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The cerebral activity preceding voluntary, self-paced ankle dorsiflexion movements while seated was compared with that before a stepping movement of the same foot while standing in four patients with isolated gait ignition failure. Results within the patients group were variable, but all exhibited some increase in the Bereitschaftspotential (BP) amplitude when stepping as compared with sitting, similar to that seen in normal subjects. This differs from previous results in patients with Parkinson's disease in which stepping was not accompanied by a normal increase in BP amplitude. This difference suggests that the mechanisms responsible for the start hesitation that is common to both Parkinson's disease and gait ignition failure may differ in the two conditions.

The syndrome of gait ignition failure is described in six patients in whom difficulty initiating walking was the major symptom. The gait had elements of parkinsonism with start and turn hesitation, shuffling, and freezing. Unlike parkinsonism, however, the gait was relatively normal once entrained; the posture was upright, and good arm swing, a normal stride length, and no festination were seen. Equilibrium was normal or near normal, and when seated or lying, rhythmic leg movements were generated normally. Facial expression, upper limb mobility, and whole body movements were well-preserved. This gait disorder differed from that seen in Parkinson's disease and the so-called "frontal" or "senile" disorders of gait and gait "apraxia." The causes of this gait syndrome are not clear but it may be due to frontal lobe vascular disease and/or focal degeneration of the frontal lobes.