Ker-Neng Lin

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.

Weight loss, nutritional status and physical activity in patients with Alzheimer’s Disease

Abstract.The etiology of weight loss in Alzheimer’s disease (AD) patients is still uncertain. This study was designed to investigate the possible factors that might contribute to weight change of AD patients. From July 1999 to June 2001, we recruited 51 AD patients and 27 non-demented controls. Demographic data, neuropsychological tests, Geriatric Depression Scale-Short Form, eating behavior questionnaire, dietary and physical activity diaries, anthropometric and laboratory measures of nutritional status were assessed. More than half of our AD patients developed body weight loss, and overall, the AD patients were significantly thinner than the non-demented subjects. Anthropometric and laboratory measures suggested a poorer nutritional status in the AD patients. The AD patients had fewer daily physical activities. More AD patients had the problem of poor appetite. However, daily calorie intake was not significantly different between the two groups. The AD patients, especially those who presented with body weight loss, even consumed more calories per body weight kilogram (kg) per day. In the food composition analysis, AD patients took more carbohydrate than controls. Multivariate regression analysis showed the existence of AD and poor appetite were the main risk factors of weight loss. We suggest that the pathophysiological process in AD gives rise to the changes of appetite and metabolic state in AD patients, and that these changes contribute to the weight loss.

Cutoff Scores of the Cognitive Abilities Screening Instrument, Chinese Version in Screening of Dementia

The purpose of this study of dementia screening was to obtain different cutoff scores of the Cognitive Abilities Screening Instrument, Chinese versions (CASI C-2.0) for subjects with different educational backgrounds. The diagnosis of dementia was based on the Diagnostic and Statistical Manual of Mental Disorders, ed 3 revised or ed 4 criteria. To diagnose Alzheimer’s disease, the guidelines of the National Institute of Neurological and Communicative Disorders and Stroke and Alzheimer’s Disease and Related Disorders Association was followed. The severity of dementia was determined on the Clinical Dementia Rating scale. Altogether 2,096 subjects, aged 65 years and more, were included. Of them, 1,178 were normal and 918 were demented. Their performance on CASI C-2.0 was influenced by their education and age. Gender difference on CASI C-2.0 scores was only significant in the illiterate, but not in the literate group. We recommend that the population be divided into three levels, namely those who (1) had no formal education (Edu = 0); (2) received 1–5 years of schooling (Edu = 1–5), and (3) received 6 or more years of education (Edu ≧6). The cutoff scores of CASI C-2.0 in the diagnosis of dementia in these three educational groups were as follows: Edu = 0: 49/50 (sensitivity = 0.83; specificity = 0.85); Edu = 1–5: 67/68 (sensitivity = 0.83; specificity = 0.91), and Edu ≧6: 79/80 (sensitivity = 0.89; specificity = 0.90).

Prevalence and subtypes of dementia in a rural Chinese population.

We conducted a single-stage community-based study of dementia on all registered residents ≥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 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.

Functional Disability Profiles in Amnestic Mild Cognitive Impairment

Background/Aims: Instrumental activities of daily living (IADL) can be impaired in mild cognitive impairment (MCI), and the severity of functional disability predicts Alzheimer’s disease (AD) in amnestic MCI (aMCI). This study investigated the functional profiles of aMCI in a Chinese population. Methods: The Disability Assessment for Dementia scores of 56 subjects with single-domain aMCI (sd-aMCI) and 94 with multiple-domain aMCI (md-aMCI) were compared with normal controls (n = 64) and mild AD patients (n = 102). Results: Both the sd-aMCI (2.5 ± 2.5) and md-aMCI (3.7 ± 3.5) groups had more impaired IADL items than the controls (0.7 ± 1.7). Their IADL scores were intermediate, between the control and AD groups. sd-aMCI subjects presented deficits in 7 IADL items involving the ‘meal preparation’, ‘telephoning’, ‘finance’, ‘medications’, ‘housework’, and ‘leisure’ subscales. md-aMCI subjects presented deficits in 14 IADL items involving all subscales of daily activities. The Mini-Mental State Examination and Modified Trail-Making Test Part B scores were the major neuropsychological correlates of IADL performance in aMCI. Conclusion: IADL can be impaired in both sd-aMCI and md-aMCI. Including the functional ability assessment in the evaluation of aMCI may help clinicians to provide appropriate suggestions to maintain daily functioning.

Posterior ischemia during an attack of transient global amnesia.

Background The popular concept that cerebral ischemia causes transient global amnesia has been difficult to prove by cerebral blood flow studies during attacks because the transient global amnesia attacks are so short. Case Description We performed single-photon emission computed tomography (SPECT) of the brain and neuropsychological assessment in a 37-year-old woman during a 10-hour attack and twice thereafter. A neuropsychological evaluation 3 hours after the onset of transient global amnesia revealed severe impairment of recent memory and verbal fluency, both of which returned to normal 2 and 28 days later, respectively. A 99mTc-labeled hexamethylpropyleneamine oxime SPECT of the brain performed 6 hours after the onset showed multiple perfusion defects in both occipital lobes, the medial left temporal lobe, and the left thalamus. A second brain SPECT performed 3 days later showed perfusion defects in only the occipital regions. A third brain SPECT performed 28 days later was normal. The patients brain computed tomographic scan, electroencephalogram, duplex ultrasound of the carotid artery, and echocardiogram were normal Conclusions The perfusion defects revealed by the brain SPECT during the transient global amnesia attack indicated ischemia in the territory of the posterior cerebral arteries, which partially resolved in 3 days and completely resolved by 28 days.

The Three-Item Clock-Drawing Test: A Simplified Screening Test for Alzheimer’s Disease

The Clock-Drawing Test (CDT) has been used to screen for Alzheimer’s disease (AD) as a supplement to cognitive tests that focus on memory impairment. We examined a comprehensive scoring system of the CDT in screening of AD in a Chinese population and derived a simplified scoring system. All 403 (144 AD and 259 nondemented) subjects were administered the CDT, including both the drawing part (CDT-D) and the copying part (CDT-C). The Cognitive Abilities Screening Instrument and the Clinical Dementia Rating were also administered. Stepwise discriminant analysis was used to develop a simplified CDT scoring system. The optimal CDT cutoff scores (CDT-D: 10/11; CDT-C: 12/13) show intermediate sensitivity (CDT-D: 66.7%; CDT-C: 51.4%) and specificity (CDT-D: 74.5%; CDT-C: 74.1%). The simplified 3-item CDT scoring system, with a cutoff score of 2/3, has a sensitivity of 72.9% and a specificity of 65.6%; it can be used as a quick test for AD screening.

Cognitive Reserve: A SPECT Study of 132 Alzheimer’s Disease Patients with an Education Range of 0–19 Years

This study examines the associations between education, cerebral perfusion, and cognitive test performance among 132 patients with Alzheimer’s disease. The participants had had between 0 and 19 years of formal schooling, and had either mild or moderate dementia according to the Clinical Dementia Rating Scale. Cerebral perfusion was evaluated by the 99mTc-hexamethylpropylene amine oxime single photon emission computed tomography. The Mini-Mental State Examination and the Cognitive Abilities Screening Instrument were used to assess cognitive performance. For patients at each clinical dementia severity level, statistical parametric mapping was used to examine voxel by voxel the association between education and cerebral perfusion, and Pearson’s correlation coefficients were calculated between education and cognitive test scores. Years of formal schooling had negative associations with cerebral perfusion and positive associations with cognitive test scores. The brain regions showing a significant education effect on perfusion involved bilateral posterior association areas in mild dementia, and bilateral parieto-temporo-frontal areas in moderate dementia. The present findings indicate that the cognitive reserve effect starts at the low end of the education range. They also suggest that the main effect of more education is a more facile use of alternative brain circuits instead of locally increased synaptic connections.

The Alzheimer’s Disease Assessment Scale: Findings from a Low-Education Population

We constructed a Chinese version of the cognitive component of the Alzheimer’s Disease Assessment Scale (ADAS-Cog). In order to accommodate illiteracy, the Chinese version used pictures instead of words for assessing recall and recognition. The Chinese ADAS-Cog was administered to 125 individuals with no dementia, 127 with questionable dementia, and 77 with Alzheimer’s disease (AD). Their age range was 51–92 years and their education range was 0–20 years. The Chinese ADAS-Cog had high internal consistency (Cronbach’s alpha = 0.87) and very high interrater reliability (intraclass correlation coefficient, or ICC, = 0.99) and test-retest reliability (ICC = 0.96). It had high correlations with scores on the Clinical Dementia Rating Scale (Pearson’s r = 0.85), the Cognitive Abilities Screening Instrument (CASI, Pearson’s r = –0.88), and CASI-estimated scores on the Mini-Mental State Examination (Pearson’s r = –0.85). Performance on the Chinese ADAS-Cog was uninfluenced by age or gender, nor by education level except within the low education range of 0–6 years. Its memory items were best for early detection of dementia; its language items were best for monitoring the progression of dementia. This study found that the Chinese ADAS-Cog is a good instrument for use with Chinese AD patients.

Accelerated hippocampal atrophy rates in stable and progressive amnestic mild cognitive impairment

Studies suggest that smaller hippocampal volume predicts Alzheimers disease (AD) in mild cognitive impairment (MCI). However, few studies have demonstrated decline rates in cognition and hippocampal volume in MCI subjects with stable clinical presentation. Furthermore, the effects of apolipoprotein E (ApoE) on the change rates of medial temporal structures and cognition in MCI are rarely investigated. Fifty-eight subjects with amnestic MCI and 20 normal aging elderly controls received annual neuropsychological and magnetic resonance imaging (MRI) assessments. Annual decline rates in neuropsychological test scores, hippocampal and amygdalar volumes were calculated. ApoE genotypes were examined. Nineteen (32.7%) MCI subjects converted to AD during an average 22.5-month follow-up period. The annual hippocampal atrophy rate was correlated with a decline in memory test scores. The presence of the ApoE varepsilon4 allele did not affect the change rates in neuropsychological test scores and medial temporal structures volume. Compared to subjects with stable MCI (MCI-S) and normal aging, progressive MCI (MCI-P) had the highest annual decline rates in cognition and hippocampal volume. Logistic regression analysis showed that higher annual decline rates in hippocampal volume and global cognitive test scores were associated with conversion to AD. Furthermore, although MCI-S subjects had little cognitive decline, their hippocampal atrophy rates were higher than those of normal aging controls. Therefore, accelerated hippocampal atrophy rates may be an early and important presentation in MCI subjects.