Jong Inn Woo

Posterior cingulate cortex atrophy and regional cingulum disruption in mild cognitive impairment and Alzheimer's disease

This study aimed to investigate the atrophy of the posterior cingulate cortex (PCC) and medical temporal lobe (MTL) structures (i.e., the entorhinal cortex (ERC) and hippocampus) and the regional disruption of the cingulum bundle in mild cognitive impairment (MCI) and Alzheimers disease (AD) patients. The relationships between atrophy of these structures and regional cingulum disruption were also explored. Three-dimensional MRI and diffusion tensor imaging were applied to 19 MCI, 19 probable AD patients, and 18 normal controls (NC). Fractional anisotropy (FA) values were obtained from three different regions of the cingulum. Both MCI and AD patients showed decreased PCC volumes compared with NC. ERC atrophy was also significant in AD and MCI, while hippocampus atrophy was significant only in AD. MCI patients showed a significant FA decrease in the parahippocampal cingulum (PH-C), whereas AD patients had lower FA values in the posterior cingulate cingulum (PC-C) and PH-C, as compared with NC. However, the middle cingulate cingulum (MC-C) showed no significant FA differences between groups. Moreover, the volumes of MTL structures were significantly correlated with PH-C and PC-C FA values. In terms of PCC functional deficit in MCI or early AD, our results support both the direct effect of PCC atrophy itself and the indirect effect of cingulum fiber degeneration secondary to MTL atrophy.

A nationwide survey on the prevalence of dementia and mild cognitive impairment in South Korea.

We investigated the prevalence of dementia and mild cognitive impairment (MCI) and the factors associate with risk of dementia from a representative nationwide sample of Korean elders. 8,199 randomly-sampled Koreans aged 65 years or older were invited to participate in the Phase I screening assessment using Mini-Mental State Examination by door-to-door home visit, and 6,141 subjects (response rate = 74.9%) responded. Among them, 2,336 subjects were invited to participate in the Phase II diagnostic assessment for dementia and MCI, and 1,673 subjects responded (response rate = 71.6%). Diagnostic assessments were administered using the Korean version of the Consortium to Establish a Registry for Alzheimers Disease Assessment Packet (CERAD-K) Clinical Assessment Battery. The CERAD-K Neuropsychological Assessment Battery was used for diagnosing MCI. Age-, gender-, education-, and urbanicity-standardized prevalence of dementia was estimated to be 8.1% (95% CI = 6.9-9.2) for overall dementia and 24.1% (95% CI = 21.0-27.2) for MCI. Alzheimers disease (AD) was the most prevalent type (5.7%) followed by vascular dementia (2.0%). Amnestic subtype (20.1%) was much more prevalent than nonamnestic subtype in MCI (4.0%). Older age, being male, lower education level, illiteracy, smoking, and histories of head trauma or depression were associated with increased dementia risk, and alcohol use and moderately intense exercise were associated with decreased dementia risk. We expect numbers of dementia patients to double every 20 years until 2050 in Korea and expect AD to account for progressively more dementia cases in the future.

The Prevalence of Dementia in Older People in an Urban Population of Korea: The Seoul Study

OBJECTIVES: To estimate prevalence of dementia and its subtypes in older people in Seoul, a metropolitan area of Korea, and compare these findings with estimates reported for other populations.

Whole-brain Functional Networks in Cognitively Normal, Mild Cognitive Impairment, and Alzheimer’s Disease

The conceptual significance of understanding functional brain alterations and cognitive deficits associated with Alzheimer’s disease (AD) process has been widely established. However, the whole-brain functional networks of AD and its prodromal stage, mild cognitive impairment (MCI), are not well clarified yet. In this study, we compared the characteristics of the whole-brain functional networks among cognitively normal (CN), MCI, and AD individuals by applying graph theoretical analyses to [18F] fluorodeoxyglucose positron emission tomography (FDG-PET) data. Ninety-four CN elderly, 183 with MCI, and 216 with AD underwent clinical evaluation and FDG-PET scan. The overall small-world property as seen in the CN whole-brain network was preserved in MCI and AD. In contrast, individual parameters of the network were altered with the following patterns of changes: local clustering of networks was lower in both MCI and AD compared to CN, while path length was not different among the three groups. Then, MCI had a lower level of local clustering than AD. Subgroup analyses for AD also revealed that very mild AD had lower local clustering and shorter path length compared to mild AD. Regarding the local properties of the whole-brain networks, MCI and AD had significantly decreased normalized betweenness centrality in several hubs regionally associated with the default mode network compared to CN. Our results suggest that the functional integration in whole-brain network progressively declines due to the AD process. On the other hand, functional relatedness between neighboring brain regions may not gradually decrease, but be the most severely altered in MCI stage and gradually re-increase in clinical AD stages.

Subclinical hypothyroidism (SCH) is not associated with metabolic derangement, cognitive impairment, depression or poor quality of life (QoL) in elderly subjects.

The objective of this study was to examine the relationship between SCH and metabolic and neuropsychiatric derangements in Korean elderly subjects. Nine hundred and eighteen euthyroid and SCH subjects aged 65 years and older were enrolled in the present study. We compared anthropometric (age, sex, blood pressure, body mass index=BMI, body fat contents=BF, waist circumference=WC and hip circumference=HC), laboratory (glucose and lipid profile, renal and liver functions, and C-reactive protein=CRP levels), and neuropsychiatric (neuropsychological function, mood, and QoL) parameters of SCH subjects with those of euthyroid subjects. Associated metabolic disorders of the subjects were also compared between the euthyroid and SCH groups. We could not observe any differences between the SCH group and the euthyroid group with regards to metabolic parameters as well as neuropsychiatric parameters. These findings may suggest that SCH does not appear to be associated with metabolic and neuropsychiatric derangement in elderly subjects.

Prevalence Estimation of Dementia in a Rural Area of Korea

OBJECTIVES: A cross‐sectional survey was conducted to estimate prevalence of dementia and to determine factors related to dementia among residents in a rural area, Yonchon county, Korea, in 1993.

Standardization of the Korean Version of the Geriatric Depression Scale: Reliability, Validity, and Factor Structure

Objective We developed a Revised Korean version of the Geriatric Depression Scale (GDS-KR) and examined its reliability, validity, and factor structures. We also estimated its optimal cutoff scores for major depressive disorder (MDD) and minor depressive disorder (MnDD) stratified by age and education. Methods The GDS-KR was administered to 888 subjects (61 MDD patients, 45 MnDD patients, and 782 normal elders). Its internal consistency and test-retest reliability were examined. Its concurrent validity was evaluated using Pearson correlation coefficients with the Korean version of the Center for Epidemiologic Studies Depression Scale (CES-D-K) and Hamilton Depression Rating Scale (HAM-D). The mean GDS-KR scores of the MDD patients, MnDD patients and normal elders were compared to evaluate its discriminant validity. To evaluate its construct validity, a principal component analysis with varimax rotation was performed. Receiver operator characteristic (ROC) curve analyses were performed to evaluate its diagnostic ability. Results Chronbachs coefficient alpha for the GDS-KR was 0.90 and the test-retest reliability was 0.91 (p<0.01). The Pearson correlation coefficients of the GDS-KR scores with the CES-D-K and HAM-D scores were 0.63 (p<0.01) and 0.56 (p<0.01), respectively. The GDS-KR consisted of 5 factors. The optimal cut-off scores of the GDS-KR were 16/17 for MDD only and 15/16 for both MDD and MnDD. The optimal cutoff scores of the GDS-KR were higher in the less educated and younger subjects. The diagnostic accuracy for MDD of the GDS-KR was higher than that of the CES-D. Conclusion The GDS-KR was found to be a reliable and valid questionnaire for screening MDD and MnDD in late life.

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.

Microstructural alteration of the anterior cingulum is associated with apathy in Alzheimer disease.

OBJECTIVES To identify regional alterations of white matter integrity associated with apathy in Alzheimer disease (AD). DESIGN Cross-sectional study. SETTING University Dementia Clinic. PARTICIPANTS Fifty-one very mild or mild probable AD subjects. INTERVENTION Volumetric magnetic resonance imaging with diffusion tensor imaging. MEASUREMENTS Volume of interest analyses were performed to compare regional fractional anisotropy (FA) between apathy and apathy-free group, and to test linear relationship between regional FA and apathy severity. Apathy was assessed by the Neuropsychiatric Inventory. RESULTS Apathy group showed significantly lower FA values than apathy-free group in the left anterior cingulum (A-C), regardless of concomitant depression and psychotropic medications. Left A-C FA values also had significant linear relationship with apathy-composite scores as a measure of apathy severity, even after controlling gray matter density of the ipsilateral anterior cingulate cortex. CONCLUSIONS Our findings support that communication failure between the anterior cingulate cortex and other brain structures via the A-C contributes to the development and aggravation of apathy in AD, additionally supporting the general notion of disconnection syndrome for clinical manifestation of AD.

Prevalence of major depressive disorder and minor depressive disorder in an elderly Korean population: Results from the Korean Longitudinal Study on Health and Aging (KLoSHA)

OBJECTIVE We investigated the prevalence, risk factors and impact of major depressive disorder (MDD) and minor depressive disorder (MnDD) in a randomly selected community-dwelling Korean elderly population. METHOD This study was conducted as a part of the Korean Longitudinal Study on Health and Aging (KLoSHA). A study population of 1118 Korean elders was randomly sampled from residents of Seongnam, Korea aged 65 years or older. Standardized face-to-face interviews and neurological and physical examinations were conducted on 714 respondents using the Korean version of Mini International Neuropsychiatric Interview. MDD was diagnosed according to the DSM-IV criteria, and MnDD according to research criteria proposed in Appendix B of the DSM-IV criteria. RESULTS Age-, gender- and education-standardized prevalence rates in Korean elders aged 65 years or older were estimated as 5.37% (95% CI=3.72-7.03) for MDD, 5.52% (95% CI=3.84-7.19) for MnDD, and 10.89% (95% CI=8.60-13.17) for overall late-life depression (LLD). A prior MDD episode (OR=3.07, 95% CI=1.38-6.82 in MDD, OR=3.44, 95% CI=1.49-7.94 in MnDD), female gender (OR=3.55, 95% CI=1.53-8.24 in MDD, OR=2.68, 95% CI=1.19-6.04 in MnDD) and history of stroke or TIA (OR=3.45, 95% CI=1.62-7.35 in MDD, OR=2.95, 95% CI=1.34-6.52 in MnDD) were associated with the risks of both MDD and MnDD. Lack of formal education (OR=2.75, 95% CI=1.30-5.85) and low income (OR=2.83, 95% CI=1.02-7.88) were associated with the risk of MDD only. Quality of life (QOL) of the MDD and MnDD patients was worse than that of non-depressed elders (P<0.001, ANOVA). CONCLUSION MnDD was as prevalent as MDD in Korean elders and impacted QOL as MDD did. MnDD patients may increase in the future with accelerated population aging and westernization of lifestyle in Korea.