1.Development of an RGB-depth camera-based gait analysis system: a single-case study of a patient with stroke
Min Cheol CHANG ; Juyeon KIM ; Jun Sung MOON ; Wooktae PARK ; Gun Woo LEE ; Yoo Jin CHOO
Journal of Yeungnam Medical Science 2026;43(1):15-
Alterations in gait patterns often indicate health status, and their analysis enables the diagnosis and assessment of various health conditions. This study aimed to develop a noncontact gait analysis system using red, green, and blue-depth (RGB-D) cameras and to evaluate its potential clinical applicability. A single case study was conducted to assess changes in the gait patterns of a patient with stroke before and after the application of an ankle-foot orthosis. Twenty walking trials were recorded to evaluate the key gait parameters. The custom RGB-D camera-based gait analysis system demonstrated the potential to rapidly quantify key gait parameters in the patient. Compared with normative data, it effectively identified characteristic stroke-related gait impairments such as shorter step lengths and slower gait speeds. However, the intraclass correlation coefficient analysis indicated low measurement reliability. Although the stance time and minimum knee angle on the left and right sides exceeded the standard error of measurement (SEM), no changes exceeded the minimal detectable change (MDC) criteria. Moreover, other gait parameters did not show significant changes beyond SEM or MDC, limiting the interpretability of the results. Therefore, further technological developments and data collection are required to improve test-retest reliability and sensitivity to change.
2.Evaluating Rituximab Failure Rates in Neuromyelitis Optica Spectrum Disorder: A Nationwide Real-World Study From South Korea
Su-Hyun KIM ; Ju-Hong MIN ; Sung-Min KIM ; Eun-Jae LEE ; Young-Min LIM ; Ha Young SHIN ; Young Nam KWON ; Eunhee SOHN ; Sooyoung KIM ; Min Su PARK ; Tai-Seung NAM ; Byeol-A YOON ; Jong Kuk KIM ; Kyong Jin SHIN ; Yoo Hwan KIM ; Jin Myoung SEOK ; Jeong Bin BONG ; Sohyeon KIM ; Hung Youl SEOK ; Sun-Young OH ; Ohyun KWON ; Sunyoung KIM ; Sukyoon LEE ; Nam-Hee KIM ; Eun Bin CHO ; Sa-Yoon KANG ; Seong-il OH ; Jong Seok BAE ; Suk-Won AHN ; Ki Hoon KIM ; You-Ri KANG ; Woohee JU ; Seung Ho CHOO ; Yeon Hak CHUNG ; Jae-Won HYUN ; Ho Jin KIM
Journal of Clinical Neurology 2025;21(2):131-136
Background:
and Purpose Treatments for neuromyelitis optica spectrum disorder (NMOSD) such as eculizumab, ravulizumab, satralizumab, and inebilizumab have significantly advanced relapse prevention, but they remain expensive. Rituximab is an off-label yet popular alternative that offers a cost-effective solution, but its real-world efficacy needs better quantification for guiding the application of newer approved NMOSD treatments (ANTs). This study aimed to determine real-world rituximab failure rates to anticipate the demand for ANTs and aid in resource allocation.
Methods:
We conducted a nationwide retrospective study involving 605 aquaporin-4-antibody-positive NMOSD patients from 22 centers in South Korea that assessed the efficacy and safety of rituximab over a median follow-up of 47 months.
Results:
The 605 patients treated with rituximab included 525 (87%) who received continuous therapy throughout the follow-up period (median=47 months, interquartile range=15–87 months). During this period, 117 patients (19%) experienced at least 1 relapse. Notably, 68 of these patients (11% of the total cohort) experienced multiple relapses or at least 1 severe relapse.Additionally, 2% of the patients discontinued rituximab due to adverse events, which included severe infusion reactions, neutropenia, and infections.
Conclusions
This study has confirmed the efficacy of rituximab in treating NMOSD, as evidenced by an 87% continuation rate among patients over a 4-year follow-up period. Nevertheless, the occurrence of at least one relapse in 19% of the cohort, including 11% who experienced multiple or severe relapses, and a 2% discontinuation rate due to adverse events highlight the urgent need for alternative therapeutic options.
3.Evaluating Rituximab Failure Rates in Neuromyelitis Optica Spectrum Disorder: A Nationwide Real-World Study From South Korea
Su-Hyun KIM ; Ju-Hong MIN ; Sung-Min KIM ; Eun-Jae LEE ; Young-Min LIM ; Ha Young SHIN ; Young Nam KWON ; Eunhee SOHN ; Sooyoung KIM ; Min Su PARK ; Tai-Seung NAM ; Byeol-A YOON ; Jong Kuk KIM ; Kyong Jin SHIN ; Yoo Hwan KIM ; Jin Myoung SEOK ; Jeong Bin BONG ; Sohyeon KIM ; Hung Youl SEOK ; Sun-Young OH ; Ohyun KWON ; Sunyoung KIM ; Sukyoon LEE ; Nam-Hee KIM ; Eun Bin CHO ; Sa-Yoon KANG ; Seong-il OH ; Jong Seok BAE ; Suk-Won AHN ; Ki Hoon KIM ; You-Ri KANG ; Woohee JU ; Seung Ho CHOO ; Yeon Hak CHUNG ; Jae-Won HYUN ; Ho Jin KIM
Journal of Clinical Neurology 2025;21(2):131-136
Background:
and Purpose Treatments for neuromyelitis optica spectrum disorder (NMOSD) such as eculizumab, ravulizumab, satralizumab, and inebilizumab have significantly advanced relapse prevention, but they remain expensive. Rituximab is an off-label yet popular alternative that offers a cost-effective solution, but its real-world efficacy needs better quantification for guiding the application of newer approved NMOSD treatments (ANTs). This study aimed to determine real-world rituximab failure rates to anticipate the demand for ANTs and aid in resource allocation.
Methods:
We conducted a nationwide retrospective study involving 605 aquaporin-4-antibody-positive NMOSD patients from 22 centers in South Korea that assessed the efficacy and safety of rituximab over a median follow-up of 47 months.
Results:
The 605 patients treated with rituximab included 525 (87%) who received continuous therapy throughout the follow-up period (median=47 months, interquartile range=15–87 months). During this period, 117 patients (19%) experienced at least 1 relapse. Notably, 68 of these patients (11% of the total cohort) experienced multiple relapses or at least 1 severe relapse.Additionally, 2% of the patients discontinued rituximab due to adverse events, which included severe infusion reactions, neutropenia, and infections.
Conclusions
This study has confirmed the efficacy of rituximab in treating NMOSD, as evidenced by an 87% continuation rate among patients over a 4-year follow-up period. Nevertheless, the occurrence of at least one relapse in 19% of the cohort, including 11% who experienced multiple or severe relapses, and a 2% discontinuation rate due to adverse events highlight the urgent need for alternative therapeutic options.
4.Evaluating Rituximab Failure Rates in Neuromyelitis Optica Spectrum Disorder: A Nationwide Real-World Study From South Korea
Su-Hyun KIM ; Ju-Hong MIN ; Sung-Min KIM ; Eun-Jae LEE ; Young-Min LIM ; Ha Young SHIN ; Young Nam KWON ; Eunhee SOHN ; Sooyoung KIM ; Min Su PARK ; Tai-Seung NAM ; Byeol-A YOON ; Jong Kuk KIM ; Kyong Jin SHIN ; Yoo Hwan KIM ; Jin Myoung SEOK ; Jeong Bin BONG ; Sohyeon KIM ; Hung Youl SEOK ; Sun-Young OH ; Ohyun KWON ; Sunyoung KIM ; Sukyoon LEE ; Nam-Hee KIM ; Eun Bin CHO ; Sa-Yoon KANG ; Seong-il OH ; Jong Seok BAE ; Suk-Won AHN ; Ki Hoon KIM ; You-Ri KANG ; Woohee JU ; Seung Ho CHOO ; Yeon Hak CHUNG ; Jae-Won HYUN ; Ho Jin KIM
Journal of Clinical Neurology 2025;21(2):131-136
Background:
and Purpose Treatments for neuromyelitis optica spectrum disorder (NMOSD) such as eculizumab, ravulizumab, satralizumab, and inebilizumab have significantly advanced relapse prevention, but they remain expensive. Rituximab is an off-label yet popular alternative that offers a cost-effective solution, but its real-world efficacy needs better quantification for guiding the application of newer approved NMOSD treatments (ANTs). This study aimed to determine real-world rituximab failure rates to anticipate the demand for ANTs and aid in resource allocation.
Methods:
We conducted a nationwide retrospective study involving 605 aquaporin-4-antibody-positive NMOSD patients from 22 centers in South Korea that assessed the efficacy and safety of rituximab over a median follow-up of 47 months.
Results:
The 605 patients treated with rituximab included 525 (87%) who received continuous therapy throughout the follow-up period (median=47 months, interquartile range=15–87 months). During this period, 117 patients (19%) experienced at least 1 relapse. Notably, 68 of these patients (11% of the total cohort) experienced multiple relapses or at least 1 severe relapse.Additionally, 2% of the patients discontinued rituximab due to adverse events, which included severe infusion reactions, neutropenia, and infections.
Conclusions
This study has confirmed the efficacy of rituximab in treating NMOSD, as evidenced by an 87% continuation rate among patients over a 4-year follow-up period. Nevertheless, the occurrence of at least one relapse in 19% of the cohort, including 11% who experienced multiple or severe relapses, and a 2% discontinuation rate due to adverse events highlight the urgent need for alternative therapeutic options.
5.Why large language models cannot possess consciousness: an integrated information theory perspective
Dong Ah SHIN ; Pyung Goo CHO ; Gyu Yeul JI ; Sang Hyuk PARK ; Soo Heon KIM ; Yoo Jin CHOO ; Min Cheol CHANG
Journal of Yeungnam Medical Science 2025;42(1):79-
Background:
The question of whether large language models (LLMs) possess consciousness has been increasingly debated. Integrated information theory (IIT) offers a quantitative framework for assessing consciousness through a measure of integrated information.
Methods:
This study applied IIT principles to the architecture of transformer-based LLMs, focusing on causal integration, temporal persistence, and system irreducibility. Ablation experiments on Generative Pretrained Transformer 2 (GPT-2) were performed, selectively removing individual attention heads and measuring changes in perplexity as a behavioral proxy for integrated information to empirically approximate the measure of integrated information.
Results:
The ablation study of a single attention head produced minimal or negative changes in perplexity in four out of five representative sentences, indicating redundancy or noise. Only one sentence revealed a significant increase in perplexity change (ΔPPL +11.29), reflecting a localized but nonessential contribution. A comparison with biological systems demonstrated that LLMs meet the IIT criterion of differentiation, but fail to meet the criteria of integration, causal closure, and temporal persistence. These findings confirm that LLMs are architecturally decomposable, lack persistent internal states, and do not sustain global causal irreducibility. Philosophical considerations, including Searle’s Chinese Room argument, further support the idea that the linguistic fluency of LLMs arises from syntactic manipulation rather than semantic understanding.
Conclusion
Current LLMs do not satisfy the structural and informational requirements of consciousness under IIT. Although capable of simulating intelligent language, LLMs remain unconscious systems with a negligible amount of integrated information, underscoring the distinction between linguistic competence and conscious experience.
6.The applicability of noncontact sensors in the field of rehabilitation medicine
Yoo Jin CHOO ; Jun Sung MOON ; Gun Woo LEE ; Wook-Tae PARK ; Min Cheol CHANG
Journal of Yeungnam Medical Science 2024;41(1):53-55
A noncontact sensor field is an innovative device that can detect, measure, or monitor physical properties or conditions without direct physical contact with the subject or object under examination. These sensors use a variety of methods, including electromagnetic, optical, and acoustic technique, to collect information about the target without physical interaction. Noncontact sensors find wide-ranging applications in various fields such as manufacturing, robotics, automobiles, security, environmental monitoring, space industry, agriculture, and entertainment. In particular, they are used in the medical field, where they provide continuous monitoring of patient conditions and offer opportunities in rehabilitation medicine. This article introduces the potential of noncontact sensors in the field of rehabilitation medicine.
7.Effect of prehabilitation on patients with frailty undergoing colorectal cancer surgery:a systematic review and meta-analysis
Min Cheol CHANG ; Yoo Jin CHOO ; Sohyun KIM
Annals of Surgical Treatment and Research 2023;104(6):313-324
Purpose:
The effect of prehabilitation in patients with frailty undergoing colorectal cancer surgery remains controversial. This meta-analysis aimed to assess the impact of prehabilitation before colorectal surgery on the functional outcomes and postoperative complications in patients with frailty undergoing colorectal cancer surgery.
Methods:
PubMed, EMBASE, Cochrane Library, and Scopus databases were searched for articles published up to November 9, 2022. We included randomized and non-randomized trials in which the effects of prehabilitation in patients with frailty undergoing colorectal cancer surgery were investigated against a control group. Data extracted for our metaanalysis included the 6-minute walk test (6MWT), postoperative incidence of complications (Clavien-Dindo classification ≥IIIa), comprehensive complication index (CCI), and length of stay (LOS) in the hospital.
Results:
Compared with the control group, we found a significant improvement in the incidence of postoperative complications and shorter LOS in the hospital in the prehabilitation group. However, the 6MWT and CCI results showed no significant differences between the 2 groups.
Conclusion
Prehabilitation in patients with frailty who underwent colorectal cancer surgery improved the incidence of postoperative complications and LOS in the hospital. Hence, clinicians should consider conducting or recommending prehabilitation exercises prior to colorectal cancer surgery in patients with frailty.
8.Deep Learning Analysis to Automatically Detect the Presence of Penetration or Aspiration in Videofluoroscopic Swallowing Study
Jeoung Kun KIM ; Yoo Jin CHOO ; Gyu Sang CHOI ; Hyunkwang SHIN ; Min Cheol CHANG ; Donghwi PARK
Journal of Korean Medical Science 2022;37(6):e42-
Background:
Videofluoroscopic swallowing study (VFSS) is currently considered the gold standard to precisely diagnose and quantitatively investigate dysphagia. However, VFSS interpretation is complex and requires consideration of several factors. Therefore, considering the expected impact on dysphagia management, this study aimed to apply deep learning to detect the presence of penetration or aspiration in VFSS of patients with dysphagia automatically.
Methods:
The VFSS data of 190 participants with dysphagia were collected. A total of 10 frame images from one swallowing process were selected (five high-peak images and five low-peak images) for the application of deep learning in a VFSS video of a patient with dysphagia. We applied a convolutional neural network (CNN) for deep learning using the Python programming language. For the classification of VFSS findings (normal swallowing, penetration, and aspiration), the classification was determined in both high-peak and lowpeak images. Thereafter, the two classifications determined through high-peak and low-peak images were integrated into a final classification.
Results:
The area under the curve (AUC) for the validation dataset of the VFSS image for the CNN model was 0.942 for normal findings, 0.878 for penetration, and 1.000 for aspiration. The macro average AUC was 0.940 and micro average AUC was 0.961.
Conclusion
This study demonstrated that deep learning algorithms, particularly the CNN, could be applied for detecting the presence of penetration and aspiration in VFSS of patients with dysphagia.
9.Use of Machine Learning in Stroke Rehabilitation: A Narrative Review
Yoo Jin CHOO ; Min Cheol CHANG
Brain & Neurorehabilitation 2022;15(3):e26-
A narrative review was conducted of machine learning applications and research in the field of stroke rehabilitation. The machine learning models commonly used in medical research include random forest, logistic regression, and deep neural networks. Convolutional neural networks (CNNs), a type of deep neural network, are typically used for image analysis.Machine learning has been used in stroke rehabilitation to predict recovery of motor function using a large amount of clinical data as input. Recent studies on predicting motor function have trained CNN models using magnetic resonance images as input data together with clinical data to increase the accuracy of motor function prediction models. Additionally, a model interpreting videofluoroscopic swallowing studies was developed and investigated. In the future, we anticipate that machine learning will be actively used to treat stroke patients, such as predicting the occurrence of depression and the recovery of language, cognitive, and sensory function, as well as prescribing appropriate rehabilitation treatments.
10.A Multicenter, Open-Label, Observational Study Evaluating the Quality of Life After Using a Hydrophilic-Coated Catheter (SpeediCath) With Self-Intermittent Catheterization
Kwang Jin KO ; Myung-Soo CHOO ; Sun-Ouck KIM ; Jang Hwan KIM ; Kyung Jin CHUNG ; Eun Sang YOO ; Myung Ki KIM ; Won Jin CHO ; Jong Bo CHOI ; Jihwan LEE ; Kyu-Sung LEE
International Neurourology Journal 2022;26(4):308-316
Purpose:
We evaluated the change in patient quality of life after the use of a hydrophilic-coated catheter (SpeediCath) in adults requiring intermittent catheterization (IC).
Methods:
This was a multicenter, open-label, observational study using the Patient Perception of Intermittent Catheterization (PPIC) questionnaire and the Intermittent Self-Catheterization questionnaire (ISC-Q) and safety at 12 and 24 weeks in adult patients who had already used other type of catheters prior to switching to SpeediCath or in patients undergoing self-IC for the first time for any reason.
Results:
Among a total of 360 subjects, 215 (59.7%) were women, and the mean age was 62.0±13.2 years. At 24 weeks, the satisfaction rate after using SpeediCath was 84.1%, and 80% of patients responded that they could easily perform IC. In total, 81.6% of patients were willing to continue using SpeediCath. The mean ISC-Q score was 54.90±18.65 at 24 weeks. Men found less interference in their daily life by performing IC than women and found it easier to handle the catheter before it was inserted into the urethra. At week 12, the mean change in ISC-Q was significantly greater in patients <65 years (20.24±23.55) than in those ≥65 years (7.57±27.70, P=0.049), but there was no difference at 24 weeks. The most common adverse events were urinary tract infection in 9.72%, gross hematuria in 2.78%, and urethral pain in 1.39%.
Conclusions
The use of a SpeediCath provided good quality of life for patients who needed self-IC regardless of age or sex.

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