[Finger imitation difficulty, constructional disorder and classical apraxias].

: In the field of apraxia study, difficulty of finger pattern imitation was generally considered as parts of classical apraxias, i.e. ideomotor apraxia or limbkinetic apraxia. But there were some authors who considered it more related to constructional ability. To bring some clarity to this ambiguity, we studied 139 right-handed unilateral brain-damaged subjects: 70 with left hemisphere lesion and 69 with right hemisphere lesion: on various tasks. Three types of manual movements, i.e. object manipulation, representational movement to verbal command and finger imitation, and constructional task were tested. As for manual praxis, response patterns elicited were recorded according to Kaplan's original method, which was slightly modified. Responses were categorized as apractic only when either no movement was elicited, or when the response was amorphous or parapraxic. Of the 139 subjects tested, 35 subjects were classified as apractic in at least one category of the three types of manual praxis and 60 subjects were categorized as showing constructional disorder. Object manipulation disturbance was observed in 9 subjects. Finger imitation difficulty was seen in 16. Disturbance of representational movement to verbal command was confirmed in at least 17 subjects and was not determined in 7 more subjects who had comprehension difficulty to spoken language. With regard to relationship between apractic disorders and laterality of hemisphere lesions, object manipulation difficulty and deficient representational movement to verbal command was seen only in the left hemisphere lesions. On the contrary, finger imitation difficulty was found in either hemisphere lesion and has no tendency toward lateralization.(ABSTRACT TRUNCATED AT 250 WORDS)