Demonstration of posturographic parameters of squat-stand activity in hemiparetic patients on a new multi-utility balance assessing and training system

Postural symmetry evaluation using phase approximations of the follow-up CoP trajectories

This paper presents a method of postural symmetry evaluation implementing the so-called follow-up posturography. The method boils down to the assessment of similarity of the phase approximation of the counter-clockwise follow-up CoP (Center of Pressure) trajectory and the mirror image against the y-axis of the phase approximation corresponding to the clockwise follow-up CoP trajectory. The usability of the presented approach was tested on the data collected in the group of 30 patients rehabilitated after total hip arthroplasty. The observed difference between the values of the proposed postural symmetry coefficient obtained at the end and at the beginning of the rehabilitation program was statistically significant (p < 0.001). These values, however, were not significantly correlated with the values of postural symmetry coefficients computed in static posturography. Lack of significant correlations between the coefficients supports the reasoning that the new postural symmetry evaluation method quantifies symmetry of posture in terms of dynamic mechanisms, which are not manifested in the case of static posturography. As a major advantage of the herein discussed approach one can distinguish its potential to evaluate postural symmetry in dynamic conditions using relatively inexpensive single-plate posturographic platform.

Reliability of upright weight-bearing distribution measures obtained by computed baropodometry for participants with and without post-stroke hemiparesis

Background/Aims

Measurements from force platforms and digital scales have been applied to classify weight-bearing distribution in post-stroke hemiparesis. However, an intermediate tool – computed baropodometry – is breaking new ground in this field of diagnosis, with a need to report its reliability. Intra-test and test/retest reliabilities of the percentage of total body weight borne by the predominantly used hemibody calculated from computed baropodometry in participants with and without chronic hemiparesis was investigated in this study.

Methods

A total of 40 participants were evaluated and combined for age and sex in two different groups. Repeated measures were taken to analyse differences among records obtained from averages during 5, 10 or 20 seconds (intra-test reliability) and between the test and 1-week retest (test/retest reliability) for both groups. The analysis of variance, intra-class correlation coefficient and data plotted by Bland-Altman method were administrated.

Results

The intra-test analysis did not show differences among records obtained from different time durations (5, 10 and 20 seconds). Excellent to moderate intra-class correlation coefficient values (0.794 to 0.644) between test and retest were observed in the hemiparesis group from the records obtained by short to the longer lasting time durations, while for control groups, intra-class correlation coefficient values (0.661 to 0.748) were classified as moderate.

Conclusions

Acceptable reliability was found for all participants. Moreover, improved repeatability was reported when the measures were obtained by shorter time periods for both groups.

Cross-cultural adaptation to Brazilian Portuguese of the Waterloo Footedness Questionnaire-Revised: WFQ-R-Brazil

ABSTRACT Post-stroke hemiparesis causes compensated postures, which can modify the footedness established before the impairment. Recently, a paresis severity-modulated dominance hypothesis stated that measures to detect footedness become crucial to float new ideas for neurorehabilitation strategies. The Waterloo Footedness Questionnaire-Revised (WFQ-R) represents the most acceptable measure but it had not yet been cross-culturally adapted for Portuguese spoken in Brazil. Our aim was to cross-culturally adapt the WFQ-R to Brazilian Portuguese, verifying its reliability. We completed the essential steps to cross-culturally adapt one version, tested in 12 patients with post-stroke hemiparesis and 12 able-bodied individuals, sampled by convenience, to verify reliability. Measurements were taken by two independent raters during the test and by one of them at the one-week retest. No great semantic, linguistic or cultural differences were found, and acceptable reliability was recorded. The WFQ-R-Brazil is reliable and ready for use in the Brazilian able-bodied and post-stroke hemiparesis population.

Reliability of the measures of weight-bearing distribution obtained during quiet stance by digital scales in subjects with and without hemiparesis

Described as an alternative way of assessing weight-bearing asymmetries, the measures obtained from digital scales have been used as an index to classify weight-bearing distribution. This study aimed to describe the intra-test and the test/retest reliability of measures in subjects with and without hemiparesis during quiet stance. The percentage of body weight borne by one limb was calculated for a sample of subjects with hemiparesis and for a control group that was matched by gender and age. A two-way analysis of variance was used to verify the intra-test reliability. This analysis was calculated using the differences between the averages of the measures obtained during single, double or triple trials. The intra-class correlation coefficient (ICC) was utilized and data plotted using the Bland-Altman method. The intra-test analysis showed significant differences, only observed in the hemiparesis group, between the measures obtained by single and triple trials. Excellent and moderate ICC values (0.69-0.84) between test and retest were observed in the hemiparesis group, while for control groups ICC values (0.41-0.74) were classified as moderate, progressing from almost poor for measures obtained by a single trial to almost excellent for those obtained by triple trials. In conclusion, good reliability ranging from moderate to excellent classifications was found for participants with and without hemiparesis. Moreover, an improvement of the repeatability was observed with fewer trials for participants with hemiparesis, and with more trials for participants without hemiparesis.

Design of multiple axis robotic platform for postural stability analysis

This paper presents the design and implementation of IsiMove, a new dynamic posturography platform. It allows the evaluation of the static and dynamic balance of a human placed on a force plate. IsiMove is a robotic platform open kinematic with four degrees of freedom: anteroposterior tilt, mediolateral tilt, vertical rotation, and horizontal translation. It is capable of measuring the displacement of the center of pressure over time, with a resolution of 0.1 mm for each foot and support a human of about 120 kg. IsiMove can generate various types of balance perturbations based on parameters such as direction, amplitude, frequency and shape. In this paper, we will give a description of the mechanisms that constitute our platform. First, the technical specifications of the hardware and software architecture will be presented. Then, we will provide details related to extensive experimental evaluations of the platform in both static and dynamic condition as well as result of postural stability analysis with healthy subjects and stroke patients.