Quite often, one encounters an elderly patient with only the instability and freezing components of the parkinsonian gait disorder, so-called lower-half parkinsonism. Usually, this is not a manifestation of idiopathic Parkinson disease although a few patients are responsive to l-dopa for a brief period. It may be an early manifestation of progressive supranuclear palsy, a basal ganglionic degeneration, normal pressure hydrocephalus, or widespread and frontal subcortical vascular damage as discussed further on, but it also occurs as a virtually isolated phenomenon that progresses independently of other movement disorders or of dementia. The basis is then probably a particular isolated frontal lobe degeneration (see further on). Within a few years, as pointed out by Factor and colleagues in their two papers, the patient is usually reduced to a chair-bound state.
Other very unusual gaits are sometimes observed in Parkinson disease and were particularly prominent in the postencephalitic form, which is now practically extinct. For example, such a patient may be unable to take a step forward or does so only after he takes a few hops or one or two steps backward (aptly mimicked by the Monty Python troupe in their skit, “Ministry of Silly Walks”). Or walking may be initiated by a series of short steps or a series of steps of increasing size. Occasionally such a patient may run better than he walks or walk backward better than forward. Often, walking so preoccupies the patient that talking simultaneously is impossible and requires that the individual must stop to answer a question.
Diseases characterized by involuntary movements and dystonic postures seriously affect gait. In fact, a disturbance of gait may be the initial and dominant manifestation of such diseases, and the testing of gait often brings out abnormalities of movement of the limbs and posture that are otherwise not conspicuous.
As the patient with congenital athetosis or Huntington chorea stands or walks, there is a continuous play of irregular movements affecting the face, neck, hands, and, in the advanced stages, the large proximal joints and trunk. The position of the arms and upper parts of the body varies with each step, at times giving the impression of a puppet. There are jerks of the head, grimacing, squirming and twisting movements of the trunk and limbs, and peculiar respiratory noises. One arm may be thrust aloft and the other held behind the body, with wrist and fingers undergoing alternate nonrhythmic flexion and extension, supination, and pronation. The head may incline in one direction or the other, the lips alternately retract and purse, and the tongue intermittently protrudes from the mouth. The legs advance slowly and awkwardly, the result of superimposed involuntary movements and postures. Sometimes the foot is plantarflexed at the ankle and the weight is carried on the toes; or the foot may be dorsiflexed or inverted. An involuntary movement may cause the leg to be suspended in the air momentarily, imparting a lilting or waltzing character to the gait, or it may twist the trunk so violently that the patient may fall.
In dystonia musculorum deformans and focal dystonias, the first symptom may be a limp caused by inversion or plantarflexion of the foot or a distortion of the pelvis as discussed in Chap. 4. One leg may be rigidly extended or one shoulder elevated, and the trunk may assume a position of exaggerated flexion, lordosis, or scoliosis. Because of the muscle spasms that deform the body in this manner, the patient may have to walk with knees flexed. The gait may seem normal as the first steps are taken, the abnormal postures asserting themselves as the patient continues to walk. Prominence of the buttocks owing to a lumbar lordosis, combined with flexion of one or both legs at the hip, gives rise to the so-called dromedary gait of Oppenheim. In the more advanced stages, walking becomes impossible owing to torsion of the trunk or the continuous flexion of the legs.