A new classification of higher level gait disorders in patients with cerebral multi-infarct states

Background: cerebral multi-infarct states may lead to gait disorders in the absence of cognitive impairment. Where these gait disorders occur in the absence of neurological signs they have been termed gait apraxia or more recently higher-level gait disorders. In this paper we hypothesise three main types based on presumptive sites of anatomical damage: (a) Ignition Apraxia, where damage is predominantly in the supplementary motor area and its connections, with good responses to external clues; (b) Equilibrium Apraxia, where damage is predominantly in the pre-motor area in its connections, with poor responses to external cues and (c) Mixed Gait Apraxia. Subjects: the clinical features and measured gait parameters of 13 patients with cerebral multi-infarct states and higher-level gait disorder are described (7 with Ignition Apraxia and 6 with Equilibrium Apraxia) along with those of 6 healthy elderly control subjects. Methods: baseline gait characteristics were assessed on a walkway, which measured the following: step lengths, width of base and velocity. Results: measured baseline gait parameters support the above hypothesis. Conclusions: it is suggested, though not proven, that patients with Ignition Apraxia could have problems with internal cueing due to lesions in the supplementary motor area or its connections whereas those with Equilibrium Apraxia could have dysfunction predominantly in the pre-motor area and its connections.