Jong Chul Youn

Diagnostic Accuracy of Mini-Mental Status Examination and Revised Hasegawa Dementia Scale for Alzheimer’s Disease

To compare the diagnostic accuracies of the Revised Hasegawa Dementia Scale (HDS-R) and Mini-Mental Status Examination (MMSE) for Alzheimer’s diseases (AD), we administered them simultaneously to 82 AD patients and 82 age- and sex-matched nondemented control subjects. The area under the receiver operator curve (AUC) for AD of the HDS-R (AUCHDS-R) and MMSE (AUCMMSE) were bigger than 0.90 indicating that both tests are useful for detecting AD. However, AUCHDS-R (0.952) was significantly larger than that of the AUCMMSE (0.902) regardless of the educational level of the subjects, indicating that the HDS-R is more accurate than MMSE in diagnosing AD. Moreover, the superiority of the HDS-R (AUCHDS-R = 0.894) to the MMSE (AUCMMSE = 0.704) remained significant in mild AD patients alone, who are the focus of screening. In conclusion, the HDS-R is better than the MMSE as a screening instrument for AD.

Prevalence of Dementia and Its Subtypes in an Elderly Urban Korean Population: Results from the Korean Longitudinal Study on Health and Aging (KLoSHA)

Background/Aims: We estimated the prevalence of dementia and its major subtypes in an elderly urban Korean population. Methods: A study population of 1,118 Korean elders was randomly sampled from the residents aged 65 years or older living in Seongnam, Korea. Standardized face-to-face interviews, and neurological and physical examinations were conducted on 714 respondents. Dementia was diagnosed according to the DSM-IV diagnostic criteria, and its subtypes were determined according to the criteria of the NINCDS-ADRDA, the NINDS-AIREN, and the consensus guideline proposed by McKeith et al. [Neurology 1996;47:1113–1124]. Results: The estimated age- and gender-standardized prevalences were 6.3% for dementia (95% CI = 4.5–8.1), 4.8% for Alzheimer’s disease (AD; 95% CI = 3.3–6.4), 1.0% for vascular dementia (VD; 95% CI = 0.3–1.8), and 0.4% for dementia with Lewy bodies (DLB; 95% CI = 0.0–0.9). The prevalence of AD consistently increased with age, whereas that of VD peaked at age 75–79 years and decreased thereafter. Of the dementia patients, 72.0% were in the very mild or mild stages of the disease. Conclusions: The prevalence of dementia in a typical urban area of Korea was estimated to be 6.3%, and AD was the most prevalent subtype. DLB was less prevalent than VD among these community-dwelling Korean elders.

Depression in Vascular Dementia Is Quantitatively and Qualitatively Different from Depression in Alzheimer's Disease

Background/Aims: To compare the prevalence and characteristics of depression in vascular dementia (VaD) and Alzheimer’s disease (AD) after adjusting for dementia severity and gender. Methods: One hundred and eight pairs of VaD and AD patients matched for dementia severity and gender were assessed. Results: Major depressive disorder (MDD) was more prevalent in the VaD group than in the AD group (20.4% in VaD, 10.2% in AD, p = 0.04, Cochran-Mantel-Haenszel, CMH, test) regardless of the dementia severity and gender. The odds ratio for developing MDD in the VaD group versus the AD group was estimated to be 2.20 (95% confidence interval = 1.02–4.74). Neurovegetative symptoms such as ‘felt tired and weak all the time’ (30.6% in VaD, 13.9% in AD, p = 0.003, CMH test) and ‘changed weight without trying’ (16.7% in VaD, 6.5% in AD, p = 0.02, CMH test) were more prevalent in the VaD group than in the AD group. Conclusion: Depression in VaD was quantitatively and qualitatively different from that in AD regardless of the severity of dementia and gender; depression was more prevalent, severer and more retarded and vegetative in VaD than in AD.

The Domain-Specific, Stage-Limited Impact of the Apolipoprotein E Epsilon-4 Allele on Cognitive Functions in Alzheimer’s Disease

To examine the impact of the APOE Ε4 allele on the cognitive functions of Alzheimer’s disease (AD) patients, we administered the eight neuropsychological tests from the Consortium to Establish a Registry for Alzheimer’s Disease Neuropsychological Assessment Battery to 118 Korean AD patients. The impact of the APOE Ε4 allele was significant in the Word List Recall Test (WLRT) and the Word List Recognition Test (WLRcT) only, and its impact was confined to the very mild AD (VMAD) patients (F = 7.65, d.f. = 2, p < 0.01 for WLRT; F = 3.27, d.f. = 2, p = 0.04 for WLRcT). In the VMAD group, the performance on the two tests of the APOE-Ε4-positive patients was poorer than that of the APOE-Ε4-negative patients. Our findings suggest that the impact of the APOE Ε4 allele on cognitive functions in AD may be domain specific and confined to the early stage of AD.

Discrimination of normal aging, MCI and AD with multimodal imaging measures on the medial temporal lobe

This study aimed to compare the discrimination accuracy of hippocampal volume (HC-Vol), parahippocampal cingulum fractional anisotropy (PHC-FA), hippocampal glucose metabolism (HC-Glu), and any combination of the three measurements among normal control (NC), mild cognitive impairment (MCI), and Alzheimers disease (AD). Three-dimensional MRI, diffusion tensor imaging, and FDG-PET were applied to age- and gender-matched 17 NC, 17 MCI, and 17 mild AD patients. Subjects also underwent a neuropsychological test battery including three verbal episodic memory tests. Logistic regression analyses were systematically conducted to select the best model for between-group discrimination. PHC-FA plus HC-Vol model, HC-Glu only model, and the model combining all three modalities were finally chosen for NC vs. MCI (discrimination accuracy: 79.4%), MCI vs. AD (73.5%), and NC vs. AD discrimination (94.1%), respectively. All the three imaging measures also showed significant correlation with all three episodic memory tests. These findings support that each imaging measure, respectively, and their combination have a stage-specific potential as a useful neuroimaging marker for detection and progression monitoring of early stage of AD.

Development of the Subjective Memory Complaints Questionnaire

Aim: We aimed toevaluatethe psychometric properties of the Subjective Memory Complaints Questionnaire (SMCQ). Methods: The reliability of the SMCQ was evaluated by testing its internal consistency and test-retest reliability. Pearson correlation analyses were performed to assess the concurrent validity. Confirmatory factor analysis was used to evaluate the construct validity. Diagnostic ability for dementia was tested with receiver operator characteristic curve analyses. Results: Cronbach’s α coefficient and intraclass correlation coefficients of the SMCQ were 0.864 and 0.828 (p < 0.001), respectively. The SMCQ scores were significantly correlated with the scores on Camdex Memory Complaint Questionnaire, Seoul Informant Report Questionnaire for Dementia and cognitive tests from the CERAD (Consortium to Establish a Registry for Alzheimer’s Disease) neuropsychological test battery (p < 0.01). The results of confirmatory factor analyses confirmed that the SMCQ consisted of subjective memory complaints (SMC) for general memory and for everyday memory. The SMCQ score discriminated well between nondemented elderly without dementia and those with dementia (p < 0.01). The area under the curve value of the SMCQ was 0.84, indicating that it had high diagnostic ability. Conclusion: The SMCQ was found to be a brief, reliable and valid questionnaire for evaluating SMC. It might be useful for evaluating the cognition of elderly subjects when reliable informants are not available.

Prevalence of neuropsychiatric syndromes in Alzheimer's disease (AD)

This study aimed to estimate the prevalence and explore the multidimensional complexity of the neuropsychiatric syndromes of AD. Neuropsychiatric symptoms and syndromes of 216 subjects with probable and possible AD diagnosed by NINCDS-ADRDA criteria were evaluated by the Korean version of behavior rating scale for dementia (BRSD-K). The prevalence rate of six neuropsychiatric syndromes (depressive symptoms, inertia, vegetative symptoms, irritability/aggression, behavioral dysregulation, psychotic symptoms) and comorbid neuropsychiatric syndromes were calculated according to the Clinical Dementia Rating scale. To investigate the relationship among neuropsychiatric syndromes, logistic regression analyses were performed. About 95% of patients with AD had one or more neuropsychiatric symptoms and syndromes during the past month. Among the neuropsychiatric syndromes, irritability/aggression (76.2%) was the most frequent, followed by apathy (72.3%) and depressive symptoms (68.0%). About 90% of the subjects had one or more comorbid neuropsychiatric syndromes. The mean numbers of comorbid neuropsychiatric syndromes were significantly varied according to the severity of disease (p<0.05). Depressive symptoms were significantly associated with vegetative symptoms and irritability/aggression (p<0.05). Inertia and psychotic symptoms were significantly associated with vegetative symptoms and behavioral dysregulation, respectively (p<0.05). This study demonstrated that neuropsychiatric syndromes of AD were highly prevalent and involved complex relationships among them.

Association of alpha-2-macroglobulin deletion polymorphism with sporadic Alzheimer’s disease in Koreans

Alpha-2-macroglobulin (A2M) deletion polymorphism was recently reported to be associated with Alzheimers disease (AD) in a way comparable to apolipoprotein E (APOE) polymorphism in a family-based study. However, the association of A2M deletion polymorphism with AD has not been consistently replicated in successive case-controlled studies. In order to evaluate whether this A2M polymorphism is associated with AD in Koreans, we examined the frequencies of the A2M deletion (D) allele and D-bearing genotypes in a group of Koreans composed of 100 sporadic AD patients and 203 control subjects. The frequency of the deletion (D) allele (P=0.046) was significantly different between the total group of AD patients and the controls, although the frequency of the D-bearing genotypes did not attain significance (P=0.078). When the subjects were stratified according to age at onset, there was significant difference in the frequencies of the D allele (P=0.044) and D-bearing genotypes (P=0.041) between late-onset AD patients (> or =65 years) and the controls. However, no significant difference was observed between early-onset AD patients (<65 years) and the control group. Additionally, when we divided the late-onset AD and control subjects by APOE epsilon4 status, the difference of the A2M D allelic frequency was significant only in the APOE epsilon4 negative subjects (P=0.015). In conclusion, our data suggests that the A2M D allele is a modest risk factor for late-onset sporadic AD in Koreans, and the AD risk conferred by the A2M D allele increases in APOE epsilon4 negative subjects.

Smoking in elderly Koreans: Prevalence and factors associated with smoking cessation

The aims of this study were to investigate the prevalence of smoking and to explore the factors associated with smoking cessation. 1118 Koreans were randomly sampled from the residents aged 65 years or older living in Seongnam, Korea. Structured face-to-face interviews with neurological and physical examinations were conducted to the 714 respondents. A current smoker was defined as a person who had been smoking at least one cigarette per day for 1 year, and a past smoker as a person who used to smoke but had not smoked in the past 1 year. Nicotine dependence was defined as having the Fagerström Test for Nicotine Dependence (FTND) score of 4 or higher. Age- and gender-standardized prevalence of ever smoker, past smoker and current smoker among the elderly Koreans aged 65 and over were estimated to be 36.3% (95% CI=32.7-39.8), 24.4% (95% CI=21.2-27.5) and 11.9% (95% CI=9.5-14.3), respectively. Current smokers were much more prevalent in men (23.3%) than in women (3.9%), but did not decline with advancing age in both genders. 36.0% (21 men, 10 women) of the current smokers were nicotine-dependent. The smokers with depression or alcohol use disorder (AUD) were less likely and those who were educated more or inhaled smoke more deeply were more likely to quit smoking. Thus, smoking is common in the elderly men, and treatments of depression and AUD may be helpful in increasing smoking cessation rate among elderly Koreans.

The Severe Cognitive Impairment Rating Scale – An Instrument for the Assessment of Cognition in Moderate to Severe Dementia Patients

Background/Aims: This study aimed to develop a brief, reliable and valid test for cognitive function of severely demented patients. Methods: We constructed the Severe Cognitive Impairment Rating Scale, which consisted of 11 items covering memory, language, visuospatial function, frontal function and orientation, and investigated its reliability and validity on 267 subjects [normal: 65, very mild Alzheimer’s disease (AD): 42, mild AD: 58, moderate AD: 36, severe AD: 44, profound AD: 22]. Results: The internal consistency obtained by Cronbach’s coefficient α was 0.93. The interrater reliability and test-retest reliability in the moderately to severely impaired subjects with an MMSE score of ≤14 was 0.99 (p < 0.001) and 0.90 (p < 0.001), respectively. It showed significant correlation with Severe MMSE (r = 0.96, p < 0.01), MMSE (r = 0.86, p < 0.01) and Clinical Dementia Rating (r = –0.83, p < 0.01). It was robust to both the floor effect in the severe/profound stage of AD and the ceiling effect in the mild/moderate stage of AD. Exploratory factor analysis yielded 2 factors (automatic informational processing and controlled informational processing) accounting for 73.5% of the total variance. Conclusions: The Severe Cognitive Impairment Rating Scaleis a valid and reliable test for evaluating the cognitive function of advanced AD patients.