An eight-week single-blind randomised controlled trial on dual task balance training and motor imagery practice in ischaemic stroke survivors

The purpose of this study was to find the effects of motor imagery on balance and mobility of stroke patients.This was a single-blind randomised controlled trial which included a total of 30 patients. These patients were assigned into two group: experimental (n=15) and control (n=15) by sealed envelope method. Functional Reach Test (FRT), Time Up and Go Test (TUGT), Berg Balance Scale (BBS), and Movement Imagery Questionnaire (MIQ) were used as assessment tools. The overall mean age of the participants was 52.63 ±8.78 years. Between groups analysis showed non-statistically significant difference (p>0.05) in FRT but significant difference in TUGT, BBS, and MIQ-3 (p<0.009) after eight weeks of training. Within group analysis showed statistically significant difference (p<0.05) for all outcome measures. This study concluded that motor imagery is an effective treatment strategy for improving balance and mobility in stroke patients and brings better results as compared to conventional treatments.


Introduction
Stroke is the leading cause of disability worldwide. 1Basic activities of daily living in patients who suffer a stroke are limited due to the impairments in sensory, motor, balance gait, and cognitive deficits.Independent walking is a prerequisite in many activities of life.Stroke patients always have difficulty in restoring this function and gait has long been recognised as a key goal in rehabilitation. 2arious neurological rehabilitation protocols are widely being used by physical therapists in the treatment of gait and balance problems in stroke patients. 3The goal of applying different concepts is to promote motor learning for efficient motor control in various environments, thereby improving participation and function.Motor imagery is a patient-centred approach in which the patient actively engages through cognition and mental imaginationMotor imagery (MI) is the envisioning of an activity without its physical execution; it is an active process where the representation of an activity is internally replicated inside working memory without any performed action. 4It has been reported in numerous studies that motor imagery, when used in combination with traditional treatment, makes a difference in relearning the tasks and improves motor skills. 5According to recent literature, the gait capability of stroke patients has been noted to have progressed after motor imagery training. 6Therefore, this study aimed to determine the combined effects of motor imagery and dual task training on balance and gait in stroke patients.

Method and Results
This was a randomised control trial (RCT), done at Abuzar Medical and Diagnostic Centre, Rawalpindi from April 2020 to october 2020 and registered in clinical trial.govidentifier: NCT04086004.The sample size was calculated using G*power version 3,with effect size 0.9, power 0.8 and alpha (α) error 0.05 for a priori power analysis, while using one-tail t test for the difference between two independent means. 7Non-probability convenient sampling technique was used.A total of 30 participants were recruited for the study and 29 completed the intervention (Figure 1) .Patients were enrolled after taking the informed consent.Inclusion criteria were: patients having modified ranking disability level scale 2-3, chronic and sub-acute patients, capability of walking on the ground for at least ten metres with or without using an assistive device, intact cognition, insignificant visual or body spatial hemi-neglect and acceptable level of capability for functioning imagery (at least 32 or greater score on the Revision of Movement Imagery Questionnaire). 8Those who fulfilled the inclusion criteria were randomly assigned into experimental (n=15) and control group (n=15) by sealed envelope method.Baseline assessment was done at 0 week, in fourth week and post-intervention i.e. eighth week.A trained physical therapist who was not aware of the subjects' group assignment evaluated the patients.No adverse effects were observed during the intervention.0][11] The details of intervention protocol are listed in figure 2. In the experimental group seven tasks were designed and each task was performed for four minutes with maximum repetitions along with motor imagery practice.In the control group, the same intervention was given except motor imagery.(figure2) IBM Statistics SPSS v21.0.(IBM Corp. Armonk.NY, USA) was used for statistical analysis.Shapiro Wilk Test was used to check the normality of the data.The data was not normally distributed (p<0.05)so non-parametric tests were applied for analysis.To find between the group differences Mann Whitney U test was applied.Friedman Test was used for within the group analysis and to see the difference at different time intervals Wilcoxon sign rank test was used.0.05 alpha level of significance was maintained.
The current study sample with a mean age of 52.63 ± 8.78 in experimental group and 52.56 ± 7.78 years in control group comprised both males and females.There was one dropout in the experimental group.Table 1 shows the group means for age and stroke onset and the frequency counts for gender and hemiparetic side.There were no statistically significant differences between the groups at baseline on all variables.For between the group analyses, the TUGT, BBS, and Movement Imagery Questionnaire (internal imagery) final assessment shows significant difference between the experimental and control groups  after the intervention, whereas the results were nonsignificant (p>0.05) for FRT which shows that both the groups improved equally in forward reach test.MIQ3 (External imagery) shows significant (p<0.05)results in the fourth and eighth week between the two groups.The kinesthetic imagery group of MIQ 3 shows significant improvement after the intervention.The total score of MIQ3 showed statistically significant difference between both the groups.(Table2) Within the group analysis for FRT, TUGT, BBS, and MIQ3 showed statistically significant (p<0.05)results.(Table3) The results of the current study demonstrated that patients' mobility (TUGT), dynamic balance (BBS), and risk of fall (TUGT) was greatly reduced in experimental group as compared to the control group.

Discussion
The current study determines the additional effects of motor-imagery practice with the training of dual tasking in stroke patients.Motor imagery (MI) aims to produce body's internal picture of movements without generating any motor output. 12This technique helps in improving functional performance, neuro plasticity through neural and cortical reorganisation in post-stroke patients.Motor imagery training(MIT) also has an important role in improving cognitive abilities of the patients because when the patient imagines that he is performing different tasks, it affects cortex motor activity. 13Stroke impairs the gait and mobility of the patient due to spasticity.It is commonly observed that patients had difficulty in maintaining the balance while walking, due to which the risk of fall increases two-fold.It was observed that motor imagery training and task specific exercises reduces spasticity and improves lower limb motor functions. 14n this study the outcome measures used for mobility and balance assessment were TUGT and BBS; the mean score of both the tests increased at the end of the intervention.Results reported a statistically significant (p<0.05)improvement after treatment in both the groups and even better results when related to the motor imagery training .The study reported that patients can actively perform sit-to-stand and stand-to-sit tasks.These findings are similar to those reported previously in the literature, claiming that combined motor imagery training of lower extremity promotes relearning of rising, sitting tasks, and symmetrical use of lower limb muscles during sit-to-stand tasks in post-stroke hemiparesis. 15any studies in literature reported that task-specific training speed up the body's recovery process, especially the lower limb dexterity, thus reducing long-term disability and associated socio-economic burden. 16,17mitations: This study has few limitations which need to be considered; the results of this study cannot be generalised due to small number of patients in both groups.After intervention various neurophysiological changes took place in the brain which were not measured through any tool.Another drawback is that the retention effects of motor imagery technique was not measured.
Recommendations:It is recommended that future research should be conducted via larger-scale studies, exploring the effects of motor imagery in different stroke types and phases, and investigating the long-term retention of the intervention effects.

Conclusion
This study concluded that motor imagery is an effective treatment strategy for balance and mobility in stroke patients and brings better results as compared to conventional treatments.

Table - 1
: Baseline Demographic Characteristics of the Control and Experimental Group

Table - 2
: Between group analysis for FRT, TUGT and BBS and MIQ 3.