Reduplicative paramnesia in patients with focal brain damage.

Reduplicative paramnesia (RP) has drawn attention as a distinct behavioral syndrome caused by focal brain damage. To elucidate the pathogenesis of RP, we assessed its prevalence among patients with focal brain damage and followed those patients with typical RP. Seventy-seven patients with focal brain damage (47 with left hemispheric, 21 with right hemispheric, and 9 with bilateral damage) were assessed for the presence of RP using a questionnaire intended to elucidate this condition. Two patients showed typical RP for place, and four patients showed atypical RP (three for place and one for person); altogether, these six patients constituted 7.8% of the sample. In three patients, the lesions were situated in the right hemisphere; in two, the lesions were bilateral (right dominant); and in one, the lesions were in the left hemisphere, indicating the relative importance of right hemispheric damage and a possible contributory role of additional left hemispheric damage in RP. The case studies of patients with typical RP suggest the heterogeneity of the underlying cognitive factors in RP.

[Agraphia of the left hand--its characteristics and mechanism of development].

We observed 62 y.o. right-handed woman, whose truncus of corps callosum was damaged by infarction of left anterior cerebral artery, that was verified by coronal CT scan finding. She was apraxic and agraphic only with left hand. We examined the characteristics of her unilateral left agraphia from the point of quantitative and qualitative views. These analysis seemed to reveal three main characteristics of unilateral left agraphia of this patient. These were as follows; 1) productive, 2) neographic and 3) iterative. Another important feature of this patient was the mute state during her left-hand writing. Her left agraphia could not explained by apraxic factor, because her copying capacity was remarkably preserved in comparison with her dictation or written naming ability. Furthermore, this agraphia was not aphasic because her right-hand writing was almost intact. We agreed with Yamadori who insisted that this type of agraphia was neither apraxic nor aphasic, but the particular third agraphia which was named as "disconnection agraphia". We considered that the mute state during her left-hand writing might some kind of transient aphasia, which may reflect the functional disturbance of left hemisphere, and the reduced energy in the left hemisphere could increase the activity of right hemisphere. Partial interhemispheric disconnection might induce transient "linguistic anosognosia" in this patient. We believe that these transient hyperactivity and transient linguistic anosognosia could generate above mentioned characteristics of her left agraphia; productive, neographic and iterative.