Chapter 82 Functional and Dissociative (Psychogenic) Neurological Symptoms
Terminology
Psychiatric Terminology
Conversion disorder (DSM-IV 300.11) is based on the Freudian idea that intolerable psychological conflict leads to the conversion of distress into physical symptoms. The current definition requires that the symptoms are “not feigned” and that psychological factors judged to be “associated with the symptom or deficit because conflicts or other stressors precede the initiation or exacerbation of the symptom or deficit” be present. In practice, these two criteria are so untestable, they are likely to be dropped from the DSM-5. The conversion hypothesis is now just one of many competing hypotheses trying to explain these symptoms (Stone et al., 2010a).
Other Terminology
Our preferred terms for motor/sensory symptoms and blackouts unexplained by disease are functional and dissociative because they describe a mechanism and not an etiology, they sidestep an illogical debate about whether symptoms are in the mind or the brain, and they can be used easily with patients. For simplicity, the term functional is used in this chapter, although psychogenic remains a popular term, especially among U.S. neurologists (Espay et al., 2009).
Psychogenic, psychosomatic, and somatization all describe an exclusively psychological etiology.
Nonorganic, nonepileptic describes what the problem is not, rather than what it is.
No diagnosis. Many neurologists, even when faced with clear evidence of a functional/psychogenic neurological problem, are in the habit of making no diagnosis at all and simply concluding that there is no evidence of neurological disease (Friedman and LaFrance, Jr., 2010).
Epidemiology in Neurology and Other Medical Specialties
A number of studies of neurological practice have found that around one-third of neurological outpatients present with symptoms the neurologist does not think relate to neurological disease. In half of these (around one-sixth of all patients) the neurologist makes a primary “functional” or “psychogenic” diagnosis. The rest have some neurological disease but symptoms out of proportion to that disease (Stone et al., 2009). These figures mirror those in other medical specialties where functional symptoms comprise around a third to half of patients seeing a cardiologist, gastroenterologist, rheumatologist, and other specialty practices. Table 82.1 lists functional symptoms and syndromes according to specialty. Patients with functional neurological symptoms have much higher rates of these other non-neurological functional symptoms (Crimlisk et al., 1998).
Table 82.1 Functional Symptoms and Syndromes According to Medical Specialty
| Specialty | Symptoms |
|---|---|
| Gastroenterology | Irritable bowel syndrome |
| Respiratory | Chronic cough, brittle asthma (some) |
| Rheumatology | Fibromyalgia, chronic back pain (some) |
| Gynecology | Chronic pelvic pain, dysmenorrhea (some) |
| Allergy | Multiple chemical sensitivity syndrome |
| Cardiology | Atypical/noncardiac chest pain, palpitations (some) |
| Infectious diseases | (Postviral) chronic fatigue syndrome, chronic Lyme disease (where physician disagrees that there is ongoing infection) |
| Ear, nose, and throat | Globus sensation, functional dysphonia |
| Neurology | Nonepileptic attacks, functional weakness and sensory symptoms |
| Psychiatry | Depression, anxiety |
Studies of patients with functional neurological symptoms have shown that they report just as much physical disability and are more distressed than patients with neurological disease. Patients with these symptoms are more likely to be out of work because of ill health than the general population (Carson et al., 2010). Findings are similar in other specialties.
Clinical Assessment of Functional and Dissociative (Psychogenic) Symptoms
General Advice in History Taking
1. Start by making a list of all physical symptoms. Patients with functional symptoms typically have multiple physical symptoms. Making a list of them at the beginning avoids symptoms cropping up later, helps build rapport, and allows an early appreciation of the main difficulties. Do not, however, take detailed information about every symptom at this stage. Always ask about fatigue, pain, sleep disturbance, memory and concentration symptoms, and dizziness. It may seem counterintuitive to be seeking more symptoms in someone who is already polysymptomatic, but sometimes these symptoms, especially fatigue, are reluctantly volunteered even though they often cause the most limitation.
2. Dissociative symptoms. Dizziness, if present, may turn out to be dissociative in nature (e.g., feeling “spaced out,” “there but not there,” or “unreal”). Patients have trouble describing dissociation, partly because it is hard to describe but also because they fear the symptoms indicate “craziness.” Depersonalization describes feeling disconnected from your own body; derealization is a feeling of being disconnected from your surroundings.
3. Onset. The onset in patients with weakness and movement disorders is sudden in around half of patients. Physical injury, pain, or acute symptoms of dissociation or panic are common in this situation. More gradual-onset symptoms are often associated with fatigue.
4. What can the patient do? Patients with functional symptoms have a tendency to report what they can no longer do rather than what they can do. While it is helpful to hear about previous function, ask what they are able to do—do they enjoy it?
5. Look for other functional symptoms and syndromes (see Table 82.1). The more they have, the more likely it is that the presenting neurological complaint is functional. Patients can rotate between different specialists, with none appreciating their vulnerability to functional symptoms in general.
6. Ask the patient what they think is wrong and what should be done. If they or their family have been concerned or wondering about a specific neurological disease such as multiple sclerosis, Lyme disease, or “trapped nerves,” this information is important to tailoring an explanation for the diagnosis later on. Do they have health anxiety? Do they think they are irreversibly damaged? Efforts at rehabilitation may be futile unless beliefs about damage can be altered. In one prospective study of outpatients, beliefs about irreversibility predicted outcome more than age, physical disability, and distress (Sharpe et al., 2009). What happened with previous doctors and why have they come to see you? Some patients seek diagnosis and treatment, others are simply looking for a label for a problem they do not expect to resolve.
7. Avoid blunt questions about depression and anxiety. It is not necessary for the purposes of neurological diagnosis to make an accurate assessment of a patient’s psychological state on the first visit. The diagnosis of functional symptoms should be made on the basis of the physical symptoms. It often may be wise to leave questions about emotions for later; only a minority of patients with functional symptoms believe that stress or psychological factors have anything to do with their symptoms, in contrast to patients with disease who commonly attribute their symptoms to stress (Stone et al., 2010b). Patients with functional symptoms do have high rates of depression and anxiety but are often wary of questions about their emotions. They often feel that the doctor is angling to blame their physical symptoms on them personally. Blunt questions like, “Are you depressed or anxious?” may not therefore yield accurate answers. Instead try the following:
For depression, ask about activities they can do and whether they get enjoyment from them; if not, they may have anhedonia. If hospitalized, do they look forward to visits from friends and family? Look at the patient—are they miserable or avoiding eye contact? Or try framing questions around the physical symptoms: “Does your weakness get you down?” Depression is likely when there is persistent anhedonia or low mood most of the time, with four or more of the following: fatigue, sleep disturbance, suicidal ideation, poor memory or concentration, psychomotor retardation/agitation, or feelings of worthlessness/guilt and/or suicidal ideation.
8. Do not always expect psychological comorbidity or life events. Depression and anxiety are common, but around one-third of patients will have neither. Likewise, although some patients have a history of a recent life event or stress, this is not always present. Sometimes the panic attack or physical injury that triggered the symptom is the most stressful life event, and the presence of the symptom then serves to perpetuate the anxiety. Avoiding a diagnosis of functional symptoms in someone just because they seem “normal” is as great an error as making the diagnosis simply because the patient has a lot of obvious psychological comorbidity.
General Advice in Specific Physical Diagnosis
The diagnosis of functional symptoms should always be made on the basis of either:
Clinical features typical of a functional/dissociative diagnosis (e.g., a typical thrashing dissociative [nonepileptic] attack with side-to-side head movements and eyes closed for 5 minutes).
La belle indifference (smiling indifference to disability) has no diagnostic value, since it may be present in neurological disease (Stone et al., 2006). When it is present, it often reflects a conscious desire on the patient’s behalf to appear happy in a situation where they are aware they are under psychiatric “suspicion,” or alternatively may indicate factitious disorder.
Blackouts/Dissociative (Nonepileptic) Attacks
Dissociative (nonepileptic) attacks are the most common type of symptom unexplained by disease seen in neurological practice (Schacter and LaFrance, Jr., 2010). Studies have estimated that up to 1 in 7 patients in a “first fit” clinic, 50% of patients brought in by ambulance in apparent status epilepticus, and around 20% to 50% of patients admitted for videotelemetry have this diagnosis. Peak incidence is in the mid-20s; females predominate 3 : 1. Later-onset patients in their 40s and 50s have a 1 : 1 gender ratio and typically have health anxiety and a history of recent “organic” health problems (Duncan et al., 2006).
The diagnosis is usually made on the basis of the observable features of an attack, preferably recorded using video electroencephalography (EEG) (Table 82.2). No one feature should be used on its own to make a diagnosis, but some are more reliable than others (Avbersek and Sisodiya, 2010). Data on the reliability of these signs have largely been taken from studies of videotelemetry; these signs are less reliable when based on witness descriptions.
Table 82.2 Differentiating Dissociative (Nonepileptic) Attacks from Generalized Tonic-Clonic Epileptic Seizures
| Dissociative Attacks | Epileptic Seizures | |
|---|---|---|
| HELPFUL | ||
| Duration over 2 minutes* | Common | Rare |
| Fluctuating course* | Common | Rare |
| Eyes and mouth closed* | Common | Rare |
| Resisting eye opening | Common | Very rare |
| Side-to-side head or body movement* | Common | Rare |
| Opisthotonus, arc de cercle | Occasional | Very rare |
| Visible large bite mark on side of tongue/cheek/lip | Very rare | Occasional |
| Dislocated shoulder | Very rare | Occasional |
| Fast respiration during attack | Common | Ceases |
| Grunting/guttural ictal cry sound | Rare | Common |
| Weeping/upset after a seizure* | Occasional | Very rare‡ |
| Recall for period of unresponsiveness* | Common | Very rare |
| Thrashing, violent movements | Common | Rare |
| Postictal stertorous breathing* | Rare | Common |
| Pelvic thrusting*† | Occasional | Rare§ |
| Asynchronous movements*† | Common | Rare |
| Attacks in medical situations | Common | Rare |
| NOT SO HELPFUL | ||
| Stereotyped attacks | Common | Common |
| Attack arising from sleep | Occasional | Common |
| Aura | Common | Common |
| Incontinence of urine or feces* | Occasional | Common |
| Injury* | Common¶ | Common |
| Report of tongue biting* | Common | Common |
* Endorsed by a recent systematic review (Avbersek, A., Sisodiya, S., 2010. Does the primary literature provide support for clinical signs used to distinguish psychogenic nonepileptic seizures from epileptic seizures? J Neurol Neurosurg Psychiatry 81, 719-725.).
† These signs unhelpful in distinguishing nonepileptic attacks from frontal lobe seizures.
§ Frontal lobe epilepsy. Nonepileptic attacks do appear to arise from sleep, but video electroencephalogram (EEG) usually shows this not to be true sleep. Attacks arising from EEG-documented sleep are suggestive of epilepsy.
¶ Especially carpet burns and bruising.
Attention has shifted in recent years to diagnosis using subjective experience of the attack. Patients with dissociative attacks typically do not volunteer a prodrome. Indeed, studies analyzing dialogue between neurologists and patients have shown that the lack of any attempt to describe a prodrome may be of diagnostic value in itself, since patients with epilepsy usually do attempt to describe their prodrome when present, compared to patients with dissociative attacks who describe the disability associated with the attack (Reuber et al., 2009). However, if questioned, many patients with nonepileptic attacks will admit to a brief prodrome with features of panic (Goldstein and Mellers, 2006) (Fig. 82.1). If obtained, this is useful information that gives the clinician windows into both understanding the nature of the attacks (a mechanism related to panic attacks in which the patient dissociates) and possible treatment (teaching the patient distraction techniques to use during this warning phase to avert the attack and following treatment principles for panic disorder). As some patients recover, they may experience awareness during the attack itself.
Video EEG may be supplemented by an open suggestion protocol to help record an attack (Benbadis et al., 2000). Deceptive placebo induction with saline or a tuning fork is more controversial. Postictal prolactin measurement (to detect high prolactin after a generalized seizure) has fallen out of favor owing to problems with the reliability and timing of the test. Diagnostic pitfalls include coexistent epilepsy (present in 5%–20% of patients), frontal lobe seizures, sleep-related movement disorders, and paroxysmal movement disorders.
Weakness/Paralysis
Weakness as a functional symptom is more common in females and typically presents in the mid-thirties but like all functional symptoms can occur in children and the elderly. Estimates of incidence are around 5/100,000, comparable to multiple sclerosis. Comorbidity with other functional symptoms, especially fatigue and pain, is almost invariable. The most common presentation is unilateral weakness with no good evidence for left-sided or nondominant preponderance, followed by monoparesis and paraparesis. Complete paralysis is less common clinically (Stone et al., 2010b).
The onset is sudden in around 50% of patients. In the acute presentation, there are often symptoms of a panic attack, dissociative seizure, or an immediate trigger such as a physical injury, acute pain, migraine, a general anesthetic, or an episode of sleep paralysis (Stone et al., 2011). When the onset is more gradual, there is typically a history of fatigue, pain, or immobility on which the weakness becomes superimposed gradually over time. The weakness seen in complex regional pain syndrome type 1 (CRPS1) (Birklein et al., 2000) has the same clinical features as functional weakness.
Pattern of weakness. In functional weakness, the limb is usually globally weak or often demonstrates the inverse of pyramidal weakness, with the flexors weaker in the arms and the extensors weaker in the legs.
Hoover sign. Hip extension must be weak for this test to work. The presence of hip extension weakness itself in an ambulant patient is a positive sign of functional weakness. If hip extension returns to normal during contralateral hip flexion against resistance, this demonstrates structural integrity of the motor pathways (Fig. 82.2). The test is easiest to do with the patient in the sitting position. We find it useful to demonstrate this sign to the patient and relatives to indicate that the diagnosis is being made on the basis of positive criteria. This test may be false positive when there is cortical neglect.
