Exploring cued and non-cued motor imagery interventions in people with multiple sclerosis: a randomised feasibility trial and reliability study

Abstract

Background: Motor imagery (MI) is increasingly used in neurorehabilitation to facilitate motor performance. Our previous study results demonstrated significantly improved walking after rhythmic-cued MI in people with multiple sclerosis (pwMS). The present feasibility study was aimed to obtain preliminary information of changes in walking, fatigue, quality of life (QoL) and MI ability following cued and non-cued MI in pwMS. The study further investigated the feasibility of a larger study and examined the reliability of a two-dimensional gait analysis system.

Methods: At the MS-Clinic, Department of Neurology, Medical University of Innsbruck, Austria, 15 adult pwMS (1.5-4.5 on the Expanded Disability Status Scale, 13 females) were randomised to one of three groups: 24 sessions of 17 min of MI with music and verbal cueing (MVMI), with music alone (MMI), or non-cued (MI). Descriptive statistics were reported for all outcomes. Primary outcomes were walking speed (Timed 25-Foot Walk) and walking distance (6-Minute Walk Test). Secondary outcomes were recruitment rate, retention, adherence, acceptability, adverse events, MI ability (Kinaesthetic and Visual Imagery Questionnaire, Time-Dependent MI test), fatigue (Modified Fatigue Impact Scale) and QoL (Multiple Sclerosis Impact Scale-29). The reliability of a gait analysis system used to assess gait synchronisation with music beat was tested.

Results: Participants showed adequate MI abilities. Post-intervention, improvements in walking speed, walking distance, fatigue, QoL and MI ability were observed in all groups. Success of the feasibility criteria was demonstrated by recruitment and retention rates of 8.6% (95% confidence interval, CI 5.2, 13.8%) and 100% (95% CI 76.4, 100%), which exceeded the target rates of 5.7% and 80%. Additionally, the 83% (95% CI 0.42, 0.99) adherence rate surpassed the 67% target rate. Intra-rater reliability analysis of the gait measurement instruments demonstrated excellent Intra-Class Correlation coefficients for step length of 0.978 (95% CI 0.973, 0.982) and step time of 0.880 (95% CI 0.855, 0.902).

Conclusion: Results from our study suggest that cued and non-cued MI are valuable interventions in pwMS who were able to imagine movements. A larger study appears feasible, however, substantial improvements to the methods are required such as stratified randomisation using a computer-generated sequence and blinding of the assessors.

Trial registration: ISRCTN ISRCTN92351899. Registered 10 December 2015.

Keywords: Fatigue; Feasibility; Motor imagery; Motor imagery ability; Multiple sclerosis; Physiotherapy; Quality of life; Reliability two-dimensional gait analysis; Rhythmic cueing; Walking.

Fig. 1

CONSORT flow diagram for pilot and feasibility studies

Fig. 2

Representative image of the 2D video-based gait assessment

Fig. 3

Representative image of the accuracy evaluation of the video analysis software calibration

Fig. 4

Walking performance pre- and post-intervention. a Walking Speed. b Walking distance. Medians are shown by lines in the centre of the box-plots; the interquartile ranges are indicated by the boxes and ranges by the whiskers. Abbreviations: MI group = non-cued motor imagery group; MMI group = music-cued motor imagery group; MVMI group = music- and verbally cued motor imagery group; T25FW = Timed 25-Foot Walk; 6MWT = 6-Minute Walk Test. The grey boxes indicate the baseline data and the white boxes present the post-intervention data

Fig. 5

Total fatigue pre- and post-intervention. The red line represents the cut-off point for fatigue as defined at ≥38 points on the MFIS [48]. Medians are shown by lines in the centre of the box-plots; the interquartile ranges are indicated by the boxes and ranges by the whiskers. Abbreviations: MFIS = Modified Fatigue Impact Scale; MI group = non-cued motor imagery group; MMI group = music-cued motor imagery group; MVMI group = music- and verbally cued motor imagery group. The grey boxes indicate the baseline data and the white boxes present the post-intervention data

Fig. 6

Quality of life pre- and post-intervention. a Physical quality of life. b Psychological quality of life. Medians are shown by lines in the centre of the box-plots; the interquartile ranges are indicated by the boxes and ranges by the whiskers. Abbreviations: MI group = non-cued motor imagery group; MMI group = music-cued motor imagery group; MSIS-29 = Multiple Sclerosis Impact Scale-29 MVMI group = music- and verbally cued motor imagery group

Fig. 7

MI ability pre- and post-intervention. a MI vividness. b Mental chronometry during MI. Abbreviations: KVIQ-G-10 = Kinaesthetic and Visual Imagery Questionnaire-10, German short version: Medians are shown by lines in the centre of the box-plots; the interquartile ranges are indicated by the boxes and ranges by the whiskers; MI group = non-cued motor imagery group; MMI group = music-cued motor imagery group; MVMI group = music- and verbally cued motor imagery group. The grey boxes indicate the baseline data and the white boxes present the post-intervention data