Background: The risk of falling in patients with chronic obstructive pulmonary disease (COPD) is higher than healthy people, imposing a great financial burden on patients due to clinical diagnosis and treatment. This study aimed to compare static balance between two groups of healthy people and COPD patients, based on cognitive tasks and vision tests, using linear and non-linear analyses. Materials and Methods: A total of 15 patients with COPD and 14 age-and gender-matched healthy individuals were recruited in this study. Variations in the center of pressure were recorded in both medial-lateral (ML) and anteriorposterior (AP) directions by implementing visual feedback and cognitive tasks, with the subject standing on a force plate. Data related to the center of pressure were analyzed in the AP and ML directions by linear methods (i. e., standard deviation of displacement, standard deviation of maximum velocity, average velocity, and phase plane). Also, the nonlinear method (Lyapunov exponents) was used in both directions. Results: The cognitive tasks improved the center of pressure variables in both groups. In association with the vision tests, only lack of vision had a significant effect on the patients. The results of the linear analysis in the ML direction were significantly higher in the COPD group as compared to the healthy group,however, the results were not significant in the AP direction. Also, the nonlinear analysis showed significant differences between the groups. Conclusion: Use of both linear and non-linear analyses is necessary for evaluating the balance of patients with breathing difficulties. balance disorders in COPD patients were mostly in the ML direction,therefore, Postural deformities might be one of the reasons for balance problems in the AP direction.

Background: Coronary Artery Bypass Graft (CABG) surgery is associated with several complications. balance disorders have been reported in patients. The impairments were associated with fall-related injuries and increase the possibility of morbidity, mortality, and healthcare costs. The present study aimed to compare Postural balance before and after CABG surgery in patients with established coronary artery disease. Methods: This cross-sectional study was conducted on 87 patients aged 45-65 years who had undergone CABG surgery through the great saphenous vein. Participants were enrolled into the study by convenience sampling. To assess static balance, individuals were asked to perform the Single Leg Stance Test (SLST). In addition, dynamic balance was measured by the Y-balance test, and the Functional Reach Test (FRT) was conducted before and after CABG surgery. These clinical tests were performed during the week before surgery and repeated one month after that. Paired t-test was used to compare the Y-balance scores, and Wilcoxon test was used to compare the mean values of other outcomes before and after CABG surgery. A level of P<0. 05 was considered statistically significant. Results: The results revealed a significant decrease in static and dynamic balance after CABG surgery (P<0. 001). A significant reduction was also observed in the mean FRT scores in the postoperative period (P<0. 001). Conclusion: CABG surgery through the great saphenous vein influenced balance in patients with coronary artery disease.

Purpose: Postural balance deficit is one of the common post-stroke disabilities. Providing visual biofeedback while balance activities are performed is a way to improve Postural balance disorders following stroke. But among the research published, there is incoherency about the positive effects of visual biofeedback therapy. The purpose of this study was to investigate the effects of using visual biofeedback as an adjunct to physical therapy exercises on recovery of Postural balance of stroke patients.Methods: A total of thirty-one hemiplegic stroke patients were included in this study and randomly assigned into case and control groups. Both groups received four weeks conventional physical therapy interventions and balance training exercises. During balance training, the case group received visual biofeedback, whereas the control group did not receive visual information. balance performance of stroke patients were examined quantitatively using the Equi-Test testing system and Biodex stability system, walking performance was evaluated by Timed Up and Go tests, and the patients were assessed using the modified Barthel index for activities of daily living. Data were collected before starting, during, and after completion of the rehabilitation program. Repeated measure analyses of variance were performed to evaluate rehabilitation effects and independent samples T tests were done to quantify the effects of visual biofeedback.Results: No significant differences between the groups were detected in any of the outcome variables after completion of the program. Noticeable improvements were found in dynamic balance function, mobility, and activities of daily living of both groups, whereas no statistically significant improvements were found in static balance after rehabilitation.Conclusion: Both rehabilitation protocols created advances in the Postural control system of stroke patients. Visual biofeedback balance training did not produce extra advantage for balance ability of participants who received this treatment program in comparison with those who were treated without visual biofeedback. The results showed that dynamical tasks scores and activitybased measures better than static balance measures reflect the recovery effects.