Gait and Station

It is possible to learn more about neurologic status from watching a patient walk than from any other single procedure, and observation of gait should always be part of a neurologic examination. Abnormalities of gait are a common clinical problem with numerous causes, both neurologic and non-neurologic. A careful general evaluation is always necessary to exclude a non-neurologic cause.

Station is the way a patient stands, gait the way she walks. Standing and walking are active processes that depend upon a number of factors and reflex responses. The mechanisms are complex, especially in the human, whose biped gait and erect position over a narrow base require more efficient maintenance and control of equilibrium than is necessary in quadrupeds. Gait and station may be affected by abnormalities of proprioception, abnormalities of muscle power or tone, abnormalities of vestibular function, and by dysfunction of the basal ganglia, the cerebellum, or their connections.

Neurologic causes of an abnormal gait include conditions as varied as foot drop due to peroneal nerve palsy, myopathy, hydrocephalus, and cerebellar degeneration. The various gait abnormalities have different findings on physical examination in regard to the gait itself, such as a steppage pattern as opposed to a pelvic waddle. The differential diagnosis of the gait abnormality is also very dependent on the history and the other clinical signs present. Some of the more common abnormal gait patterns are summarized in Table 33.1.

EXAMINATION OF STATION

Station is the patient’s attitude, posture, or manner of standing. The healthy individual stands erect with her head up, chest out, and abdomen in. Abnormality of station may be an important indicator of neurologic disease. Station is tested by having the patient stand, feet closely together, noting any unsteadiness or swaying. More rigorous testing includes having the patient stand eyes open and eyes closed, on one foot at a time, on toes and heels, and tandem with one heel in front of the toes of the other foot. She may be given a gentle push to see whether she falls to one side, forward, or backward.

Patients with unsteadiness standing often attempt to compensate by placing the feet wide apart in order to stand on a broader and steadier base. In cerebellar disease, the patient usually stands on a broad base and there is swaying, to more or less an equal degree, with eyes open and closed. With a lesion of the vermis, the patient may sway backward, forward, or to either side. With a
lesion of one hemisphere she sways or falls toward the affected side. Unilateral vestibular disease also causes falling toward the affected side. In a unilateral, cerebellar hemispheric lesion, or in a unilateral vestibulopathy, the patient may tilt the head toward the involved side with the chin rotated toward the sound side, with the shoulder on the involved side somewhat higher than the other and slightly in front of it. If the patient is given a light push—first toward one side and then toward the other—with a cerebellar hemispheric lesion she will lose balance more easily when pushed toward the involved side. If asked to stand on one foot at a time, the patient with a cerebellar hemispheric lesion may be unable to maintain equilibrium standing on the ipsilateral foot, but may stand without difficulty on the contralateral foot.

TABLE 33.1 Some of the More Common Neurologic Abnormalities of Gait

Gait Disorder	Gait Characteristics	Usual Associated Findings
Spastic	Stiff legged, scissoring (wooden soldier)	Hyperreflexia, extensor plantar responses
Cerebellar ataxia	Wide based, reeling, careening (drunken sailor)	Heel-to-shin ataxia, other cerebellar signs
Sensory ataxia	Wide based, steppage	Positive Romberg, impaired joint position sense
Hemiparetic	Involved leg spastic, circumduction, often with foot drop	Weakness, hyperreflexia, extensor plantar response
Parkinsonian	Small steps, flexed posture, shuffling, festination	Tremor, rigidity, bradykinesia
Marche à petits pas	Small steps, slow shuffling	Dementia, frontal lobe signs
Foot drop (unilateral or bilateral)	High steppage pattern to clear the toes from the floor, double tap with toe strike before heel strike	Foot dorsiflexion weakness
Myopathic	Exaggerated “sexy” hip motion, waddling, lumbar hyperlordosis	Hip girdle weakness

The Romberg Sign

When proprioception is disturbed, the patient may be able to stand with eyes open, but sways or falls with eyes closed (Romberg or Brauch-Romberg sign). The Romberg sign is often misunderstood and misinterpreted. The essential finding is a difference between standing balance with eyes open and closed. In order to test this function, the patient must have a stable stance eyes open and then demonstrate a decrease in balance with eyes closed, when visual input is eliminated and the patient must rely on proprioception to maintain balance.

The Romberg test can be difficult to interpret. There is some variability, even among expert examiners, in how the Romberg test is performed and interpreted. Many patients sway slightly with eyes closed, and minimal amounts of sway, especially in elderly patients, are seldom significant. Minor, normal swaying may stop if the patient is simply asked to stand perfectly still. Most clinicians discount sway at the hips, and insist on seeing sway at the ankles before calling the test positive; some require the patient take a corrective step to the side; and some that the patient nearly fall. Some require the patient be barefoot. The “sharpened” or tandem Romberg is done by having the patient stand in tandem position with eyes open and closed; the limits of normality for this variation are conjectural.

The Romberg sign is used primarily as a test of proprioceptive, not cerebellar, function. The pioneering nineteenth-century clinicians thought it was particularly useful in separating tabes dorsalis from cerebellar disease. In fact, patients with cerebellar disease, particularly disorders of the vestibulocerebellum or spinocerebellum, may have some increase in instability with eyes closed, but not usually to the degree seen with impaired proprioception. A patient with an acute unilateral vestibulopathy may fall toward the side of the lesion when standing with eyes closed. Patients with cerebellar disease, or those with severe weakness, may not have a stable base eyes open. It may help to have the patient widen stance to the point where they are stable eyes open, then close the eyes, and check for any difference. Only a marked worsening of balance with eyes closed qualifies as a positive Romberg sign. A patient who cannot maintain balance feet together and eyes open does not have a positive Romberg.

Some histrionic patients will sway with eyes closed in the absence of any organic neurologic impairment (false Romberg sign). The swaying is usually from the hips and may be exaggerated. If the patient takes a step, the eyes may remain closed, which never happens with a bona fide Romberg. The instability can often be eliminated by diverting the patient’s attention. Effective distractors are to ask the patient to detect numbers the examiner writes with her finger on the forehead, wiggle the tongue, or to perform finger-to-nose testing. Having the shoes off and watching the toe movements may be very informative. The toes of the patient with histrionic sway are often extended; the patient with organic imbalance flexes the toes strongly and tries to grip the floor.

PHYSIOLOGY OF GAIT

The brainstem and spinal cord in lower forms contain “central pattern generators,” which are groups of interneurons that coordinate the activity in pools of motor neurons to produce patterned movements. Although the existence of such cell groups in humans is unproven, locomotion likely depends on activity in pattern generators. The pattern generators control the activity in lower motor neurons that execute the mechanics of walking. Higher centers in the subthalamus and midbrain, particularly the pedunculopontine nucleus, modulate the activity in the spinal cord pattern generators through the reticulospinal tracts.

EXAMINATION OF GAIT

The first step in analyzing gait is to check the width of the base. The wider the base the worse the balance, and spreading the feet farther apart is the first compensatory effort in most gait disorders. Under normal circumstances the medial malleoli pass within about 2 in of each other during the stride phase, a narrow and well-compensated gait. Any spread more than this may signal some problem with gait or balance.

The forefoot on each side should clear the ground to about the same degree; asymmetry of toe lift may be the earliest evidence of foot drop. A shortened stride length may be early evidence of bifrontal or extrapyramidal disease. Excessive movement of the hips may occur with any process causing proximal muscle weakness. Note the reciprocal arm swing; a decreased swing on one side is sometimes an early indicator of hemiparesis or hemi-parkinsonism. Watch the hands for tremor or chorea.

Tandem walking stresses the gait and balance mechanisms even further. Elderly patients may have difficulty with tandem gait because of obesity or deconditioning. In relatively young patients with a low likelihood of neurologic disease, a quick and effective substitute for the Romberg is simply to have the patient close her eyes while walking tandem. This is a difficult maneuver and has high value as a screening test. Having the patient walk briskly and then stop abruptly on command, or make quick turns, first in one direction and then in the other, may bring out ataxia and incoordination not noticeable on straightaway walking. The patient may be asked to walk sideways and overstep, or cross one foot over the other. Having the patient walk on heels and toes may bring out weakness of dorsiflexion or plantar flexion. An excellent screening test is to have the patient hop on either foot.
This simultaneously assesses lower-extremity strength, especially of the gastrosoleus, plus balance functions. Individuals who can hop adroitly on either foot are unlikely to have significant neurologic disease. Note whether the patient has any obvious orthopedic limitations, such as a varus deformity of the knee, genu recurvatum, pelvic tilt, or any other abnormalities.

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