FREEHAB clinical evaluation of a prototype physiotherapy device v1.0
Research type
Research Study
Full title
FREEHAB within session evaluations of a prototype device for improving patients’ sit to stand movements
IRAS ID
316393
Contact name
Jonathan Rossiter
Contact email
Sponsor organisation
University of Bristol
ISRCTN Number
ISRCTN12643856
Duration of Study in the UK
0 years, 9 months, 28 days
Research summary
Research summary
After a stroke or acquired head injury some patients have weakness in the limbs on one side of the body. Weakness in the quadriceps muscles of the legs particularly makes moving from sitting to standing difficult. Patients struggle to rise completely or are slow and poorly coordinated in getting up. As part of our FREEHAB project we have developed a wearable prototype device to help patients get from sitting to standing. The wearable device is designed to assist patients' own muscles to help them to stand up. In this first investigation of the effectiveness of the device we aim to see if wearing the device will improve patients’ sitting to standing performance and to evaluate the acceptability and safety of the device. Within a single session, the tests will be carried out in a Human Movement Analysis Laboratory at the University of the West of England, Bristol. Participants’ sitting to standing performance will be compared when not wearing the device, and when wearing the device with the assist function turned off and when wearing it when the assist function is switched on and active.Summary of results
These findings should be considered preliminary, as the kinetic and kinematic datasets have only recently been cleaned and processed, and exploratory analyses are ongoing. The research team is continuing to integrate, compare, and interpret data collected from the device alongside data obtained from the motion capture system and pressure plate. Internal research funding has been allocated to support completion of the analyses and preparation of study outputs, including submission for peer-reviewed publication, within the current academic year.A total of 14 participants were recruited to the study. Of these, 9 participants provided sufficiently complete datasets for inclusion in the current analyses. This reduction was primarily attributable to technical challenges associated with motion capture marker poor visibility of joint markers caused by the device, as well as pressure plate issues affecting the first two participants. The findings reported below are therefore based on the n = 9 participants with complete datasets. Ongoing analyses will seek to maximise inclusion of usable data from the remaining participants wherever appropriate.
The primary outcome measure was centre of mass vertical velocity during the lift-off phase of the sit-to-stand (STS) task. We hypothesised that use of the device would reduce centre of mass vertical velocity. Preliminary findings indicate an earlier increase in centre of mass velocity during STS when using both Mode 1 and Mode 2 in n=3. Participant P011 also demonstrated an earlier increase when the device was worn but switched off. Additional filtering and processing of the centre of mass data are still required, and this may identify subtle changes in additional participants. For the remaining participants, centre of mass velocity profiles were comparable across conditions, suggesting that the device either increased centre of mass velocity or produced no measurable change. No evidence was observed to support the hypothesis that the device reduced centre of mass vertical velocity.
The secondary outcome measure was knee joint angular velocity, which reflects the speed of movement during the transition from sitting to standing. We hypothesised that use of the device would increase knee joint velocity. This was observed in n=6 participants. However, increases in peak knee velocity were also evident when the device was worn but switched off, suggesting that some benefits may be attributable to the physical presence of the device rather than its active assistance. Although not hypothesised a priori, changes in hip and knee flexion symmetry were observed when the device was operated in Mode 1, Mode 2, and, in some cases, when worn but switched off. These changes were identified in participants P003 (Mode 1 only), P008, P011, and P012. Notably, these participants generally reported feeling confident while using the device and perceived that it enabled them to perform a greater number of STS repetitions. Several potential explanations warrant further investigation. These include reduced compensatory movement patterns arising from increased confidence, decreased reliance on trunk flexion to generate momentum, enhanced joint position awareness, or a mechanical effect of the device in limiting knee collapse during movement.
The final secondary outcome measure was weight-bearing asymmetry (WB asymmetry). This outcome was quantified using force data recorded under each foot and expressed either as the percentage of load borne by the right and left limbs or as a right-to-left loading ratio, where 50% distribution or a ratio of 1.0 represents perfect symmetry. No consistent patterns were observed across participants, and therefore there is currently no evidence to support the hypothesis that the device improves weight-bearing symmetry during STS performance.
We recognise that these analyses are based on a relatively small sample and that the findings should therefore be interpreted with caution. Any conclusions presented in the final report will be appropriately qualified. Nevertheless, we did not anticipate that the device would be equally effective for all participants. Consequently, the observed variability in response is of particular interest and may provide valuable insight into the characteristics of individuals who are most likely to benefit from the intervention. Future analyses will explore participant demographic and clinical variables collected during the initial assessment, including age, body mass, and time since stroke onset, to determine whether these factors help explain the differences observed in device response.
REC name
West of Scotland REC 4
REC reference
23/WS/0111
Date of REC Opinion
11 Aug 2023
REC opinion
Further Information Favourable Opinion