Sangyoon Lee

Dr. Sangyoon Lee


Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

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

Representative Publications

View All Publications
31 October 2012 in BMC Neurology
Verified
Journal Article
Open access
PDF file
TSTakao Suzuki
Takao Suzuki
Hiroyuki ShimadaHiroyuki Shimada
Hiroyuki Shimada
Hyuma MakizakoHyuma Makizako
Hyuma Makizako
TDTakehiko Doi
Takehiko Doi
DYDaisuke Yoshida
Daisuke Yoshida
Hyuntae ParkHyuntae Park
Hyuntae Park
To examine the effects of a multicomponent exercise program on the cognitive function of older adults with amnestic mild cognitive impairment (aMCI). Design: Twelve months, randomized controlled trial; Setting: Community center in Japan; Participants: Fifty older adults (27 men) with aMCI ranging in age from 65 to 93 years (mean age, 75 years); Intervention: Subjects were randomized into either a multicomponent exercise (n = 25) or an education control group (n = 25). Subjects in the multicomponent exercise group exercised under the supervision of physiotherapists for 90 min/d, 2 d/wk, for a total of 80 times over 12 months. The exercises included aerobic exercises, muscle strength training, and postural balance retraining, and were conducted using multiple conditions to stimulate cognitive functions. Subjects in the control group attended three education classes regarding health during the 12-month period. Measurements were administered before, after the 6-month, and after the 12-month intervention period; Measurements: The performance measures included the mini-mental state examination, logical memory subtest of the Wechsler memory scale-revised, digit symbol coding test, letter and categorical verbal fluency test, and the Stroop color word test. The mean adherence to the exercise program was 79.2%. Improvements of cognitive function following multicomponent exercise were superior at treatment end (group × time interactions for the mini-mental state examination (P = 0.04), logical memory of immediate recall (P = 0.03), and letter verbal fluency test (P = 0.02)). The logical memory of delayed recall, digit symbol coding, and Stroop color word test showed main effects of time, although there were no group × time interactions. This study indicates that exercise improves or supports, at least partly, cognitive performance in older adults with aMCI.

Hyuma MakizakoHyuma Makizako
Hyuma Makizako
Hiroyuki ShimadaHiroyuki Shimada
Hiroyuki Shimada
TDTakehiko Doi
Takehiko Doi
KTKota Tsutsumimoto
Kota Tsutsumimoto
RHRyo Hotta
Ryo Hotta
SLSangyoon Lee
Sangyoon Lee
Social frailty domains may play an important role in preventing physical decline and disability. The aim of this study is to examine the impact of social frailty as a risk factor for the future development of physical frailty among community-dwelling older adults who are not yet physically frail. A total of 1226 physically non-frail older adults were analyzed to provide a baseline. Participants completed a longitudinal assessment of their physical frailty 48 months later. Their baseline social frailty was determined based on their responses to five questions, which identified participants who went out less frequently, rarely visited friends, felt less like helping friends or family, lived alone and did not talk to another person every day. Participants with none of these characteristics were considered not to be socially frail; those with one characteristic were considered socially pre-frail; and those with two or more characteristics were considered socially frail. At the four-year follow-up assessment, 24 participants (2.0%) had developed physical frailty and 440 (35.9%) had developed physical pre-frailty. The rates of developing physical frailty and pre-frailty were 1.6% and 34.2%, respectively, in the socially non-frail group; 2.4% and 38.8%, respectively, in the socially pre-frail group; and 6.8% and 54.5%, respectively, in the socially frail group. Participants classified as socially frail at the baseline had an increased risk of developing physical frailty, compared with participants who were not socially frail (OR = 3.93, 95% CI = 1.02–15.15). Participants who were socially frail at the baseline also had an increased risk of developing physical pre-frailty (OR = 2.50, 95% CI = 1.30–4.80). Among independent community-dwelling older adults who are not physically frail, those who are socially frail may be at greater risk of developing physical frailty in the near future. Social frailty may precede (and lead to the development of) physical frailty.

13 March 2019 in Alzheimer's Research & Therapy
Verified
Journal Article
Open access
PDF file
Hiroyuki ShimadaHiroyuki Shimada
Hiroyuki Shimada
TDTakehiko Doi
Takehiko Doi
SLSangyoon Lee
Sangyoon Lee
Hyuma MakizakoHyuma Makizako
Hyuma Makizako
Although previous studies have revealed many factors related to mild cognitive impairment (MCI) reversion, information about reversible factors related MCI reversion is limited, impeding the development of intervention strategies. The aim of the present study was to examine whether reversible factors such as lifestyle activities are associated with MCI reversion in elderly individuals using the National Center for Geriatrics and Gerontology—Study of Geriatric Syndromes database. A total of 396 community-living older adults (age ≥ 65 years) participated in the study. They were classified as reverters or non-reverters from mild cognitive impairment to normal cognition. We assessed lifestyle activities, potential confounding factors of cognitive decline, and reversion of mild cognitive impairment. In a completed data set of 396 participants, 202 participants (51.0%) reverted from MCI to normal cognition. The reversion rate in participants for whom we imputed data was 34.3%. In the imputed group, a logistic regression model showed that the odds ratios (ORs) for reversion were significantly higher in participants who drove a car (OR 1.50, 95% confidence interval (CI) 1.41–1.60), used a map to travel to unfamiliar places (OR 1.12, 95% CI 1.06–1.18), read books or newspapers (OR 1.54, 95% CI 1.37–1.73), took cultural classes (OR 1.10, 95% CI 1.04–1.15), attended meetings in the community (OR 1.22, 95% CI 1.16–1.28), participated in hobbies or sports activities (OR 1.09, 95% CI 1.03–1.16), and engaged in fieldwork or gardening (OR 1.14, 95% CI 1.08–1.21). The imputed sample showed that non-reverters were more likely to discontinue fieldwork or gardening (11.0% vs. 6.1%) than reverters during the follow-up period. Specific lifestyle activities may play important roles in MCI reversion in older adults. The longitudinal data indicate that it is reasonable to recommend that individuals continue to engage in fieldwork or gardening to increase their chance of recovery from MCI.

30 August 2018 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
Hiroyuki ShimadaHiroyuki Shimada
Hiroyuki Shimada
TDTakehiko Doi
Takehiko Doi
SLSangyoon Lee
Sangyoon Lee
Hyuma MakizakoHyuma Makizako
Hyuma Makizako
LCLiang-Kung Chen
Liang-Kung Chen
HAHidenori Arai
Hidenori Arai
Cognitive frailty, defined as the presence of both frailty and cognitive impairment, is a risk factor for adverse events in older adults. However, prevalence rates of cognitive frailty are low (1.1–2.5%), so primary screening is unsuitable in community settings. The aim of the study was to examine whether a new definition of cognitive frailty, which was developed for primary screening, is useful to predict incident dementia in community-dwelling older adults. A total of 4570 older adults participated in the study (2326 women; average age, 71.9 ± 5.5 years). We defined physical frailty as the presence of ≥1 of the following symptoms: slow walking speed and muscle weakness. Cognitive impairment was defined as ≥1 symptom of cognitive impairment, indicated by an age- and education-adjusted score that was ≥1.5 standard deviations below the reference threshold in word list memory, attention, executive function, and processing speed tests. Cognitive frailty was defined as comorbid physical frailty and cognitive impairment. The incidence of dementia was determined using data collected by the Japanese Health Insurance System over 36 months. The prevalence rates of physical frailty, cognitive impairment, and cognitive frailty were 17.5%, 15.3%, and 9.8%, respectively. Cognitive impairment (hazard ratio [HR]: 2.06, 95% confidence interval [95% CI]: 1.41–3.02) and cognitive frailty (HR: 3.43, 95% CI: 2.37–4.97) were found to be significant risk factors for dementia. However, the association between dementia and physical frailty was not significant (HR: 1.13, 95% CI: 0.76–1.69). Individuals with comorbid physical frailty and cognitive impairment could have a higher risk of dementia than healthy older adults or older adults with either physical frailty or cognitive impairment alone.

27 September 2019 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
Hiroyuki ShimadaHiroyuki Shimada
Hiroyuki Shimada
SLSangyoon Lee
Sangyoon Lee
TDTakehiko Doi
Takehiko Doi
SBSeongryu Bae
Seongryu Bae
KTKota Tsutsumimoto
Kota Tsutsumimoto
HAHidenori Arai
Hidenori Arai
There has been less research conducted on the psychological aspects of frailty than on the physical and cognitive characteristics of frailty. Thus, we aimed to define psychological frailty, clarify its prevalence, and investigate the relationship between psychological frailty and lifestyle activity or disability incidence in older adults in Japan. The participants in our study were 4126 older adults (average age 71.7 years) enrolled in the National Center for Geriatrics and Gerontology-i87uStudy of Geriatric Syndromes (NCGG-SGS). We characterized physical frailty of the following as ≥ 3: slow walking speed, muscle weakness, exhaustion, low physical activity, and weight loss. We used the Geriatric Depression Scale 15 items version (GDS-15) to screen for depressive mood, indicated by 5 points or more on the scale. The co-presence of physical frailty and depressive mood was defined as psychological frailty. The incidence of disability was determined using data from the Japanese long-term care insurance system over 49 months. We found that the prevalence of physical frailty, depressive mood, and psychological frailty were 6.9%, 20.3%, and 3.5%, respectively. Logistic regression indicated that the odds ratios for loss of lifestyle activities were significantly higher in participants with psychological frailty for going outdoors using the bus or train, driving a car, using maps to go to unfamiliar places, reading books or newspapers, cognitive stimulation, culture lessons, giving advice, attending community meetings, engaging in hobbies or sports, house cleaning, fieldwork or gardening, and taking care of grandchildren or pets. During the follow-up period, 385 participants (9.3%) developed a disability. The incidence of disability was associated with both physical and psychological frailty in the fully adjusted model. However, no significant association between disability and depressive mood was found. We conclude that individuals with psychological frailty had the highest risk of disability. Future policies should implement disability prevention strategies among older adults with psychological frailty.

Verified
Journal Article
Open access
PDF file
SBSeongryu Bae
Seongryu Bae
KHKenji Harada
Kenji Harada
SLSangyoon Lee
Sangyoon Lee
KHKazuhiro Harada
Kazuhiro Harada
KMKeitaro Makino
Keitaro Makino
Hiroyuki ShimadaHiroyuki Shimada
Hiroyuki Shimada
The aim of this study was to examine cortical thickness changes associated with a multicomponent exercise intervention combining physical exercise and cognitive training in older adults with cognitive decline. This study involved a secondary analysis of neuroimaging data from a randomized controlled trial with 280 older adults having cognitive decline who were randomly assigned to either a multicomponent exercise group (n = 140) that attended weekly 90-minute exercise and cognitive training sessions or a health education control group (n = 140). The cortical thickness and cognitive performance were assessed at the baseline and at trial completion (10 months). The cortical thickness in the frontal and temporal regions was determined using FreeSurfer software. Cognitive performance was evaluated using the Gerontology-Functional Assessment Tool (NCGG-FAT). The cortical thickness significantly increased in the middle temporal (p < 0.001) and temporal pole (p < 0.001) in the multicomponent exercise group compared with the control group. Cortical thickness changes were significantly associated with change in trail making test (TMT)-A, TMT-B, and story memory after a 10-month multicomponent exercise intervention. This study suggests that multicomponent exercise programs combining physical exercise and cognitive training have important implications for brain health, especially in providing protection from age-related cortical thinning.