感覚間相互作用の障害—パーキンソン病の新しい認知機能障害

Impairment of Cross-modality: A New Cognitive Dysfunction in Parkinson's Disease

対象の認知に関連する感覚は多くの場合単一ではなく複数にまたがっており，さらに感覚間で相互作用が起きている。一方で，パーキンソン病は嗅覚の障害を含めさまざまな認知機能障害を引き起こすことが示されているが，近年の研究において，パーキンソン病は視覚と嗅覚の感覚間相互作用にも障害をきたすことが報告された。本論では，感覚間相互作用の処理モデルとパーキンソン病の病態機序を踏まえながら，感覚間相互作用の障害を考察する。さらにその障害が病気の前兆指標として使用できる可能性を議論する。

Abstract

It is known that Parkinson's disease impairs various cognitive functions including olfaction. However, until recently it was unclear whether Parkinson's disease also affects cross-modal function of vision and olfaction. A recent study showed that odor evaluation in patients with Parkinson's disease is unaffected by visual information, while healthy controls overestimated smell, when sniffing odorless liquid while viewing pleasant or unpleasant visual cues. Dopamine transporter deficit in the striatum, in particular in the posterior putamen, correlated with the limited visual effect in patients with Parkinson's disease. The findings suggest that Parkinson's disease impairs cross-modal function of vision and olfaction due to posterior putamen deficit. This review discusses that the cross-modal dysfunction may serve as the basis of novel precursor assessment of Parkinson's disease.