Investigating the effects of visual biofeedback therapy on recovery of postural balance in stroke patients using a complexity measure.

Background and 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 publications, 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. Materials and methods: A total of 31 hemiplegic stroke patients were recruited in this study and randomly assigned into case and control groups. Both groups received 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 EquiTest testing system. Center of pressure data were collected before starting, during, and after completion of the rehabilitation program and a nonlinear complexity measure, approximate entropy (ApEn), calculated and used for the analysis. Results: No significant between-group differences were detected after completion of the program. Noticeable increase was found in ApEn values of both groups along anterior-posterior direction, whereas no statistically significant improvement was found along mediolateral direction after rehabilitation. Conclusion: Both rehabilitation routines 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.