軽度認知障害のスクリーニングの試み―Short Test of Mental Status日本語版（STMS-J）の有用性の検討

Screening of Mild Cognitive Impairment: Utility of the Japanese version of the Short Test of Mental Status

抄録

　認知症の治療研究の進展に伴い，認知症は発症前介入により進行を抑制できる可能性が出てきた。そこで，Petersenらによって提唱された認知症の前段階とされる軽度認知障害（MCI）のスクリーニングが重要となってくる。今回，彼らの作成したthe Short Test of Mental Statusの日本語版（STMS-J）を作成後，健常者53名および外来受診者160名に施行し，信頼性と妥当性，有用性について検討した。STMS-JのCronbachのα係数は0.87と高い内的整合性を示し，平行検査法や再検査法でも高い妥当性を示した。健常群とMCI群とのカットオフ値を28/29点とすると，感度・特異度ともに90％以上であった。したがって，STMS-JはMCIをスクリーニングするうえで有用であることが示唆された。

　Recent advances in the treatment of dementia suggest that the onset of dementia can be delayed using clinical measures. Petersen and his colleagues proposed that mild cognitive impairment (MCI) is a precursor of dementia, and currently, screening for MCI is considered to be extremly important. They also reported the usefulness of the Short Test of Mental Status (STMS) for screening of MCI. In this study, we developed the Japanese version of the STMS (STMS-J) and examined its reliability, validity and usefulness for screening of MCI by investigating 160 outpatients and 53 healthy controls. The internal consistency of STMS-J was sufficiently high (α＝0.87). The correlation coefficients were significantly high at the time of parallel inspection (rs＝0.75, p＜0.0001)and test-retest (rs＝0.39, p＝0.0006). This suggested that the STMS-J had high validity. The cut-off STMS-J scores for the control and MCI groups were set at 28 and 29, respectively, and the sensitivity and specificity at these cutoff values were over 90%. These findings strongly suggest the significant usefulness of the STMS-J for screening of MCI.