Force platform feedback for standing balance training after stroke

Auditory biofeedback substitutes for loss of sensory information in maintaining stance

The importance of sensory feedback for postural control in stance is evident from the balance improvements occurring when sensory information from the vestibular, somatosensory, and visual systems is available. However, the extent to which also audio-biofeedback (ABF) information can improve balance has not been determined. It is also unknown why additional artificial sensory feedback is more effective for some subjects than others and in some environmental contexts than others. The aim of this study was to determine the relative effectiveness of an ABF system to reduce postural sway in stance in healthy control subjects and in subjects with bilateral vestibular loss, under conditions of reduced vestibular, visual, and somatosensory inputs. This ABF system used a threshold region and non-linear scaling parameters customized for each individual, to provide subjects with pitch and volume coding of their body sway. ABF had the largest effect on reducing the body sway of the subjects with bilateral vestibular loss when the environment provided limited visual and somatosensory information; it had the smallest effect on reducing the sway of subjects with bilateral vestibular loss, when the environment provided full somatosensory information. The extent that all subjects substituted ABF information for their loss of sensory information was related to the extent that each subject was visually dependent or somatosensory-dependent for their postural control. Comparison of postural sway under a variety of sensory conditions suggests that patients with profound bilateral loss of vestibular function show larger than normal information redundancy among the remaining senses and ABF of trunk sway. The results support the hypothesis that the nervous system uses augmented sensory information differently depending both on the environment and on individual proclivities to rely on vestibular, somatosensory or visual information to control sway.

Estimates of Quality and Reliability With the Physiotherapy Evidence-Based Database Scale to Assess the Methodology of Randomized Controlled Trials of Pharmacological and Nonpharmacological Interventions

Background and Purpose. Systematic reviews and meta-analyses often include an evaluation of the methodological quality of the individual studies that have been included, and are usually conducted by at least 2 individuals. The objective of this study was to assess the methodological quality and reliability of a series of randomized controlled trials (RCTs) of both pharmacological and nonpharmacological interventions by use of the 10-item Physiotherapy Evidence-Based Database (PEDro) Scale. Methods. Two abstractors independently reviewed 81 RCTs assessing a variety of interventions. The Cohen kappa statistic and the intraclass correlation coefficient (ICC) were used to assess agreement between abstractors. Results. The average total PEDro scores were 5.94 (SD=1.43) for all studies combined, 6.88 (SD=1.2) for pharmacological studies, and 5.29 (SD=1.26) for nonpharmacological studies. The median score for pharmacological studies was significantly higher than that for nonpharmacological studies (7 versus 5). Pair-wise kappa scores ranged from a low of .452 for concealed allocation among drug trials to perfect agreement (1.00) for randomization and reporting of results from between-group comparisons. The ICCs associated with the cumulative PEDro score were .91 (95% confidence interval [CI]=.83–.94) for all studies, .89 (95% CI=.78–.95) for pharmacological studies, and .91 (95% CI=.84–.952) for nonpharmacological studies. Discussion and Conclusion. The methodological quality for pharmacological interventions was significantly higher than that for nonpharmacological interventions. There was good agreement between raters at an individual item level and in total PEDro scores. A lack of reporting clarity, poor organization of the report, or the failure to include salient details contributed to less-than-perfect agreement between raters. [Foley NC, Bhogal SK, Teasell RW, et al. Estimates of quality and reliability with the Physiotherapy Evidence-Based Database Scale to assess the methodology of randomized controlled trials of pharmacological and nonpharmacological interventions.Phys Ther. 2006;86:817 – 824.]

EFFECTS OF VISUAL FEEDBACK THERAPY ON POSTURAL CONTROL IN BILATERAL STANDING AFTER STROKE: A SYSTEMATIC REVIEW

OBJECTIVE

To establish whether bilateral standing with visual feedback therapy after stroke improves postural control compared with conventional therapy and to evaluate the generalization of the effects of visual feedback therapy on gait and gait-related activities.

DESIGN

A systematic review.

METHODS

A computer-aided literature search was performed. Randomized controlled trials and controlled clinical trials, comparing visual feedback therapy with conventional balance treatments were included up to April 2005. The methodological quality of each study was assessed with the the Physiotherapy Evidence Database scale. Depending on existing heterogeneity, studies with a common variable of outcome were pooled by calculating the summary effect-sizes using fixed or random effects models.

RESULTS

Eight out of 78 studies, presenting 214 subjects, were included for qualitative and quantitative analysis. The methodological quality ranged from 3 to 6 points. The meta-analysis demonstrated non-significant summary effect-sizes in favour of visual feedback therapy for weight distribution and postural sway, as well as balance and gait performance, and gait speed.

CONCLUSION

The additional value of visual feedback therapy in bilateral standing compared with conventional therapy shows no statistically significant effects on symmetry of weight distribution between paretic and non-paretic leg, postural sway in bilateral standing, gait and gait-related activities. Visual feedback therapy should not be favoured over conventional therapy. The question remains as to exactly how asymmetry in weight distribution while standing is related to balance control in patients with stroke.