右外側型脳内出血に伴った nonaphasic misnaming の１例

Abstract

A typical case of nonaphasic misnaming (Weinstein and Kahn) was reported. The patient, 65 year-old right-handed male, suffered from right putaminal hemorrhage exibiting left hemiplegia. A month after the stroke, a difficulty in object naming was developed. Paticularly, he showed a selective difficulty in naming things related to his illness such as doctor, nurse and medical instruments. There were marked neologims and perseverations. His spontaneous speech was fluent,and articulation, comprehension, repetition, reading and writing were normal. At the same time, he showed marked denial of his illness and marked cofabulation as seen in Korsakoff's syndrome, though he was fully alert and not amnesic. There was neither unilateral spatial neglect nor hemiasomatognosia. The lesion confirmed by CT scan was in the right basal ganglia and in the subcortical white matter extending inferiorly into the right mesial temporal lobe. EEG demonstrated focal slow wave focus in the posterior part of the right hemisphere. It is speculated that nonaphasic misnaming has a common defect with the phenomena such as denial of illness and confabulatory responses. One possible explanation is a disconnection hypothesis proposed by N. Geschwind (1965), in this paticular case, disconnection of the left hemisphere speech area from the right-sided limbic region (the right mesial temporal lobe) and / or from the right parietal lobe. Thus the disconnnected speech zone might be responsible in responding with misnaming, cofabulation and denial of illness.