アルツハイマー病の日常生活機能障害（functional impairment）に影響する要因—記憶障害の指標で重症度を統制した検討

Factors affecting functional impairment in Alzheimer's Disease : A study controlling for disease severity with an index of memory impairment

抄録

　記憶障害が軽度の患者に対象を限定することで重症度を統制し，アルツハイマー病（AD）の日常生活機能障害に影響を与える要因を検討した。Clinical Dementia Rating（CDR）の記憶の評定が軽度かつ全般重症度評定がごく軽度〜中等度の間である183症例を対象として，CDRの全般重症度評定（0.5 or 1 or 2）を従属変数，患者属性，認知機能障害，神経精神症状の指標を独立変数として順位相関係数を求めた。Mini-Mental State Examination（MMSE）得点，Alzheimer's Disease Assessment Scale（ADAS）の単語再生，再認課題の成績，Frontal Assessment Battery（FAB）得点およびNeuropsychiatric Inventory with Caregiver Distress Scale（NPI-D）の無為・無関心の評定と全般重症度評定との間に，効果量が中等度以上の相関を認めた。軽度ADの日常生活機能障害の背景要因として，記憶障害，遂行機能障害，自発性低下の3つが重要であることが示された。

Objective: To examine the factors that affect the functional impairment in Alzheimer's disease（AD）after controlling for disease severity by limiting eligibility to patients with mild impairment of everyday memory. Subjects: 183 AD patients with a Clinical Dementia Rating（CDR）of 1（mild）for the memory sub-item and a CDR overall severity rating between 0.5（very mild）and 2（moderate）. Methods: We obtained rank correlation coefficients with the overall severity rating of CDR（0.5 or 1 or 2）as the dependent variable and with the indices of patient attribute, cognitive impairment, and neuropsychiatric symptom as independent variables. Results: The effect sizes of the correlation coefficients were moderate or more between the overall severity rating and following indices; the MMSE scores, the Alzheimer's Disease Assessment Scale（ADAS）Word Recall and Recognition scores, the Frontal Assessment Battery（FAB）scores, and ratings on the Apathy/Indifference subscale in the Neuropsychiatric Inventory with Caregiver Distress Scale（NPI-D）. Conclusion: Memory impairment, executive dysfunction, and apathy were important factors for the functional impairment in AD patients with mild impairment of everyday memory.