, cannot be identified, but certain limbic or emotional factors may play a role in that gifted clinician’s skill. Although therapists are trained to be skilled observers of patient behavior, the development of “master clinician” capabilities also requires self-awareness on the part of the helping professional. “Behavioral activity can often tell us about the inner state of another or ourselves” (p. 19).²⁸⁰ The willingness to be aware of one’s own internal state increases the therapist’s ability to perceive subtleties in the patient’s responses.

Achieving a limbic neutral state in the client by carefully modifying the therapeutic environment will facilitate effective motor learning. There are many core tenets and techniques necessary to effectively achieve this neutral state, internal and external therapeutic environment, and optimal learning in the client.

Trust.

Trust is a critical component of a successful therapy session.²⁸¹ The therapist gains the client’s trust by his or her actions. The therapist may also build trust through sincere acknowledgment that the patient has life-limiting functional problems and that those problems are limiting normal participation. Trust is further developed when the therapist’s words can be supported by data. When the therapist can illustrate the presence of functional limitations and generate a treatment plan with the patient using objective data, a bond and trust between the patient and the therapist are created.²⁸² In today’s environment the use of reliable, valid, objective tests and measures allows for this form of communication, which has not existed to the same extent in the past. Honesty and truth lead to trust.^{119,283–287}

A trusting relationship is strengthened when an agreement or “contract” can be established that sets the boundaries for discomfort (fatigue, dizziness, nausea, imbalance) or pain that the patient will experience within a therapeutic session. As one example, telling a person that you will not hurt them is a therapist-patient contract. If the therapist continually ranges a joint beyond a pain-free range, that behavior is dishonest and untruthful and will not lead to trust. Trust can be earned by stopping as soon as the client verbalizes symptoms or shows pain with a body response such as a grimace. Being sensitive to a patient’s pain, no matter the cause, and working with the patient to eliminate that pain often lead to very strong bonding and trust that will lead to compliance and learning. Ignoring the pain may be perceived as insensitivity and lack of caring, which can lead to distrust and often resistance to learning or performance.

As another example, a patient with vestibular dysfunction associated with significant dizziness and nausea will experience symptoms within the course of recovery (adaptation and compensation), but those symptoms must be carefully controlled in intensity and duration. Symptoms poorly controlled can trigger an ANS or GAS cascade and elevate the limbic state, preventing learning and recovery and destroying trust.

Because these symptoms can be overt or covert, the therapist needs to be aware of both the physical and emotional responses of the patient. The use of analog or perceived exertion scales can be a valuable way to make the covert more overt to the therapist. Symptoms are valuable to the therapist as well as the patient to create environments for change, but the intensity of those stimuli need close monitoring because they can dramatically affect motor responses and ultimately overwhelm the CNS and prevent learning. Compliance to participate is limbic, and the limbic system has tremendous control over intentional movement, no matter the context of the environment.¹¹⁹

Once a client gives his or her trust, a clinician can freely move with the client and little resistance caused by fear, reservations, or need to protect the self will be felt or observed. When the patient is limbic neutral (the limbic network is emotionally neutralized), the tightness or limitations in movement that are present on examination can be considered true impairments within those systems or subsystems. Examination and interventions at this time will more consistently reflect true motor performance. Once limbic neutral has been achieved and examination is complete, it is recommended, for example, that if the pain is a result of peripheral tightness or joint immobility, the therapist does not elicit pain during that session. Deal with those issues in the next session after gaining the trust of the client. Trust by the therapist or the client does not mean lack of awareness of potential danger. Trust means acceptance that although the danger is present, the potential for harm, pain, or disaster is very slight and the expected gain is worth the risk (in this case, delay in intervention). In Figure 5-10, the student’s trust that the instructor will not hurt her can be seen by her lack of protective responses and by her calm, relaxed body posture. The student is aware of the potential of the kick but trusts her life to the skills, control, and personal integrity of the teacher. Those same qualities are easily observed in patient-therapist interactions when watching a gifted clinician treat clients. The motor activities in a therapeutic setting may be less complex than in Figure 5-10, but in no way are they less stressful, less potentially harmful, or less frightening from the client’s point of view.

In addition, therapists must first trust themselves enough to know that they can effect changes in their clients.^7,288 Understanding one’s own motor system, how it responds, and how to use one’s hands, arms, or entire body to move someone else is based partly on procedural skills, partly on declarative learning, and partly on self-confidence or self-trust. Trusting that one, as a therapist, has the skill to influence the motor response within the patient has a limbic component. If a therapist has self-doubts about therapeutic skills, that doubt will change performance, which will alter input to the client. This altered input can potentially alter the client’s output and vary the desired responses if the client’s motor system cannot run independently.

Responsibility.

Very close to the concept of trust is the idea of responsibility. Accepting responsibility for our own behavior seems obvious and is accepted as part of a professional role.²⁸⁹ Accepting and allowing the client the right to accept responsibility for her or his own motor environment are also key elements in creating a successful clinical environment and an independent person.*

Figure 5-11 illustrates the concept through the following example: The instructor asked the student to perform a motor act, in this case, to perform a kick to the teacher’s head. The kick was to be very strong or forceful and completed. The student was instructed not to hold back or stop the kick in any way, even though the kick was to come within a few inches of the teacher’s head. This placed tremendous responsibility on the student. One inch too far might dangerously hurt the instructor, yet one inch too short was not acceptable. The teacher knew the student had the skill, power, and control to perform the task and then passed the responsibility to the student. The student was hesitant to assume the responsibility, for the consequence of failure could have been very traumatic. However, the student trusted that the teacher would not ask for the behavior unless success was fairly guaranteed. That trust reduced anxiety and thus neutralized the neurochemical limbic effect on the motor system of the student, giving her optimal motor control over the act.²⁹² Once the task was completed successfully, the student gained confidence and could repeat the task with less fear or emotional influence while gaining refinement over the motor skill.

Although the motor activities described in this example are complex and different from functional activities practiced within the clinic by therapists and clients, the dynamics of the environment relate consistently with client-therapist roles and expectations. A gifted clinician knows that the client has the potential to succeed. When asked to perform, the client trusts the therapist and assumes responsibility for the act. The therapist can facilitate the movement or postural pattern, thereby ensuring that the client succeeds. This feeling of success stimulates motivation for task repetition, which ultimately leads to learning. The incentive to repeat and learn becomes self-motivating and then becomes the responsibility of the client. As the therapist relinquishes control and empowers the client to more and more of the function, novelty to the learning is occurring.

Current literature has shown that people are more motivated by novelty and change than by success at mastery or accomplishment of a goal.^90,292,293 The limbic complex and its interwoven network throughout the nervous system play a key role in this behavioral drive.²⁹⁴ The task itself can be simple, such as a weight shift, or as complex as getting dressed or climbing onto and off of a bus. No matter what the activity, the client needs to accept responsibility for her or his own behavior before independence in motor functioning can be achieved. Although the motor function itself is not limbic, many variables that lead to success, self-motivation, and feelings of independence are directly related to limbic and prefrontal lobe circuitry. The variance and self-correction within the movement expression also create novelty and motivation to continue to practice.^90,292–295

As another clinical example of responsibility, in a patient with vestibular dysfunction and dizziness compounded by anxiety, symptoms of dizziness are necessary during treatment to drive CNS change. The therapist has a responsibility to prescribe the appropriate activities, dosage (intensity, timing, and so on), and environment to retrain sensory organization and balance (motor output). The patient can be given the responsibility of monitoring and managing her or his own symptoms within these activities, for instance, by agreeing on the maximal level of dizziness the patient and therapist are willing to accept within the therapeutic activity. A tool as simple as a verbal or visual analog scale can empower the patient to manage symptoms, dampen the limbic network response, and improve motor output for balance control.

Flexibility and openness.

Another component of a successful clinical environment deals with learning and flexibility on the part of the therapist. A master clinician sees and feels what is happening within the motor control output system of the client. Letting go of preestablished belief of what will happen is difficult.^296,297 It is important for a clinician to be open to what is present as the motor expression. This openness is critical to actually identifying what is being expressed by the nervous system of the patient. Master clinicians do not get stuck on what they have been taught but use that as a foundation or springboard for additional learning. Learning is constantly correlated to memories and new experiences.

To the therapist, each client is like a new map, sparsely drawn or sketchy at the beginning, but one that is constantly revised as the terrain (client) changes. The initial medical diagnosis may link to many paths provided within the map, but the comorbidities can result in great variance among patients.²⁹⁸ That initial map might be a critical care pathway for the client, given her or his neurological insult. That pathway is a map, but only a sketchy one, and may not even be a map that a particular patient falls within in spite of his or her medical diagnosis. It is the therapist’s responsibility to evaluate the patient and determine whether that pathway or map will work or is working and when changes in that map need to be altered. That is, the therapist must let go of an outdated map or treatment technique and create a new one as the environment and motor control system of the client change. This transference or letting go of old maps or ideas is true for both the client and therapist. If a position, pattern, or technique is not working, then the clinician needs to change the map or directions of treatment and let the client teach the therapist what will work. The ability to change and select new or alternative treatment techniques is based on the attitude of the therapist toward selecting alternative approaches. Willingness to be flexible and open to learning is based on confidence in oneself, a truly emotional strategy or limbic behavior. Master clinicians have learned that the answers to the patient’s puzzle are within the patient, not the textbooks.

Figure 5-12 depicts two maps with a beginning point and a terminal outcome or goal in each. The parameters of the first map illustrate the boundaries of that therapist’s experience and education. The clinician, through training, can identify what would seem to be the most direct and efficient way or path toward the mutually identified goal of the therapist and client. When the client becomes a participant within the environment or map, what would seem like a direct path toward a goal might not be the easiest or most direct path for the client. If empowerment of the client leads to independence, then allowing and encouraging the client to direct therapy may provide greater variability, force the client to problem solve, and lead to greater learning. The therapist needs to recognize when the client is not going in the direction of the goal. For example, the client is trying to perform a stand-pivot transfer and instead is falling. If it is important to practice transfers, then practicing falling is inappropriate and the environment (either internal or external) needs modification. Falling can be learned and practiced at another time. Once both strategies are learned, the therapist must empower the patient to take ownership of the map. In the examples of transferring, if the therapist asks the client to practice transfers and if the client starts to fall, a change in required motor behavior must be made and the opportunity given to the client to self-correct. In that way the client is gaining independent control over a variety of environmental contexts and outcomes. Within the same figure (Figure 5-12) is a second map. That second map might represent another professional’s interaction and goal with the same client. It is during these overlapping interactions that both professionals can empower the patient to practice, and that practice will help lead to those functional goals established by both practitioners. In some situations a clinician from one profession may guide a client toward obtaining the functional skill necessary for a member of the second profession to begin guiding the client toward the expected outcomes of the second profession. These interlocking dependencies of the client and the professions are illustrated in Figure 5-12. If the client begins therapy striving for the first goal and ends at the functional outcome of the second goal, then additional functional outcomes have been achieved and both professions interacted for the ultimate prognosis for the patient. That interaction requires respect and openness of both professionals toward each other as well as toward the client. Those attitudes and ultimate behaviors are limbic driven.

Matching maps should be a collaborative effort instead of coincidence. These collaborative efforts include interactions with all professions within the rehabilitation setting. Occupational and physical therapists are very familiar with collaboration, and both often approach interventions as a team effort. There are many additional therapists and individuals within that same setting who could also collaborate. Recreational therapists, psychologists, nurses, family members, and music therapists are but a few. Within a profession such as music therapy, the existence of two maps may overlap within a multidimensional environment. When a physical or occupational therapist needs to challenge a patient, the music therapist may be able to calm the system at the same time (overlapping maps). Research on affective responses to consonance and dissonance in music supports the creation of a map within a rehabilitation environment that could overlap with either physical, occupational, or speech therapy. Words such as relaxed or calm correlated positively with higher levels of consonance in the music, whereas adjectives associated with negative emotions (unpleasant, tense, irritable, annoying, dissonant, angry) were found to correlate positively with higher levels of dissonance.¹³³ Creating a whole environment where potential frustrations within motor learning could be balanced with higher levels of consonance in the music would potentially balance the limbic network emotional response within the overlapping maps and bring balance or stability to the limbic network’s influence on motor learning and control. A later study by Peretz and colleagues¹⁴⁸ related the same variables to a happy-sad rating task. Given the research evidence for activity within the limbic network as it relates to music,^144,299 motor learning,³⁰⁰ and cognitive enhancement,³⁰¹ a natural multiple map system would be easy to incorporate within a therapeutic setting. The clinician needs to appreciate the uniqueness of each map while holding onto the concept of the interaction of the two maps.

Substance abuse (see chapter 24).

The anterior temporal lobe (especially the hippocampus and amygdala) has a lower threshold for epileptic seizures than do other cortical structures.⁵⁶ This type of epilepsy is produced by use of systemic drugs such as cocaine and alcohol. The seizure is often accompanied by sensory auras and alterations in behavior, with specific focus on mood shifts and cognitive dysfunction.³⁰⁵ Obviously, the precise association between behavior and emotions or temporolimbic and frontolimbic activity is not understood, yet the associations and thus their impact on a therapeutic setting cannot be ignored.^217,306

Whether street bought, medically administered, or ingested for private or social reasons (such as in alcohol consumption), drugs and alcohol can have dramatic effects on the CNS and often are associated with limbic behavior.³⁰⁷ Korsakoff syndrome, caused by chronic alcoholism and its related nutritional deficiency, is identified by the structural involvement of the diencephalon with specific focus on the mammillary bodies, and the dorsal medial and anterior nucleus of the thalamus⁵⁶ usually shows involvement (see the anatomy section and Figure 5-13). This syndrome is not a dementia but rather a discrete, localized pathological state with specific clinical signs. The most dramatic sign observed in a client with Korsakoff syndrome is severe memory deficits.^{252,308–310} These deficits involve declarative memory and learning losses, but the most predominant problem is short-term memory loss.³¹¹ As the disease progresses, clients generally become totally unaware of their memory loss and are unconcerned. Initially, confabulation may be observed,³¹² but in time most clients with a chronic condition become apathetic and somewhat withdrawn and are in a profound amnesic state. They are trapped in time, unable to learn from new experiences because they cannot retain memories for more than a few minutes and are unable to maintain their independence^{252,308–310,313}; many may become social isolates and homeless.

The use of alcohol affects not only adults but also children and adolescents. Still another population of children affected by alcohol abuse has surfaced as a specific clinical problem. These children are infants who have the effects of fetal alcohol syndrome. A variety of researchers have investigated the effects of alcohol and other toxic drugs on neuromotor and cognitive development.314–319

Alzheimer disease (see chapter 27).

In Alzheimer disease, the hippocampus and nucleus basalis are the most severely involved structures, followed by neurofibrillar degeneration of the anterotemporal, parietal, and frontal lobes.^{252,320–323}

Initially the symptoms fall into several categories: emotional, social, and cognitive. Usually the symptoms have a gradual onset. Depression and anxiety often are seen during the early phases because of the neuronal degeneration within the prefrontal lobes and limbic network.^{322,324–326} During the second stage, the emotional, social, and intellectual changes become more marked. Clients have difficulty with demands, business affairs, and personal management. Their memory and cognitive processing continue to deteriorate, whereas their awareness of the problem is often still insightful, causing additional anxiety and depression. During this phase clients may be unable to recognize familiar objects and become scared because they are losing control of the environment both internally and externally. Thus the client may become combative out of a defensive (fight-or-flight) autonomic response. For that reason, therapists need to make sure the client feels safe during therapy to optimize the learning and compliance. The third phase manifests itself with moderate to severe aphasic, apraxic, and agnosic problems. Object agnosia, the failure to recognize objects, is a typical sign of advancing Alzheimer disease. Distractibility and inattentiveness are also common signs of this third stage. The final stage of Alzheimer disease is marked by an individual who is uncommunicative, with little meaningful social interaction, who often takes on the features of the Klüver-Bucy syndrome (see Chapter 13). Thus they exhibit emotional outbursts, inappropriate sexual behaviors, severe memory loss, constant mouth movements, and often a flexor-type postural pattern. In this latter phase, the client is virtually decorticate and clinically indistinguishable from persons with other dementias. The prognosis of Alzheimer disease was only a few years ago totally bleak, but today there are hopes that in the future, pharmacological interventions may slow and even reverse the damage inflicted by this disease.^327–330

In spite of future treatments, the continual degeneration of the limbic network is a key distinguishing factor in Alzheimer disease.^{109,331–333} Many clients in the past have been misdiagnosed as having other problems such as intracranial tumors, normal pressure hydrocephalus, multiinfarct dementia, or alcoholic or chronic drug intoxication.^334–337 Similarly, many clients with tumors, multifaceted dementias, alcoholism, or heart attacks resulting in hippocampal damage may be diagnosed with Alzheimer disease. When the disease is correctly evaluated and diagnosed, however, it becomes obvious that the limbic-cortical area involved from phase 1 through the last phase is interacting with other areas of the brain and constantly affecting the behavioral patterns of the patient.^338–341 Owing to the neurochemical sensitivity and production within the limbic network, drugs are often used to prevent or slow the progression of Alzheimer disease (see Chapter 36).^342–346 Similarly, a genetic predisposition has been found in some patients with Alzheimer disease^56,347–349; thus, gene therapy may prove to have great therapeutic value.³⁵⁰ Because music is able to activate many different brain areas, it is particularly valuable in the treatment of persons at all stages of Alzheimer disease³⁵¹ and can effectively be used during physical or occupational therapy. Long after declarative memory is lost, individuals can sing entire songs (procedural memory), dance with a loved one they no longer recognize (procedural memory), or be soothed and calmed by hearing someone who cares about them singing familiar favorite songs or lullabies (limbic response). This is why the power of music is so great, especially as observed in individuals with Alzheimer disease who have lost declarative memory. In earlier phases of the disease, individuals who have lost words can recall words such as song lyrics through the linking with melody. When melody is lost, individuals still retain rhythmic responses. At the palliative stage of Alzheimer disease care, agitated patients are observed to calm to simple music such as familiar lullabies. Thus Alzheimer disease patients are able to continue to respond to music through the progression of the disease, and the response to rhythm may represent overlearned motor responses that are tied to positive limbic states. For example, nonambulatory individuals, when presented with familiar and preferred music, may stand and move with the rhythm of the sound. Their bodies may remember how to dance with the spouse whose name they no longer know.³⁵² A physical or occupational therapist can instruct a caregiver to use music as part of everyday activities. The therapeutic effects of music to engage and maintain attention, activate long-term memory, and modulate emotion states are well suited to the needs of both the person with Alzheimer disease and his or her caregivers.³⁵²

Head injury (see chapter 24).

Vestibular disorders.

The vestibular system has extensive neuronal connections and commissural influences on the limbic network and structures; conversely, the limbic network has significant influence on the vestibular nuclei. Details of the neuroanatomical connections are described later in this chapter.

It is generally accepted that vestibular dysfunction results in erroneous input to the CNS. This erroneous sensory information creates a mismatch between the external (afferent) cues and the internal conceptual model for movement contained by the cerebellum. This mismatch creates an imbalance in vestibular and cerebellar signals to the CNS, flooding the central limbic structures and resulting in symptoms such as vertigo, motion sickness, nausea, or decreased postural control. Detection of this mismatch results in an attempt by the cerebellum to compensate for the imbalance, which becomes a core tenet of recovery.³⁷⁸ Alternately, this neural stimulation may create an internal stressor, and trigger an adverse limbic response, such as a GAS response.

Newer evidence from animal research has demonstrated that vestibular lesions result in dramatic changes in the morphology and function of the hippocampus. Of note is that bilateral vestibular lesions have been associated with hippocampal atrophy. The hippocampus makes unique contributions to memory, both spatial and nonspatial. Thus vestibular lesions impair learning and memory, particularly those tasks that require spatial processing. In addition to the more well known deficits in spatial and gravitational orientation for balance control, vestibular lesions can also result in impaired cognition, learning, and memory through damage to this connection. Decreased concentration, thought processes, and memory are among the most common complaints in patients with vestibular disorders. In the past these complaints were often attributed to competitive resources, suggesting that cognitive resources were being devoted to the basic tasks of staying balanced during function. It is now clear that there is a true physiologic explanation for these secondary symptoms, which are quite limiting to activity and participation in normal daily activities, particularly working. It has also been suggested that treatment activities that stimulate the function of the vestibular system also stimulate activity within the hippocampus and can improve memory, which has important implications for treatment.379–387

Thus vestibular dysfunction can influence the therapeutic environment both in the assessment and the treatment of this system. However, the vestibular system is not a primary consideration of most physicians and therapists during evaluation. On the basis of benchmarking data from within specialized balance centers, the average patient with a vestibular disorder (dizziness or imbalance) travels within the medical system an average of 52 months before finding a solution. During this time, he or she has seen on average four physicians. There is also at least one visit to the emergency department in crisis and one visit to a psychiatrist. Typically there has been no rehabilitation referral or intervention during this time.³⁸⁸

The patient with a chronic vestibular disorder can have myriad symptoms, including vegetative, autonomic, motoric, cognitive, psychological, and behavioral symptoms that are often misdiagnosed during this search for an outcome as other, more serious medical diagnoses. As an example, of those patients diagnosed with dizziness or imbalance of a psychologic origin, evidence has determined that more than 70% of these patients have underlying vestibular dysfunction on key vestibular function tests (electronystagmography and calorics, rotary chair, computerized dynamic posturography, auditory brain stem response, and acoustic reflexes).^{233,235,389–391} Conversely, of those patients with chronic dizziness and imbalance, only 16% were found to have dizziness of a true psychogenic origin.³⁹² Acknowledgment of a patient’s symptoms, use of data, and explanation (in understandable detail) that there is a physiologic explanation for his or her complaints builds the client-therapist relationship and begins to neutralize the client’s abnormal limbic state (anxiety versus depression). It can lower the GAS or autonomic cascade, maximizing the treatment time before the onset of limiting symptoms (i.e., raise the symptom threshold).

Even patients with motion sickness have documentable physiologic and functional changes. Some of the best current evidence is in our military personnel with symptoms of motion sickness. On examination, these soldiers have physiological changes identifiable by results of rotary chair (60% with abnormally long time constants) and computerized dynamic posturography (70% with abnormal sensory organization test [SOT] condition 5 and 6).³⁹³

Patients who have sustained a mild head injury, postconcussive syndrome, blast exposure or injury (positive or negative pressure event), or whiplash often have concomitant involvement of the vestibular apparatus or nuclei. This often goes undetected within the initial medical workup and management plan excepting in specialty vestibular practices.393–397 When the disorder is undetected and left unchecked, the patients do not respond to standard treatment interventions. They also complain of atypical symptoms or responses to these typical treatments. When the patient does not respond in predictable ways to standard treatment, the label “aphysiological” is applied, particularly in situations where disability or secondary gain is a factor. Fortunately there are well established performance criteria that can effectively differentiate true balance or vestibular impairment from embellishment for secondary gain.³⁹⁸ (Refer to Chapters 22A and 22B.)

In treatment, recovery is based on long-term compensation mediated by the cerebellum, and symptoms must be reproduced for recovery to occur. However, stimulation of the vestibular system must be controlled, with every effort made to maintain a limbic (emotional) neutral state. Some patients have true vestibular dysfunction that affects only motor responses, whereas other patients have true limbic psychiatric problems that do not manifest themselves with vestibular symptoms. These two behaviors are located at the polar ends of the curve between limbic motor and vestibular motor dysfunction. Before prescribing appropriate intervention strategies, the clinician must be clear regarding the degree of limbic overlay on the vestibular dysfunction, and the question “What are the best vestibular and limbic interactive environments that will challenge and drive neuroplastic change?” must be answered. Although researchers^233,390 have identified tools that differentiate the two extremes, today researchers are trying to clarify the midrange of patients who clearly have symptoms on the basis of the interaction of both systems.^398,399 Development of tools that can further discriminate whether the behaviors are first driven by vestibular and followed by limbic responses, or vice versa, is a key to treatment planning.

Parkinson disease.

The motor impairments seen in individuals with Parkinson disease are widely accepted, understood, and treated by physical and occupational therapists (see Chapter 20). What is not commonly synthesized by physical and occupational therapists, no matter the working environment (hospital, outpatient, rehabilitation, home health), is that individuals diagnosed with Parkinson disease often have limbic involvement.

Masked expression is accepted as a motor sign of this disease and is linked directly to the rigidity expressed within the motor system. Yet, a masked expression is also associated with fear as an emotion (see Figure 5-6). Similarly, the ability to extinguish this fear response or masked expression is also based on the infralimbic prefrontal lobe and the number of dopamine receptors.⁴⁰⁰ These areas may not be directly damaged by Parkinson disease, but the amount of available dopamine is dramatically reduced. Given this interaction, patients with Parkinson disease may have difficulty facially expressing what they are feeling. Thus, when a therapist sees a patient with a fixed facial expression, that therapist cannot draw a conclusion from that facial expression.

Similarly, depression is commonly associated with any individual with a degenerative disease.^401,402 Obviously, depression from a neuroanatomical perspective is housed with the limbic system. Depression from a motor response perspective causes lower postural tone with increased flexion in the neck (see Figure 5-8, B). This pattern within the trunk is also often described as the postural patterns of an individual with Parkinson disease. The question arises, “Is the tone generated from the motor system alone, from the limbic influence on the motor system alone, or from a combination of the two?”

Individuals working in a psychological setting (inpatient and outpatient) may focus on the psychoemotional problems without addressing the functional motor involvement. It is not infrequent that an individual with this disease may simultaneously exhibit signs of psychosis and other potential psychiatric problems.403–407 It is critical for therapists, despite the physical setting, to develop and understand the entire spectrum of the problems associated with this disease.

Cerebrovascular accidents (see chapter 23).

The most common insult in CVA results in occlusions within tributaries of the middle cerebral artery.⁵⁶ When this occlusion is in the right hemisphere, studies have shown that clients are often confused and exhibit metabolic imbalance.⁴⁰⁸ The primary problem of this confused state is inattention. After brain scans, it has been shown that focal lesions existed within both the reticulocortical and limbic cortical tracts, suggesting direct limbic involvement in many middle cerebral artery problems.⁶⁶

With the use of magnetic resonance imaging (MRI), specific lesion deficits after CVA can help physicians and therapists identify specific motor and limbic behavioral problems that would limit quality of life of the patients.409–411 Many clients who have had a CVA do not have direct limbic involvement, yet the stresses placed on the client,^412,413 whether external or internal, are often reflected in the limbic network’s influence over cognition and the motor control systems.⁴¹⁴ Everyday existence as well as performance of motor tasks required during therapy are usually valued highly in the client’s life. This value or stress placed on the limbic network overflows into the motor system and never allows it to relax, as observed by noting the increase of tonus in the unaffected leg. The client is usually unaware of this buildup of tonus but can release it once attention is drawn to it. If attention is never directed toward these tension buildups, a therapist trying to decrease tonus in the affected arm or leg will always be interacting with the associated patterns from the less-involved extremities.

Tumor (see chapter 25).

Any brain tumor, regardless of whether it directly affects the limbic structures, will certainly arouse the limbic network because of the stress, anxiety, and emotional overlays of the diagnosis. The degree of emotional involvement will obviously affect the declarative learning of the client as well as the limbic network’s influence over motor response.

Tumors specifically arising within limbic structures^415,416 can cause dramatic changes in the client’s emotional behavior and level of alertness, especially with hypothalamic tumors.⁴¹⁷ The behaviors reported include aggressiveness, hyperphagia, paranoia, sloppiness, manic symptoms, and eventual confusion.⁵⁶ Tumors within the hypothalamus cause not only behavioral abnormalities but also autonomic endocrine imbalances, including body temperature changes, menstrual abnormalities, and diabetes insipidus.¹⁰⁹

When the tumor is located within the frontal and temporal lobes, associated with limbic structures, psychiatric problems may manifest, ranging from depression to anorexia to psychosis.^109,418 Obsessive-compulsive disorder resulting from limbic tumor has been used as a tumor marker for relapse.⁴¹⁹ Amnesia has been reported in patients with dorsomedial thalamus, fornix, midbrain, and reticulolimbic pathway lesions. This again reinforces the importance of the limbic network’s role in storage.^109,420,421

The neurochemistry within the limbic network is very complex and will be discussed within the next large section, but even without a keen understanding of the specific chemistry, therapists need to recognize behavior and mood changes within the client. These changes often signal neurochemical problems affecting the individual’s motor system. If medical intervention includes medicine, pharmacists should be able to explain how those behaviors are being regulated by pharmacological intervention. Literature is now reporting that what were once thought idiopathic seizures are now believed to be neurochemical imbalances with the limbic structure and may someday be controlled with medications that directly affect the immune system.⁴²²

Ventricular swelling after spinal defects in utero, central nervous system trauma, and inflammation (see chapters 15, 24, and 26).

Although the effects of ventricular swelling after trauma, inflammation, and in utero cerebrospinal malformations are not discussed in great detail in the literature with respect to limbic involvement, the proximity of the lateral and third ventricle to limbic structures cannot be ignored. It is common knowledge that most people exposed to hot, humid weather begin to swell; become more irritable, less tolerant, and moody; and may complain of headaches. Some people become aggressive, others lethargic. All these behaviors are linked to some extent with limbic function. Thus, ventricular swelling causing hydrocephalus, whether caused by trauma, inflammation, or obstruction, would potentially affect the limbic structures. Reported behavioral changes such as seizures, memory and learning problems, personality alterations, alertness, dementia, and amnesia can be tied to direct or indirect limbic activity.⁵⁶

Summary of clinical problems affected by limbic involvement.

It is easy to identify limbic problems when the behaviors deviate drastically from normal responses. It is much more difficult to determine subtle behavior shifts in clients. The therapist should be sensitive to these minor mood shifts because they may represent early signs of future problems. Similarly, noting that a particular client is always irritable and has difficulty learning on hot days should help direct the therapist toward establishing a treatment session that regulates humidity and temperature to optimize the learning environment. The limbic network is not just a neurochemical bundle of nuclei and axons found within the brain. It is a pulsating center that links perception of the world and the way an individual responds to that perception. Quality of life is a value, and that value has a strong limbic component. If functional outcomes leading to maintaining or improving the quality of life of our clients is the goal of both physical and occupational therapy,^291,423,424 then the limbic network is no less important during examination, evaluation, prognosis, and intervention than the motor system itself.