Tae Hui Kim

REM sleep behavior disorder in the Korean elderly population: prevalence and clinical characteristics.

STUDY OBJECTIVES To examine the prevalence and clinical characteristics of REM sleep behavior disorder (RBD) and subclinical RBD in the Korean elderly population. DESIGN A community-based Korean Longitudinal Study on Cognitive Aging and Dementia and time-synchronized video-polysomnography (vPSG) in a laboratory. SETTING Sleep laboratory in a university hospital. PARTICIPANTS 348 individuals aged 60 years or older. INTERVENTION N/A. MEASUREMENTS AND RESULTS Among 696 subjects who were invited to participate in a vPSG study, 348 completed the vPSG. RBD was diagnosed when subjects showed REM sleep without atonia (RSWA) in the vPSG, and had history of complex and vigorous behaviors during sleep or abnormal REM sleep behaviors in the vPSG. Subjects with RSWA but no abnormal REM sleep behaviors were diagnosed with subclinical RBD. Seven subjects (5 male, 2 female) had RBD, three of whom (1 male, 2 female) had Parkinson disease. Two subjects reported history of sleep-related injury. The crude prevalence of RBD and idiopathic RBD was 2.01% (95% confidence interval [CI] = 0.54% to 3.49%) and 1.15% (95% CI = 0.03% to 2.27%). An age and sex-adjusted prevalence estimate of RBD and idiopathic RBD in the Korean elderly was 2.01% and 1.34%. Eighteen subjects were diagnosed with subclinical RBD, and the prevalence of subclinical RBD was estimated to be 4.95%. CONCLUSIONS RBD and subclinical RBD are not rare in the elderly in the community with abnormal REM sleep behaviors of RBD being mild to injurious and violent. The clinical significance and long-term progression of subclinical RBD needs to be further explored, given the prevalence and its possible relation to RBD.

Predictive validity and diagnostic stability of mild cognitive impairment subtypes

Mild cognitive impairment (MCI) is subclassified into four subtypes by the presence of impairment in the memory domain (amnestic vs nonamnestic) and the number of impaired cognitive domains (single vs multiple). However, predictive validity for outcomes of these criteria and the diagnostic stability of the subtypes are questionable.

Cognitive Impairment in Age-related Macular Degeneration and Geographic Atrophy

PURPOSE To investigate cognitive function in patients with early and late age-related macular degeneration (AMD) compared with an elderly, community-dwelling Korean population without AMD. DESIGN Case-control study. PARTICIPANTS We enrolled 170 AMD patients and 190 non-AMD community-based controls. METHODS A comprehensive battery for cognitive function evaluation consisting of 15 psychological tests, including a depression evaluation test, was used. Cognitive function scores were adjusted for age, gender, education, and visual acuity (VA). We categorized AMD as early AMD, exudative AMD, or geographic atrophy. MAIN OUTCOME MEASURES The primary outcome measure was the degree of cognitive impairment, as assessed by the Korean versions of the Consortium to Establish a Registry for Alzheimers Disease Neuropsychological Assessment Battery, Benton Visual Retention Test, and Digit Span Test Forward and Backward. RESULTS Patients with AMD showed lower global cognition scores than did normal controls (mean Mini-Mental State Examination [MMSE] score, 24.97 vs 25.99; P<0.001). Among cognitive functions, visuospatial function, verbal memory, visual memory, and frontal function were impaired in AMD patients relative to normal controls. The rate of mild cognitive impairment (MCI) was higher in AMD patients than in controls (52.4% vs 26.8%; P<0.001), with an odds ratio (OR) of 3.127 (95% confidence interval, 1.855-5.271) after adjustment for age, education, and VA. Geographic atrophy was associated with the highest risk of MCI (OR, 4.431; 95% confidence interval, 1.413-13.898) and a clinically significant reduction in MMSE scores (23.42) relative to the controls. There was a trend of worsening cognitive function test scores from the controls to the early AMD, then the exudative AMD, and finally the geographic atrophy patients, after adjustment for covariates. AMD patients with poor VA (≤20/100) had 6 times the risk of MCI as AMD patients with good or moderate VA (>20/100). CONCLUSIONS Patients with AMD, especially those with the geographic atrophy subtype, are at greater risk for cognitive impairment than are non-AMD control subjects. In the visual rehabilitation of AMD patients, potential cognitive impairment should be taken into consideration.

Korean Version of Frontal Assessment Battery: Psychometric Properties and Normative Data

Background: We developed the Korean version of the Frontal Assessment Battery (FAB-K), evaluated its psychometric properties and constructed normative data for Korean elders. Methods: FAB-K was administered to 300 Alzheimer’s disease (AD) patients and 635 normal controls. Reliability of FAB-K was evaluated by testing its internal consistency, test-retest and inter-rater reliabilities. Validity of FAB-K was evaluated by testing discriminant validity for AD and concurrent validity with other frontal function tests. Age- and education-specific normative data of FAB-K were developed. Results: Cronbach’s α, inter-rater reliability and test-retest reliability of FAB-K were 0.802, 0.980 (p < 0.001) and 0.820 (p < 0.001), respectively. FAB-K exhibited significant correlations with the scores of MMSE and other frontal function tests (p < 0.01). Total and item scores of FAB-K were lower in AD patients than in controls and became worse as clinical dementia rating increased (F = 192.026, d.f. = 4, p < 0.001). The optimal cut-off score of FAB-K for AD was determined as 10/11, where sensitivity and specificity for AD were 0.717 and 0.827, respectively. Normative data were stratified by 3 age groups and 4 education groups. Conclusion: The FAB-K is a valid and reliable instrument for evaluating frontal dysfunction, and may be useful for screening AD.

The effects of topical α-hydroxyacids on the normal skin barrier of hairless mice

Background α‐hydroxyacids (AHA), such as glycolic acid and lactic acid, have recently been used in cosmetic and dermatological formulations. However, the mechanisms of action of these substances have not been well documented.

Plasma adiponectin elevation in elderly individuals with subsyndromal depression

Adiponectin, one of the adipokines, has believed to play a role in developing of depression, but the relationship between plasma adiponectin and depressive disorder is still unclear. To investigate the association between plasma adiponectin and depressive disorders, we measured plasma adiponectin concentrations in 785 randomly sampled elderly Koreans including 41 patients with major depressive disorder (MDD), 46 with minor depressive disorder (MnDD), and 61 with subsyndromal depression (SSD). Plasma adiponectin levels were different among the diagnostic groups (df=3, F=4.928, P=0.002). The plasma adiponectin level in the SSD patients was higher than in the non-depressed controls (NC) (12.48 ± 8.38 μg/ml versus 9.27 ± 6.21 μg/ml, P=0.001, Tukeys post hoc comparison). However, plasma adiponectin levels in the MnDD and MDD patients were comparable with those found in the NC (P>0.1, Tukeys post hoc comparison). The elevation of plasma adiponectin in the SSD patients remained significant in men (P=0.002, Tukeys post hoc comparison) but not in women. In the subjects without MDD and MnDD, plasma adiponectin level was positively correlated with the Hamilton Depression Rating Scale score (r=0.156, P<0.001) and the Geriatric Depression Scale (r=0.117, P=0.002). When men and women were analyzed separately, these significant correlations were confined to men. Circulating adiponectin concentration may play a role in compensation on process for depressive mood.

Effects of social supports on burden in caregivers of people with dementia

BACKGROUND Social support programs for dementia caregivers were widely used in order to reduce care burden. We investigated which types of social supports can reduce psychological and non-psychological burdens of dementia caregivers, and explored the mechanism of those social supports. METHODS We evaluated 731 community-dwelling dementia patients and their caregivers from the National Survey of Dementia Care in South Korea. We investigated the five types of social supports (emotional support, informational support, tangible support, positive social interaction, affectionate support) using the Medical Outcomes Study Social Support Survey in each caregiver. The mechanisms of specific types of social support on psychological/non-psychological burden were examined using path analysis. RESULTS Positive social interaction and affectionate support reduced psychological burden via direct and indirect paths. Tangible support reduced the non-psychological burden via direct and indirect paths. Informational support and emotional support were not helpful for reducing psychological or non-psychological burden. A maximum of 20% of psychological burden could be relieved by positive social interaction and 10.3% of that could be reduced by affectionate support. Tangible support was associated with a 15.1% maximal improvement in non-psychological burden. CONCLUSIONS In order to reduce caregiver burden in dementia effectively, psychosocial interventions should be tailored to target type of caregiver burden.

Effects of Sleep Apnea Syndrome on Delayed Memory and Executive Function in Elderly Adults

To identify differences in cognitive function between elderly adults with sleep apnea syndrome (SAS) and healthy controls.

Cough in the Elderly Population: Relationships with Multiple Comorbidity

Background The epidemiology of cough in the elderly population has not been studied comprehensively. The present study aimed to investigate the epidemiology of cough in a community elderly population, particularly in relation with their comorbidity. Methods A cross-sectional analysis was performed using a baseline dataset from the Korean Longitudinal Study on Health and Aging, a community-based elderly population cohort study. Three types of cough (frequent cough, chronic persistent cough, and nocturnal cough) were defined using questionnaires. Comorbidity was examined using a structured questionnaire. Health-related quality of life was assessed using the Short Form 36 questionnaire. Results The prevalence was 9.3% for frequent cough, 4.6% for chronic persistent cough, and 7.3% for nocturnal cough. In multivariate logistic regression analyses, smoking, asthma and allergic rhinitis were found to be risk factors for cough in the elderly. Interestingly, among comorbidities, constipation and uncontrolled diabetes mellitus (HbA1c ≥ 8%) were also found to have positive associations with elderly cough. In the Short Form 36 scores, chronic persistent cough was independently related to impairment of quality of life, predominantly in the mental component. Conclusions Cough has a high prevalence and is detrimental to quality of life in the elderly. Associations with smoking, asthma and rhinitis confirmed previous findings in younger populations. Previously unrecognised relationships with constipation and uncontrolled diabetes mellitus suggested the multi-faceted nature of cough in the elderly.

COSMIC (Cohort Studies of Memory in an International Consortium): An international consortium to identify risk and protective factors and biomarkers of cognitive ageing and dementia in diverse ethnic and sociocultural groups

BackgroundA large number of longitudinal studies of population-based ageing cohorts are in progress internationally, but the insights from these studies into the risk and protective factors for cognitive ageing and conditions like mild cognitive impairment and dementia have been inconsistent. Some of the problems confounding this research can be reduced by harmonising and pooling data across studies. COSMIC (Cohort Studies of Memory in an International Consortium) aims to harmonise data from international cohort studies of cognitive ageing, in order to better understand the determinants of cognitive ageing and neurocognitive disorders.Methods/DesignLongitudinal studies of cognitive ageing and dementia with at least 500 individuals aged 60 years or over are eligible and invited to be members of COSMIC. There are currently 17 member studies, from regions that include Asia, Australia, Europe, and North America. A Research Steering Committee has been established, two meetings of study leaders held, and a website developed. The initial attempts at harmonising key variables like neuropsychological test scores are in progress.DiscussionThe challenges of international consortia like COSMIC include efficient communication among members, extended use of resources, and data harmonisation. Successful harmonisation will facilitate projects investigating rates of cognitive decline, risk and protective factors for mild cognitive impairment, and biomarkers of mild cognitive impairment and dementia. Extended implications of COSMIC could include standardised ways of collecting and reporting data, and a rich cognitive ageing database being made available to other researchers. COSMIC could potentially transform our understanding of the epidemiology of cognitive ageing, and have a world-wide impact on promoting successful ageing.