Dong Hyun Yoon

Dr. Dong Hyun Yoon

Seoul National University
orcid

Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
31 October 2018 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
DYDong Hyun Yoon
Dong Hyun Yoon
SHSu Seung Hwang
Su Seung Hwang
DLDong Won Lee
Dong Won Lee
CLChung Gun Lee
Chung Gun Lee
Wook SongWook Song
Wook Song
Cognitive frailty is a heterogeneous clinical manifestation characterized by the simultaneous presence of physical frailty and cognitive impairment. The objective of this study was to investigate the association between physical frailty and cognitive function in rural community-dwelling older Korean adults, taking four cognitive domains into account. We carried out a cross-sectional population-based study which enrolled 104 community-dwelling elderly. Physical frailty phenotype, as well as its individual criteria, were used. Cognitive functioning was examined in the four domains of memory, processing speed, cognitive flexibility, and working memory. Demographic data, lipid profile, muscle strength, physical function, and 25-hydroxyvitamin D (25[OH]D) concentration collected from questionnaire interviews and assessments were included. Of the 104 older adults (77% female), 24.3% were classified as robust, 49.6% as prefrail, and 16.5% as frail. Linear regression analyses showed that the severity of frailty index was associated with four cognitive domains Muscle strength (i.e., Grip strength, Knee extensor and flexor), physical function (i.e., SPPB and Gait speed), and 25[OH]D were associated with poorer cognitive function. Within our population of Korean rural community-dwelling older adults, physical frailty status, muscle strength, physical functions, and biochemical measurements were associated with poorer cognitive function. Synchronicity of physical frailty and cognitive dysfunction may contribute to the negative health-related effects associated with aging.

Verified
Journal Article
Open access
PDF file
DYDong Hyun Yoon
Dong Hyun Yoon
JLJun-Young Lee
Jun-Young Lee
SSSeong A Shin
Seong A Shin
YKYu Kyeong Kim
Yu Kyeong Kim
Wook SongWook Song
Wook Song
Background: Cognitive frailty and impairment are phenotypically and pathophysiologically correlated with physical frailty. We examined associations between accumulation of amyloid-β in the brain as a brain imaging biomarker and phenotypes of physical frailty (weight loss, weakness, exhaustion, slowness, low physical activity) in older adults with mild cognitive impairment (MCI) and cognitive frailty. Methods: Cross-sectional associations between brain amyloid-β accumulation measured with 11C-Pittsburgh compound B (PiB)-positron emission tomography (PET) and physical frailty were examined in 48 elderly participants (mean age: 75.1 ± 6.6 years; 73% female). Cortical and regional standard uptake value ratios (SUVRs) were obtained. Main outcome measures included frailty phenotypes and physical functions (gait speed, short physical performance battery, and Timed Up and Go tests). Results: Mean cortical region of interest and regional SUVRs (frontal cortex, temporal cortex, parietal cortex, precuneus/posterior cingulate cortex (PC/PCC), hippocampus, basal ganglia, and global SUVR) were associated with gait speed, Timed Up and Go, and short physical performance battery (PC/PCC, basal ganglia). In addition, SUVRs of all brain regions were significantly linked to weakness. Conclusion: SUVRs of all brain regions revealed an association between brain amyloid-β accumulation and weakness. Furthermore, global SUVRs (frontal cortex, temporal cortex, parietal cortex, PC/PCC, hippocampus, basal ganglia) were associated with gait parameters.

27 March 2019 in Brain and Behavior
Verified
Journal Article
Open access
PDF file
JYJung‐Hae Youn
Jung‐Hae Youn
SRSeung‐Ho Ryu
Seung‐Ho Ryu
JLJun‐Young Lee
Jun‐Young Lee
SPSoowon Park
Soowon Park
SCSeong‐Jin Cho
Seong‐Jin Cho
DYDong Hyun Yoon
Dong Hyun Yoon
Background: Metamemory is the process of monitoring and controlling one's memory. Improving metamemory may reduce the memory problem in old age. We hypothesized that metamemory training (MMT) would improve cognition in older adults with subjective memory complaints and change the brain region related to metacognition.Method: We recruited and randomized older adults to the multi‐strategic memory training of 10 weekly 90‐min sessions, based on the metamemory concept or usual care. Cognitive tests including the Elderly Verbal Learning Test, Simple Rey Figure Test, Digit Span, Spatial Span, Categorical Fluency, and the Boston Naming Test were done in 201 participants, together with magnetic resonance imaging (MRI) in 49 participants before and after training.Results: A total of 112 in the training group and 89 in the control group participated. The training group had a significant increase in long‐term delayed free recall, categorical fluency, and the Boston Naming test. In MRI, the mean diffusivity of the bundles of axon tracts passing from the frontal lobe to the posterior end of the lateral sulcus decreased in the training group.Conclusion: These results indicate that the MMT program has a positive impact on enhancing older people’ cognitive performance. Improved white matter integrity in the anterior and posterior cerebrum and increased cortical thickness of prefrontal regions, which related to metacognition, possibly suggest that the effects of the MMT would be induced via the enhancement of cognitive control.

5 October 2023 in Gait & Posture
Verified
Journal Article
Closed access
DYDong Hyun Yoon
Dong Hyun Yoon
JKJeong-Hyun Kim
Jeong-Hyun Kim
KLKyuwon Lee
Kyuwon Lee
JCJae-Sung Cho
Jae-Sung Cho
SJSeong-Ho Jang
Seong-Ho Jang
SLShi-Uk Lee
Shi-Uk Lee

11 October 2020 in Nutrients
Verified
Journal Article
Open access
PDF file
DYDong Hyun Yoon
Dong Hyun Yoon
GHGa-Young Han
Ga-Young Han
SHSu Seung Hwang
Su Seung Hwang
DLDong Won Lee
Dong Won Lee
JKJin-Soo Kim
Jin-Soo Kim
Wook SongWook Song
Wook Song
Background: Fatigue is one of the major health conditions induced by excessive stress or abnormal immune function or defective antioxidant systems. Placental extract has been reported to have various effects such as immune modulation and cellular regeneration. Fermented porcine placenta (FPP) is a safe nontoxic material, which is highly valuable as a functional food. The aim of this study was to investigate the anti-fatigue effects of FPP supplementation compared with a placebo product. Methods: In this double-blind, parallel, randomized, and placebo-controlled trial 84 healthy males and females, aged between 30 and 60 years were randomized to 320 mg of FPP once daily or placebo. The main outcome measures included efficacy of fatigue-inducing treadmill exercise on physical fatigue and fatigue-related parameters based on the questionnaire administered. Results: The IL-1β mRNA expression and fatigue severity scale were changed significantly after 8 weeks of treatment with fermented porcine placenta compared with placebo (p < 0.05). Cortisol levels were significantly improved in participants younger than 45 years following treatment with FPP compared with placebo. Furthermore, the lactate and myoglobin levels were improved significantly in participants with BMI ≥ 23 kg/m2 (p = 0.045 and p = 0.011, respectively) following treatment with FPP versus placebo. Conclusions: Our study showed that FPP supplementation significantly ameliorated fatigue-related parameters and subjective symptoms in healthy adults. Therefore, our results indicate that FPP supplementation induced anti-fatigue effect by regulating the inflammatory response.

19 September 2018 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
JPJuhyun Park
Juhyun Park
DYDong Hyun Yoon
Dong Hyun Yoon
SYSangjun Yoo
Sangjun Yoo
SCSung Yong Cho
Sung Yong Cho
MCMin Chul Cho
Min Chul Cho
HJHyeon Jeong
Hyeon Jeong
We evaluated the efficacy of progressive resistance training of the pelvic floor muscle for post-prostatectomy incontinence. In this prospective study, 59 patients who underwent radical prostatectomy were evaluated preoperatively. Continence was sequentially assessed within 2 weeks postoperatively, and an exercise regimen was initiated at 6- and 12-weeks. The primary outcome was continent status and the secondary outcome was changes in muscle strength and endurance after the exercise intervention. Continence was defined as no urine loss in a 1h pad test. A total of 59 patients participated in this study. Six patients dropped out of the study because of non-compliance and orthopedic problems. Of the remaining 53 patients, 31 (58.5%) achieved pad-free continence at 12 weeks postoperatively. The patients were divided into two groups based on their continence status, and no statistically significant difference was observed in age, body mass index, prostate volume, prostate-specific antigen, pathological Gleason score sum, and pathological T stage. Meanwhile, preoperative maximal urethral closure pressure and change in hip extensor muscle strength and endurance during the 12-week exercise program were significantly higher in the continent group. In multivariate analysis, change in hip extensor muscle strength was the only significant parameter predicting achievement of continence status (Odds ratio, 1.039; p = 0.045). The changes in hip extensor muscle strength in the current exercise program was an independent predictor of continence status after radical prostatectomy. A large-scale prospective study on the relationship between extensor muscle strength and urinary incontinence should be explored in future.