Characteristics of mini-mental status examination in subtype of mild cognitive impairment: Using a decision tree analysis

Abstract

Background: Previous studies reported that apathy was shown in almost half of sub cortical vascular dementia (SVD) and Alzheimer’s disease (AD) patients, and in 15% of mild cognitive impairment (MCI) subjects. Our aim is to elucidate the differences of clinical features of apathy between very mild SVD (vm SVD) and very mild AD (vm AD) subjects. Methods: We obtained the agreement from 200 community dwellers, aged 75+ years living in Kurihara, Northern Japan. We utilized clinical examination, Clinical Dementia Rating (CDR), MRI, blood tests and neuropsychological tests. Of the 200 subjects, there were 57 with a CDR 0 (healthy), 111 with a CDR 0.5 (MCI), and 32 with a CDR 1+ (dementia). We divided CDR 0.5 subjects into 3 groups, 12 with vm SVD, 38 with vm AD and 61 with other types. All vm SVD subjects met the Erkinjuntti’s criteria; memory deficits, executive function disturbances, neurological signs present and lacunar infarctions in basal ganglia or white matter hyper intensity on MRI. All vm AD subjects met possible AD as per the NINCDS-ADRDA criteria. They showed no cerebral infarctions, no neurological signs, or no abnormalities of blood test causing dementia. The two CDR 0.5 groups diagnosed as vm SVD and vm AD were compared. There were no significant differences between the two groups for age, sex, educational level, MMSE (22.2 v.s. 22.8) and Geriatric Depression Scale (5.3 v.s. 3.8). To assess apathy, we used the Clinical Assessment for Spontaneity part 3 (CAS3) which estimated their apathy through a questionnaire given to each subject’s caregiver. We examined the differences between the two groups for CDR domains; Community Affairs (CA), Home and Hobbies (HH) and Personal Care (PC), and CAS3. Results: There were no significant differences between the vm SVD and vm AD groups in CA, HH and PC. However, the apathy score of the vm SVD group was severer than the vm AD group in CAS3 (3.8 v.s. 2.0, p1⁄40.02). Conclusions: The results suggest that vm SVD subjects have severer apathy compared with vm AD subjects. Earlier therapeutic intervention would be needed for vm SVD patients who showed apathy in a community.