The Japanese journal of neuropsychology

Full Text of this Article
in Japanese PDF (260K)

ArticleTitle	A progress of apraxia study
Language	J
AuthorList	Naoyasu Motomura
Affiliation	Osaka Kyoiku University
Publication	Japanese Journal of Neuropsychology: 23 (3), 176-181, 2007
Received
Accepted
Abstract	Hugo Liepmann coined and defined apraxia as "the disturbance of learned purposeful movements in extremities." He classified this apraxia into three types; that is, limb kinetic apraxia, ideomotor apraxia and ideational apraxia. The confusion of the term of apraxia was pointed out. Then, the lesion, the functional imaging study and the hypotheses of underlying mechanism in apraxia was reviewed. In this review, ideomotor apraxia (IMA) was defined as the inability to pantomime meaningful gestures and ideational apraxia is the inability to manipulate objects. The lesion for IMA has been thought the left parietal lobe but not a few cases of IMA demonstrated other brain lesions. Rizzolatti et al. (1996) have found mirror neurons in F5 area in the frontal lobe, which is active in not only pantomiming gestures but also observing gestures. The mirror neurons are found in the Broca area in human beings and the Broca area may be related pantomiming gestures in human beings. Then the hypotheses of IMA was reviewed. There have been several hypotheses in IMA; dysfunction of symbolization, motor sequential disturbance, motor performance hypothesis and visuokinetic motor engram deficit hypothesis. It is still controversial issue which hypothesis is most reasonable. In ideational apraxia, the left parietal lobe and the bilateral parietal lobe has been reported (Liepmann, 1920, Poeck et al, 1984, Buxbaum et al. 2005). Imazu et al. (2007) postulated the inferior parietal lobe and the premotor frontal lobe is important in imaging and manipulating objects. The underlying mechanism of IA was reviewed. Some authors (De Renzi et al. 1988, Heilman 1985) have postulated that IA has semantic memory disturbances. However, it is still controversial issue and further studies must be done in near future.
Keywords	apraxia, ideomotor apraxia, ideational apraxia