Yasuyoshi Sekita

Prevalence and Cognitive Performances of Clinical Dementia Rating 0.5 and Mild Cognitive Impairment in Japan. The Tajiri Project

The borderline zone condition between normal aging and dementia is a major issue of concern. Although the term mild cognitive impairment (MCI) is popular, its prevalence and neuropsychological features have not been fully investigated. We investigated the prevalence and neuropsychological features for Clinical Dementia Rating (CDR) 0.5 and MCI. For normal aging, the effects of age and educational level on cognitive performance were examined. We examined 1501 older residents (46.8%) in Tajiri 65 years of age and older. They performed the Cognitive Abilities Screening Instrument (CASI). Depressive scores and subjective memory complaints were also evaluated. There was no age effect but an educational effect on cognitive performance in healthy adults. We found the overall prevalence of CDR 0.5 to be 30.2%, whereas that of MCI was only 4.9%. All CASI domains were deteriorated except for long-term memory and visual construction in the CDR 0.5 participants compared with healthy adults, suggesting that CDR 0.5 is similar to very mild Alzheimer disease. Memory complaints’ data suggested that it would be better to exclude memory complaints from the MCI criteria. We considered that the concept of CDR 0.5 would be more applicable to community residents rather than that of the MCI.

Cognitive function and frontal lobe atrophy in normal elderly adults: Implications for dementia not as aging‐related disorders and the reserve hypothesis

Abstract We examined the relations between cognitive function and age and education in the normal elderly population. As per the community‐based stroke, dementia, and bed confinement pre‐vention in the town of Tajiri, neuropsychological assessments, including the Cognitive Ability Screening Instrument (CASI), were performed for 99 randomly selected normal elderly subjects. We assessed the frontal function (working memory, word fluency, Trail‐Making Tests, CASI subitems of list‐generating fluency, attention, and concentration/mental manipulation), language function (proverbs, CASI subitem language), non‐language function (the digit symbol test of the Wechsler Adult Intelligence Scale‐Revised (WAIS‐R), CASI subitem visual construction), memory (Alzheimers Disease Assessment Scale recall/recognition, story recall, CASI subitems short and long‐term memory, the Rey‐Osterrieth Complex Figure Test), and the global function (CASI subitems orientation and abstraction and judgment). We found that the only test affected by age was the digit symbol test of the WAIS‐R. The effects of education were distributed among various tests. There was a significant correlation between age and the frontal lobe atrophy in the lower educated group. The present findings suggest that cognitive function is spared by the aging process itself and dementia should be considered as age‐related, not aging‐related disorders, and that education might have a protective effect on cognitive change, supporting the reserve hypothesis.

Five-year retrospective changes in hippocampal atrophy and cognitive screening test performances in very mild Alzheimer's disease: the Tajiri Project

Abstract. The medial temporal lobe, especially the hippocampus, is important for normal cognitive function, especially for memory, and is the region with the earliest and most extensive pathological changes in Alzheimers disease (AD). We investigated the atrophic changes of the hippocampus over a 5-year period and its relation to cognitive screening test performances in normal elderly subjects, those with very mild AD, and patients with AD. Fifty-seven elderly subjects without a moderate or greater degree of cerebrovascular disease as shown by MRI were randomly selected from the town of Tajiri. Thirty-three subjects with a clinical dementia rating (CDR) of 0 (normal), 18 CDR-0.5 (very mild AD) subjects, and six CDR-1&2 (AD) subjects underwent MRI and the Mini Mental State Examination (MMSE) twice during the period. Retrospective changes in the hippocampal width and the MMSE scores were evaluated. There were significant CDR group effects for the changes in the mean bilateral hippocampal widths and the MMSE scores. Normal subjects did not show cognitive decline, although there was a slight tendency for hippocampal atrophy. A significant and meaningful Spearmans correlation was noted between left hippocampal atrophy and the MMSE scores over the 5-year period for the CDR-0.5 group. These CDR-0.5 subjects met the MCI (mild cognitive impairment) criteria as proposed by the consensus paper. Findings suggested that normal elderly subjects maintain a high level of cognitive functions for at least 5 years, although hippocampal atrophy might occur. Atrophic change of the left hippocampus might be a good marker of the very early stage of AD.

Therapeutic psychosocial intervention for elderly subjects with very mild Alzheimer disease in a community: The Tajiri Project

Elderly subjects with mild memory impairment but not apparent dementia are the focus of early intervention trials. To examine the effects of structural psychosocial intervention for elderly subjects with very mild Alzheimer disease, i.e., Clinical Dementia Rating 0.5. The design is a prospective study. The experimental group (14 Clinical Dementia Rating 0.5 subjects) and the control group (11 Clinical Dementia Rating 0.5 subjects) were studied. Subjects with cerebrovascular disease as shown by magnetic resonance imaging were excluded. The experimental group participated in activities in a day-care-like setting once a week over a period of 6 months, whereas the control group did not. Each group was reevaluated after approximately 9 months. The effects of intervention were evaluated by cognitive tests, affective scales, a global clinical measure, an observation scale in the sessions, and a projective test. The experimental group showed a significant improvement on the word fluency test, whereas the control group showed a significant decline on the Mini-Mental State Examination, the digit span, and the Trail Making-A test. The experimental group revealed significantly higher levels on the Mini-Mental State Examination and the digit span compared with the control group after the 6-month intervention. A significant improvement was found for the global clinical measure, the observation scale, and the projective test in the experimental group after the intervention. After controlling the potential confounders (age, educational level, baseline cognitive, and affective status) in a multiple regression analysis, the same results were found. We considered that psychosocial intervention had beneficial effects for subjects with very mild Alzheimer disease.

Corpus Callosum Atrophy, White Matter Lesions, and Frontal Executive Dysfunction in Normal Aging and Alzheimer's Disease. A Community-Based Study: The Tajiri Project

BACKGROUND AND OBJECTIVES Cerebral MRIs of normal aging and Alzheimers disease (AD) frequently reveal corpus callosum (CC) atrophy, white matter hyperintensity (WMH), and hippocampal atrophy. However, their relationship or the relationship between these findings and cognitive function has not been fully studied. We investigated the relationship between CC atrophy, WMH, and hippocampal atrophy, together with frontal executive dysfunction in both normal aging and AD. METHOD We examined 170 randomly selected residents from a designated community: 99 Clinical Dementia Rating (CDR) 0 (healthy, control group, HC) participants, 54 CDR 0.5 (very mild AD) patients, and 17 CDR 1 & 2 (probable AD) patients. By means of MRI, WMH and CC atrophy were visually rated. Four portions of the CC and the hippocampal width were measured. A Mini-Mental State Examination and Cognitive Abilities Screening Instrument (CASI) were performed to assess global function. For the frontal function, the CASI subitems of attention and word fluency, letter-based fluency, the Digit Symbol test of the WAIS-R, and Trail Making Tests were performed. RESULTS Those patients with CDR 1 & 2 had both hippocampal and CC atrophy, whereas the CDR 0.5 patients had only hippocampal atrophy. Frontal executive dysfunction was associated with CC atrophy in both the HC and AD groups. Significant Spearman correlations were noted between CC atrophy and WMH in both groups. The combined effect of CC atrophy and WMH was noted only in the verbal fluency test in the HC group. CONCLUSION In both groups, CC atrophy was associated with frontal executive dysfunction. The combined effect of CC atrophy and WMH in normal aging was probably due to subclinical ischemic conditions.

Executive dysfunction can explain word‐list learning disability in very mild Alzheimer's disease: The Tajiri Project

Abstract  Elderly people with questionable dementia (i.e. a Clinical Dementia Rating (CDR) of 0.5) have been focused on as representing the borderline zone condition between healthy people and dementia patients. Many of them are known to have pathologic traits of very mild Alzheimers disease (AD). Although they present mild memory disorder, the underlying mechanism has not been fully investigated. Herein is reported the mechanism of learning disability in very mild AD. Eighty‐six CDR 0.5 participants and 101 age‐ and education‐matched healthy controls (CDR 0) were randomly selected from a community in the town of Tajiri, Miyagi Prefecture. The word‐recall task of the Alzheimer Disease Assessment Scale–Japanese (i.e. learning and recall of 10 words) was administered. The numbers of words recalled in each trial and those never recalled throughout the trials were compared for the two CDR groups. The serial‐position function was depicted for three parts (i.e. primary, middle, and recency). The CDR 0.5 group recalled significantly fewer words than the CDR 0 group. The number of never‐recalled words was greater in the CDR 0.5 group. A remarkable difference was found in the middle part of the word list. The number of never‐recalled words of the CDR 0.5 group was greater in the middle part. The large number of never‐recalled words accounted for the poor learning performance of very mild AD participants. The results suggested that very mild AD participants have difficulty in learning and retaining words in the middle part of the word‐list because of a functional decline of the central executive system.

Neuropsychosocial features of very mild Alzheimer's disease (CDR 0.5) and progression to dementia in a community: the Tajiri project.

The borderline condition between normal aging and dementia should be detected to predict further deterioration. The authors cross-sectionally analyzed neuropsychological data, memory complaints, and social activities for communitydwelling older adults. The rate of decline from Clinical Dementia Rating (CDR) 0.5 to dementia during a 3-year interval was also analyzed. Short-term memory rather than long-term memory was found to be sensitive in distinguishing those with CDR 0 from those with CDR 0.5. Relatives’ observations of memory decline rather than subjective memory complaints were significantly different. Participants with CDR 0.5 reported fewer problems with social activities than did their relatives. Ten of the 29 CDR 0.5 participants (34.5%) showed cognitive decline, the decliners showing lower scores on short-term memory and orientation at the baseline condition. The neuropsychological data showed CDR 0.5 to be similar to very mild Alzheimer’s disease. It would be better if subjective complaints were excluded from the criteria of the borderline condition.

A study of periventricular hyperintensity. I. Normal brain aging

Fifty-two patients with cerebrovascular risk factors without neurological abnormalities were examined by magnetic resonance imaging and were evaluated for their periventricular hyperintensity (PVH) on T2-weighted images. We assumed that PVH was not a mere focal finding of the brain but a kind of marker for condition related to arteriosclerosis and cerebral ischemia, and we tried to devise a model screening test, using common parameters available in most ordinary hospitals, to predict PVH. Multiple regression analysis was performed by setting up the PVH% (the volume percentage of PVH to cranial cavity) as a dependent variable and twenty-seven variables associated with general medical examination and brain atrophy as explanatory variables. We found that arteriosclerotic changes in the body as well as brain atrophy were significantly correlated with PVH, and that PVH could be predicted with a high contribution ratio of 0.70. It is clinically important to examine the elderly with our screening test to predict PVH in order to detect the early stages of ischemia.

The changing role of health care IC card systems

Health care researchers and professionals have had increasing interest in the development of Internet-based solutions in health care, casting doubt on the future of IC card systems. However, IC cards used in conjunction with Internet-based health information systems may be more viable than either system alone. We conducted a worldwide survey to explore the possibilities of such a combined system. Our analysis shows that there is considerable awareness of the concept of Internet-based health care services among the professionals of IC card projects. In addition, our results indicate that IC cards could play a major role in health care systems as authorization keys that permit access to health information.

A statistical approach to the prediction of the possible presence of pollutant chemicals in the environment

In the present study, trials were performed to examine the applicability of Hayashis theory of quantification (second type) to prediction of the possible presence (i.e., detection) or absence (nondetection) of a given chemical in the environment. The dependent variables employed were the results of a nationwide environmental monitoring on pollutant chemicals conducted by the Environment Agency of Japan. When 102 chemicals were analyzed utilizing five factors as independent variables--annual production, use pattern, n-octanol/water partition coefficient (Po/w), water solubility, and biodegradability--it was found that production, use pattern, and Po/w are the major contributing factors in the prediction. Further studies with 186 chemicals utilizing these three factors as the independent variables showed that, through the combined evaluation of the results of analyses with three pairs out of the three variables, the absence of a chemical in the environment at an analytically meaningful level can be predicted with a success rate of 94.4%. The rate for the presence was 76.4%.