History and examination

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4 History and examination

Introduction

The neurological examination is traditionally taught using a disease or ablative lesion-orientated model. While this approach may help to detect the presence of both serious and benign disorders, it is less helpful for the practitioner who wishes to investigate and estimate the physiological functional integrity of the nervous system. A more functional approach to the neurological examination heightens the examiner’s sensitivity to physiological aberrations responsible for the vast majority of neurological symptoms. At the same time, a practitioner using this approach is more likely to detect subtle signs of pathology.

The practitioner who intends to utilise the functional approach of examination must be concerned with the identification of ablative lesions and the presence of disease processes, but must also attempt to identify any physiological lesions manifesting themselves as subclinical physical symptoms.

For example, if a patient presents with a recent history of an inner ear infection complicated by hearing loss and balance disturbances, one might assume the possibility of potential damage to the vestibular and/or cochlear hair cells, which are the receptors responsible for balance and hearing. At follow-up after a course of antibiotics, a commonly occurring scenario is that the patient states that their hearing has returned and their balance is no longer a concern to them but they are starting to experience migraines, which they had not experienced before. The vestibular system can have a profound influence on peripheral resistance due to disynaptic or polysynaptic connections between vestibular neurons and the tonic vasomotor neurons of the rostral ventrolateral medulla. The purpose of these connections is for protection against orthostatic stress. Should a comprehensive examination focused on the functional state of the vestibular-cerebellar and medullary areas show dysfunction or asymmetry of function in this patient, it would be of great value to the patient for you to address the central consequences of the inner ear infection and attempt to reduce the vasomotor dysregulation that has no doubt developed during the course of their illness. Treatment, involving appropriate afferent stimulation and exercises aimed at restoring symmetry and integrity to the vestibular system and associated brainstem nuclei, should be a primary consideration in this patient’s management, in addition to any pharmaceutical approach also applied.

In learning the traditional approach to the neurological examination a student or inexperienced practitioner may be less interested in minor asymmetries of cranial nerve function or motor and sensory signs, especially when the history does not alert to serious pathology. This is not the case in the functional examination where minor asymmetries or altered functional output are of great significance in the analysis of the physiological lesion. Each test must be performed with alert observational skills and meticulous care, comparing the results bilaterally when possible.

The functional neurological examination aims to elicit information about mental, sensory, and motor functions. Sensory functions are analysed by observing the patient’s mental or motor response to stimulation of the various sensory receptors in the head and body. Motor functions are analysed by observing the patient’s requested or spontaneous volitional actions. Sensory and motor functions can also be analysed by observing both muscle and glandular responses to sensory stimulation. The muscles and glands are the final common effector systems of the body. Their responses are normally dependent on the output from complex neuronal integration and, as such, can be utilised in assessment of the functional state of the neuron pools that control their output. Reflexogenic systems, such as opticokinetic stimulation and vestibulo-occular stimulation can also be utilised in gaining an understanding of the patient’s functional state.

The five parameters of effector response are important clues in gauging the cis of upstream neuron systems

The response of an effector (e.g. muscle) to a stimulus or command is largely dependent on the central integrative state (CIS) of the presynaptic neuronal pool projecting to the motor neuron of the effector. Therefore, the CIS of a neuronal pool can be predicted or estimated by observing the characteristics of the motor response of the downstream motor neuron to a unit stimulus. The parameters of the effector response observed can be summarised under the following observational findings:

All of the responses observed during the functional examinations performed on a patient, should be evaluated with the above parameters in mind. It is also important to visualise the pathways actively involved in producing the actions that one is examining. This allows the practitioner the advantage of performing additional or more detailed tests directed at the same pathways throughout the examination should disparities in the patient’s responses become apparent.

Latency and velocity of a response

The latency refers to the time between the presentation of a stimulus and the motor, sensory, autonomic, or behavioural response of the patient. This provides information concerning conduction time along nerve axons and spatial and temporal summation occurring in the neurons involved in the functional action chain of the response. The velocity of the response is another window of spatial and temporal summation and conduction time.

The time to summation (TTS) and time to peak summation (TTSp) are terms that describe, respectively, the latency and average velocity of effector responses. The pupillary action observed in response to a light stimulus offers a good illustration of these concepts. Under normal conditions, the pupils will respond with a relatively equal TTS and TTSp in both eyes when stimulated with an equal light stimulus. However, in the situation where the central integrative state of the neurons in the right Edinger–Westphal nucleus or mesencephalic reticular formation is further away from threshold, the TTS of the right eye would be expected to be increased from that of the left. The same result may be expected when measuring the velocity of the response, or an increased time to maximal pupil constriction (increased TTSp). The same result, that is increased TTS and TTSp in the right eye, may be found with an afferent pupil defect such as would occur if the right eye end organ was impeded by a photoreceptor or axonal conduction deficit such as in retinal or optic nerve dysfunction. Thus there is the need for a complete fundoscopic and visual acuity examination when unequal pupil responses are present.

The longitudinal level of the lesion

When examining a patient, the practitioner needs to consider that dysfunction at any level of the pathway, from the sensory receptor to the effector, may result in aberrant findings during an examination of body function. The usually considered longitudinal levels that may be involved in a dysfunctional output response include the following: the receptor or effector, the afferent or efferent pathways of the peripheral nerve, the spinal cord, the brainstem or cerebellum, the thalamus or basal ganglia, the cortex. It is important to remember that a dysfunction at one longitudinal level of the neuraxis may result in dysfunction at other levels also.

The following example illustrates the concept. A patient presents with unilateral ptosis. The cause of the ptosis might be occurring at the effector level involving the ACh receptors of the orbicularis oculi muscle as in myasthenia gravis. The cause of the ptosis might be occurring at the peripheral nerve level as could occur in a partial third nerve compression palsy. The cause of the ptosis may involve disruption of the sympathetic fibres to the levator palpebrae superiorus muscle at any point along the sympathetic projections from the hypothalamus, through the spinal cord, the superior cervical ganglia, and postsynaptic projections that follow the oculomotor nerve to the muscle as in Horner’s syndrome. Alternatively, it may be caused by asymmetric cortical output resulting in overstimulation of the pontomedullary reticular formation (PMRF), which has inhibited sympathetic output to the eyelid.

A complete history and examination of the patient would enable the correct diagnosis without too much difficulty in this case.

Approaches to developing a differential diagnosis

Before discussing the history and physical examination procedures in general, it is necessary to give some thought to the reason for performing these activities in the first place. The history and physical examination are procedures that allow the practitioner to develop a clinical impression of the state of health or disease of the patient. Based on the clinical impression, the practitioner then arrives at a working diagnosis of the patient’s condition and develops the most appropriate approach to treatment of the patient.

The process of arriving at a diagnosis usually first involves the development of a differential diagnosis, which is the consideration of a number of alternative diagnostic possibilities in light of the history. The list of differential diagnoses is then systematically reduced by the results obtained from further tests performed on the patient. The most common tests utilised clinically include the examination procedures that compose the physical examination, laboratory blood or body fluid analysis, diagnostic imaging such as plain film X-rays, MRI, fMRI, or PET scans, and electrophysiological evaluations such as qEEG, EEG, and EMG.

Space limitations only allow for a brief overview and suggested approach to differential diagnosis at this time, but several excellent texts on the subject can be found in the additional reading section at the end of the chapter.

One approach to developing a differential diagnosis is to consider the possible causes of the patient’s presenting symptom picture with respect to a list of major classifications of pathological processes. The major classifications include vascular disorders, infectious conditions, neoplastic disorders, neurological disorders, degenerative disorders, inflammatory disorders, congenital disorders, connective tissue disorders, autoimmune disorders, trauma, endocrine disorders, and soft tissue disorders. The pneumonic VINDICATES can be used to remember the major classifications for this approach.

Once a clear history has been taken from the patient, possibilities from each category can be considered and analysed in light of the symptom picture that the patient has presented with. The following example should illustrate the approach: A 54-year-old male presents with a history of low back pain that radiates into his left leg. The patient works as a construction worker and has a 30-year history of smoking. Diagnostic possibilities based on the VINDICATES approach should be considered (Table 4.1).

Table 4.1 Diagnostic possibilities utilising the VINDICATES pneumonic

V=Vascular Deep vein thrombus, varicose veins, Burger’s disease, heart failure, myocardial infarction (atypical presentation), abdominal aortic aneurysm, arthrosclerosis
I=Infection Meningitis, HIV, osteomyelitis
N=Neoplastic, Neurological All carcinomas including emphasis on prostate carcinoma, lung carcinoma—Pancoast tumour, tumours of spinal cord and brain—Schwannomas, glioma, MM, Mets, osteosarcoma, Ewings sarcoma. Herniated or prolapsed vertebral disc, sciatic neuralgia, cervical spondylitic myelopathy, piriformis syndrome, cauda equine syndrome, neurogenic claudication
D=Degenerative Spondylosis of IVF, osteoarthritis, DISH
I=Inflammatory Osteomyelitis, RA, AS, EA, more arthropathie, gout
C=Cartilagenous, Congenital, Connective tissue

A=Autoimmune RA, Sjögren’s , MS, SLE, AIDS T=Trauma E=Endocrine S=Soft tissue (involvement)

Order of the history and examination process

Any healthcare practitioner with training in clinical and neural science has the ability to perform the neurological history and examination in a proficient manner. The key is to develop a routine that can easily be remembered, that can be performed in logical sequential order, and that can be easily improvised for different patient presentations. Two systematic approaches to the neurological examination include the anatomical and functional approaches. The anatomical approach requires examination of the nervous system in a rostrocaudal order (i.e. brain, brainstem/cranial nerves, spinal cord, spinal nerves, receptors, etc.), while the functional approach requires examination of related functions in groups (i.e. mental, motor, sensory, visceral, etc.). A combination of these two approaches is likely to be more efficient, less repetitive, and more appropriate for both the history-taking process and examination as well.

Greater efficiency may be achieved by limiting movement of the patient and using each tool or each type of test only once throughout the examination. If possible, the patient should be assessed in the sitting, standing, and lying positions once and should be assessed in a rostrocaudal order for each function tested. This will reduce the frequency of switching between tools and patient positions. Each instrument used in the examination should be laid out in order of use and within easy reach of the practitioner. With this orderly approach, the practitioner will be less likely to miss any component of the examination (DeMyer 1994). For example, it might be more efficient for the practitioner to determine sensitivity to pain at all levels from the ophthalmic division of the trigeminal nerve to sacral innervated regions, rather than switching between motor and sensory tests at each level.

Details gathered from the neurological history and examination may only provide information concerning the type and location of aberrant neuronal function. A thorough physical and orthopaedic examination and laboratory or ancillary neurodiagnostic tests may be more useful in establishing the aetiology in some cases.

The following lists provide an overview of the breadth of information concerning the neurological history and examination. This should serve as a useful reference and template.

The neurological history

2. General Health History

3. Social History

4. Systems History (special senses, motor, sensory, autonomic, mental)

Learning these questions as a basis for taking a neurological history can help the practitioner to gain experience by learning more about classic and unusual symptom patterns.

The neurological examination

There are numerous excellent texts that cover neurological examination techniques and these have been outlined in the Further Reading section. What will be attempted here is a description of examination techniques or procedures that either differ from the norm or are not covered in traditional texts. As each technique is encountered in the text it will be expanded on to explain in detail the approach necessary. First, some neurodiagnostic testing equipment often utilised in functional neurology will be discussed.

Neurodiagnostic tests

A variety of neurodiagnostic testing equipment can be utilised to investigate or objectively quantify dysfunction. These include:

1. Video nystagmography (VNG)—for objective analysis and documentation of visual tracking, saccade, and optokinetic dysfunction, spontaneous nystagmus with and without visual fixation, unilateral weakness (canal paresis) and directional preponderance (central asymmetry) via caloric irrigation, positional tests, and others.

2. Vestibular evoked myogenic potentials (VEMPs)—for objective analysis of certain components of the vestibulocollic reflex. Latency and amplitude of motor signals to the sternocleidomastoid (SCM) muscle are measured following stimulation of the saccule with loud auditory stimuli.

3. Balance platform—Objective analysis of postural sway in various conditions using a force platform.

4. Electrocochleography—Objective analysis of short latency responses from the cochlear apparatus and nerve.

5. Auditory brainstem responses—Objective analysis of brainstem responses to auditory stimuli to complement VEMPs.

6. Electroencephalography (EEG) and qEEG—the neuron electrical activity is measured over the scalp by very powerful receptors and then amplified to produce wave patterns that can be used to give objective projections of the state of brain function. This technique has become very powerful with the addition of source localisation software such as that offered by the Key institute which can combine low-resolution tomographic analysis (LORETA) and MRI anatomical library data to give very accurate localisation of EEG data.

7. Advanced imaging—MRI, CT, Doppler ultrasound if history and examination suggests ablative lesion of sinister aetiology or if patient is not responding to care. To be discussed further.

8. Audiometry—also useful and it is important that copies of all reports concerning hearing, vision, balance, and imaging are requested.

The examination process

Examination of the pupils

Pupil size reflects a balance in tone between the sympathetic and parasympathetic nervous systems. You can get a reasonable measure of the actual sympathetic tone in the patient by measuring the resting pupil size in darkness. The sympathetic tone represents the degree of dilation of the pupil but the degree of resting vascular constriction in vascular smooth muscle in most parts of the body. Vestibular, cerebellar, and cortical influences on both sympathetic and parasympathetic tone should also be considered.

Various components of the pupil light reflex are subserved by each component of the autonomic nervous system. The TTA, amplitude of constriction, smoothness and maintenance of constriction, TTF, and time to redilation of the pupil response need to be measured and recorded in each pupil. These are all aspects of the pupil light reflex that have been researched and correlated with central integrative state of the various contributing components of the nervous system.