Inspection

Because one is speaking to the diseased organ, but addressing the ill patient, and doing so in a heightened environment of observation, it is important to assess function “by bush glasses and by opera glasses.” Try to catch a few moments at least of the patient before they sense you are observing them and look for how the patient holds themselves, moves, talks, and engages with others or with objects. It may be quite different than with the clinician or provide a sense of ecological validity that standard examination maneuvers can never be extrapolated to reveal. FLOAT NOT FOUND

Follow the patient to the examination room to observe their gait and compare it to the demonstration they provide when you are standing in front of them asking to test their walk. There may be differences that indicate malingering or functional neurological conditions. Often the instructions given during examination maneuvers can be loaded with placebo and nocebo by clinicians; this can be of great advantage when psychiatric overlay is suspected in mixed conditions or there is an “effort-dependent” examination. Alternatively, there may be some gestalt sense that comes about when you see the person in the waiting room (how stiff they hold themselves) that you would miss during your busy history taking. Use the walk to and from the waiting room and some conversation as an opportunity to get a view of their form and function, which will help you estimate if the minute findings of your microscopic maneuvers on examination are insightful or incidental.

A Brief Note About Dominance

Ascertaining so-called “dominance” is a classical attribution of the neurological examination, because by it we orient our findings to a map of functional anatomy. We will not know our right hemisphere from our left hemisphere based on the deficits. There are scales for estimating dominance. The modern clinician should consider what is meant by this provocative and problematic term. Dominance of one hemisphere implies subordination of the other, but by what criteria? A clinician should try to identify the “eloquent” hemisphere (the one primarily responsible for language functions). Generally the handedness of the individual will be contralateral to the eloquent hemisphere, but even amongst “left-handers” a strong faction is believed to localize language to the left hemisphere, and it would seem other faculties arrange themselves accordingly. A safe bet is to assign eloquence to the left hemisphere unless other parts of the examination point otherwise.

Depth of Consciousness

First, determine the depth of consciousness (described as hypervigilant, alert, confused, drowsy, stupor, or coma), which is accomplished by establishing the threshold of response to environmental cues (Does the patient arouse or respond to voice, touch, or noxious stimulation?). The level of consciousness must be determined to the satisfaction of the examiner, because the level constricts the scope of subsequent properties of the mental status—and in many cases, the rest of the neurological examination.

For example, if a person is in a coma, the clinician cannot determine anything about the faculty of speech. It is no use to ask the patient to repeat, “No ifs, ands, or buts.” A facetious and extreme example, it nevertheless emphasizes a point that in more nuanced cases—such as general confusional or inattentive states—becomes particularly important. If a patient has poor attention, can the examiner be sure the patient truly has lost certain faculties of speech, or are they merely too inattentive to follow the examiner’s question.

Orientation

After establishing that the patient is conscious and possesses enough attention and concentration to be coherent to the present circumstance, and communicates reliably, the clinician can then begin to explore other structures of mental life. Orientation is a sense of one’s whereabouts and “whenabouts,” for without knowing our place in the present moment, we cannot direct ourselves to purposeful ends. Orientation is mapped by asking the patient who they are, where are they, why are they here in this place, how did they get here, and what is going on currently in personal, local, and national news? There is a difference between the historical or remembered orientation (the map) versus the ability to orient when needed (the use of a compass). Traditionally, orientation refers to the historical or remembered sense, rather than the patient’s ability to orient. There is a value judgment in the ecological validity of historical/remembered orientation. What is “Tuesday” to a retired person with no schedule but his meals and TV shows or a medical resident whose day begins Tuesday morning but ends Wednesday afternoon? Find out what the patient does with his days and then you can try to ascertain if his degree of orientation is sufficient for the schedule he offers. In some sense, we should be paying attention to the patient’s ability to reorient to updated information or new circumstances, and so cues should be provided to see if the patient can guide themself to the same lights you steer by.

Language

Although there is implicitly a rudimentary test of communication during the attentional and concentrative assessment, more is required to evaluate language’s several features. The briefest assessment would be to determine if a person’s speech is fluent or nonfluent (which assesses their ability to make themselves known to us) and if they can comprehend what is being told to them (which assesses our ability to make our wishes known to them). Language is the bridge of ideas and will play a substantial role in further assessment, and, more importantly, in management and recovery. Traditionally, in right-handers and many left-handers, the seat of language production is in the left frontal lobe and its reception in the left temporal lobe.

When listening to the patient, we naturally hear the thematic content of the message, but the language evaluation requires the examiner to tune into the compositional elements of the message (words qua syntax like in primary school sentence diagraming). Put another way, the patient can be talking nonsense because the content of the message is delusional or the composition of the message is denatured. Are their words vague, general terms (saying “animal” for “squirrel”) and they seem to understand what the examiner is saying? This could be a semantic issue. Are their words mispronounced and a struggle to get out with their slurred, slowed speech? This could be a nonfluency issue. Do they speak slowly and have trouble putting together sentences because they cannot think of the words anymore? This could be a logopenic issue. Are they smoothly speaking but the lyric sounds like a foreign language? This could indicate a fluent aphasia.

After listening to the patient’s fluency the first screening test is word finding and confrontational naming. In the former a definition is given and the patient is requested to provide the word (e.g., “What do soldiers wear on their backs when they jump out of a plane?” is answered with “parachute.”), while the latter is tested by confronting the patient with an object or an image. Impairments of either indicate an “anomia” (difficulty naming) and signify some insult to the faculty of language.

Next, a patient is asked to repeat phrases of increasing length and complexity, which indicate how robust conduction from the posterior temporal to the anterior opercular processes are intact. The power of repetition is not dependent on intelligibility and patients could be asked to repeat “no ifs, ands, or buts” versus “passoogmetunkapil” for short sensical and nonsensical phrases and longer ones like, “The clowns are in the circus ring” or “Twas brillig and the slithy toves did gyre and gimble in the wabe.” Commending to memory a pangram containing all the phonemes (e.g., “With tenure, Suzie’d have all the more leisure for yachting, but her publications are no good.”) will provide you with an opportunity to listen for articulation issues as well. The same is true for writing, and it may be useful to commend to memory a few sentences that use all the letters (e.g., “The quick brown fox jumped over the lazy dog.”). In repetition, one is paying attention to how long and how complex a sentence can be repeated, and when the repetition fails, how is it being denatured. Is their elision and substitution of words but overall preservation of the sentence’s theme signaling a working memory issue, or, are there impairments in the production of the word itself or tripping in the cadence of the phrases as they are being spoken to completion, which would indicate a language problem?

Comprehension is another element of language testing. An impression of comprehension will manifest during the give-and-take of a history in the precision of patient responses to the examiner’s questions. Some questions can purposefully stress syntax to betray subtle deficits. Asking the patient, “If the lion is eaten by the lamb, which one died?” could by probability of the nouns be guessed the lamb, but one who comprehends the grammar will name the lion. Command following of increasing linguistic complexity is another way to assess language comprehension with single commands, then multistep commands, then out-of-sequence commands, then contralateral commands, and all this in composite. Asking the patient, “Before sticking out your tongue, but after pointing to the ceiling with your left hand, put your right hand over your eyes” should result in the raising of a left hand, the covering of eyes with the right hand, and the sticking out of their tongue in that order.

Fluency, naming, and repetition, and comprehension are the key components of characterizing traditional aphasia patterns. Language is a matter of linking ideas formulaically; impairments in speech are almost always present in writing. If the patient is literate, asking the patient to follow a written command, read a sentence aloud, or write a written response to a written prompt are ways of assessing how the apparatus of reading engages other language processes. Every patient with a communication problem should be asked to speak and to write to determine if it is an articulation problem (dysarthria) or a language problem (aphasia), because communication is impaired in both speech and written word in language disorders.

To demonstrate the above categorization, consider three classic aphasias: Broca, Wernicke, and conduction aphasia. Broca aphasia is nonfluent with a better preservation of comprehension. Wernicke aphasia is the converse of Broca, preserving fluency but losing comprehension of others. Wernicke predicted that there must be a band connecting the comprehending temporal lobe to the fluent frontal lobe for which repeating or dictating speech is carried through. Sure enough, a conduction aphasia localizes to the arcuate fasciculus that bridges Broca and Wernicke areas and is an aphasia marked by the inability to repeat (a loss of parroting) with relative sparing of other fluent or comprehensive elements.

There are additional properties of communication that can be evaluated. While the left frontal-temporal structures are involved in language as described above, the right frontal-temporal structures are involved in related processes like prosody (the musicality and rhythmicity of speech), with additional localizations to the cerebellum and the coarse scanning speech of a robocaller or the inebriated. Offering poetic lines of different meters will detect the ability to entrain prosodic rhythms (e.g., “Shall I compare thee to a summer’s day?” vs. “Much of a which of a wind”). The difference between “lighthouse keeping” and “light housekeeping” is in its prosody. Some patients cannot produce this distinction, which is a more anterior or frontal lesion, while others cannot hear the difference, which is a more posterior and temporal lesion.

Attention and Concentration

Attention is a flashlight. It can be focused to accomplish a simple task among competing stimuli. It has an object . This can be tested by simple commands such as inviting the patient to open or close their eyes, stick out their tongue, or count the number of fingers shown to them. Concentration is a bucket. It holds vigilance across time and environmental disturbance. It has an objective . This can be tested by sustained or complex commands like inviting the patient to count backward by threes or spell WORLD or TRUCK backward. For standardized tests, Trails A (connecting a sequence of dots from 1 to 25) and Trails B (connecting a sequence of set-shifting numbers and letters 1–13 and A–L) have easily obtained norms by age and education and reflect attention and concentration, respectively.

Impulsivity and perseveration are the dark sides of attention and concentration. Contradictory commands like, “tap once when I tap twice; tap twice when I tap once,” or “tap once when I tap once; don’t tap when I tap twice,” catch perseveration or impulsivity.

Deficits in attention, concentration, or excesses of impulsivity and perseveration implicate the frontal lobes and their attendant circuits.

Memory

The resilience of prior experience and knowledge’s traces on the brain and the pathways for their recovery are traditionally tested by immediate registration of a few words, items, or a task; then short-term recall of items, words, or tasks at longer and longer intervals such as after 5 minutes, 10 minutes, or 15 minutes. There may be some lateralization with language-based memories processed through the left hippocampus and spatially based memories in the right hippocampus. Therefore one trick at the start of the interview is to show the patient an object and where you are hiding it, telling them as you do that it is the patient’s task to remind you before you leave the room that there is a hidden object and where it is located. Episodic memory of recent autobiographical or current events can be inquired of but demands corroboration by another source. Semantic memory of common facts about their world is essentially a game of high-frequency Jeopardy (e.g., Who was the first president of the United States? On what continent can the country Slovenia be found?), but educational background impacts responses, so it becomes important to determine the baseline fund of world knowledge. Patients often know much about something that the clinician knows precious little. A brief biography of the person (e.g., Where did they grow up?, What is their occupation?, Do they have any hobbies?) is needed for assurances of semantic memory. A chronology of their disease is insufficient.

Spatial, Constructive, and Gestural Properties

The inner world tries to make sense of the outer world to perform many day-to-day functions, from tying one’s shoes to getting around town. Space is divided into the personal (body), peripersonal (within our grasp), and extrapersonal (the environmental stage across which we move and navigate). Humans’ midline symmetry makes questions of right-left discrimination easy enough to assess by asking the patient to indicate the side of a specific body part. Praxis is the ability to carry out overlearned sequence commands by miming or with the materials necessary to complete it set before them. Manual praxis should be tested on both sides for one-limb actions (e.g., swat a bug, brush off a shoulder; hammer a nail, cut with scissors, use a key to unlock and open a door) as well as a few cooperative maneuvers (e.g., shuffle and deal a deck of cards or thread a needle and sew, tie your shoes or a necktie). Oral-buccal praxis is demonstrated by pretending to blow out a candle, lick an ice cream cone, suck on a straw, grin, or scowl. Emblematic gestures can be assessed by asking the patient to show you disagreement and agreement (thumbs-up, thumbs-down). Constructional abilities can be investigated by having the patient draw or copy shapes or build forms from blocks, navigate, or interpret directions of familiar places or locations.

Integrative Functions of Mental Status

Insight into a patient’s own case and circumstance can be impaired (an anosognosia), and those patients who recognize their deficit can be impaired by judging the impairment with indifference (an anosodiaphoria). These are crucial components to assessing a person’s capacity in making medical decisions. Reasoning can be assessed through presenting hypothetical scenarios in which a problem is to be solved or a moral dilemma is to be resolved. The patient’s answers only tell us what they say they should do. It tells us with no assurance if, when actually in that situation themselves, they would act as they say they do.

Some basic thematic perception or consequential reasoning can be obtained by showing the patient an illustration depicting a dynamic interpersonal issue and asking the patient to surmise the consequences of it or the reasons for its outcome. In the classic “Cookie Thief” illustration used in stroke assessment a distracted mother is unaware of both an overflowing sink as well as her son about to fall off a stool in his pursuit of a top-shelf cookie jar. One could ask the patient why the sink is overflowing, or why the child might not have just asked his mother for the cookies, or what the mother will feel when she discovers her fallen child. Like physical strength, metaphysical strength testing is confrontational and is only reliably graded if the examiner is without deficiencies of their own.

While talking with the patient and observing their behavior, the patient’s mood (how they feel) and affect (how they display how they feel) are not to be neglected, and if needed can be provoked by asking the patient to act out in voice and gesture a short script (e.g., I want you to say this line, “The snow will be melting soon,” as if you are happy and then as if you are disappointed), or asking them to read your emotion as you act out a line.

Cranial Nerves

It is here deficits disclose a localization to the brainstem. There are 12 paired cranial nerves (CNs). Each pair should be compared to its fellow for relative deficits too subtle to apprehend if tested twinly.

For olfactory testing, ask the patient to close their eyes and depress first one nostril and then the other as various familiar scents such as chocolate or coffee are presented. Avoid a noxious substance like alcohol or ammonia, which tests the trigeminal nerve’s afferent divisions.

Optic testing includes visual acuity with a Snellen chart or using a newspaper (headlines are about 20/400, subheadlines 20/200, column 20/60, and want ads 20/40). For visual field testing, divide the visual fields like a cartesian plot, and, checking each eye individually, briefly present one, two, or five fingers for their counting. Holding out your fingers too long and patients will throw a saccade in their direction, but just a flash of one, two, or five fingers briefly is all that is required for it to register in their vision for counting. Funduscopic assessment and pupillary reaction should be tested after vision screening so that the blinding light does not interfere with acuity.

Extraocular movements are innervated by the oculomotor, trochlear, and abducens nerves. A sweep of superior, inferior, and inward eye movements as well as presence of ptosis would identify oculomotor nerve problems and, if partial, could indicate partial nerve, individual nerve, or primary muscular problems. Failure of lateral eye movements abducting an eye from primary gaze would signify an abducens nerve or muscle injury. A head tilt to correct one’s vision would indicate trochlear nerve weakness. When assessing a patient with double vision, it is important to test the movements with both eyes open and with one eye closed at a time. Double vision in one eye only is an eye or lens problem, not a neuro-ophtho problem. Double vision that resolves when one eye is covered suggests a neuro-ophtho problem.

Trigeminal nerve function is assessed gently by applying a bitter cold instrument (or pinprick, or the sharp end of a broken Q-tip) and by light touch of facial sensation on the forehead (V ₁ ), the maxillary prominence (V ₂ ), and between the lower corner of the mouth and the chin (V ₃ ). The trigeminal nerve controls the muscles of mastication, so asking the patient to bite or clamp down and feeling these muscles can give a sense of atrophy or weakness.

The muscles of facial expression, tearing and salivation, sensation of external ear canal, and taste on the anterior two-thirds of the tongue are controlled by the facial nerve. A screening assessment includes how the patient can wrinkle their brow, smile, and puff out their cheeks, and slowed or reduced activation compared to the fuller and faster side would indicate a weakness.

Hearing is facilitated by the vestibulocochlear nerve. The cochlear apparatus’s appreciation of a finger rub agitating the air near the ear assesses high-frequency hearing, whereas a finger tap near the ear assesses low-frequency hearing. An asymmetric impairment can then be defined with a low-frequency tuning fork under a modified Rinne test. Tell the patient they are going to listen to the tone of the tuning fork in one of two positions, off the mastoid process behind the ear or next to the ear itself. Those who hear the tone clearer through the mastoid have better bone than air conduction and this represents a conductive hearing loss; those who hear the tone better in the air have better air conduction and therefore have a sensorineural hearing loss. Further definition of whether the hearing loss is cochlear or retrocochlear (i.e., of the nerve as from schwannoma or cortical deafness from stroke or tumor) can be discerned by whispering 5 or 10 words in each ear clearly. Unless the cochlear-based sensorineural loss is quite severe, a close whisper will still be intelligible, but if the damage is retrocochlear in the nerve or cortex, then fewer words will be intelligible on the affected ear than the unaffected ear. The vestibular system is embarrassed when balance and torsional, latent, non–direction changing nystagmus is present.

Swallowing and the gag reflex are accomplished by the glossopharyngeal and vagus nerves, so observation of palatal asymmetry can indicate weakness. Asking the patient to stick their tongue out to look for atrophy or deviation can indicate ipsilateral hypoglossal weakness. If the patient knows they could previously roll their tongue lengthwise, asymmetry in the roll-up can indicate both side and severity of impairment. In cases of functional tongue weakness, recovery of weakness by tongue curling can be the essential and only positive feature to make the diagnosis.

Assessing shoulder shrug and rotation of the head for asymmetric weakness will expose a defect in spinal accessory nerves.

Movement and Power

Inspection of the muscle should begin with a simple differentiation of increased or decreased bulk. If there is reduced bulk, are fasciculations seen? If there is increased bulk, is it hard or spongy? In testing motor activity of a muscle, ensure good support and rest of all joints except the one about which the muscle attends.

Next, consider movements. Are they purposeful and voluntary or are there additional movements including tremor, dystonia, chorea, and dyskinesia, or are there reduced movements such as bradykinesia or breakdown in the smooth nature of the movements? Having the patient tap their fingers, or if arthritis is their excuse, rotate their hand at the wrist as if screwing in a lightbulb can betray these slower, ratcheting movements. These are considerations both while the person is distracted and when they are focusing on their movements. At times, an examiner may ask a patient to rest their hands in their lap, relax as best they can, and then tell the months of the year backward or count backward by fours. The goal is not their accuracy but that in distraction, sometimes hyperkinetic movements emerge. Examination of finer impairments in the fingers and hands can sometimes be exposed by having the patient hold a pen at the terminus and draw Archimedes spirals and a large “X’s” across the page with both hands to look for oscillations or micrographia.

In passive range of motion about a joint, consider whether a muscle’s tone is either increased or decreased. If tone is increased, define its character as spastic (velocity dependent), paratonic (force dependent), or lead pipe rigid (constant, independent of force or velocity).

Assessment and grading of power are better described as full to confrontation, partial resistance, maintains posture against gravity, facilitated with gravity removed, activation of muscle without movement across the joint, or no activity whatsoever. Numbers are really only helpful if kept to the strict Medical Research Council grading scale and are best when tested by the same clinician over time rather than with intra-clinician scoring. The limb should be positioned by the clinician so that the muscle’s action is isolated across one joint in the face of gravity, and the remainder of the limb otherwise supported. Take, for example, a wrist-drop. It could be a stroke at the hand-knob area of the frontal lobe contralateral to the injured hand, which would result in all the actions of the hands to be weakened. It could also be a radial nerve palsy at the spiral groove, which should spare muscles controlled by the median and ulnar nerves. If the hand’s strength is assessed flailing about and flopped over the wrist, the leverage exerted by even well-working tendons controlled by median and ulnar nerves is limited, so all the fingers appear weak. But once the hand is aligned on a plane, strength of the flexor pollicis longus and the abductor digiti minimi seem to reappear, but wrist extension and finger extension (properties of the radial nerve) remain weakened. The patient is prescribed a tincture of time for a stunned nerve instead of tissue plasminogen activator for a presumed stroke, and all because of an examiner’s punctilious technique in assessing power.

Once the patient is positioned for testing, the clinician then tells the patient to activate the muscle before providing you provide resistance. Avoid saying “don’t let me pull you” which can be confusing. Rather instruct to “push,” “pull,” “lift,” and “keep it strong” are straightforward. This gives you a chance to see and feel: no activation (0), a flicker (1), activation in the plane of rest (2), sustained activation against gravity (3), some engagement against the clinician’s resistance (4), and full strength (5). Strength is graded by the maximum achieved, not what was maintained. A patient that almost beats you in an arm wrestling match had a 5, even if in the end you overpowered him.

Sensation

The sensory examination should consider both primary modalities, including pain and temperature, light touch, vibration, joint position, and, if these are sufficiently intact, integrative higher cortical sensory modalities such as texture, shape, forms, weights, stereognosis, and graphesthesia.

For the primary modalities, it is useful to have access to diagrams of the dermatomes (the arrangement of sensation of a given nerve root) as well as a chart of the individual territories of the peripheral nerve so you have something to compare your findings to. If the patient makes a specific complaint of sensory changes, ask them with one finger to trace as best they can the areas involved and you take note of it (sometimes even asking them to use a marker to outline it). Next, the examiner should start in the center of the involved area and work outward to inward with the stimulus (temperature, pinprick, vibration, proprioception, light touch) to see if they all track in a similar territory or if there is splitting or irregularities, as these have localizing value (presence of temperature and pinprick but absence of vibration or proprioception, e.g., indicate a large-fiber neuropathy, and even a dorsal column spinal cord disorder). The distribution of the impairment across a territory on the skin is important, but so is the dispersal of the degree of its impairment. Something equally impaired distally and proximally without a gradient may be more central, whereas something which is worse distally and improves proximally suggests a peripheral process.

The “degree” of impairment is tested differently for different stimuli. Sharp does not require you to carry pins. Snap off a Q-tip or a tongue depressor and hold it between your fingers loose enough that with a quick light jab into your hand, the sharp end makes contact with the palm but yields to it, rebounding gently backward through your fingers rather than pressing forward into your skin. A sense of sharp with minimal depression on the surface is what you are looking for. Some examiners assess a patient’s response to cold, but one should ensure that the cool metal of a tuning fork is sufficient; if not it can be run under cold water. For vibration a low-frequency tuning fork should be placed firmly on a bony protuberance to resonate while the examiner waits until the vibration extinguishes. In the case of testing vibration on a finger or toe the examiner places their finger on the undersurface being tested. In this way if they still feel the vibration coursing through flesh and bone to the opposite side while the patient no longer does, the examiner can be sure confrontationally there is an impairment. Position sense (proprioception) is an alternate to vibration. The examiner passively moves a finger or toe across a joint and marks the degree of excursion from a neutral position that the patient first appreciates when it moved and in what direction .

Extinction of stimuli is an important parietal sign. It can be specific and affect personal space (does not dress/wash/shave one side of face/body, or when touching the patient’s left and right hands simultaneously, they appreciate only one hand being touched). It can affect peripersonal space (in line bisection the division is displaced off the meridian, or in cancellation/word-finding tests targets are missed on one side of the visual field, or when presented with two stimuli, they ignore one side’s stimulus). It can also affect extrapersonal space (does not appreciate a side of the room and/or sounds/sights/activity on a particular side of the room). A visually impaired patient moves their head to get the rest of their world into the remaining visual field. A neglectful patient sees no reason to; their world is a fragment viewed as complete.

These tests are usually performed on the appendages where sensitivity will be greatest, such as the fingertips or palm, but axial proprioceptive health should be examined by having the patient perform a Romberg test. The patient stands with feet together heel to heel and toe to toe with arms outstretched before them and then closes their eyes. If they broaden their stance or move to support themselves with a wall or offered arm, the test is positive.

Coordination

Appendicular coordination of movements can be assessed by finger to nose, heel to shin, or rapid alternating movements for signs of dysmetria, inconsistent in amplitude, and degree of impaired estimation of the target. Having the patient’s index finger follow yours around but not make contact, as if your mirrored twin, can be very sensitive and reduces the excuse of arthritis at the shoulder inhibiting accuracy. Indeed, an arm cast to the hand, so long as the metacarpophalangeals are exposed, can mirror minute movements accurately. Incidentally, asterixis can be assessed with just a raised finger, too, not only with a hyperextended hand at the wrist. Some examiners are not able to see subtle irregular movements, but they can hear them. Have the patient tap a rhythm out with their finger on the table, an overturned cup, or the pendant of their wearable telemetry and listen for the wobble in the rhythm. Alternatively, making a small circle on a piece of paper and asking the patient to peck with their pen as accurately as they can in the circle with both hands will provide a measurable account of the accuracy and precision lost to dysmetrias. Axial coordination is judged from dysmetria of the trunk during changes in the patient’s position from lying to sitting, sitting to standing, and maintaining

Gait and Stance

The patient’s spontaneous gait should be examined for signs of broadening stance (a general sign of imbalance), reduced clearance (dropped foot), a reduction in stride length (shuffling), a scissoring gait, the number of steps to complete a turn, and an inefficient or uneconomical gait. The examiner can influence the gait to put stress on the nervous system by asking the patient to walk backward, run, or walk heel to toe.

Reflexes

A reflex is a short arc between afferent sensory and efferent motor components. Testing reflexes can quickly survey the general health of the nervous system because a careful balance must be maintained for normal reflexes. We describe the reflexes here, but generally, they should be incorporated into your examination when you are evaluating the relevant portion of the neuroaxis (those pertaining to the cortex when evaluating cortical function, cranial nerve reflexes when evaluating the cranial nerves, etc.). But for convenience, we present them here.

Cortical (or “frontal”) release signs, the glabellar tap for parkinsonism, or the suck, snout, and grasp represent higher cortical inhibitions that govern certain behavioral reflexes. More localizable cortical reflexes are the antigravity reflexes of decortication posturing (flexed arms and legs extended) and decerebration posturing (extended and pronated arms and legs extended).

Pupillary constriction to direct and consensual light as well as near are important for evaluating CN II-III connectivity. The corneal reflex tests CN V and VII, the jaw jerk tests CN V and VII, and the gag reflex tests CN X actions.

There are superficial, nociceptive reflexes whose irritation results in motor response (e.g., abdominal, cremasteric, bulbocavernosus, anal wink, plantar). And there are the deeper proprioceptive reflexes elicited with a hammer on tendons. Reduced proprioceptive reflexes signify either weakened sensory inputs (from neuropathy) or weakened motor outputs (lower motor neuron injuries in the peripheral nervous system). In contrast, increased reflexes bespeak loss of governing inhibitor mechanisms and therefore signal aberrant upper motor neuron injuries of the central nervous system. To test a reflex, support the limb isolating the joint across which the muscle and tendon are to be tested. The muscle should be slightly loaded by this position so that the tendon is a little stretched. Then the tendon is lightly struck. If clonus is provoked, this is a grade of 4. If activation of the muscle is accompanied by an unrelated muscle across an additional joint, that is a grade of 3. If only the muscle in question is activated, that is a grade of 2. If the muscle does not activate unless a distracting maneuver is performed (e.g., clenched jaw, patient hooks fingers and pulls apart), that is a grade of 1. If despite such maneuvers there is no activation, that is a grade of 0.

The Functional Examination

Conversion disorders, today referred to as “functional neurological disorders,” are disturbances in which the complaint is superficially mimicking a neurological symptom (weakness, ataxia, aphasia), and yet the fundamental integrity of the nervous system’s anatomic structure is preserved. Hence the word “functional,” indicating somehow an uncoupling between structural and functional impairments. This can sometimes be called a “hardware” versus “software” dichotomy in which functional syndromes are bugs in the “software” of planning and feedback in experience or execution of action. The core element on examination for functional phenomena is to demonstrate distractible recovery and/or entrainable distortions to the presentation. A person with an essential tremor in their left hand when outstretched will maintain the same frequency and amplitude regardless of if they start to waffle and waver their right hand fast or slow. However, in a functional disorder the speed or amplitude in the nonaffected hand will influence the affected hand, thus entraining it. The “astasia abasia” of functional gaits can often be distracted into normal function when the patient is asked to walk backward or slide across the floor as if ice skating, or waltz with the interviewer, or hop. A functionally blind person can be asked to read random words on cards, but inserting a card with profanity can often elicit a smile or blush or dilation of the pupils to indicate it was read and registered subconsciously. The Hoover test is a familiar test that has its application for functional neurological presentations. Functional examinations often require the clinician to consider the patient’s problem and devise bespoke maneuvers to distract or entrain in such a way that it can definitely be shown that components of the nervous system seemingly lesioned are in fact working perfectly. In other words, the examiner demonstrates the person has preserved function that would be incompatible with the symptom in question if those structures responsible for that function were actually lesioned. Functional examinations can pose a challenge to the uninterested clinician, but their successful application yields a diagnosis and provides means of explaining afterward to patient how the test shows whatever they fear, like multiple sclerosis or stroke, cannot be. That physical reassurance can often be curative.