脳血管障害患者における大脳半球損傷の左右差が聴覚的空間探索に与える影響

Laterality of cerebral hemisphere damage on auditory space search in stroke patients

要旨：脳血管障害を呈した患者は聴覚的空間探索能力の低下を疑うことがある．本研究の目的は脳血管障害患者の聴覚的空間探索能力の低下を，臨床的かつ自然な定位方法（頸部回旋）を用いた簡便な方法で検討し，大脳半球損傷の左右差が聴覚的空間探索にどのように影響を与えるか明らかにすることである．結果，健常群と比較し右半球損傷群は，左右前空間の音源に対する絶対的ズレが大きくなるが，左半球損傷群は右前空間のみ有意に大きくなる．また，左前空間では右半球損傷群は左半球損傷群より有意に絶対的ズレが大きい．よって大脳半球損傷の左右差による聴覚的空間探索能力低下は生じ，それは視覚同様，右頭頂葉の特異的関与があると示唆される．

　This study examined if search of auditory space has an effect on laterality in stroke patients suffering from cerebral unilateral damage. Twenty-one subjects (10 with right hemisphere damage and 11 with left hemisphere damage) rotated their necks toward a sound source while wearing an eye mask. We measured the distance between the sound source and the position pointed by the laser pointer on the brim of a cap. In the left space, the distance of position aberration in the right hemisphere damage group was significantly higher than in the normal group and in the left hemisphere damage group. In the right space, the left hemisphere damage group and the right hemisphere damage group had significantly greater distance of position aberration than the normal group. However, significant differences were not found between the left hemisphere damage group and the right hemisphere damage group.

　The results suggest that the right cerebral hemisphere specifically controls auditory space search.