高齢認知症患者におけるTrail Making Testの意義—軽度認知障害およびアルツハイマー病患者における検討

Significance of the Trail Making Test in elderly dementia patients: Studies in patients with mild cognitive impairment and Alzheimer's disease

　アルツハイマー病(AD)の特徴は健忘症状であるが，遂行機能障害も初期から認められる．そこで本研究では，高齢患者を対象として注意，遂行機能を反映するTrail Making Test(TMT)の意義について検討した．対象は，健常高齢群12名(82.3±5.1歳)，軽度認知障害(MCI)群12名(83.6±6.0歳)，AD群13名(82.8±6.1歳)である．方法はTMT日本版とMMSE，RCPMを実施し，各群間における検査結果の関連性を検討した．その結果，AD群のTMTの所要時間はMCI群とは差がなく，健常高齢群に対し有意な延長を認めた．B/A値の異常を示した割合は，AD群はMCI群，健常高齢群に比し有意に高かった．またMMSE，RCPMとの間に有意な相関を認めたが，成績が乖離する症例が存在した．以上より80歳を超える高齢者では，TMTのB/A値の指標がADの鑑別に有意義であり，遂行機能評価の一助になると考えられた．

　The characteristic symptom of Alzheimer's disease (AD) is amnesia, and there is research that executive dysfunction is also recognized from the very early stage of the disease process. The cognitive basis for executive function is complicated, and it seems to be greatly affected by aging. This study investigated the significance of the Trail Making Test (TMT), which reflects attention and executive function, in evaluating elderly patients. The subjects were 12 healthy elderly (HE) subjects, 12 subjects with mild cognitive impairment (MCI) , and 13 AD subjects. They were tested with TMT, Mini-Mental State Examination (MMSE), and Raven's Coloured Progressive Matrices (RCPM). The time required for TMT in the AD group was not different from that in the MCI group, but it was significantly longer than in the HE group. The ratio of abnormal B/A value was significantly higher in the AD group than in the MCI and HE groups. There were significant correlations between TMT and both MMSE and RCPM, but there were some subjects whose performance showed difference. Thus, the B/A value of TMT was found useful for the differentiation of AD and for evaluation of execution function in elderly patients.