Prevalence of senile dementia in a rural community in Japan: the Tajiri project

Gender-specified mediation of depression between sleep quality and short-term memory in older adults: Study in a semi-closed Island of Xiamen, China

BACKGROUND

Both the quality of sleep and depression impact short-term memory (STM) while they influence each other. However, the underlying mechanisms are not yet clear. Herein, we aimed to explore the mediating effect of depression between sleep quality and STM in older adults and further test the gender differences in this relationship.

METHODS

A cluster sampling survey was carried out among 903 residents that were aged 60+ years in a semi-closed island of Xiamen, China, in 2019. The subjects' sleep quality and depression were measured using the Pittsburgh Sleep Quality Index (PSQI) and the 15-item Geriatric Depression Scale (GDS-15), respectively. The three-item recall test was utilized to measure STM function. Mediation analyses were performed using the structural equation model and bias-corrected bootstrap method. Next, the Wald-test was utilized to determine gender differences in the pathway.

RESULTS

Overall, 355 men and 508 women, with a mean age of 69.55 and 70.97, respectively, had valid data on the main variables. Depression was found to mediate the effect of sleep quality on STM (a*b = -0.076, p < 0.05). Interestingly, while this indirect effect existed in the female group (a_f *b_f  = -0.126, p < 0.05), it did not in the male group (a_m *b_m  = 0.017, p = 0.677). The Wald-test indicated no gender differences in the pathway from sleep quality to depression (p = 0.303). However, the pathway from depression to STM function was found to be significantly stronger for females than males (p = 0.0198).

CONCLUSION

Higher sleep quality was found to be associated with improved STM function. Furthermore, the association was found to be regulate indirectly by lower depressive symptoms for females, but directly for males. Therefore, appropriate psychological interventions may be beneficial to the maintenance of STM for older adults, particularly for women.

Prevalence of idiopathic normal-pressure hydrocephalus in the elderly population of a Japanese rural community

The prevalence of idiopathic normal-pressure hydrocephalus (NPH) in a community was investigated by retrospective analysis of data from a previous community-based study of 170 randomly selected elderly residents aged 65 years or older. Magnetic resonance (MR) images of the subjects were reviewed for the specific structural features of idiopathic NPH, i.e. ventricular enlargement and narrow cerebrospinal fluid (CSF) space at high convexity and high midline areas. The clinical features of idiopathic NPH, gait disturbance, urinary incontinence, and cognitive impairment, were evaluated on the basis of records of the subjects' neurological examinations, a health questionnaire, the Mini-Mental State Examination, and Clinical Dementia Rating. Thirteen of the 170 subjects showed lateral ventricular enlargement greater than 0.3 on Evans' index. Five subjects (2.9%) demonstrated both ventricular enlargement and narrow CSF space at the high convexity/midline. All five subjects with these MR imaging signs had cognitive impairment, one had gait disturbance, and one had urinary incontinence. The present study found 2.9% of community-dwelling elderly subjects showed radiological and clinical features consistent with idiopathic NPH.

Utility of the clinical dementia rating in Asian populations

Consistent with the worldwide demographic trend of population aging, dementia is expected to become a burgeoning public health problem in Asian populations. Thus, there is a pressing need for reliable and valid methods of dementia diagnosis and staging that are applicable in heterogeneous Asian populations. The Clinical Dementia Rating (CDR) is an informant-based global assessment scale with established reliability and validity that has been widely utilized as a severity-ranking scale in many studies of Asian populations. From a diagnostic standpoint, the CDR is congruent with the Diagnostic and Statistical Manual of Mental Disorders approach of dementia diagnosis. It exhibits excellent discriminatory ability in the very mild stages of dementia, a useful property that is germane to the surging interest in mild cognitive impairment and related concepts. Limitations of the CDR include its length of administration, reliance on clinical judgment and collateral source information, and relative insensitivity as a measure of change in interventional studies. Since the exercise of clinical judgment is inherent in scoring, CDR raters should be mindful of the influence of cultural factors on premorbid lifestyle, informant reliability and performance in certain CDR test items (especially those pertaining to the categories of judgment and problem solving, community, and home and hobbies). Thus, in future studies that involve the nascent use of the CDR in Asian populations, it is recommended that any transcultural adaptation of CDR items be described in detail and appropriate validation studies be carried out before adopting the CDR as a yardstick measure of assessment. The potential of adapted versions of the CDR in chronic care settings and advanced cases should be explored. An integrative approach, combining brief informant interview in conjunction with brief objective cognitive testing, could be a viable strategy for dementia screening in the clinical and research setting that warrants further evaluation in Asian populations.

Non-verbal learning is impaired in very mild Alzheimer's disease (CDR 0.5): normative data from the learning version of the Rey-Osterrieth Complex Figure Test

Mild cognitive impairment (MCI) is a transitional state between normal aging and dementia. Although there have been some studies on the role of verbal memory in learning ability, there have been no reports on the part played by visual memory. In the present study, the Rey-Osterrieth Complex Figure Test (RCFT) was given to healthy subjects and to those with MCI to determine if visual memory was maintained in these two groups. Additionally, normative data from the learning version of the RCFT for Japanese subjects were examined, for purpose of reference. The participants consisted of 381 clinical dementia rating (CDR) 0 subjects and 137 CDR 0.5 subjects who could perform the full set of RCFT tasks. The CDR 0 group had significantly higher scores than the CDR 0.5 group in all trials. The CDR 0 participants also showed a significant step-by-step learning effect, while the CDR 0.5 participants did not show a significant learning effect. These results suggest that the CDR 0 participants maintained intact learning abilities of encoding and retrieval, while the CDR 0.5 participants did not do so; but further studies will be needed to clarify these findings.

Different MRI findings for normal elderly and very mild Alzheimer's disease in a community: Implications for clinical practice

To investigate magnetic resonance imaging (MRI) findings of very mild dementia, 485 participants were randomly selected in a community. Three hundred and forty participants were of Clinical Dementia Rating (CDR) 0 (healthy), 113 were of CDR 0.5 (questionable dementia), and 32 were of CDR 1 and 2 (including 20 Alzheimer's disease, AD). Cortical atrophy, white matter lesion, etc., were visually assessed. We found that each part of the brain showed atrophy in older adults for CDR 0. For CDR 0.5, the relationships between MRI findings and age were weaker, and for AD, there were no such relationship. Atrophy related with dementia severity was found to be limited to the lateral and medial temporal lobes. For CDR 0.5, amygdala atrophy was the only finding indicating CDR effect but no age effect. The amygdala or anterior entorhinal atrophy is important for discriminating very mild dementia from normal elderly.

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 community-dwelling 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.

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.

Executive dysfunction can explain word-list learning disability in very mild Alzheimer's disease: the Tajiri project

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 Alzheimer's 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.

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.

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

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 prevention 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 (Alzheimer's 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.

Elderly Japanese emigrants to Brazil before World War II: I. Clinical profiles based on specific historical background

OBJECTIVE

To research the demographic and clinical profiles of elderly Japanese emigrants, who arrived in Brazil before World War II, in order to give them appropriate psychogeriatric care.

DESIGN

Elderly Japanese immigrants aged 65 years and over, belonging to the Miyagi Association in the São Paulo Metropolitan Area, were targeted. They emigrated from Miyagi Prefecture to Brazil and are now living in the area. We were able to interview 166 respondents. All data were gathered using standardized interview methods covering (a) free interview about the immigration history, (b) demographics, and (c) physical status.

RESULTS

Through the free interview, we found their immigration histories, which affected their clinical profiles. The mean age and educational level were 77.5 years and 6.3 years, respectively. Sixty per cent of them immigrated when they were younger than 14. Ninety-four per cent of them still keep Japanese nationality. Fifty-seven per cent of them usually use Japanese, while 10% of them use Portuguese. Although their emigration histories were hard, 76% of them perceived their health as being excellent or relatively good. The percentages of subjects with histories of disease were hypertension, 52.5%; cardiac disease, 20.8%; diabetes mellitus, 24.2%; and hyperlipidemia, 25.0%, which were affected by the Brazilian environment.

CONCLUSION

The elderly Japanese who emigrated to Brazil before World War II have a unique historical and demographic background. Their clinical profiles cannot be fully understood without knowing their histories. They definitely need high quality international psychogeriatric care.

Elderly Japanese emigrants to Brazil before World War II: II. Prevalence of senile dementia

BACKGROUND

We previously showed the prevalence of dementia in the town of Tajiri (Miyagi Prefecture, Japan), and found it to be 8.0%. The first population-based study on dementia in Brazil (Catanduva) disclosed the prevalence as being 7.1%. To evaluate the effects of environment on development of dementia, elderly Japanese immigrants living in Brazil were examined. Brazil is the country with the largest number of Japanese immigrants.

METHODS

All immigrants aged 65 years and over from Miyagi Prefecture, living in the four cities of the São Paulo Metropolitan area were targeted (n = 192). We were able to examine 166 subjects (86.5%). The diagnosis of dementia was based on the DSM-IV with the severity assessed by the CDR (clinical dementia rating) scales. The cognitive ability screening instrument (CASI) was used for neuropsychological assessment.

RESULTS

Thirteen subjects were diagnosed with dementia, CDR 1-3, the prevalence being 7.8%. Older subjects suffered more from dementia, and, paradoxically, the more highly educated subjects also suffered more. All the CASI items, except for long-term memory and visual construction, significantly deteriorated in the CDR 0.5 group compared with the CDR 0 group.

COMMENTS

The prevalence of dementia was not thought to be affected by environmental factors. A paradoxically higher rate of dementia in the more educated subjects was probably due to the historical problems of the immigrants. Intact CASI item long-term memory in the CDR 0.5 group indicated that suspected dementia patients could maintain this function. This is the first epidemiological study on dementia in elderly Japanese immigrants in Brazil.

Depressive symptoms and associated factors in a cognitively normal elderly population: the Tajiri Project

BACKGROUND AND OBJECTIVE

Since depression is one of the main problems of elderly subjects, it is important to examine the prevalence of this condition and to identify associated factors.

METHODS

A total of 1525 cognitively normal subjects aged 65 years and over in the town of Tajiri, a typical agricultural town in Japan, were analysed. Their MMSE (mini-mental state examination) scores were 24 or over. Depressive state was assessed by Zung's SDS (self-rating depression scale) with a comprehensive interview to examine ADL, demographics and symptoms associated with illness, etc. The prevalence of depression was calculated. To determine the factors associated with depression, the t-test and the Chi-square test were used. To examine the relative strength of each factor, logistic regression analysis was performed.

RESULTS

The ratio of the depressive subjects was 6.4%, lower than those of previous reports, probably due to the effect of excluding dementia subjects. The ratio for older females aged 80 years and over was 14.3%, which was significantly higher than that of the males. Among socio-demographic factors, sex, age, number of children and perception of economic status, were significantly related. For health status and ADL, such factors as perception of health and medical history of heart disease and rheumatism were related. For familial and social status, factors such as daily activity and several conversation abilities were related. The logistic regression analysis indicated that perception of health and daily activity were associated.

CONCLUSIONS

In this study, we isolated some factors related to depression in a cognitively normal population. Knowledge of such factors is important for appropriate mental care of aged subjects.