Subjective memory complaint in relation to cognitive performance and depression: a longitudinal study of a rural Chinese population.

OBJECTIVES: To examine the associations of subjective memory complaint (SMC) in old age with (a) objective test performance, (b) past and subsequent cognitive decline, and (c) depression. DESIGN: A group of community residents were examined twice during a 3-year period. SETTING: Two townships on a rural Chinese islet. PARTICIPANTS: A total of 543 men and women aged 65 years and older. MEASUREMENTS: During each examination, neurologists interviewed and examined all participants for dementia and asked the question, "Do you have trouble with your memory?" In addition, research assistants administered (a) the Cognitive Abilities Screening Instrument (CASI) to assess cognitive abilities, including long-term memory (LTM) and short-term memory (STM), and (b) the Geriatric Depression Scale-Short Version (GDS-S) to assess symptoms of depression. RESULTS: At each examination, almost half of the subjects acknowledged having trouble with their memory (the SMC+ group). At both examinations, the SMC+ group scored significantly lower on the CASI and significantly higher on the GDS-S than the SMC- group. However, the presence of SMC was not associated with faster cognitive decline over the past or subsequent 3 years. There were no consistent associations between SMC and the demographic variables of age, gender, and education at the two examinations. Logistic regression analysis showed that SMC was associated with poorer memory test scores after controlling for gender, age, education, and depression. CONCLUSIONS: SMC was associated with poorer objective memory performance even after controlling the effect of depression and demographic data, but SMC did not predict faster cognitive decline or dementia over 3 years.

The effects of childhood residence in Japan and testing language on cognitive performance in late life among Japanese American men in Hawaii.

OBJECTIVES: To examine the association of years spent in Japan during childhood with cognitive test performance in late life among Japanese American men, and to assess the influence of the language used for testing on this association. DESIGN: A cross-sectional study. SETTING/PARTICIPANTS: A total of 3734 Japanese American men, aged 71-93 years, who were first- or second-generation migrants and living on Oahu Island, Hawaii. MEASUREMENTS: The outcome variable was cognitive test performance assessed using the Cognitive Abilities Screening Instrument (CASI), which was developed for cross-cultural studies of cognitive impairment. The explanatory variable of main interest was the number of years spent in Japan during school-age childhood years (ages 6-17). The associations of CASI scores with childhood years in Japan was evaluated using a stepwise multiple linear regression model in which a total of 40 potential confounders were included as covariates. RESULTS: In the total sample, there was an inverse association between CASI scores and middle childhood years in Japan. This association remained significant after controlling for age, education, socioeconomic status, traditional Japanese food consumption, pulmonary function, apolipoprotein E4, proficiency in speaking Japanese, and other possible confounders. When data were analyzed separately for subgroups according to the language preferred at testing (English or Japanese), associations between childhood years in Japan and CASI scores were in opposite directions negative for the group tested in English and positive for the group tested in Japanese. The interaction between the testing language and childhood years in Japan was statistically significant. CONCLUSIONS: There was an inverse association between years spent in Japan during school-age years of childhood and cognitive test performance in late life. This association could not be accounted for by age, education, or other confounding factors. However, this finding was not observed in participants who preferred being tested in Japanese. To assess cognitive test performance in older people, it is of prime importance to use the most optimal language for testing, usually the subject's native language.

ApoE genotype in relation to AD and cholesterol: a study of 2,326 Chinese adults.

OBJECTIVE: To calculate the frequencies of apolipoprotein E (apoE) alleles in a large Chinese community sample and to compare the serum cholesterol levels of epsilon2, epsilon3, and epsilon4 carriers. BACKGROUND: In comparison with Western populations, a lower frequency of the apoE epsilon4 allele among the Chinese has been proposed as one factor for the lower prevalence of AD found in Chinese populations, but there are insufficient Chinese data on epsilon4 frequency that are based on large community samples. In addition, although Western studies have repeatedly found a lower cholesterol level in epsilon2 carriers and a higher cholesterol level in epsilon4 carriers in comparison with epsilon3 homozygotes, two Chinese studies have yielded inconsistent findings between them. METHODS: During the incidence phase of an epidemiologic survey of several neurologic disorders in a Chinese community, the authors took blood samples from 2,326 participants to determine the apoE genotypes and to measure cholesterol levels. RESULTS: The allelic frequencies of epsilon2, epsilon3, and epsilon4 were 11.8%, 76.4%, and 11.8% among 17 AD patients, and 7.8%, 84.1%, and 8.1% for the entire sample. The mean cholesterol level of the epsilon2 carriers was significantly lower, and that of the epsilon4 carriers significantly higher, than that of the epsilon3 homozygotes. CONCLUSIONS: The obtained epsilon4 rate of 8.1% is lower than most of the Western findings, and this may account in part for the lower prevalence of AD found among the Chinese. The associations between the apoE genotype and serum cholesterol level are similar between Chinese and white populations.

Depressive disorders in Chinese patients with Alzheimer's disease.

OBJECTIVE: The present study was to investigate the prevalence and potential risk factors of depressive disorders in Chinese patients with Alzheimer's disease (AD). METHOD: A series of consecutive AD patients from the Memory Disorders Clinic of the Veterans General Hospital, Taipei were studied. Psychiatric diagnosis was made according to DSM-III-R criteria with the use of the Structured Clinical Interview for DSM-III-R (SCID). The Chinese version of the Cognitive Abilities Screening Instrument (CASI) and the Hamilton Depression Rating Scale (HDRS) were also applied. Primary caregivers were interviewed for the Clinical Dementia Rating (CDR) scale, the Barthel Index and the Alzheimer's Deficit Scale (ADS). RESULTS: Among 141 AD patients, seven (5.0%) were diagnosed with major depression, 11 (7.8%) with dysthymia and five (3.5%) with depressive disorder not otherwise specified. Women were at elevated risk for depressive disorders and had more severe symptoms of depression. CONCLUSIONS: The prevalence of depressive disorders among Chinese AD patients is in the middle of the range of western findings. The risk factor for depression is female gender.

Cerebral vasculopathy in sickle cell anemia: diagnostic contribution of positron emission tomography.

Children with sickle cell anemia (SS) have an increased risk for cerebral vasculopathy with stroke (CVA) and cognitive impairment. The present study examines the extent to which adding positron emission tomography (PET) to magnetic resonance imaging (MRI) can improve the detection of cerebral vasculopathy. Whereas MRI has been the prime modality for showing anatomical lesions, PET excels at assessing the functional metabolic state through glucose utilization 2-deoxy-2 [18F] fluoro-D-glucose (FDG) and microvascular blood flow ([15O]H2O). Forty-nine SS children were studied. Among them, 19 had clinically overt CVA, 20 had life-threatening hypoxic episodes or soft neurologic signs, and 10 were normal based on neurological history and examination. For the entire sample of 49 subjects, 30 (61%) had abnormal MRI findings, 36 (73%) had abnormal PET findings, and 44 (90%) showed abnormalities on either the MRI or the PET or both. Of the 19 subjects with overt CVA, 17 had abnormal MRI (89%), 17 had abnormal PET (89%), and 19 (100%) had either abnormal MRI or PET or both. Among the 20 subjects with soft neurologic signs, 10 (50%) had abnormal MRI, 13 (65%) had abnormal PET, and 17 (85%) had abnormal MRI and/or PET. Six (60%) of the 10 neurologically normal subjects had abnormal PET. Among the 30 subjects with no overt CVA, 25 (83%) demonstrated imaging abnormalities based on either MRI or PET or both, thus, silent ischemia. Lower than average full-scale intelligence quotient (FSIQ) was associated with either overt CVA or silent ischemic lesions. Four subjects who received chronic red blood cell transfusion showed improved metabolic and perfusion status on repeat PET scans. In conclusion, (1) the addition of PET to MRI identified a much greater proportion of SS children with neuroimaging abnormalities, particularly in those who had no history of overt neurologic events. (2) PET lesions are more extensive, often bihemispheric, as compared with MRI abnormalities. (3) PET may be useful in management as a tool to evaluate metabolic improvement after therapeutic interventions, and (4) the correlation of PET abnormalities to subsequent stroke or progressive neurologic dysfunction requires further study.

Hemispheric differences in serial reversal learning: a study with commissurotomy patients.

A serial reversal learning task involving tactile-proprioceptive discrimination and manual responses was presented alternately to the left and the right hemisphere of four "split-brain" patients. In each trial, one of two rods that differed in both diameter and surface texture was placed in the patient's hand out of view. The patient was trained to match it to samples according to either size or texture and non-verbal audio visual feedback was used to signal the correctness of each response. After reaching five consecutively correct responses, the feature to be matched was switched. When the patient again made five consecutively correct responses, the feature to be matched was reversed back. This procedure was repeated until the end of a 200-trial training run. The two hemispheres learned equally readily on the first learning task. The right hemisphere had much greater difficulty in learning the reversals than the left hemisphere and this was not attributable to a strong tendency to stay with a previously correct match. Learning with the left hemisphere showed relatively stable performance across successive reversals, whereas that with the right hemisphere showed high lability. Control trials showed that the hemispheres were equally competent in making the basic tactile-proprioceptive discriminations. Comparisons with the findings on (a) three control patients and (b) training with unrestricted visual input showed that learning with two hemispheres was easier than learning with either one alone; performance regulated by both hemispheres was also more stable.

Prevalence and subtypes of dementia in a rural Chinese population.

We conducted a single-stage community-based study of dementia on all registered residents > or =65 years in age in a rural Chinese community. Neurologists conducted semistructured interviews and examined all participants; they also interviewed family members in cases where dementia was suspected. The diagnosis was made by consensus according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 3rd ed, revised (DSM-III-R). Among the 2,055 contacted individuals, 1,736 (84.5%) participated in the study and 44 ( 13 men and 31 women) were diagnosed as having dementia, including 35 (80%) with probable Alzheimer disease (AD) and 3 (7%) with vascular dementia (VsD). The rates of dementia were 0.5% for ages 65-74 years, 2.9% for ages 75-84 years, and 12.0% for ages 85-101 years. The overall rate was 2.5% for age > or =65 years. After controlling for age, neither a lack of formal education nor being a woman was a risk factor for dementia. At 2-year follow-up, 30 of the 44 demented participants had died, yielding a 2-year survival rate of 32%. The present results corroborated our previous findings of lower prevalence rates of dementia among the Chinese than among Western populations, and both genetic and sociocultural factors may have contributed to the low rates. The lack of neuroradiological imaging studies in the present study may have contributed to the finding of an unusually low rate of VsD.

The effects of age, education, and ethnicity on verbal fluency.

A group of 317 healthy participants between 54 and 99 years of age performed a verbal fluency task. The participants included Chinese, Hispanic, and Vietnamese immigrants, as well as White and African American English speakers. They were given 1 min to name as many animals as possible in their native language. The results showed that more animal names were produced by younger people and those with more education. Language background was also an important factor: The Vietnamese produced the most animal names and the Spanish speakers produced the fewest. The exaggerated difference between these two groups is attributed to the fact that Vietnamese animal names are short (predominantly 1 syllable) while the Spanish animal names are longer than any other language in this study (2 and 3 syllables per word). Finally, although the ethnic groups named different animals, and appeared to vary in the variety of animal names they used, these factors did not affect overall verbal fluency performance.

Depressive disorders among older residents in a Chinese rural community.

BACKGROUND: Two recent surveys of depression among Chinese elderly people sampled different populations, used different case ascertainment methods and resulted in a seven-fold difference in prevalence rates. The present study was conducted to compare prevalence rates obtained with two commonly used methods in the same population, and to examine the risk factors for depression. METHODS: The target population included all residents aged 65 years and over in a rural Chinese community. Participants were interviewed for demographic and medical information, examined by a neurologist and administered Chinese versions of the Geriatric Depression Scale-Short Form (GDS-S), the Cognitive Abilities Screening Instrument (CASI) and an Activities of Daily Living (ADL) form. Individuals who screened positive on the GDS-S were also interviewed by a psychiatrist for diagnosis according to the DSM-III-R criteria. RESULTS: Among the 1313 participants, 26% screened positive on the GDS-S and 13% were diagnosed as having a depressive disorder, including 6.1% with major depression. Individuals with depressive disorders were more likely to have poor ADL scores, lower CASI scores, and chronic physical illnesses. They were also more likely to be female, older, illiterate and without a spouse, but adding these variables did not increase the overall association with the GDS-S score. CONCLUSIONS: Depression was quite common in this Chinese rural geriatric population. The prevalence rate was twice as high when judged by depression symptomatology rather than clinical diagnosis. The critical risk factors were functional impairments, poor cognitive abilities and the presence of chronic physical illnesses.

The Kinmen Neurological Disorders Survey (KINDS): a study of a Chinese population.

We conducted an epidemiological study of several neurological disorders among the Chinese aged 50 years or older on the islet of Kinmen. All participants were interviewed and examined by neurologists. From the targeted population of 5,061 individuals, 3,915 (77.4%) of them completed the evaluations. Among the 4,087 individuals with whom face-to-face contact was made, the refusal rate was 4.2%. The disorders of interest were dementia, Parkinson's disease, essential tremor, stroke, transient ischemic attacks, and migraine. Among the 3,915 participants, 366 cases were found with 1 or more of the surveyed neurological disorders on the prevalence day, August 1, 1993, yielding a prevalence of 93.5/1,000. The purpose of this study, the general methodology, and some overall findings are presented in this communication in order to provide a common background for detailed findings on each disorder to be reported separately.

Prevalence of dementia in older Japanese-American men in Hawaii: The Honolulu-Asia Aging Study.

OBJECTIVE: To determine prevalence of dementia and its subtypes in Japanese-American men and compare these findings with rates reported for populations in Japan and elsewhere. DESIGN AND SETTING: The Honolulu Heart Program is a prospective population-based study of cardiovascular disease established in 1965. Prevalence estimates were computed from cases identified at the 1991 to 1993 examination. Cognitive performance was assessed using standardized methods, instruments, and diagnostic criteria. PARTICIPANTS: Subjects were 3734 Japanese-American men (80% of surviving cohort) aged 71 through 93 years, living in the community or in institutions. MAIN OUTCOME MEASURES: Age-specific, age-standardized, and cohort prevalence estimates were computed for dementia (all cause) defined by 2 sets of diagnostic criteria and 4 levels of severity. Prevalence levels for Alzheimer disease and vascular dementia were also estimated. RESULTS: Dementia prevalence by Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised ranged from 2.1% in men aged 71 through 74 years to 33.4% in men aged 85 through 93 years. Age-standardized prevalence was 7.6%. Prevalence estimates for the cohort were 9.3% for dementia (all cause), 5.4% for Alzheimer disease (primary or contributing), and 4.2% for vascular dementia (primary or contributing). More than 1 possible cause was found in 26% of cases. The Alzheimer disease/vascular dementia ratio was 1.5 for cases attributed primarily to Alzheimer disease or vascular dementia. CONCLUSIONS: Prevalence of Alzheimer disease in older Japanese-American men in Hawaii appears to be higher than in Japan but similar to European-ancestry populations. Prevalence of vascular dementia appears to be slightly lower than in Japan, but higher than in European-ancestry populations. Further cross-national research with emphasis on standardized diagnostic methods is needed.

A door-to-door survey of Parkinson's disease in a Chinese population in Kinmen.

BACKGROUND: Most published studies have shown lower prevalence rates of Parkinson's disease (PD) in Asian and black African than in Western countries, leading to the hypothesis that Asians and blacks might be protected from PD. OBJECTIVE: To investigate the prevalence of PD in a Chinese population. DESIGN: Community-based survey. SETTING: Registered residents 50 years of age or older (N = 5061) on the islet of Kinmen located off the southeastern coast of China [corrected]. METHOD: Single-phase door-to-door survey by neurologists. All participants were administered a questionnaire and received motor examinations of the Unified Parkinson's Disease Rating Scale. RESULTS: The participation rate was 96% (N = 3915) among 4158 contacted individuals. Twenty-three cases of PD were identified, including three cases with dementia. The crude prevalence rate of PD was 587 (95% confidence interval (CI), 373 to 884) per 100,000 persons 50 years of age or older. Assuming no case of PD among individuals under 50 years of age, the prevalence rate was 119 (95% CI, 80 to 169) per 100,000 for the total population. CONCLUSIONS: The prevalence rates of PD in Kinmen were much higher than those reported from mainland China, but slightly lower than those reported from more developed countries. The present findings suggest that, instead of genetic factors, differences in case-ascertainment, life expectancy, and the length of survival with PD may be more important contributors to the variations in observed PD prevalence rates.

Performance on a smell screening test (the MODSIT): a study of 510 predominantly illiterate Chinese subjects.

The 12-item Modular Smell Identification Test (MODSIT) was administered to 239 male and 271 female Chinese subjects whose age ranged from 50 to 92 years (68.3 +/- 10.9) and whose education ranged from 0 to 20 years (2.5 +/- 4.3). Every participant was examined by a physician and was found to be free of dementia, stroke, and Parkinson's disease. Different from the standard procedures, only one-third of each odor pad was used for each subject, the four odor choices were presented orally for the majority of subjects, and they were not forced to make a selection when they could not detect or identify the odor. The average level of performance was 46% correct. The score was negatively associated with age, positively associated with education and with performance on a dementia screening test, and corroborated with subjects' report of smell deterioration in recent years. Nonsmokers and women performed better than smokers and men. The 12-item MODSIT had an internal consistency reliability of 0.73 and a 7-month retest stability of 0.57 with different examiners. The MODSIT is satisfactory for group studies, even when administered with suboptimal procedures such as those used in the present study.

Prevalence and subtypes of dementia in Taiwan: a community survey of 5297 individuals.

OBJECTIVE: To study the prevalence rate of dementia in Taiwan, the relative frequencies of its subtypes, and its associations with age, education, gender, and residence location. PARTICIPANTS: A total of 2753 men and 2544 women from four urban and four rural communities participated. Their age ranged from 41 to 88 years; 28% of them were at least 65 years old. Their education ranged from 0 to 20 years; 27% of them had less than 1 year of formal schooling. DESIGN: Phase I was a screening survey by trained nurses who administered a Chinese version of the Mini-Mental State Examination, the MMSE-T1, to all participants. Phase II involved the assessment for dementia by neurologists on the 1521 individuals who had scored less than 24 on the 30-point MMSE-T1. MAIN RESULTS: Thirty-one cases of dementia were identified by the DSM-III-R criteria, including 18 cases of Alzheimer's disease, 10 cases of vascular dementia, and three cases of other dementias. The prevalence rate in individuals aged 65 and over was 2.0%. Aging and illiteracy were associated with higher rates of dementia; gender and residence location made no difference. CONCLUSIONS: The prevalence rate of dementia was low in this Chinese population. Consistent with common findings from other parts of the world, a high rate of dementia was associated with older age and illiteracy, and Alzheimer's disease was the most frequent cause.

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) as a screening tool for dementia for a predominantly illiterate Chinese population.

The Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE) provides ratings of an individual's changes in everyday cognitive functions during the previous 10 years. Original studies conducted in Australia showed that its score was not influenced by the subjects' educational backgrounds and that it performed at least as well as the Mini-Mental State Examination (MMSE) as a screening instrument for dementia. The subjects of the present study were Chinese and included 399 community residents and 61 dementia patients. Their ages ranged from 50 to 92 years; their education levels ranged from 0 to 19 years, and 63% of them had never attended school. We administered the IQCODE to informants and the Cognitive Abilities Screening Instrument (CASI), from which a CASI-estimated score of the MMSE (MMSE-CE) can be obtained, to the subjects. The diagnosis of dementia was made independently by physicians according to the DSM-III-R criteria based on semistructured interview and testing, neurologic examination, and standardized assessments of cerebral vascular disease, Parkinson's disease, and depression. The Chinese IQCODE showed no association with the subjects' education level or gender, low association with their age, and moderately high association with their MMSE-CE score. The area under the receiver operating characteristic curve of the IQCODE was significantly larger than that of the MMSE-CE for the whole group and for the subgroup with 1 to 19 years of education but not for the subgroup with 0 years of education. Nine of the 26 items of the IQCODE could be deleted without appreciable reduction in sensitivity and specificity. The IQCODE (1) can be shortened to 17 items, (2) had good cross-cultural applicability, and (3) was better than the MMSE-CE as a screening tool for dementia in a population with large variation in educational backgrounds.

Performance on a dementia screening test in relation to demographic variables. Study of 5297 community residents in Taiwan.

OBJECTIVE: To examine the relation between performance on a dementia screening test and the demographic variables of age, education, gender, and urban vs rural residency. DESIGN: Community survey with cluster sampling. SETTING: One urban and one rural community from each of four geographic regions in Taiwan, Republic of China. PARTICIPANTS: A total of 5265 nondemented individuals approximately equally divided between men and women and between urban and rural residency with a range in age from 41 to 88 years and in education from 0 to 20 years. MAIN OUTCOME MEASURE: Score on a Chinese adaptation of the Mini-Mental State Examination. RESULTS: Lower test scores were associated with older age and less education. The decrease in score with age was faster among participants who had never attended school. Better performance by men and by urban residents was found only among participants with fewer than 6 years of schooling. In this group, the magnitudes of sex and residency differences were comparable among those subjects aged 41 to 64 years and those aged 65 to 88 years. Women who had never worked outside of the home performed poorer than those who had worked outside of the home. CONCLUSIONS: The influence of educational background on test performance is most evident in individuals with less education. Commonly used dementia screening tests may be unfair to poorly educated individuals, especially women and rural residents. Efforts should be made to develop ecologically relevant cognitive tests for the intended study populations. To help distinguish test bias from different rates of cognitive decline, the study populations should include individuals in predementia age ranges.

The Cognitive Abilities Screening Instrument (CASI): a practical test for cross-cultural epidemiological studies of dementia.

The Cognitive Abilities Screening Instrument (CASI) has a score range of 0 to 100 and provides quantitative assessment on attention, concentration, orientation, short-term memory, long-term memory, language abilities, visual construction, list-generating fluency, abstraction, and judgment. Scores of the Mini-Mental State Examination, the Modified Mini-Mental State Test, and the Hasegawa Dementia Screening Scale can also be estimated from subsets of the CASI items. Pilot testing conducted in Japan and in the United States has demonstrated its cross-cultural applicability and its usefulness in screening for dementia, in monitoring disease progression, and in providing profiles of cognitive impairment. Typical administration time is 15 to 20 minutes. Record form, manual, videotape of test administration, and quizzes to qualify potential users on the administration and scoring of the CASI are available upon request.

Opportunities and challenges in international collaborative epidemiologic research of dementia and its subtypes: studies between Japan and the U.S.

Estimates of the prevalence rates for dementia vary significantly among countries. Such variation may be explained, at least in part, by methodologic differences in studies. The disparities in prevalence rates of dementia subtypes, particularly Alzheimer's disease and multi-infarct dementia, are especially apparent in studies conducted in Eastern and Western countries. In Japan and China, the prevalence of multi-infarct dementia exceeds that of Alzheimer's disease, whereas in the West, Alzheimer's disease predominates in the vast majority of studies. Clearly, cross-cultural studies of incidence using standard methods are needed to investigate whether a true difference in risk exists, and which risk factors differentially contribute to this variation. Migrant studies of genetically homogeneous populations offer a unique opportunity to answer these questions. This article explores the value of migrant studies, their application to etiologic questions of dementia and its subtypes, and recommendations concerning how to conduct such studies.