Seongjun Yoon

Bio: Seongjun Yoon is an academic researcher. The author has contributed to research in topics: Gait analysis & Outpatient clinic. The author has an hindex of 2, co-authored 5 publications receiving 9 citations.

Functional Age Predicted by Electronic Short Physical Performance Battery Can Detect Frailty Status in Older Adults.

Abstract: Purpose The importance of evaluating frailty status of older adults in clinical practice has been gaining attention with cumulative evidence showing its relevance in clinical outcomes and decision-making. We aimed to develop and validate whether the functional age predicted by an electronic continuous short physical performance battery (eSPPB) could predict frailty status. Patients and Methods We reviewed medical records of outpatients (N=834) of Asan Medical Center, aged 51-95 years. We used the eSPPB data of 717 patients as a development cohort, and that of 117 patients, who also underwent comprehensive geriatric assessments, as a validation cohort. Frailty index was calculated by counting deficits of 45 geriatric items including comorbidities, daily functions, mobility, mood, and cognition. For functional age, we used balance score (0-4), gait speed (m/s), and stand-up time (s) measured 5 times in the chair rise test. Results From the development cohort, we established a functional age using the formula (83.61 - 1.98*[balance score] - 5.21*[gait speed] + 0.23*[stand-up time]), by multivariate linear regression analysis with chronological age as a dependent variable (R2 = 0.233). In the validation cohort, the functional age positively correlated with frailty index (p < 0.001). C-statistics classifying frailty (defined as frailty index ≥0.25) was higher (p < 0.001) with functional age (0.912) than that with chronological age (0.637). A cut-off functional age of ≥77.2 years maximized Youden's J when screening for frailty, with sensitivity of 94.4% and specificity of 80.8%. Conclusion A newly developed functional age predictor using eSPPB parameters can predict the frailty status as defined by the deficit accumulation method and may serve as a physical biomarker of human aging.

Development and Validation of 2D-LiDAR-Based Gait Analysis Instrument and Algorithm.

Abstract: Acquiring gait parameters from usual walking is important to predict clinical outcomes including life expectancy, risk of fall, and neurocognitive performance in older people. We developed a novel gait analysis tool that is small, less-intrusive and is based on two-dimensional light detection and ranging (2D-LiDAR) technology. Using an object-tracking algorithm, we conducted a validation study of the spatiotemporal tracking of ankle locations of young, healthy participants (n = 4) by comparing our tool and a stereo camera with the motion capture system as a gold standard modality. We also assessed parameters including step length, step width, cadence, and gait speed. The 2D-LiDAR system showed a much better accuracy than that of a stereo camera system, where mean absolute errors were 46.2 ± 17.8 mm and 116.3 ± 69.6 mm, respectively. Gait parameters from the 2D-LiDAR system were in good agreement with those from the motion capture system (r = 0.955 for step length, r = 0.911 for cadence). Simultaneous tracking of multiple targets by the 2D-LiDAR system was also demonstrated. The novel system might be useful in space and resource constrained clinical practice for older adults.

Comparison of Human Interpretation and a Rule-Based Algorithm for Instrumented Sit-to-Stand Test.

Abstract: Background The five times sit-to-stand test (5STS) is one of the most commonly used tests to assess the physical performance of lower extremities. This study assessed the correlation between human interpretation (5STShuman) and a rule-based algorithm (5STSrule) using instrumented 5STS with two sensors. Methods We analyzed clinical records of 148 patients who visited the geriatric outpatient clinic of Asan Medical Center between December 2020 and March 2021 and underwent physical performance assessment using the electronic Short Physical Performance Battery (eSPPB) protocol. For STS, time-weight and time-distance curves were constructed using a loadcell and light detection and ranging (LiDAR). We manually assessed the grids of these curves to calculate 5STShuman, while 5STSrule used an empirical rule-based algorithm. Results In the study population, the mean 5STShuman and 5STSrule times, i.e., 12.2±0.4 and 11.4±0.4 seconds, respectively, did not differ significantly (p=0.232). Linear regression analysis showed that 5STShuman and 5STSrule were positively correlated (β=0.99, R2=0.99). The measures also did not differ (p=0.381) in classifying sarcopenia according to the Asian Working Group Society criteria, with C-indices of 0.826 for 5STShuman and 0.820 for 5STSrule. Conclusion An empirical rule-based algorithm correlated with human-interpreted 5STS and had comparable classification ability for sarcopenia.

Comparison of Two Electronic Physical Performance Batteries by Measurement Time and Sarcopenia Classification.

Abstract: The Short Physical Performance Battery (SPPB) is a widely accepted test for measuring lower extremity function in older adults. However, there are concerns regarding the examination time required to conduct a complete SPPB consisting of three components (walking speed, chair rise, and standing balance tests) in clinical settings. We aimed to assess specific examination times for each component of the electronic Short Physical Performance Battery (eSPPB) and compare the ability of the original three-component examinations (eSPPB) and a faster, two-component examination without a balance test (electronic Quick Physical Performance Battery, eQPPB) to classify sarcopenia. The study was a retrospective, cross-sectional study which included 124 ambulatory outpatients who underwent physical performance examination at a geriatric clinic of a tertiary, academic hospital in Seoul, Korea, between December 2020 and March 2021. For eSPPB, we used a toolkit containing sensors and software (Dyphi, Daejeon, Korea) developed to measure standing balance, walking speed, and chair rise test results. Component-specific time stamps were used to log the raw data. Duration of balance examination, 5 times sit-to-stand test (5XSST), and walking speed examination were calculated. Sarcopenia was determined using the 2019 Asian Working Group for Sarcopenia (AWGS) guideline. The median age was 78 years (interquartile range, IQR: 73,82) and 77 subjects (62.1%) were female. The total mean eSPPB test time was 124.8 ± 29.0 s (balance test time 61.8 ± 12.3 s, 49.5%; gait speed test time 34.3 ± 11.9 s, 27.5%; and 5XSST time 28.7 ± 19.1 s, 23.0%). The total mean eQPPB test time was 63.0 ± 25.4 s. Based on the AWGS criteria, 34 (27.4%) patient’s results were consistent with sarcopenia. C-statistics for classifying sarcopenia were 0.83 for eSPPB and 0.85 for eQPPB (p = 0.264), while eQPPB took 49.5% less measurement time compared with eSPPB. Breakdowns of eSPPB test times were identified. Omitting balance tests may reduce test time without significantly affecting the classifying ability of eSPPB for sarcopenia.

Development and validation of 2D-LiDAR-based gait analysis instrument and algorithm

Abstract: Acquiring gait parameters from usual walking is important to predict clinical outcomes, including life expectancy, risk of fall, and neurocognitive performance, in older people. For comprehensive gait analysis, instruments such as marker-based motion analysis systems and walkways with pressure sensor arrays are necessary. Traditional instruments are bulky, complex, expensive, and intrinsically intrusive. Requirements of dedicated spaces for installation and specialized staff make it difficult to utilize traditional gait analysis instruments in most outpatient clinics. We present a novel gait analysis tool that is small, highly accurate, easy-to-use, and non-intrusive and is based on two-dimensional light detection and ranging technology. Using an object-tracking algorithm, we conducted a validation study of spatiotemporal tracking of ankle locations of subjects by comparing our tool with a gold standard modality. Our tool showed successful acquisition of gait parameters from usual walking motions and trackability with multiple targets in noisy conditions, including typical clinical environments.

Long-term effect of a 24-week multicomponent intervention on physical performance and frailty in community-dwelling older adults.

Abstract: Introduction Multicomponent interventions improve physical function and frailty in older adults, but their long-term benefit remains uncertain. Methods This prospective non-randomised study was conducted in 383 older Koreans (mean age, 76.8 years; female 72.3%) who were living alone or receiving medical aid. Of these, 187 individuals chose to receive a 24-week intervention that consisted of group exercise, nutritional supplements, depression management, deprescribing and home hazard reduction. The remaining 196 individuals received usual care. We compared the short physical performance battery (SPPB) score (0-12 points), frailty phenotype scale (0-5 points) and deficit-accumulation frailty index (0-1) at baseline, 6, 18 and 30 months. Results After 1:1 propensity score matching (n = 117 per group), the mean SPPB scores for the intervention and comparison groups were 7.6 versus 7.6 at baseline, 10.7 versus 7.1 at 6 months (mean difference, 3.5; 95% confidence interval [CI], 2.8-4.2), 9.1 versus 7.8 at 18 months (1.3; 95% CI, 0.6-2.0) and 8.6 versus 7.5 at 30 months (1.1; 95% CI, 0.4-1.8). The intervention group had lower frailty phenotype scale (1.1 versus 1.8; difference, -0.7; 95% CI -1.0 to -0.3) and frailty index (0.22 versus 0.27; difference, -0.04; -0.06 to -0.02) at 6 months, but similar scores at 18 and 30 months. The 30-month mean institutionalisation-free survival time was 28.5 months in the intervention group versus 23.3 months in the comparison group (difference, 5.2 months; 95% CI, 3.1-7.4). Conclusions The 24-week multicomponent intervention showed sustained improvement in physical function, temporary reduction in frailty and longer institutionalisation-free survival over 30 months.

Short Physical Performance Battery as a Crosswalk Between Frailty Phenotype and Deficit Accumulation Frailty Index.

Abstract: BACKGROUND Growing evidence supports the clinical importance of evaluating frailty in older adults, with its strong outcome relevance. We aimed to assess whether the Short Physical Performance Battery (SPPB) correlates with frailty status according to phenotype and deficit accumulation models and can be used as a link between these models. METHODS We analyzed records of 1064 individuals from the Aging Study of Pyeongchang Rural Area, a population-based, prospective cohort from South Korea. Frailty was determined using the Cardiovascular Health Study (CHS) phenotype (phenotype model), 26- and 34-item frailty indices (deficit accumulation model). Associations of SPPB score and frailty with a composite outcome of mortality or long-term institutionalization were assessed. Crosswalks for SPPB, the CHS frailty phenotype, and the frailty index were created. RESULTS The mean age of the study population was 76.0 years, and 583 (54.8%) were women. According to the CHS phenotype, 26- and 34-item frailty indices, 242 (22.7%), 161 (15.1%), and 280 (26.3%) participants, respectively, had frailty. Sensitivities/specificities for classifying CHS phenotype, 26- and 34-item frailty indices were 0.93/0.55, 0.71/0.84, and 0.80/0.83 by SPPB cut points of ≤9, ≤6, and ≤7, respectively. C-index of SPPB score (0.78) showed a predictive ability for the composite outcome that was comparable to that of CHS frailty phenotype (0.79), 26- (0.78), and 34-item frailty indices (0.79). CONCLUSIONS We could create a crosswalk linking frailty phenotype and frailty index from correlations between SPPB and frailty models. This result may facilitate clinical adoption of the frailty concept in a broader spectrum of older adults.

Four different frailty models predict health outcomes in older patients with stable chronic obstructive pulmonary disease

Abstract: Frail patients with chronic obstructive pulmonary disease (COPD) face a higher risk of adverse outcomes, but there is no clear consensus on which frailty measures are most suitable for COPD patients. Herein we evaluated the ability of frailty measurements in predicting 1-year acute exacerbation, hospitalization, and mortality in older patients with COPD.A total of 302 patients [median age: 86 years (IQR: 80-90), 22.2% female] were admitted to the Department of Geriatric Medicine were prospectively enrolled in this study. Frailty status was assessed using the Fried Frailty Phenotype (FFP), Clinical Frailty Scale (CFS), Frailty Index of Accumulative Deficits (FI-CD), and Short Physical Performance Battery (SPPB). Cox proportional hazard regression and Poisson regression were used to evaluating the association of the adverse outcomes with frailty as assessed using the four instruments. The discrimination accuracy of these tools in predicting the 1-year all-cause mortality was also compared.Prevalence of frailty ranged from 51% (using FFP) to 64.2% (using CFS). The four frail instruments were associated with 1-year mortality. After an average follow-up time of 2.18 years (IQR: 1.56-2.62 years), frailty as defined by four instruments (except for FI-CD), was associated with death [FFP: Hazard ratio (HR) = 3.11, 95% confidence interval (CI) 1.30-7.44; CFS: HR = 3.68, 95% CI 1.03-13.16; SPPB: HR = 3.74, 95% CI 1.39-10.06). Frailty was also associated with acute exacerbation (using FFP) and hospitalization (using FFP, CFS, and FI-CD). Frail showed a moderate predictive ability [area under the curve ranging (AUC) 0.70-0.80] and a high negative predictive value (0.98-0.99) for 1-year mortality.With the four different frailty assessment tools, frailty was associated with poor prognosis in older patients with stable COPD. The FFP, CFS, FI-CD, and SPPB instruments showed similar performance in predicting 1-year mortality.

The Aging Study of Pyeongchang Rural Area (ASPRA): Findings and Perspectives for Human Aging, Frailty, and Disability.

Abstract: The Aging Study of Pyeongchang Rural Area (ASPRA) is a population-based, prospective cohort study of older adults in Pyeongchang, South Korea. Since the initial enrollment of 382 participants, the ASPRA has been maintained and has conducted comprehensive geriatric assessments annually, gradually expanding its population and coverage area. As a cohort study of aging-related conditions and their functional consequences, the ASPRA leveraged Pyeongchang's relatively low annual population movement rate and its healthcare delivery system, which was largely maintained by community health posts. Since its establishment, the ASPRA has reported numerous observational and multicomponent intervention studies on functional decline, geriatric syndrome, and frailty. Here, we discuss the findings and perspectives of ASPRA studies. We hope that the ASPRA enables the further implementation of a longitudinal study design on geriatric parameters and the development of public health strategies targeting aging-related conditions, especially in resource-limited community settings.