半側無視における視覚的探索方略の検討

The search strategies in unilateral spatial neglect

要旨：半側無視における視覚的探索課題の応答分析は従来，正誤数，およびその分布について行われてきた．しかしながら，日常生活ではこれらの要因に加え，外界からの情報に基づいた注視点の合目的的な移動が重要となる．そこで，半側無視における視覚的探索の方略を明らかにするため，右脳損傷15名，左脳損傷16名，非脳損傷20名を対象とし，図形抹消課題における抹消方略を検討した．左半側無視では右始まり・縦型の固定された抹消方略を示し，半側無視を呈さない群では多様な抹消方略を示した．半側無視において固定的なパターンが生じた原因として，注意の右半球優位性，注意解放の障害，視覚的情報処理促通の障害の3点が考えられた．

　The search strategies in patients with unilateral spatial neglect have been investigated with the distribution of hits and error. But, the movement of attention and visual scanning that are based on a condition to accomplish the purpose are significant in activities of daily living. Therefore, in order to clarify search patterns in patients with unilateral spatial neglect, we investigated the search strategies of cancellations performed by 15 patients with right-sided cerebro-vascular lesion, 16 patients with left-sided, 20 with nocerebro-vascular lesions. The cancellation of patients with left unilateral spatial neglect appeared on the right edge of the form, and moved in a vertical direction. The strategies of others were various. We thought that stereotypic search patterns of unilateral spatial neglect arose from the predominance of attention on the right hemisphere, difficulties in disengaging of attention from ipsilesional, activating disposal of visual information.