Postural instability years after stroke

Enhancing Dynamic Balance and Postural Stability in Stroke Patients: The Impact of Immersive Virtual Reality Training

Introduction Stroke is a major neurological event resulting from reduced or blocked blood flow to the brain, leading to significant morbidity. Immediate medical attention is essential to minimize brain damage and improve outcomes since it leads to many clinical deficits like locomotor impairment, instability in postural control, tonic alterations of the affected musculature, and an array of neurological dysfunctions if left unnoticed. Immersive virtual reality (VR) has emerged as a novel therapeutic tool in stroke rehabilitation, offering engaging and realistic environments for therapy. This study aims to evaluate the effectiveness of immersive VR training combined with functional gait exercises in improving dynamic balance and postural stability in stroke patients, compared to VR training alone. Methods This comparative study included 30 subjects from Madha Medical College and Hospital, Chennai, Tamil Nadu, India, divided into two groups. Group A (n=15) received immersive VR combined with functional gait exercises, while Group B (n=15) received immersive VR alone. Subjects were aged 40-60 years with stable blood pressure and a stroke duration of two weeks to six months. The study spanned 12 weeks, with 30-minute sessions on alternate days. Dynamic balance and postural stability were assessed using the Functional Gait Assessment (FGA) and Falls Efficacy Scale (FES). Pre-test and post-test scores were evaluated using parametric tests. Results Post-test mean values showed significant improvements in both groups. Group A demonstrated greater effectiveness, with lower FES scores (mean 36.66 ± 11.12) than Group B (mean 46.66 ± 9.75). FGA scores were higher in Group A (mean 28.00 ± 0.925) compared to Group B (mean 26.06 ± 1.66). Significant differences were observed in pre-test and post-test values within each group, supporting the hypothesis that combined VR and gait exercises offer superior rehabilitation outcomes. Conclusions Immersive VR combined with functional gait exercises significantly improves dynamic balance and postural stability in stroke patients compared to VR alone. This integrated approach can enhance motor function recovery, increase independence, and improve the quality of life. VR's capability to simulate real-life activities and provide immediate feedback allows for personalized rehabilitation programs. Further research is required to validate these findings and optimize VR-based rehabilitation protocols.

Effect of lower limb resistance training on ICF components in chronic stroke: A systematic review and meta-analysis of RCTs

BACKGROUND

Resistance training (RT) effectively promotes functional independence after stroke.

OBJECTIVES

To investigate the effect of lower limb RT on body structure and function (muscle strength, postural balance), activity (mobility, gait) and participation (quality of life, impact of stroke on self-perceived health) outcomes in individuals with chronic stroke.

METHODS

Six databases were searched from inception until September 2022 for randomized controlled trials comparing lower limb RT to a control intervention. The random-effects model was used in the meta-analyses. Effect sizes were reported as standardized mean differences (SMD). Quality of evidence was assessed using the GRADE approach.

RESULTS

Fourteen studies were included. Significant improvements were found in body structure and function after lower limb RT: knee extensors (paretic side - SMD: 1.27; very low evidence), knee flexors (paretic side - SMD: 0.51; very low evidence; non-paretic side - SMD: 0.52; low evidence), leg press (paretic side - SMD: 0.83; very low evidence) and global lower limb muscle strength (SMD: -1.47; low evidence). No improvement was found for knee extensors (p = 0.05) or leg press (p = 0.58) on the non-paretic side. No improvements were found in the activity domain after lower limb RT: mobility (p = 0.16) and gait (walking speed-usual: p = 0.17; walking speed-fast: p = 0.74). No improvements were found in the participation domain after lower limb RT: quality of life (p > 0.05), except the bodily pain dimension (SMD: 1.02; low evidence) or the impact of stroke on self-perceived health (p = 0.38).

CONCLUSION

Lower limb RT led to significant improvements in the body structure and function domain (knee extensors and flexors, leg press, global lower limb muscle strength) in individuals with chronic stroke. No improvements were found in the activity (mobility, gait [walking speed]) or participation (quality of life, impact of stroke on self-perceived health) domains.

PROSPERO REGISTRATION NUMBER

CRD42021272645.

Assistive Technology Involving Postural Control and Gait Performance for Adults with Stroke: A Systematic Review and Meta-Analysis

This study aimed to comprehensively summarize assistive technology devices for postural control and gait performance in stroke patients. In the study, we searched for randomized controlled trials (RCTs) published until 31 December 2022 in four electrical databases. The most frequently applied assistive technology devices involving postural stability and gait function for stroke patients were robot-assistive technology devices. Out of 1065 initially retrieved citations that met the inclusion criteria, 30 RCTs (12 studies for subacute patients and 18 studies for chronic patients) were included in this review based on eligibility criteria. The meta-analysis included ten RCTs (five studies for subacute patients and five for chronic patients) based on the inclusion criteria of the data analysis. After analyzing, the variables, only two parameters, the Berg balance scale (BBS) and the functional ambulation category (FAC), which had relevant data from at least three studies measuring postural control and gait function, were selected for the meta-analysis. The meta-analysis revealed significant differences in the experimental group compared to the control group for BBS in both subacute and chronic stroke patients and for the FAC in chronic stroke patients. Robot-assistive training was found to be superior to regular therapy in improving postural stability for subacute and chronic stroke patients but not gait function. This review suggests that robot-assistive technology devices should be considered in rehabilitative approaches for postural stability and gait function for subacute and chronic stroke patients.

Receiver Operating Characteristic Curve Analysis of the Somatosensory Organization Test, Berg Balance Scale, and Fall Efficacy Scale–International for Predicting Falls in Discharged Stroke Patients

Background: Although fall prevention in patients after stroke is crucial, the clinical validity of fall risk assessment tools is underresearched in this population. The study aim was to determine the cut-off scores and clinical validity of the Sensory Organization Test (SOT), the Berg Balance Scale (BBS), and the Fall Efficacy Scale–International (FES-I) in patients after stroke. Methods: In this prospective cross-sectional study, we analyzed data for patients admitted to a rehabilitation unit after stroke from 2018 through 2021. Participants underwent SOT, BBS, and FES-I pre-discharge, and the fall incidence was recorded for 6 months. We used an area under the receiver operating characteristic curve (AUC) to calculate predictive values. Results: Of 84 included patients (median age 68.5 (interquartile range 67–71) years), 32 (38.1%) suffered a fall. All three tests were significantly predictive of fall risk. Optimal cut-off scores were 60 points for SOT (AUC 0.686), 35 and 42 points for BBS (AUC 0.661 and 0.618, respectively), and 27 and 29 points for FES-I (AUC 0.685 and 0.677, respectively). Conclusions: Optimal cut-off scores for SOT, BBS, and FES-I were determined for patients at risk for falls after a stroke, which all three tools classified with a good discriminatory ability.

Evaluation of Postural Sway in Post-stroke Patients by Dynamic Time Warping Clustering

Post-stroke complications are the second most frequent cause of death and the third leading cause of disability worldwide. The motor function of post-stroke patients is often assessed by measuring the postural sway in the patients during quiet standing, based on sway measures, such as sway area and velocity, which are obtained from temporal variations of the center of pressure. However, such approaches to establish a relationship between the sway measures and patients' demographic factors have hardly been successful (e.g., days after onset). This study instead evaluates the postural sway features of post-stroke patients using the clustering method of machine learning. First, we collected the stroke patients' multi-variable motion-capture standing-posture data and processed them into t s long data slots. Then, we clustered the t-s data slots into K cluster groups using the dynamic-time-warping partition-around-medoid (DTW-PAM) method. The DTW measures the similarity between two temporal sequences that may vary in speed, whereas PAM identifies the centroids for the DTW clustering method. Finally, we used a post-hoc test and found that the sway amplitudes of markers in the shoulder, hip, knee, and center-of-mass are more important than their sway frequencies. We separately plotted the marker amplitudes and frequencies in the medial-lateral direction during a 5-s data slot and found that the post-stroke patients' postural sway frequency lay within the bandwidth of 0.5–1.5 Hz. Additionally, with an increase in the onset days, the cluster index of cerebral hemorrhage patients gradually transits in a four-cluster solution. However, the cerebral infarction patients did not exhibit such pronounced transitions over time. Moreover, we found that the postural-sway amplitude increased in clusters 1, 3, and 4. However, the amplitude of cluster 2 did not follow this pattern, owing to age effects related to the postural sway changes with age. A rehabilitation doctor can utilize these findings as guidelines to direct the post-stroke patient training.