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Objective To establish the reference standard of the median nerve conduction study (NCS) in Korea. Methods A total of 648 median motor and 602 median sensory NCSs from 349 Korean healthy volunteers were tested and analyzed prospectively. Equipment calibration, assessment of intra- and inter-rater reliability, and the NCSs per se were conducted according to a predetermined protocol. A reference standard was established from uncertainty components for the following parameters: the onset and peak latencies; the baseline-to-peak and peak-to-peak amplitudes; the area and duration of the negative wave; and the nerve conduction velocity. The effects of sex, age and stimulation intensity were analyzed. Results Each measured value of 648 median motor and 602 median sensory nerves were obtained and presented with both mean and expanded uncertainties, as well as mean and standard deviations. The cut-off values with expanded uncertainty were determined for different age and sex groups. After adjusting for anthropometric covariates, all parameters except duration were affected by age, and sex appeared to influence both duration and area. While stimulation intensity significantly affected some parameters including latencies, the effect sizes were negligible. Conclusion We propose the median NCS reference standard using the largest Korean dataset ever available. The use of the traceable and reliable reference standard is anticipated to promote more accurate and dependable diagnosis and appropriate management of median neuropathies in Korea.

Abstract Muscle strength assessments are vital in rehabilitation, orthopedics, and sports medicine. However, current methods used in clinical settings, such as manual muscle testing and hand-held dynamometers, often lack reliability, and isokinetic dynamometers (IKD), while reliable, are not easily portable. The aim of this study was to design and validate a wearable dynamometry system with high accessibility, accuracy, and reliability, and to validate the device. Therefore, we designed a wearable dynamometry system (WDS) equipped with knee joint torque sensors. To validate this WDS, we measured knee extension and flexion strength in 39 healthy adults using both the IKD and WDS. Comparing maximal isometric torque measurements, WDS and IKD showed strong correlation and good reliability for extension (Pearson’s r: 0.900; intraclass correlation coefficient [ICC]: 0.893; standard error of measurement [SEM]: 9.85%; minimal detectable change [MDC]: 27.31%) and flexion (Pearson’s r: 0.870; ICC: 0.857; SEM: 11.93%; MDC: 33.07%). WDS demonstrated excellent inter-rater (Pearson’s r: 0.990; ICC: 0.993; SEM: 4.05%) and test–retest (Pearson’s r: 0.970; ICC: 0.984; SEM: 6.15%) reliability during extension/flexion. User feedback from 35 participants, including healthcare professionals, underscores WDS's positive user experience and clinical potential. The proposed WDS is a suitable alternative to IKD, providing high accuracy, reliability, and potentially greater accessibility.

Background Although stroke is commonly perceived as occurring in older adults, traumatic brain injury, one of the risk factors for stroke, is a leading cause of death in the younger adults. This study evaluated stroke risk in young‐to‐middle‐aged adults based on traumatic brain injury severity and stroke subtypes. Methods and Results For this retrospective, population‐based, cohort study, data of adults aged 18 to 49 years who were diagnosed with traumatic brain injury were obtained from the Korean National Health Insurance Service between 2010 and 2017. Traumatic brain injury history was measured based on the International Classification of Diseases, Tenth Revision (ICD‐10), codes. Posttraumatic brain injury stroke risk was analyzed using a time‐dependent Cox regression model. At baseline, 518423 patients with traumatic brain injury and 518 423 age‐ and sex‐matched controls were included. The stroke incidence rate per 1000 person‐years was 3.82 in patients with traumatic brain injury and 1.61 in controls. Stroke risk was approximately 1.89 times as high in patients with traumatic brain injury (hazard ratio, 1.89 [95% CI, 1.84–1.95]). After excluding stroke cases that occurred within 12 months following traumatic brain injury, these significant associations remained. In the subgroup analysis, patients with brain injury other than concussion had an approximately 9.34‐fold risk of intracerebral hemorrhage than did the controls. Conclusions Stroke prevention should be a priority even in young‐to‐middle‐aged adult patients with traumatic brain injury. Managing stroke risk factors through regular health checkups and modifying health‐related behaviors is necessary to prevent stroke.

Introduction: Timely diagnosis and prognostication of Alzheimer's disease (AD) and mild cognitive impairment (MCI) are pivotal for effective intervention. Artificial intelligence (AI) in neuroradiology may aid in such appropriate diagnosis and prognostication. This study aimed to evaluate the potential of novel diffusion model-based AI for enhancing AD and MCI diagnosis through superresolution (SR) of brain magnetic resonance (MR) images. Methods: 1.5T brain MR scans of patients with AD or MCI and healthy controls (NC) from Alzheimer's Disease Neuroimaging Initiative 1 (ADNI1) were superresolved to 3T using a novel diffusion model-based generative AI (d3T*) and a convolutional neural network-based model (c3T*). Comparisons of image quality to actual 1.5T and 3T MRI were conducted based on signal-to-noise ratio (SNR), naturalness image quality evaluator (NIQE), and Blind/Referenceless Image Spatial Quality Evaluator (BRISQUE). Voxel-based volumetric analysis was then conducted to study whether 3T* images offered more accurate volumetry than 1.5T images. Binary and multiclass classifications of AD, MCI, and NC were conducted to evaluate whether 3T* images offered superior AD classification performance compared to actual 1.5T MRI. Moreover, CNN-based classifiers were used to predict conversion of MCI to AD, to evaluate the prognostication performance of 3T* images. The classification performances were evaluated using accuracy, sensitivity, specificity, F1 score, Matthews correlation coefficient (MCC), and area under the receiver-operating curves (AUROC). Results: Analysis of variance (ANOVA) detected significant differences in image quality among the 1.5T, c3T*, d3T*, and 3T groups across all metrics. Both c3T* and d3T* showed superior image quality compared to 1.5T MRI in NIQE and BRISQUE with statistical significance. While the hippocampal volumes measured in 3T* and 3T images were not significantly different, the hippocampal volume measured in 1.5T images showed significant difference. 3T*-based AD classifications showed superior performance across all performance metrics compared to 1.5T-based AD classification. Classification performance between d3T* and actual 3T was not significantly different. 3T* images offered superior accuracy in predicting the conversion of MCI to AD than 1.5T images did. Conclusions: The diffusion model-based MRI SR enhances the resolution of brain MR images, significantly improving diagnostic and prognostic accuracy for AD and MCI. Superresolved 3T* images closely matched actual 3T MRIs in quality and volumetric accuracy, and notably improved the prediction performance of conversion from MCI to AD.

Abstract Some individuals with mild traumatic brain injury (mTBI), also known as concussion, have neuropsychiatric and physical problems that last longer than a few months. Symptoms following mTBI are not only impacted by the kind and severity of the injury but also by the post-injury experience and the individual's responses to it, making the persistence of mTBI particularly difficult to predict. We aimed to identify prognostic blood-based protein biomarkers predicting 6-month outcomes, in light of the clinical course after the injury, in a longitudinal mTBI cohort (N = 42). Among 420 target proteins quantified by multiple-reaction monitoring-mass spectrometry assays of blood samples, 31, 43, and 15 proteins were significantly associated with the poor recovery of neuropsychological symptoms at

Abstract Objective The aim of this study is to assess the value of using videofluoroscopic swallowing study (VFSS) for assessing vocal fold paralysis. Methods This was a retrospective study of patients who underwent VFSS with a vocal fold testing maneuver from June 2020 to February 2022, and who had undergone laryngoscopy within 2 weeks before or after VFSS. The vocal fold testing maneuver consisted of making an ‘e’ sound for about 2–3 seconds during VFSS anterior–posterior (AP) view. The diagnostic value of the VFSS was evaluated by a trained reviewer, who assessed the presence and laterality of vocal fold paralysis by examining videos of the patients performing the vocal fold testing maneuver. Intra‐rater reliability was determined by evaluation of the videos by the same reviewer 2 weeks later, and inter‐rater reliability was determined by evaluation by a second reviewer. Results Seventy patients were enrolled in the study. The positive predictive value was 91.43% and the intra‐rater and inter‐rater reliabilities, as determined by Cohen's kappa value, were 0.746 and 0.824 respectively. Conclusions The presence and laterality of vocal fold paralysis were identified accurately and reliably by the reviewers, showing that VFSS can be used to assess vocal fold paralysis. Level of evidence 2.

Abstract The sequential 4-channel neuromuscular electrical stimulation (NMES), based on the normal contractile sequences of swallowing-related muscles, is a new rehabilitative treatment. The objective of this study was to explore the mechanism of the rehabilitative effect of the 4-channel NMES using kinematic analysis of videofluoroscopic swallowing study (VFSS) data. For this post-hoc analysis, we included a subset of participants from the prospective randomized controlled study on the clinical effectiveness of the sequential 4-channel NMES compared with that of the conventional 2-channel NMES. Seventeen subjects (11 and six in the 4- and 2-channel NMES groups, respectively) were eligible for the kinematic analysis of VFSS data. The hyoid bone movement was analyzed by evaluating the distance and time parameters with four peak points (A, B, C, D). The 4-channel NMES group showed significant improvement in vertical distances (A–C), horizontal distance (A–B, A–C), time interval (A–B–C) and total time, compared with their pretreatment data. The 2-channel NMES group showed significant improvements in time interval (A–B); however, the Euclidean distance (A–D) and mean velocity of the Euclidean distance (A-C) were significantly decreased. When the two groups were directly compared, the 4-channel group showed significantly greater improvement in horizontal distance (A–B), Euclidean distance (A–D), time interval (A–B–C), and mean velocity the Euclidean distance (A–D). The results in this study suggest that the sequential 4-channel NMES might lead to the physiologic circular movement of the hyoid bone during swallowing, and therefore be an effective treatment for dysphagia. Trial registration: Clinicaltrials.gov, registration number: NCT03670498.

Abstract Background Dual-task training in Parkinson’s disease (PD) improves spatiotemporal gait parameters, cognition, and quality of life. Virtual reality (VR) has been used as a therapeutic tool for patients to participate in activities in a safe environment, engage in multisensory experiences, and improve motivation and interest in rehabilitation. This study aimed to investigate the feasibility of fully immersive VR exergames with dual-task components in patients with PD. Methods We developed VR exergames (go/no-go punch game, go/no-go stepping game, and number punch game) to improve habitual behavior control using motor–cognitive dual-task performance in patients with PD. The participants underwent 10 sessions 2–3 times a week, consisting of 30 min per session. The Unified Parkinson’s Disease Rating Scale, Timed Up and Go test (TUG) under single- and dual-task (cognitive and physical) conditions, Berg balance scale (BBS), Stroop test, trail-making test, and digit span were evaluated before and after intervention. The Simulator Sickness Questionnaire (SSQ) was used to assess VR cybersickness. Usability was assessed using a self-reported questionnaire. Results Twelve patients were enrolled and completed the entire training session. The mean age of participants was 73.83 ± 6.09 years; mean disease duration was 128.83 ± 76.96 months. The Hoehn and Yahr stages were 2.5 in seven patients and 3 in five patients. A significant improvement was observed in BBS and Stroop color–word test (p = 0.047 and p = 0.003, respectively). TUG time and dual-task interferences showed positive changes, but these changes were not statistically significant. The median SSQ total score was 28.05 (IQR: 29.92), 13.09 (IQR: 11.22), and 35.53 (IQR: 52.36) before, after the first session, and after the final session, respectively; the differences were not significant. Overall satisfaction with the intervention was 6.0 (IQR: 1.25) on a 7-point Likert-type scale. Conclusions Fully immersive VR exergames combined with physical and cognitive tasks may be used for rehabilitation of patients with PD without causing serious adverse effects. Furthermore, the exergames using dual-task components improved executive function and balance. Further development of VR training content may be needed to improve motor and dual-task performances. Trial registration NCT04787549 ( https://clinicaltrials.gov/ct2/show/NCT04787549 )

Abstract Muscle strength assessment is important in predicting clinical and functional outcomes in many disorders. Manual muscle testing, although commonly used, offers suboptimal accuracy and reliability. Isokinetic dynamometers (IKDs) have excellent accuracy and reliability; but are bulky and expensive, offering limited accessibility. This study aimed to design a portable dynamometer that is accessible, accurate and reliable, and to validate the device in a general population. The portable articulated dynamometry system (PADS) is a portable device with an embedded high-precision load cell, designed to measure muscle strength with optimal accuracy. Seventy-two participants underwent maximal isometric and isokinetic knee extensor torque measurement with the PADS and IKD, respectively. The PADS results were cross-validated against IKD results using change in mean (CIM). Interrater and intra-rater reliabilities were assessed using intraclass correlation coefficients, standard error of measurement, and minimal detectable change. The PADS maximal knee extensor strength results were not significantly different from those by IKD (CIM: − 2.13 Nm; 95% CI − 4.74, 0.49 Nm). The PADS showed interrater reliability (Pearson’s r: 0.958; ICC: 0.979; SEM: 5.51%) and excellent intra-rater reliability (Pearson’s r: 0.912; ICC: 0.954; SEM: 8.38%). The proposed PADS may be an effective alternative to IKD, offering good accuracy, reliability, and potentially better accessibility.

Objective To investigate the clinical and swallowing characteristics related to respiratory infection in patients with parkinsonism. Methods One hundred and forty-two patients with parkinsonism who underwent videofluoroscopic swallowing studies (VFSS) were enrolled in this study. The initial clinical and VFSS characteristics were compared between patients with and without a history of respiratory infection in the past year. A multivariate logistic regression model was applied to identify clinical and swallowing characteristics related to respiratory infections. Results Patients with respiratory infections were older (74.75±10.20 years vs. 70.70±8.83 years, p=0.037), had a higher Hoehn and Yahr (H&Y) stage (stage IV–V, 67.9% vs. 49.1%; p=0.047), and were more likely to have a diagnosis of idiopathic Parkinson’s disease (IPD) (67.9% vs. 41.2%, p=0.011) than those without respiratory infections. Among VFSS findings, bolus formation, premature bolus loss, oral transit time, pyriform sinus residues, pharyngeal wall coatings, and penetration/aspiration were significantly worse in patients with respiratory infections (p

Objective To explore the effects of tactile stimulation using air pressure at the auricular branch of the vagus nerve on autonomic activity in healthy individuals. Methods Three types of tactile stimulation were used in this study: continuous low-amplitude, continuous high-amplitude, and pulsed airflow. The tactile stimulations were provided to the cymba concha to investigate autonomic activity in 22 healthy participants. The mean heart rate (HR) and parameters of HR variability, including the standard deviation of R-R intervals (SDNN) and root mean square of successive R-R interval differences (RMSSD) were compared at baseline, stimulation, and recovery periods. Results Two-way repeated measures ANOVA indicated a significant main effect of time on HR (p=0.001), SDNN (p=0.003), and RMSSD (p

Objective To characterize the repetitive transcranial magnetic stimulation (rTMS) induced changes in angiogenic mechanisms across different brain regions. Methods Seventy-nine adult male Sprague-Dawley rats were subjected to a middle cerebral artery occlusion (day 0) and then treated with 1-Hz, 20-Hz, or sham stimulation of their lesioned hemispheres for 2 weeks. The stimulation intensity was set to 100% of the motor threshold. The neurological function was assessed on days 3, 10, and 17. The infarct volume and angiogenesis were measured by histology, immunohistochemistry, Western blot, and real-time polymerase chain reaction (PCR) assays. Brain tissue was harvested from the ischemic core (IC), ischemic border zone (BZ), and contralateral homologous cortex (CH). Results Optical density of angiopoietin1 and synaptophysin in the IC was significantly greater in the low-frequency group than in the sham group (p=0.03 and p=0.03, respectively). The 1-Hz rTMS significantly increased the level of Akt phosphorylation in the BZ (p

Objective Dysphagia is a common clinical condition characterized by difficulty in swallowing. It is sub-classified into oropharyngeal dysphagia, which refers to problems in the mouth and pharynx, and esophageal dysphagia, which refers to problems in the esophageal body and esophagogastric junction. Dysphagia can have a significant negative impact one’s physical health and quality of life as its severity increases. Therefore, proper assessment and management of dysphagia are critical for improving swallowing function and preventing complications. Thus a guideline was developed to provide evidence-based recommendations for assessment and management in patients with dysphagia. Methods Nineteen key questions on dysphagia were developed. These questions dealt with various aspects of problems related to dysphagia, including assessment, management, and complications. A literature search for relevant articles was conducted using Pubmed, Embase, the Cochrane Library, and one domestic database of KoreaMed, until April 2021. The level of evidence and recommendation grade were established according to the Grading of Recommendation Assessment, Development and Evaluation methodology. Results Early screening and assessment of videofluoroscopic swallowing were recommended for assessing the presence of dysphagia. Therapeutic methods, such as tongue and pharyngeal muscle strengthening exercises and neuromuscular electrical stimulation with swallowing therapy, were effective in improving swallowing function and quality of life in patients with dysphagia. Nutritional intervention and an oral care program were also recommended. Conclusion This guideline presents recommendations for the assessment and management of patients with oropharyngeal dysphagia, including rehabilitative strategies.

Objective To develop a set of reference standards for tibial motor, common peroneal motor, sural sensory, and superficial peroneal sensory nerve conduction studies (NCSs) with expanded uncertainty in a healthy Korean population. Methods Standardized procedures were conducted for individual lower extremity NCSs of 199 healthy participants in their 20s (n=100) and 50s (n=99). Mean values and expanded uncertainties for parameters were analyzed with thorough consideration of multiple uncertainty factors under the International Guide to the Expression of Uncertainty in Measurement. In addition, side-to-side differences in onset latency, amplitude, and nerve conduction velocity (NCV) were analyzed. Results Mean (reference range) for distal onset latency, baseline to negative peak amplitude, NCV of tibial motor nerve in males in their 20s were 4.3 ms (3.1–5.4 ms), 7.1 mV (3.4–10.9 mV), and 50.7 m/s (42.2–59.3 m/s), respectively; sural sensory nerve baseline to negative peak amplitude in males in their 20s was 21.7 μV (8.3–35.2 μV). Including the aforementioned data, we present a vast dataset of normative mean values and expanded uncertainties for NCSs of the leg in a healthy Korean population. Furthermore, upper limits for normal side-to-side differences for onset latency, amplitude, and NCV of each nerve are suggested. Conclusion To our knowledge, this is the first study to present the reference standards of leg NCSs with consideration for multifactorial uncertainties in an Asian population. We expect these results to help practitioners make reliable and reproducible clinical decisions.

Abstract Introduction This study aimed to investigate alterations in whole‐brain functional connectivity after a concussion using graph‐theory analysis from global and local perspectives and explore the association between changes in the functional network properties and cognitive performance. Methods Individuals with mild traumatic brain injury (mTBI, n = 29) within a month after injury, and age‐ and sex‐matched healthy controls (n = 29) were included. Graph‐theory measures on functional connectivity assessed using resting state functional magnetic resonance imaging data were acquired from each participant. These included betweenness centrality, strength, clustering coefficient, local efficiency, and global efficiency. Multi‐domain cognitive functions were correlated with the graph‐theory measures. Results In comparison to the controls, the mTBI group showed preserved network characteristics at a global level. However, in the local network, we observed decreased betweenness centrality, clustering coefficient, and local efficiency in several brain areas, including the fronto‐parietal attention network. Network strength at the local level showed mixed‐results in different areas. The betweenness centrality of the right parahippocampus showed a significant positive correlation with the cognitive scores of the verbal learning test only in the mTBI group. Conclusion The intrinsic functional connectivity after mTBI is preserved globally, but is suboptimally organized locally in several areas. This possibly reflects the neurophysiological sequelae of a concussion. The present results may imply that the network property could be used as a potential indicator for clinical outcomes after mTBI.

Abstract Background Unilateral vocal cord paralysis may result from nerve compression by tumors or direct nerve injuries during tumor resections, which can cause dysphonia or dysphagia, and reduced quality of life. Objectives This prospective, single‐group study aimed to investigate the effect of percutaneous injection laryngoplasty on voice and swallowing function in patients with cancer‐related unilateral vocal cord paralysis. Methods Patients underwent percutaneous injection laryngoplasty with hyaluronic acid under local anesthesia. Stroboscopy and videofluoroscopic swallowing study were conducted to evaluate the voice‐ and swallowing‐related outcome measures, respectively. The participants were evaluated before injection laryngoplasty, as well as after two weeks and three months. Results Injection laryngoplasty significantly improved the glottal gap, vocal fold position, Maximum Phonation Time, and Voice Handicap Index‐10. Post‐hoc analysis using Bonferroni correction showed that the improvements occurred within two post‐treatment weeks and remained at three post‐treatment months. In the subgroup analysis, the patients who underwent injection laryngoplasty within 8 weeks from onset showed significantly higher improvements in the videofluoroscopic dysphagia scale and swallowing function than the patients who received the procedure after 8 weeks or more. Conclusion Percutaneous injection laryngoplasty improves glottal closure and voice in patients with cancer‐related unilateral vocal cord paralysis. Early injection laryngoplasty may lead to greater benefits on swallowing function. Level of Evidence 4.

Abstract Background To date, conventional swallowing therapies and 2-channel neuromuscular electrical stimulation (NMES) are standard treatments for dysphagia. The precise mechanism of 2-channel NMES treatment has not been determined, and there are controversies regarding the efficacy of this therapy. The sequential 4-channel NMES was recently developed and its action is based on the normal contractile sequence of swallowing-related muscles. Objective To evaluate and compare the rehabilitative effectiveness of the sequential 4-channel NMES with that of conventional 2-channel NMES. Methods In this prospective randomized case–control study, 26 subjects with dysphagia were enrolled. All participants received 2- or 4-channel NMES for 2–3 weeks (minimal session: 7 times, treatment duration: 300–800 min). Twelve subjects in the 4-channel NMES group and eleven subjects in the 2-channel NMES group completed the intervention. Initial and follow-up evaluations were performed using the videofluoroscopic dysphagia scale (VDS), the penetration-aspiration scale (PAS), the MD Anderson dysphagia inventory (MDADI), the functional oral intake scale (FOIS), and the Likert scale. Results The sequential 4-channel NMES group experienced significant improvement in their VDS (oral, pharyngeal, and total), PAS, FOIS, and MDADI (emotional, functional, and physical subsets) scores, based on their pretreatment data. VDS (oral, pharyngeal, and total) and MDADI (emotional and physical subsets) scores, but not PAS and FOIS scores, significantly improved in the 2-channel NMES group posttreatment. When the two groups were directly compared, the 4-channel NMES group showed significant improvement in oral and total VDS scores. Conclusions The sequential 4-channel NMES, through its activation of the suprahyoid and thyrohyoid muscles, and other infrahyoid muscles mimicking physiological activation, may be a new effective treatment for dysphagia. Trial registration: clinicaltrial.gov, registration number: NCT03670498, registered 13 September 2018, https://clinicaltrials.gov/ct2/show/NCT03670498?term=NCT03670498&draw=2&rank=1 .

Abstract This retrospective cohort study investigated the risk and mortality rate due to aspiration pneumonia in patients with Parkinson’s disease (PD) using a nationwide database. We identified 10,159 newly diagnosed PD patients between 2004 and 2006, and four age- and sex-matched controls for each PD patient from the National Health Insurance Service database in Korea. We analyzed the relative risk of aspiration pneumonia and mortality after the first occurrence of aspiration pneumonia until 2017. Throughout the study period, PD patients showed a higher incidence of aspiration pneumonia than their matched controls (3.01 vs. 0.59 events per 1,000 person-years), and they were at an increased risk of aspiration pneumonia (hazard ratio = 4.21; 95% confidence interval, 3.87–4.58). After the first occurrence of aspiration pneumonia, the mortality rate of PD patients was 23.9% after one month, 65.2% after 1 year, and 91.8% after 5 years, while that of controls was 30.9%, 67.4%, and 88.9%, respectively. Patients with PD are at an increased risk of aspiration pneumonia, and approximately two-thirds of the patients die within a year after experiencing aspiration pneumonia. Further studies are warranted to prevent aspiration pneumonia and implement proper treatments to prevent death after aspiration pneumonia in patients with PD.

Abstract Identification of prognostic factors for swallowing recovery in patients with post-stroke dysphagia is crucial for determining therapeutic strategies. We aimed at exploring hyoid kinematic features of poor swallowing prognosis in patients with post-stroke dysphagia. Of 122 patients who experienced dysphagia following ischemic stroke, 18 with poor prognosis, and 18 age- and sex-matched patients with good prognosis were selected and retrospectively reviewed. Positional data of the hyoid bone during swallowing were obtained from the initial videofluoroscopic swallowing study after stroke onset. Normalized hyoid profiles of displacement/velocity and direction angle were analyzed using functional regression analysis, and maximal or mean values were compared between the good and poor prognosis patient groups. Kinematic analysis showed that maximal horizontal displacement (P = 0.031) and velocity (P = 0.034) in forward hyoid motions were significantly reduced in patients with poor prognosis compared to those with good prognosis. Mean direction angle for the initial swallowing phase was significantly lower in patients with poor prognosis than in those with good prognosis (P = 0.0498). Our study revealed that reduced horizontal forward and altered initial backward motions of the hyoid bone during swallowing can be novel kinematic features indicating poor swallowing prognosis in patients with post-stroke dysphagia.

Objective To evaluate the longitudinal changes of swallowing kinematics based on videofluoroscopic swallowing studies (VFSSs) in subacute stroke patients grouped according to the method of dietary intake. Methods Sixty-nine subacute stroke patients who had taken at least 2 successive VFSSs were included. Subjects were allocated into 3 groups according to the degree of swallowing function recovery—not improved group (tube feeding recommended to patients at both studies), improved group (tube feedings recommended initially to patients and oral feeding recommended at follow-up study), and well-maintained group (oral feeding at both studies recommended to patients). Initial VFSS was performed during the subacute stage of stroke, 1 to 12 weeks after the onset of stroke, and follow-up VFSS was performed at least once. Kinematic variables were calculated by two-dimensional motion analysis of multiple structures, including the hyoid bone, epiglottis, and vocal cord. Changes of kinematic variables were analyzed in serial VFSSs. Results At the initial VFSS, the well-maintained group showed significantly larger angles of epiglottic folding than the not improved group, while at the follow-up VFSS, the improved and the well-maintained groups showed significantly larger epiglottic folding angles than the not improved group. The distribution of epiglottic folding angles was in a dichotomous pattern, and each cluster was related to the swallowing function. Conclusion This study showed that improved epiglottic folding angles are associated with the recovery of the swallowing process and suitability for oral feeding among various kinematic variables in subacute stroke patients.

Swallowing difficulty is a major health concern of the elderly population. The gold standard examination to assess swallowing function is videofluoroscopic swallowing study (VFSS). Hyoid kinematic parameters extracted from VFSS images can be quantitative indicators of swallowing difficulty. In previous studies, its tracking failures are still not resolved when passing through the mandible. Furthermore, it is difficult to be applied in kinematic analysis because the hyoid trajectories can be susceptible to irrelevant neck movements during swallowing. The aim of this study is to develop a robust algorithm for obtaining high-accuracy trajectories of the hyoid bone during swallowing with adjustment of the neck movements. We propose a CNN-based hyoid tracking algorithm which consists of single-domain networks for hyoid tracking and an attention U-Net with conditional random fields for semantic segmentation of the hyoid bone and the cervical vertebrae. The results show that the proposed method can track the hyoid bone robustly compared to the previous methods as measured by a success plot of one-pass evaluation. In addition, the proposed semantic segmentation method achieved the highest dice coefficient for the hyoid bone and the cervical vertebrae. Finally, the obtained hyoid trajectories were evaluated by a root mean squared error, relative error of range of motion, and Pearson's correlation analysis. The proposed algorithm can provide ability to automatically analyze the hyoid motions during swallowing in clinical practice and will potentially enable physician's decision making on diagnostic and therapeutic modalities based on quantitative swallowing assessments.

Purpose. To analyze ocular manifestations, visual field (VF) pattern, and VF test performance in traumatic brain injury (TBI) and stroke patients. Methods. This retrospective, cross-sectional study included 118 patients (236 eyes) with TBI and stroke who had undergone VF testing by standard automated perimetry with the central 24-2 threshold test. Clinical features including best-corrected visual acuity (BCVA), intraocular pressure (IOP), ocular manifestations, and VF test results including VF defect pattern, reliability, and global indices were analyzed and compared between the TBI and stroke patients. Results. In TBI patients, ocular manifestations included strabismus (11.1%), cataract (4.2%), and glaucoma suspect (2.8%), whereas in stroke patients, cataract (15.2%), strabismus (8.5%), diabetic retinopathy (4.9%), extraocular movement (EOM) limitation (3.0%), glaucoma suspect (3.0%), nystagmus (2.4%), drusen (1.2%), and vitreous hemorrhage (1.2%) were found. The VF test results showed that 47 eyes (85.5%) in TBI and 86 (65.2%) in stroke had VF defect; in TBI, the scattered pattern was the most common (56.4%), followed by homonymous hemianopsia (14.5%), homonymous quadrantanopia (10.9%), and total defect (3.6%), whereas in stroke, homonymous hemianopsia was the most common (31.8%), followed by scattered pattern (16.7%), homonymous quadrantanopia (12.1%), and total defect (4.5%). Only 15 eyes (27.3%) in TBI and 32 (24.2%) in stroke showed reliable VF indices. The mean deviation (MD) was −10.5 ± 7.1 dB in TBI and −9.5 ± 6.8 dB in stroke, and the pattern standard deviation (PSD) was 4.9 ± 3.3 dB in TBI and 6.1 ± 3.9 dB in stroke, without statistically significant differences between the two groups. Conclusion. Various ocular manifestations were found, and a considerable proportion of patients were experiencing VF defects and showed unreliable VF test performance. Our findings suggest that accurate evaluation and rehabilitation of visual function should be a matter of greater concern and emphasis in the management of TBI and stroke patients, besides systemic diseases.

Background: The inter- and intrarater variability of conventional computed tomography (CT) classification systems for evaluating the extent of ischemic-edematous insult following traumatic brain injury (TBI) may hinder the robustness of TBI prognostic models.Objective: This study aimed to employ fully automated quantitative densitometric CT parameters and a cutting-edge machine learning algorithm to construct a robust prognostic model for pediatric TBI.Methods: Fifty-eight pediatric patients with TBI who underwent brain CT were retrospectively analyzed. Intracranial densitometric information was derived from the supratentorial region as a distribution representing the proportion of Hounsfield units. Furthermore, a machine learning-based prognostic model based on gradient boosting (i.e., CatBoost) was constructed with leave-one-out cross-validation. At discharge, the outcome was assessed dichotomously with the Glasgow Outcome Scale (favorability: 1–3 vs. 4–5). In-hospital mortality, length of stay (>1 week), and need for surgery were further evaluated as alternative TBI outcome measures.Results: Densitometric parameters indicating reduced brain density due to subtle global ischemic changes were significantly different among the TBI outcome groups, except for need for surgery. The skewed intracranial densitometry of the unfavorable outcome became more distinguishable in the follow-up CT within 48 h. The prognostic model augmented by intracranial densitometric information achieved adequate AUCs for various outcome measures [favorability = 0.83 (95% CI: 0.72–0.94), in-hospital mortality = 0.91 (95% CI: 0.82–1.00), length of stay = 0.83 (95% CI: 0.72–0.94), and need for surgery = 0.71 (95% CI: 0.56–0.86)], and this model showed enhanced performance compared to the conventional CRASH-CT model.Conclusion: Densitometric parameters indicative of global ischemic changes during the acute phase of TBI are predictive of a worse outcome in pediatric patients. The robustness and predictive capacity of conventional TBI prognostic models might be significantly enhanced by incorporating densitometric parameters and machine learning techniques.

BackgroundPatients with parkinsonism have higher inactivity levels than the general population, and this results in increased comorbidities. Although exercise has benefits for motor function and quality of life (QOL) in patients with parkinsonism, these patients face many barriers to exercise participation, such as lack of motivation, fatigue, depression, and time constraints. Recently, the use of mobile apps has been highlighted as a remote exercise management strategy for patients with chronic diseases. ObjectiveThis study aimed to evaluate the effects of home-based exercise management with a customized mobile app on the exercise amount, physical activity, and QOL of patients with parkinsonism. MethodsThis was a prospective, open-label, single-arm pilot study. The therapist installed the app in the smartphones of the participants and educated them on how to use the app. The therapist developed an individualized multimodal exercise program that consisted of stretching, strengthening, aerobic, balance and coordination, and oral-motor and vocal exercises. Participants were encouraged to engage in an 8-week home-based exercise program delivered through a customized app. The alarm notifications of the app provided reminders to exercise regularly at home. The primary outcome was the exercise amount. The secondary outcomes were assessed using the International Physical Activity Questionnaire (IPAQ), Parkinson’s Disease Questionnaire-39 (PDQ-39), and Geriatric Depression Scale (GDS). The usability of the customized app was assessed using a self-report questionnaire. ResultsA total of 21 participants with parkinsonism completed the intervention and assessment between September and December 2020 (mean age: 72 years; women: 17/21, 81%; men: 4/21, 19%). The participants reported a significant increase in the total amount of exercise (baseline: mean 343.33, SD 206.70 min/week; 8-week follow-up: mean 693.10, SD 373.45 min/week; P

Abstract Objective We aimed to investigate the clinical significance of increased uptake in 18F‐fluorodeoxyglucose positron emission tomography in patients with peripheral nerve lesions. Methods We selected patients with unilateral peripheral nerve lesions confirmed with electromyography who had undergone 18F‐fluorodeoxyglucose positron emission tomography covering the lesions. In the denervated muscles and their contralateral corresponding pairs, a mean (SUVmean) and maximum standardized uptake value (SUVmax) were obtained from 18F‐fluorodeoxyglucose positron emission tomography images. We analyzed the difference in these values between the denervated and normal muscles. The lesion‐to‐normal ratio of the SUVmean (LNRmean) between each muscle pair was also obtained. Subgroup analysis was performed to find whether these three parameters were related to severity, abundance of abnormal spontaneous activity, and etiology. Results Twenty‐three patients with 38 denervated muscles were included. Compared to their normal counterparts, the denervated muscles showed significantly higher SUVmax (1.33 ± 0.49 vs. 1.10 ± 0.37, n = 38, P

Abstract Background Stress signals during sucking activity such as nasal flaring, head turning, and extraneous movements of the body have been attributed to incoordination of sucking, swallowing, and respiration (SSR) in premature infants. However, the association of uncoordinated sucking pattern with developmental outcomes has not yet been investigated. The aim of this study was to investigate whether uncoordinated sucking pattern during bottle-feeding in premature infants is associated with the developmental outcomes at 8–12 and 18–24 months of age (corrected for prematurity). Methods We retrospectively reviewed the medical records and video recordings for the Neonatal Oral-Motor Assessment Scale (NOMAS) of premature infants and divided them into two groups based on the presence or absence of incoordination. The Bayley-III cognition composite scores of the incoordination-positive and incoordination-negative group were compared at 8–12 and 18–24 months of age. Results Seventy premature infants exhibited a disorganized sucking pattern according to the NOMAS. The average Bayley-III cognition composite scores at 8–12 months of age were 92.5 ± 15.6 and 103.0 ± 11.3 for the incoordination-positive (n = 22) and incoordination-negative groups (n = 48), respectively (p = 0.002). The average Bayley-III cognition composite scores at 18–24 months were 90.0 ± 17.9 and 100.7 ± 11.5 for the incoordination-positive (n = 21) and incoordination-negative groups (n = 46), respectively (p = 0.005). A multiple linear regression analysis indicated that the presence of uncoordinated sucking pattern, grade 3 or 4 germinal matrix hemorrhage–intraventricular hemorrhage, and moderate to severe bronchopulmonary dysplasia were independently associated with cognitive development at 18–24 months of age. Conclusions Uncoordinated sucking pattern in premature infants was independently associated with a higher risk of abnormal developmental outcome in the cognitive domain of the Bayley-III at both 8–12 and 18–24 months. There may be a need for periodic follow-up and early intervention for developmental delay when incoordination of SSR that results in stress signals on the NOMAS is observed before 40 weeks postmenstrual age.

Objective To investigate the proportion of aspiration pneumonia cases among patients with community-acquired pneumonia in Korea. Methods This retrospective study included patients with community-acquired pneumonia who had been admitted to the emergency department of a university-affiliated tertiary hospital in Gyeonggi Province, Korea between January 1, 2016 and December 31, 2016. Among these patients, those with aspiration pneumonia were identified using ICD-10 codes (J69.*). Patients with recurrent pneumonia were excluded, as were those who were immunocompromised. The proportion of cases of aspiration pneumonia was calculated, and the characteristics and clinical outcomes of patients with aspiration pneumonia and non-aspiration pneumonia were compared. Results The proportion of aspiration pneumonia cases among patients with community-acquired pneumonia was 14.2%. Patients with aspiration pneumonia were significantly more likely to be older (p

Abstract Background While spontaneous robotic arm control using motor imagery has been reported, most previous successful cases have used invasive approaches with advantages in spatial resolution. However, still many researchers continue to investigate methods for robotic arm control with noninvasive neural signal. Most of noninvasive control of robotic arm utilizes P300, steady state visually evoked potential, N2pc, and mental tasks differentiation. Even though these approaches demonstrated successful accuracy, they are limited in time efficiency and user intuition, and mostly require visual stimulation. Ultimately, velocity vector construction using electroencephalography activated by motion-related motor imagery can be considered as a substitution. In this study, a vision-aided brain–machine interface training system for robotic arm control is proposed and developed. Methods The proposed system uses a Microsoft Kinect to detect and estimates the 3D positions of the possible target objects. The predicted velocity vector for robot arm input is compensated using the artificial potential to follow an intended one among the possible targets. Two participants with cervical spinal cord injury trained with the system to explore its possible effects. Results In a situation with four possible targets, the proposed system significantly improved the distance error to the intended target compared to the unintended ones (p

Abstract Background Robot-assisted gait training (RAGT) was developed to restore gait function by promoting neuroplasticity through repetitive locomotor training and has been utilized in gait training. However, contradictory outcomes of RAGT have been reported for patients with Parkinson’s disease (PD). In addition, the mechanism of the RAGT treatment effect is still unknown. This study aims to investigate the effects of RAGT on gait velocity in patients with PD and to unveil the mechanisms of these effects. Methods This is a prospective, single-blind, single-center, randomized controlled trial. Eligible participants will be randomly allocated to: 1) a Walkbot-S™ RAGT group or 2) a treadmill training group. The participants will receive three 45-min sessions of each intervention per week for 4 weeks. Gait speed during RAGT will be targeted to the maximal speed depending on the participant’s height; the same principle will be applied to the treadmill training group to match the training intensity. The primary outcome measure is gait speed measured by the 10-Meter Walk Test at a comfortable pace under single-task conditions. Secondary outcomes include dual-task interference, the Berg Balance Scale, Timed Up and Go test, the Korean version of the Falls Efficacy Scale-International, New Freezing of Gait Questionnaire, Movement Disorder Society-sponsored revision of the Unified Parkinson’s Disease Rating Scale, and functional connectivity measured by resting-state functional magnetic resonance imaging. Baseline assessments (T0) will be conducted to acquire clinical characteristics and outcome measure values before the intervention. Postintervention assessments (T1) will compare immediate efficacies within 3 days after the intervention. Follow-up assessments (T2) will be conducted 1 month after the intervention. Considering an alpha of 0.05 and a power of 80%, the total number of participants to be recruited is 44. Discussion This study will reveal the effect of RAGT using an exoskeletal robot, not only on gait speed, but also on gait automaticity, balance function, fall risk, quality of life, and disease severity. In addition, the study will shed new light on the mechanism of the RAGT effect by evaluating changes in gait automaticity and brain functional networks. Trial registration ClinicalTrials.gov, NCT03490578. Registered on 21 March 2018.

Objective To investigate the differences in hyolaryngeal kinematics at rest and during swallowing in the upright sitting (UP) and the lateral decubitus (LD) postures in healthy adults, and delineating any potential advantages of swallowing while in the LD posture. Methods Swallowing was videofluoroscopically evaluated in 20 healthy volunteers in UP and LD postures, based on the movements of hyoid bone, vocal folds, and the bolus head. Parameters included the Penetration-Aspiration Scale (PAS), horizontal and vertical displacement, horizontal and vertical initial position, horizontal and vertical peak position, time to peak position of the hyoid bone and vocal folds, and pharyngeal transit time (PTT). Results Nine participants were rated PAS 2 in the UP and 1 was rated PAS 2 in the LD (p=0.003) at least 1 out of 3 swallows each posture. The hyoid and vocal folds showed more anterior and superior peak and initial positions in the LD. In addition, swallowing resulted in greater vertical and smaller horizontal displacement of the hyoid in LD posture compared with UP. Time to peak position of the hyoid was shorter in LD. The maximal vertical and horizontal displacement of the vocal folds, and PTT were comparable between postures. Conclusion The results showed that the peak and initial positions of the hyoid and larynx and the pattern of hyoid movement varied significantly depending on the body postures. This study suggests that the LD posture was one of the safe feeding postures without any increased risk compared with UP posture.

Abstract Background Swallowing impairment is a common complication in various geriatric and neurodegenerative diseases. Swallowing kinematic analysis is essential to quantitatively evaluate the swallowing motion of the oropharyngeal structures. This study aims to develop a novel swallowing kinematic analysis software, called spatio-temporal analyzer for motion and physiologic study (STAMPS), and verify its validity and reliability. Methods STAMPS was developed in MATLAB, which is one of the most popular platforms for biomedical analysis. This software was constructed to acquire, process, and analyze the data of swallowing motion. The target of swallowing structures includes bony structures (hyoid bone, mandible, maxilla, and cervical vertebral bodies), cartilages (epiglottis and arytenoid), soft tissues (larynx and upper esophageal sphincter), and food bolus. Numerous functions are available for the spatiotemporal parameters of the swallowing structures. Testing for validity and reliability was performed in 10 dysphagia patients with diverse etiologies and using the instrumental swallowing model which was designed to mimic the motion of the hyoid bone and the epiglottis. Results The intra- and inter-rater reliability tests showed excellent agreement for displacement and moderate to excellent agreement for velocity. The Pearson correlation coefficients between the measured and instrumental reference values were nearly 1.00 (P

An amendment to this paper has been published and can be accessed via the original article.

It has been suggested that oral feeding trial has therapeutic implications for improving oral-motor and swallowing function in infants and young children fed via an enteral tube or gastrostomy. This study aimed to investigate whether oral feeding challenges in children with tracheostomy could improve feeding outcomes, even with the finding of aspiration compared to those who did not receive oral feeding at all. Children (age

Several treatments have been proposed to shorten the time to the attainment of full oral feeding (FOF) for premature infants, but there are only a few evaluation methods useful in estimating predictors of this period. We investigated whether specific items within the disorganized sucking patterns described by the Neonatal Oral-Motor Assessment Scale (NOMAS) could estimate the time to FOF in preterm infants with feeding difficulty. Preterm infants diagnosed with a disorganized sucking pattern in the NOMAS evaluation before 50 weeks of postmenstrual age were included. Video recordings of at least 2 min of oral feeding were further analyzed retrospectively by two assessors and the premature infants who exhibited disorganized sucking patterns (n = 109) were divided into three clusters (clusters 2–4). The observational items compatible with disorganization in the original NOMAS were divided into three groups: cluster 2 (disorganized: arrhythmical), cluster 3 (disorganized: arrhythmical + unable to sustain), and cluster 4 (disorganized: arrhythmical + incoordination ± unable to sustain) and further divided into incoordination-positive (cluster 4) and incoordination-negative groups (clusters 2 and 3). Premature infants in the incoordination-positive group (cluster 4, which means stress signals) showed a median transition time of 22 days (range: 4–121 days) which was longer than that in the incoordination-negative group (median 6 days; range: 1–25 days). Univariate linear regression analysis revealed that the presence of incoordination among disorganized sucking patterns (NOMAS cluster 4 vs. clusters 2 and 3), birth weight, total parenteral nutrition (TPN) duration, non-invasive positive pressure ventilation duration, the presence of moderate to severe bronchopulmonary dysplasia, pulmonary hypertension, sepsis, small for gestational age (SGA), and necrotizing enterocolitis are associated with the transition time to FOF. In a multivariate linear regression analysis, the variables revealed to be associated with the transition time were TPN duration, SGA, and the presence of stress signals (incoordination-positive group) among disorganized sucking patterns. When selecting premature infants to be treated with swallowing therapy, it is reasonable to pay more attention to the incoordination-positive group described in the NOMAS, that is, premature infants with stress signals to shorten the time to attain FOF.

Objective. Although evidence and guidelines recommend appropriate rehabilitation from the beginning of diagnosis in patients with Parkinson’s disease (PD), there is a lack of data addressing the utilization of rehabilitation therapies for these patients in practice. The aim of this study is to investigate the rate of rehabilitation therapy utilization over time in patients with PD using a nationwide cohort in Korea. Methods. Patients were identified using the registration code for PD in the program for rare, intractable disease from the National Health Insurance Service-National Sample Cohort database, which consists of 979,390 Korean residents. Data were divided into four periods: 2004–2006, 2007–2009, 2010–2012, and 2013–2015. We assessed the utilization of rehabilitation therapies and the associated patient characteristics. Results. The numbers of patients with PD were 384 in 2004, 855 in 2007, 1,023 in 2010, and 1,222 in 2013. The numbers of physiatrist visits per person were 0.58, 0.96, 1.97, and 2.91, in the respective periods. Among the patients, 35–40% had claims for physical therapy, 16–19% for occupational therapy, and 4–6% for swallowing therapy. There were no remarkable differences between these rates between the study periods. Sex, age, income, disability, and levodopa-equivalent dose were significantly associated with the utilization of rehabilitation therapy. Conclusion. This study demonstrated that the rate of rehabilitation therapy utilization did not change remarkably in patients with PD from 2004 to 2015 in Korea although the number of physiatrist visits increased dramatically. The present evidence and guidelines may have not been adequately integrated into clinical practice during the period of study. Additional efforts may be warranted to provide adequate rehabilitation therapies in clinical practice for patients with PD.