A patient's gait can be difficult to describe in a reproducible fashion. Observe the patient walking toward you and away from you in an open area with plenty of room. Note stance (how far apart the feet are), posture, stability, how high the feet are raised off the floor, trajectory of leg swing and whether there is circumduction (an arced trajectory in the medial to lateral direction), leg stiffness and degree of knee bending, arm swing, tendency to fall or swerve in any particular direction, rate and speed, difficulty initiating or stopping gait, and any involuntary movements that are brought out by walking. Turns should also be observed closely. When following a patient over several visits, it may be useful to time him walking a fixed distance, and to count the number of steps he took and the number of steps he required to turn around. The patient's ability to rise from a chair with or without assistance should also be recorded.
To bring out abnormalities in gait and balance, ask the patient to do more difficult maneuvers. Test tandem gait by asking the patient to walk a straight line while touching the heel of one foot to the toe of the other with each step. Patients with truncal ataxia caused by damage to the cerebellar vermis or associated pathways will have particular difficulty with this task, since they tend to have a wide-based, unsteady gait, and become more unsteady when attempting to keep their feet close together. To bring out subtle gait abnormalities or asymmetries, it may be appropriate in some cases to ask the patient to walk on their heels, their toes, or the insides or outsides of their feet, to stand or hop on one leg, or to walk up stairs.
Gait apraxia is a perplexing (and somewhat controversial) abnormality in which the patient is able to carry out all of the movements required for gait normally when lying down, but is unable to walk in the standing position, thought to be associated with frontal disorders or normal pressure hydrocephalus (KCC 5.7).
As with tests of appendicular coordination, gait involves multiple sensory and motor systems. These include vision, proprioception, lower motor neurons, upper motor neurons, basal ganglia, the cerebellum, and higher-order motor planning systems in the association cortex. Once again, it is important to test each of these systems for normal function before concluding that a gait disturbance is caused by a cerebellar lesion. Localization and diagnosis of gait disorders is described further in Neuroanatomy Through Clinical Cases, Key Clinical Concept 6.5, and Table 6.6.