要介護高齢者における睡眠・覚醒パターンと抑うつ度との関係 : 認知機能の低下した施設入所者を対象とした検討

認知機能の低下と抑うつは,ともに睡眠・覚醒パターンの変調の原因となる.しかし,認知機能が低下した高齢者の場合,抑うつや睡眠障害を自覚症状から把握することは困難である.本研究では,抑うつ度の他覚的評価法として近年開発されたCornell Scale for Depression in Dementia(CSDD)を用い,療養型病院に入所していた高齢者39名(年齢84.1±8.7歳,改訂長谷川式簡易知能評価スケール8.6±6.2点,Barthel Index 43.2±30.3点)の59日間の睡眠指標との関連を検討した.その結果として,総睡眠時間とCSDD得点との間に負の相関が認められた(r=-0.423, p=0.007).以上の結果より,認知機能の低下した高齢者でも一般集団の場合と同様,抑うつ度と睡眠障害とが関連し,また,認知機能の低下した高齢者の睡眠援助において抑うつ度を考慮するには,CSDDが有効である可能性が示唆された.

Cognitive dysfunction and depression are the most frequent psychiatric problems in the elderly population. However, it is difficult to assess the status of sleep disorder as well as depression among patients with cognitive dysfunction based on self-reported symptoms. The purpose of this study was to elucidate the relationship between sleep-wake patterns and depression among institute-dwelling elderly with cognitive dysfunction. The subjects were 39 elderly patients (age 84.1±8.7, HDS-R 8.6±6.2, Barthel Index 43.2±30.3) in a convalescent hospital. The Cornell Scale for Depression in Dementia (CSDD) was used to assess the status of depression of the elderly with cognitive dysfunction. Their 59-day sleep-wake patterns were monitored and recorded in the sleep log by nurses. The total sleep time (r=-0.423, p=0.007), the longest sleep episode at nighttime (r=-0.360, p=0.024), and intermittent awakening time at nighttime (r=0.329, p=0.041) were associated with depression. These results suggest a close relationship between depression and difficulty in sleep maintenance among the elderly with cognitive dysfunction as well as among the general population, and also that CSDD can be an efficient tool for the assessment of their depressive status. If this is true, it is important in making care plans for sleep disorders among elder patients with cognitive dysfunction to take into account the effects of depression on sleep-wake patterns.