title: Simultaneously cooperative, but serially antagonistic: a neuropsychological study of diagonistic dyspraxia in a case of Marchiafava-Bignami disease.
abstract: We describe a patient with Marchiafava-Bignami disease who showed, in addition to signs of callosal interruption, a peculiar form of diagonistic dyspraxia. Unlike the typical diagonistic dyspraxia, both of the patient's hands could simultaneously cooperate in a sequence of bimanual actions. More specifically, his right hand could start a commanded action with the cooperation of his left hand. However, once the action was completed, his left hand started an antagonistic action, undoing the result, with the cooperation of his right hand. Once this countermanding action was completed, the original action started again. These antagonistic actions repeated themselves alternately unless he was restrained. The patient's diagonistic dyspraxia was apparent in only some bimanual actions, and he showed no diagonistic dyspraxia when performing voluntary actions; the antagonistic actions occurred in response to oral commands or by imitation. Magnetic resonance imaging showed symmetrical demyelination with partial necrosis in the genu, body, and anterior splenium of the corpus callosum. We speculate that the bimanual coordination is possible because part of the corpus callosum is intact, whereas the antagonistic actions may be caused by conflict between the two hemispheres due to interhemispheric disinhibition elicited by the demyelinated part of the corpus callosum.
authors.affiliation: Department of Behavioral Neurology and Cognitive Neuroscience, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Kazumi
authors.initials: K
authors.lastname: Hirayama
authors.forename: Kaori
authors.initials: K
authors.lastname: Tachibana
authors.forename: Nobuhito
authors.initials: N
authors.lastname: Abe
authors.forename: Hideaki
authors.initials: H
authors.lastname: Manabe
authors.forename: Takahisa
authors.initials: T
authors.lastname: Fuse
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Tsukamoto
mesh_terms: D001072:Apraxias / Q000150:complications* / Q000473:pathology; D001364:Awareness; D003220:Conflict, Psychological; D003337:Corpus Callosum / Q000473:pathology*; D003711:Demyelinating Diseases / Q000150:complications / Q000473:pathology; D007839:Functional Laterality; D006801:Humans; D033182:Intention; D008279:Magnetic Resonance Imaging; D008297:Male; D054319:Marchiafava-Bignami Disease / Q000150:complications / Q000473:pathology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance