Development and validation of a new cognitive screening test: The Hong Kong Brief Cognitive Test (HKBC).

OBJECTIVES: To develop and examine the validity of a new brief cognitive test with less educational bias for screening cognitive impairment. METHODS: A new cognitive test, Hong Kong Brief Cognitive Test (HKBC), was developed based on review of the literature, as well as the views of an expert panel. Three groups of subjects aged 65 or above were recruited after written consent: normal older people recruited in elderly centres, people with mild NCD (neurocognitive disorder), and people with major NCD. The brief cognitive test, Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment Scale (MoCA), were administered to the subjects. The performance of HKBC in differentiating subjects with major NCD, mild NCD, and normal older people were compared with the clinical diagnosis, as well as the MMSE and MoCA scores. RESULTS: In total, 359 subjects were recruited, with 99 normal controls, 132 subjects with major NCD, and 128 with mild NCD. The mean MMSE, MoCA, and HKBC scores showed significant differences among the 3 groups of subjects. In the receiving operating characteristic curve analysis of the HKBC in differentiating normal subjects from those with cognitive impairment (mild NCD + major NCD), the area under the curve was 0.955 with an optimal cut-off score of 21/22. The performances of MMSE and MoCA in differentiating normal from cognitively impaired subjects are slightly inferior to the HKBC. CONCLUSIONS: The HKBC is a brief instrument useful for screening cognitive impairment in older adults and is also useful in populations with low educational level.

Screening of mild cognitive impairment in Chinese older adults--a multistage validation of the Chinese abbreviated mild cognitive impairment test.

OBJECTIVE: To develop a short cognitive test for screening mild cognitive impairment (MCI) in Hong Kong Chinese older adults. METHODS: The Chinese Abbreviated MCI (CAMCI) test was developed with a multistage process. In phase 1, a short version of the cognitive test comprising a 1-min animal fluency test and a 10-min delayed word list recall was developed and tested in 578 volunteers (community-dwelling active elderly persons). In phase 2, the CAMCI test was validated in an independent and randomly recruited sample of 459 participants in a community survey. Additionally, the predictive significance of the CAMCI test was evaluated in a group of 196 subjects assessed in phase 1 for conversion to clinical dementia at 20 months' follow-up. The discriminating power of the CAMCI test in differentiating MCI from normal control (NC) and mildly demented subjects was compared with Mini Mental State Examination (MMSE) and Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) subscales. RESULTS: The CAMCI test was found to have high discriminating power in differentiating NC from MCI and mildly demented subjects in the phase 1 volunteer sample. The receiver operating characteristics (ROC) revealed an area under the curve (AUC) of 0.91. The ROC were further validated in the phase 2 sample. The AUC of the CAMCI test was compared with MMSE and ADAS-Cog subscales. The short MCI test was comparable to the ADAS-Cog subscale in discriminating NC from MCI and demented subjects (chi(2) test, p = n.s.). Logistic regression analysis was carried out to determine significant baseline predictors for conversion to dementia at phase 3 follow-up. Both ADAS-Cog total [Exp(B) = 1.115, p = 0.028] and CAMCI [Exp(B) = 0.88, p = 0.045] scores were significant predictors for dementia status at follow-up. CONCLUSION: The CAMCI test is able to discriminate NC from MCI and mild dementia in Hong Kong Chinese older adults. Its potential for large-scale community screening for early detection of cognitive impairment in late life should be emphasized and explored.

Presynaptic regulation of quantal size by the vesicular glutamate transporter VGLUT1.

A fundamental question in synaptic physiology is whether the unitary strength of a synapse can be regulated by presynaptic characteristics and, if so, what those characteristics might be. Here, we characterize a newly proposed mechanism for altering the strength of glutamatergic synapses based on the recently identified vesicular glutamate transporter VGLUT1. We provide direct evidence that filling in isolated synaptic vesicles is subject to a dynamic equilibrium that is determined by both the concentration of available glutamate and the number of vesicular transporters participating in loading. We observe that changing the number of vesicular transporters expressed at hippocampal excitatory synapses results in enhanced evoked and miniature responses and verify biophysically that these changes correspond to an increase in the amount of glutamate released per vesicle into the synaptic cleft. In addition, we find that this modulation of synaptic strength by vesicular transporter expression is endogenously regulated, both across development to coincide with a maturational increase in vesicle cycling and quantal amplitude and by excitatory and inhibitory receptor activation in mature neurons to provide an activity-dependent scaling of quantal size via a presynaptic mechanism. Together, these findings underscore that vesicular transporter expression is used endogenously to directly regulate the extent of glutamate release, providing a concise presynaptic mechanism for controlling the quantal efficacy of excitatory transmission during synaptic refinement and plasticity.

Screening Chinese patients with eating disorders using the Eating Attitudes Test in Hong Kong.

OBJECTIVE: To evaluate the Chinese Eating Attitudes Test (EAT-26) in screening patients with anorexia nervosa (AN) and bulimia nervosa (BN) in Hong Kong. METHOD: A consecutive series of Chinese patients with BN (N = 67) and typical (fat phobic; N = 65) and atypical (nonfat phobic; N = 44) AN underwent clinical assessment and completed the EAT-26. Results were compared with those of Chinese female undergraduates (N = 646). RESULTS: The mean EAT scores for bulimic and typical AN patients were significantly higher than those of undergraduates, but the scores of atypical AN patients were anomalously low. The dieting and bulimia factor, scores and body mass indices entered the classification tree. When compared with using the conventional EAT-26 cutoff, the misclassification rate for typical AN, atypical AN, and BN changed from 41.4% to 52.3%, 88.6% to 43.2%, and 23.9% to 29.9%, respectively. DISCUSSION: Using the EAT-26 in the conventional manner would lead to an underestimate of atypical AN in community surveys. Complementary use of a classification tree improved the prediction of atypical AN, but the EAT-26 remains a suboptimal screening instrument for the community epidemiological study of AN.