Handedness in a Chinese population: biological, social, and pathological factors.

A questionnaire survey of 4143 Chinese was conducted. Social pressure for right-handed writing and eating was effective on these two target skills but showed little indirect influence on hand use in other activities. Neither primiparous birth nor birth to older mothers affected handedness. Twinning, however, seemed to be associated with both decreased right-handedness and lower intelligence.

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.

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.

Clinical subtypes of dementia of the Alzheimer type.

Clinical subtypes of dementia of the Alzheimer type were evaluated by comparing age at onset, aphasia, family history, and motor disorder in 146 individuals with progressive dementia. Early onset was significantly associated with more prevalent and more severe language disorder. Forty-five percent of all probands had familial history of dementia, but we could not differentiate relative familial risk based on age at onset or aphasia. Independent of duration of illness, myoclonus and noniatrogenic extrapyramidal disorder were associated with greater severity of dementia.

Left hemisphere pathways in reading: inferences from pure alexia without hemianopia.

In pure alexia, reading is impaired despite almost normal speech, spelling, and writing. We studied a right-handed man with pure alexia, but no hemianopia. He had more difficulty reading longer words (word-length effect), but had no selective reading impairment in phonologic or semantic analysis. Clinical-CT correlation suggests that (1) left hemisphere visual pathways crucial for reading arise from or pass close to the left occipitotemporal or inferior temporal gyrus, and (2) relevant transcallosal fibers from the right hemisphere course inferior to the posterior horn of the left lateral ventricle before ascending to left hemisphere language areas.

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.

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.

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.

The effect of lesions of the corpus callosum on finger localization.

Finger localization was studied in 10 cases of cerebral commissurotomy (four complete, six partial) and 24 normal subjects. Stimulation of one finger with the same hand responding produced ceiling performance in all subjects. Responses with the other hand (cross-localization) were 82% worse with full commissurotomy, 28% worse with the trunk of the corpus callosum sectioned, and 7% worse in the controls. The trunk of the corpus callosum normally transfers tactile information, but the splenium can subsume 50% of this function and tactile transfer with complete commissurotomy exceeded chance levels. The partially sectioned and normal male subjects showed a right-hand stimulation advantage for sequences. In both normals and partially sectioned subjects, cross-localization was poorest when mirror-image transfer of finger sequences was required, while spatial alignment of the fingers facilitated transfer. With complete commissurotomy, response hand orientation did not affect cross-localization. Thus the corpus callosum transmits the position of each hand between the hemispheres.

The Modified Mini-Mental State (3MS) examination.

The Mini-Mental State (MMS) examination is a widely used screening test for dementia. The Modified Mini-Mental State (3MS) incorporates four added test items, more graded scoring, and some other minor changes. These modifications are designed to sample a broader variety of cognitive functions, cover a wider range of difficulty levels, and enhance the reliability and the validity of the scores. The 3MS retains the brevity, ease of administration, and objective scoring of the MMS but broadens the range of scores from 0-30 to 0-100. Greater sensitivities of the 3MS over the MMS are demonstrated with the pentagon item drawn by 249 patients. A summary form for administration and scoring that can generate both the MMS and the 3MS scores is provided so that the examiner can maintain continuity with existing data and can obtain a more informative assessment.

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 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.

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.

Transcallosal, interfornicial approaches for lesions affecting the third ventricle: surgical considerations and consequences.

A group of 11 patients with a variety of lesions affecting the 3rd ventricle have been treated using a direct transcallosal interfornicial approach to the region. In 3 patients, no attendant hydrocephalus was present. In an effort to minimize potential cortical injury related to the approach, we studied the venous anatomy in the region of the coronal suture. Based on this study, appropriate flap placement and interhemispheric entry points were defined. Although no lasting, clinically apparent morbidity was observed in any of the 11 cases, we performed more sophisticated studies of the interhemispheric transfer of somesthetic and perceptual motor tasks, as well as psychometric testing related to parameters of intelligence and memory, 3 to 8 months postoperatively in 6 cases. The results and clinical material indicate that this surgical technique is a safe, feasible alternative in the management of a wide spectrum of pathological lesions within this region. A transcallosal, interfornicial approach offers excellent visualization of the entire 3rd ventricle without the dependence on hydrocephalus or an extensive extra-axial mass to enhance the exposure. With proper planning and technique, it may be accomplished with a minimum of physiological consequence.

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.

Dichotic ear effects with digits and tones: a within-subject comparison.

56 right-handed adults (23 men, 33 women) with IQs ranging from 79 to 140 on the Quick Test each performed on two dichotic tests, one with digital input, one with tonal input. The average magnitude of the right-ear advantage for digits was comparable to that of the left-ear advantage for tones, but there was greater between-subject variability with tonal input than with digital input. Ear advantage with digits was unrelated with ear advantage with tones, and high intelligence was not associated with clearly opposite directions of ear advantage for the two types of test material. The results were discussed in terms of hemispheric specializations, as well as the reliability and validity of the dichotic ear effects.

Right-left discrimination: no sex difference among normals on the Hand Test and the Route Test.

84 male and 76 female high school students were individually examined on two tests which involve right-left discrimination. The Hand Test requires distinguishing drawings of right from left hands. The Route Test involves walking out patterns with various turns according to diagrams drawn on cards. Results on both tests showed a wide range of performance, but differences between the sexes were minute and statistically nonsignificant. In addition to right-left discrimination, each test also taps different additional spatial functions. Both tests are easy to administer in clinical settings; normative data given here can be useful in evaluating patients' performance.