Koji Takabayashi’s research while affiliated with Tokyo Metropolitan Institute of Gerontology and other places

Overestimation or underestimation of functional capacity in community-dwelling older people with cognitive impairment was evaluated between the responses of subjects and family members (proxies) by cognitive function level. Out of all the residents aged 65 years and over living in Yoita town, Niigata Prefecture in 2000 (n = 1,673), 1,544 voluntarily participated in the interview survey held at community halls or at home (92.3% response). They underwent the Mini-Mental State Examination (MMSE) for assessment of cognitive function and answered questionnaires comprising socio-demographic, psychological, physical and medical, and social activity items (2000/11). According to the age of the subject and MMSE score, we defined cognitive decline (MMSE scores < 1 SD below age-specific means, n = 371). 158 pairs among 371 subjects with cognitive decline and their proxies participated in a follow-up survey (2001/11). The subjects themselves underwent MMSE again. 136 subject-proxy pairs reported any complaints of memory-related problem and evaluated higher-level functional capacity (TMIG-IC, Tokyo Metropolitan Institute of Gerontology Index of Competence). We established criteria at follow-up survey as follows: control (n = 29), MMSE scores > 1 SD below age-specific means and CDR (Clinical Dementia Rating) = 0: mild cognitive decline (MCD) (n = 54), 21 < or = MMSE scores < 1 SD below age-specific means or CDR = 0.5); and severe cognitive decline (SCD) (n = 53), MMSE scores 20 < or = CDR > 0.5. SCD subjects significantly overestimated total and Instrumental Self-Maintenance scores in TMIG-IC more than control or SCD subjects. Multiple logistic regression analyses indicated that complaints of memory by the proxy, response by spouse, and higher levels of education were extracted as significantly independent variables affecting overestimation for functional capacity. On the other hand, aging affected underestimation.

To establish a community health care system for screening community-dwelling older people with mild cognitive decline (MCD) and early diagnosis by a medical specialist. Out of all the elderly residents aged 65 years and over living in Yoita town in 2000 (n = 1673), 1544 participated in the interview survey held at community halls or at home (92.3% response). They underwent a Mini-Mental State Examination (MMSE) for assessment of cognitive function and answered questionnaires covering socio-demographic, psychological, physical and medical, and social activity items (2000/11). We defined cognitive decline as an MMSE < or = 1 SD below the age-specific mean (n = 371). Out of a total eligible population of 332, 158 pairs of subjects and their proxies participated in a follow-up survey (2001/11). The subjects themselves underwent MMSE again, and were asked for complaints of memory-related problems. Proxies answered about functional capacity and memory-related problems of subjects, for which we assessed the level of dementia with the Clinical Dementia Rating (CDR). We established criteria for encouragement to undergo detailed examination by a medical specialist as follows. 1) MMSE scores < or = 1 SD below age-specific means at both baseline and follow-up surveys, or 2) CDR > or = 0.5, and 3) not due to mental retardation. Non-participants had significant higher MMSE scores but were younger in the follow-up survey. Out of 96 subjects eligible for the detailed examination, 47 participants showed a tendency for older age with lower MMSE scores or younger age with higher MMSE scores than the average in the follow-up survey. The detailed examinations confirmed dementia of Alzheimer's type in 22 and vascular dementia in 13 on DSM-IV or magnetic resonance imaging. During our screening, 8 community care saloons were opened and the number of facilities for older people with cognitive decline is increasing. To establish a community health care system to screen and cope with community-dwelling older people with MCD in earlier stages, increased awareness of residents with slight MCD is especially important. Our attempt also suggested the importance of educational lectures, methods for testing cognitive function, and dementia care activity.

To assess individual variation in the functional capacity of community-dwelling older people who are almost independent in daily living, using the Tokyo Metropolitan Institute of Gerontology Index of Competence (TMIG-Index of Competence). Out of 74 elderly outpatients showing a total score of TMIG-Index of Competence above 10 points at baseline, 61 who remained stable during subsequent two months in terms of medical and social aspects were assessed for their functional capacity with the test-retest method using the TMIG-Index of Competence. We assessed individual variation between the tests of one month interval with correspondence rate. The ranges for score differences within which correspondence rates of 95% and over applied were as follows: within 1 point for the total score of the Index (95.1%), 0 point in the Instrumental Self-Maintenance subscale (IADL) (95.1%), and 1 point in the Intellectual Activity subscale (Intellectual Activity) (98.4%) and the Social Role subscale (Social Role) (98.3%). The variation of 1 point for the total score of the Index, and subscales of Intellectual Activity and Social Role was regarded as a possible measurement error. In other words, variations of 2 points and over for total score, subscales of Intellectual Activity and Social Role, and variations of 1 point and over for IADL should not be ignored in screening of functional capacity among older people.

Background: Cognitive impairment is a major health issue, but epidemiological data on mild cognitive decline have been almost absent in Japan. Methods: Of all residents aged 65 years and over living in Yoita town, Niigata Prefecture, Japan in the year 2000 (n = 1673), 1544 participated in the interview survey held at community halls or at home (92.3% response). They underwent the Mini-Mental State Examination (MMSE) for assessment of cognitive function and answered questionnaires comprising socio-demographic, psychological, physical and medical, and social activity items. Higher-level functional capacities were evaluated with the Tokyo Metropolitan Index of Competence (TMIG-Index of Competence). According to subject’s age and MMSE score, all subjects were classified into 3 groups: control (MMSE > 1 SD below age-specific means), mild cognitive decline (MMSE ≥ 21 and ≤ 1 SD below age-specific means), and severe cognitive decline (MMSE ≤ 20), and compared various characteristics among these groups. Results: Mean MMSE score of the subjects showed a linear decline with advancing age. Among the participants, 232 (15.2%) were classified as mild cognitive decline. Compared with the controls, the subjects with mild cognitive decline reported poorer subjective health, more depressive moods, more history of stroke, more prevalence of basic activity of daily living (BADL) disability, and lower higher-level functional capacity, even after controlling for possible confounding factors. They also reported a low level of social activities: both participating in group activities and enjoying hobbies were less frequent. Their food intake pattern tended to be monotonous. Conclusions: Older persons with mild cognitive decline comprised a substantial proportion (15.2%) of the community-dwelling older population. In addition to lower cognitive function, they had lower levels of functional capacity and social activity.