Examination of Gait

A wide-based and unsteady gait, resembling the gait that can be seen from alcohol intoxication (a drunken gait), is called gait ataxia
and suggests cerebellar dysfunction. If the patient with an ataxic gait
does not have a propensity to fall toward one particular side, the
pathology is most likely in the midline (vermis) of the cerebellum. An
ataxic gait with consistent veering to one side suggests dysfunction of
the cerebellar hemisphere on the side that the patient is falling
toward (i.e., falling toward the left suggests left cerebellar
dysfunction).

A wide-based, unsteady (ataxic) gait can
also be seen due to severe sensory dysfunction in the feet and legs;
this is referred to as a sensory ataxia. Sensory ataxias predominantly occur when there is severe proprioceptive and vibratory sensation loss in the lower extremities.

A narrow-based shuffling gait, often with a stooped posture, is called a parkinsonian gait.
There may be diminished arm swing, difficulty making turns without
taking extra steps, and a resting tremor of the hands, depending on the
cause and severity of the underlying dysfunction. The finding of a
parkinsonian gait suggests Parkinson’s disease or other causes of
parkinsonism (see Chapter 46, Examination of the Patient with a Movement Disorder).

Some patients have difficulty initiating
steps after standing and may even complain that their feet are “glued”
to the floor; after initiating gait, their steps are short and
hesitant. This gait is called an apractic gait
because the patient has normal motor mechanisms, but the brain can’t
figure out how to perform the sequence of maneuvers to walk (apraxia
refers to the inability to perform a complex task despite normal motor
function). The finding of an apractic gait suggests frontal lobe
dysfunction, such as can occur from some chronic dementing illnesses,
hydrocephalus, or structural frontal lobe lesions.

Patients with a hemiparesis often have a
characteristic hemiparetic gait. The leg is stiff and extended with
circumduction at the hip; the affected arm is also usually held in a
flexed position. Hemiparetic gaits usually occur from unilateral
cerebral hemispheric lesions affecting the corticospinal tracts; these
usually cause upper motor neuron weakness predominantly affecting
extensors of the arm and flexors of the leg, with relative preservation
of strength in arm flexors and leg extensors.

Patients with bilateral upper motor
neuron weakness in the legs have bilaterally stiff legs, which, because
of the bilateral circumduction, have a scissoring quality as the
patient propels forward. This paraparetic gait disorder most commonly
occurs due to spinal cord dysfunction, but it can also be seen due to
bilateral cerebral hemisphere lesions.

Weakness in foot dorsiflexion (foot drop) causes a characteristic gait called a steppage gait;
the patient needs to lift the leg to avoid tripping on the involved
foot. This gait disorder, which can be unilateral or bilateral, can
occur due to any cause of foot dorsiflexion weakness, usually from
peripheral etiologies.

Another kind of gait abnormality that can occur due to nonneurologic causes is called an antalgic gait.
This refers to the gait that occurs due to pain, particularly pain in
an extremity, such as due to a hip problem or other musculoskeletal
process.

Difficulty walking forward on one or both heels suggests any cause of unilateral or bilateral foot dorsiflexion weakness.

Difficulty walking forward on the one or
both toes suggests any cause of unilateral or bilateral foot
plantar-flexion weakness. The finding of difficulty walking on the
plantar-flexed foot can be a particularly helpful sign when weakness of
plantar flexion is suspected but not seen on routine motor testing.
This is because power in plantar flexors is usually quite strong, and
it may take the patient’s inability to lift his or her own weight to
confirm weakness of plantar flexion.