[Isolated tonic ambulatory flexion of the foot (author's transl)].

A tonic ambulatory foot response developed one year after clamping of an aneurysm of the contralateral carotid artery in a young adult. No motor deficiency was noted during the postoperative period, but spasm of the carotid bifurcation branches were present on arteriograms. Clinical examination and deep reflexes tests excluded pyramidal lesions. Cortical somatesthetic evoked potential recordings confirmed the absence of sensory disturbances. CT scan suggested the presence of an infarct in the territory of the anterior choroidal artery. The present findings are compared with previous reports. The etiological data and CT scan results in the present case allow reconsideration of the physiopathology of tonic ambulatory foot response in the light of current knowledge of locomotor function in animals. The tonic flexion, an "extension" dystonia of the toes, electively provoked by walking, occurring one year after the neurological accident without any pyramidal signs, could arise from a coordination synkinesis due to lesions limited to the efferent extrapyramidal system.