Effectiveness of voluntary restraint in comparison to modified constraint-induced movement therapy in people with chronic stroke

Abstract

BACKGROUND:

Constraint induced movement therapy (CIMT) has been found to be an effective intervention for the treatment of upper extremity motor disabilities in people with stroke. There are many concerns around practicality and resource issues with CIMT, consequently there are various modifications in CIMT in terms of duration of constraint and type of constraints used.

PURPOSE:

The main objective of the study was to compare the effectiveness of voluntary constraint and hand mitt use in modified CIMT (mCIMT) in people with chronic stroke.

METHODS:

The study was a pre-post experimental design. A total of 20 participants were allocated randomly to two groups, with 10 participants in each group. The outcome measures used were the Wolf Motor Function Test (WMFT, time and functional ability scale, FAS) and a Motor Activity Log (MAL), amount of use (AOU) and quality of movement (QOM). The total duration of the intervention was 4 weeks with frequency of 5 days per week. The participants in group 1 were asked to do voluntary constraint and in group 2 a hand mitt was used to restrain the use of normal hand function during the training. The activities used in hand function training were the same for both the groups.

RESULTS:

There was no significant difference between groups after the intervention for WMFT time (t = 0.63, p = 0.5), WMFT FAS (t = –0.22, p = 0.8), MAL AOU (t = –0.25, p = 0.8) and MAL QOM (t = –0.28, p = 0.7). However there was a significant difference between pre-post scores in both groups for WMFT time group 1: t = 31.4, group 2: t = 23.9, p = 0.001 p = 0.001), WMFT FAS (t = –13.5, p = 0.01, group 2: t = –16.54, p = 0.001), MAL AOU (group 1: t = –10.7, p = 0.001, group 2: t = –9.9, p = 0.001) and MAL AOU QOM (group 1: t = –8.04, p = 0.001, group 2: t = –6.7, p = 0.001).

CONCLUSION:

Voluntary restraint can be an effective alternative constraint technique used in mCIMT to improve the hand function of the affected arm in people with stroke.

Keywords

Function impairment modified constraint induced movement therapy stroke physiotherapy

1 Introduction

Upper limb paresis is a common cause of compromised independence and reduced quality of life in people with stroke. It is estimated that 80% of stroke survivors have residual paresis of upper limb and around 30–60% cannot use the affected limb. Recovery of upper extremity function is more difficult than recovery of lower limb function mainly because the patient with stroke and unilateral upper extremity dysfunction may progressively avoid using the more affected arm in favor of non-paretic extremity, leading to learned non use [1, 2]. Some argue that the quality of motor control restored is restricted to 3 months periods of spontaneous neurological recovery [3]. It has been identified that repeated task related activities lead to improved sensory motor recovery [4].

Taub and colleagues [5] proposed an intervention known as constraint induced movement therapy (CIMT) which may be used to overcome learned non-use and induce cortical reorganization. CIMT involves massed and intensive practice with the affected upper extremity for six hours or more a day, use of the unaffected extremity is restrained during 90% of waking hours [5]. CIMT has been widely used in people with stroke and unilateral upper extremity motor impairment, at various stages of recovery [6, 7].

Page and colleagues designed a modified CIMT (mCIMT) intervention that shortens both intensive training session of paretic upper extremity (30 min-day 3 days a week) and restraint time of non-affected arm (<6 hours per day) [8]. mCIMT is suggested to be a simple, inexpensive and most importantly, a patient directed treatment, that improves upper extremity function [8]. It has been confirmed that only 32% of patients comply with the CIMT restriction schedule [9]. Krawczyk et al. [10], for example, in their study used voluntary constraint as a mode of restraint in constraint-induced movement therapy. These authors observed that voluntary activity constraint of the normal intact arm produced the same effect as standard constraint [10].

There has been limited research comparing the effectiveness of voluntary constraint compared to hand mitt use in mCIMT in people with chronic stroke. Consequently this study was conducted to determine if there is any difference between the voluntary constraint and hand mitt use in the unaffected extremity during mCIMT for improving hand function in people with chronic stroke. The study hypothesized that there will be difference in improvement of hand function in people with stroke with voluntary constraint as compared to mCIMT with use of a hand mitt.

2 Method

2.1 Study design and participants

The study was a pre-post experimental design with participants randomly allocated to either of two groups by a computer generated random number list. It was approved by research and ethical committee of Indian Spinal Injury Centre Institute of Rehabilitation Sciences, New Delhi. A sample of convenience of 20 stroke patients who met the inclusion criteria and gave their consent took part in the study. The subjects were recruited from various physiotherapy clinics in New Delhi, India. A general neurological examination was done to identify eligible participants for the study. 25 people were found eligible for the study during screening, out of which five declined to participate in the study.

The set inclusion criteria for the subject selection were, first ischemic or hemorrhagic stroke, time since stroke should be at least 12 months, presence of at least 10° of active wrist extension, 10° of thumb abduction/extension, and 10° of extension at the level of the metacarpophalangeal and interphalangeal joints in at least 2 digits among the II–III–IV–V fingers [8], mini-mental state examination score≥23 [11], a score≥2.5 in Motor Activity Log [12] and spasticity≤3 in the Modified Ashworth Scale (MAS) [13]. Participants with following problems were excluded from the study: severe or uncorrected deficits of hearing, language and vision, pain in the affected arm of≥4 on a visual analogue scale, any deformity of the affected arm and seizures or recent epileptic attack affecting hand function.

2.2 Procedure

After giving informed signed consent participants had a detailed neurological examination. Following the neurological examination the hand function assessment was done using two scales, the Wolf Motor Function Test (WMFT), and the Motor Activity Log Test (MAL) [12, 14]. After assessment participants were randomly allocated to either of two groups. Participants in group 1 used voluntary restraint while participants in group 2 used a hand mitt as a mode of constraint during therapy sessions. Participants were re-assessed on the outcome scales after 4 weeks. The screening assessment and intervention was done by different physiotherapists, each with more than 5-years experience in assessment and treating people with neurological disorders. Both the physiotherapists were blinded to the study. The screening, detailed neurological examination and pre-post assessments of outcome measures were done by same physiotherapist.

2.3 Intervention

The intervention using mCIMT was for a total duration of 4 weeks with a frequency of 5 days per week. One hour of hand function training of the affected side was given per session. The participants in group 1 were asked to do voluntary constraint and in group 2 a hand mitt was used to restrain the use of the unaffected hand during mCIMT therapy sessions. After the therapy session all participants had to restrain their normal hand for 3 hours per day with respective prescribed constraint technique (voluntary constraint/hand mitt).The participants were also asked to practice those activities performed during therapy sessions at home for 30 minutes per day. The training activities used was same for both the groups. Exercise protocol included activities like the tipping-chair exercise, the cylinder grip exercise, and the pinch exercise and in-hand manipulation. If the participant was found using unaffected hand during the restraint period (group 1) or without hand mitt (group 2), the caregiver recorded the incident in a time log. The participants were instructed not to restrain the use of normal hand during activity where the balance can be compromised, such as lifting heavy objects. The caregiver was required to document the start and end time of each therapy session performed at home.

2.4 Outcome measures

2.4.1 Wolf Motor Function test (WMFT)

WMFT is a reliable and valid tool for assessing the upper extremity performance in people with stroke. The test requires the participant to perform 17 tasks. 15 of which are rated on the basis of performance time (WMFT-Time) and rest based on functional ability and strength (WMFT-FAS). For functional assessment each of the tasks is rated for quality of motion on a scale of 0–5 [14].

2.4.2 Motor Activity Log (MAL)

The MAL is a self-report scale which is a reliable and valid measure real-world, upper-extremity rehabilitation outcome and functional status assessment tool for people with mild-to-moderate hemiparesis. This instrument is a structured interview intended to examine how much and how well the subject uses their more-affected arm outside the laboratory setting. Participants are asked standardized questions about the amount of use of their more-affected arm (MAL-AOU) and the quality of their movement (MAL-QOM) during the functional activities indicated. The participants are asked to score the amount of use and quality of movement in a six point ordinal scale (0 to 5) [12].

2.5 Data analysis

Data analysis was done using SPSS 16. The independent t-test was used to analyze the changes in hand function (WMFT and MAL) between the groups. Intragroup analysis between pre-intervention and post-intervention scores outcome measures was performed using a paired t-test. Independent t-test was used to evaluate between group baseline differences in age (years), height (cm), weight (kg), time since stroke (months) and MMSE between groups. Chi-square test was used to assess difference in gender distribution and the Mann-Whitney U test was used to assess the difference in MAS score. Significance was set at p≤0.05.

3 Results

The mean (S.D) of age, time since stroke, height, weight, MMSE and MAS score gender distribution (n) of the participants in group 1 and group 2 is presented in Table 1. Both the groups were matched in terms of age (t = 0.57, p = 0.5), height (t = –0.42, p = 0.67), weight (t = 0.55, p = 0.58), time since stroke (t = –0.43, p = 0.6) MMSE scores (t = 1.83, p = 0.91) and MAS score (U = 44.50, p = 0.66). There was no difference in gender distribution between groups (χ² = 1.80, p = 0.18).

Table 1
Demographic characteristics of the participants

Group 1 N = 10 Group 2 N = 10

Gender

Male 7 6

Female 3 4

Age (years, mean, SD) 60.9 (9.3) 58.4 (10.1)

Time since stroke (months, mean, SD) 22 (7.4) 24.1 (7.1)

Height (cm, mean, SD) 162.4 (8.4) 163.8 (6.4)

Weight (cm, mean, SD) 67.7 (7.0) 65.9 (7.5)

MMSE (mean, SD) 24.9 (1.7) 23.8 (0.8)

Modified Ashworth Score (mean, SD) 1.6 (0.7) 1.7 (0.6)

	Group 1 N = 10	Group 2 N = 10
Gender
Male	7	6
Female	3	4
Age (years, mean, SD)	60.9 (9.3)	58.4 (10.1)
Time since stroke (months, mean, SD)	22 (7.4)	24.1 (7.1)
Height (cm, mean, SD)	162.4 (8.4)	163.8 (6.4)
Weight (cm, mean, SD)	67.7 (7.0)	65.9 (7.5)
MMSE (mean, SD)	24.9 (1.7)	23.8 (0.8)
Modified Ashworth Score (mean, SD)	1.6 (0.7)	1.7 (0.6)

The groups were matched in terms of outcome measures before the intervention. The between group results is summarized in Table 2 and in Figs. 1–4. There was no significant difference between group 1 and group 2 in pre-intervention scores for WMFT-time (t = 0.78, p = 0.44) and WMFT-FAS (t = –0.22, p = 0.8). It was also noted that there was no significant difference between groups for MAL-AOU (t = –0.19, p = 0.84) and MAL-QOM (t = –0.4, p = 0.6). The comparison of post-intervention scores between group 1 and 2 demonstrated no significant difference in WMFT-time (t = 0.63, p = 0.5) and WMFT-FAS (t = –0.6, p = 0.5). There was no significant difference in post intervention scores in MAL-AOU (t = –0.25, p = 0.8) and MAL-QOM (t = –0.28, p = 0.7).

Table 2

Comparison of pre and post intervention scores of Wolf Motor Function test and Motor Activity Log of between Group 1 and Group 2

Variables	Group 1 Mean±SD	Group 2 Mean±SD	t	p
WMFT-Time	Pre intervention	274.5±60.06	249.8±80.3	0.78	0.44
	Post-intervention	236.2±59.3	216.0±80.8	0.63	0.5
WMFT-FAS	Pre intervention	33±2.6	33.3±3.4	–0.22	0.8
	Post-intervention	40±2.2	40.8±3.49	–0.60	0.5
MAL-AOU	Pre intervention	63.1±6.65	63.8±9.0	–0.19	0.84
	Post-intervention	67.35±6.61	68.3±9.7	–0.25	0.8
MAL-QOM	Pre intervention	63.8±9.0	61.7±8.2	–0.4	0.6
	Post-intervention	68.3±9.7	64.8±9.1	–0.4	0.6

WMFT-Time = Wolf Motor Function test (Time in seconds); WMFT-FAS = Wolf Motor Function test - Functional Ability Scale; MAL-AOU = Motor Activity Log Amount of Use; MAL-QOM = Motor Activity Log- Quality of Movement.

Fig.1

Comparison between groups before and after training. WMFT-Wolf Motor Function test (time, FAS).

Fig.2

Comparison between groups before and after training. WMFT-Wolf Motor Function test (time, FAS).

Fig.3

Comparison between groups before and after training. MAL- Motor activity log.

Fig.4

Comparison between groups before and after training. MAL- (Motor activity log).

Within group findings are summarized in Table 3 and in Figs. 5–8. In group 1, there was a significant difference between pre and post-intervention scores for WMFT-Time (t = 31.4, p = 0.001), WMFT-FAS (t = –13.5, p = 0.001), MAL-AOU (t = –10.7, p = 0.001) and MAL-QOM (t = –8.04, p = 0.001). In group 2 the results showed a significant change in pre-post intervention scores for WMFT-time (t = 23.9, p = 0.001), WMFT-FAS, (t = 16.54, p = 0.001), and MAL-AOU (t = –9.9, p = 0.001). Participants in group 2 also demonstrated significant reduction in time taken to complete the test MAL-AOU (t = 23.9, p = 0.001) and MAL-QOM (t = –6.7, p = 0.001).

Table 3

Comparison of pre and post intervention scores of Wolf Motor Function test and Motor Activity Log within group 1 and group 2

Group	Variables	Pre-intervention values (Mean±SD)	Post-intervention values (Mean±SD)	t	p
Group 1	WMFT-Time	274.5±60.06	236.2±59.3	31.4	0.001
	WMFT-FAS	33±2.6	40±2.2	–13.5	0.001
	MAL-AOU	63.1±6.65	67.35±6.61	–10.7	0.001
	MAL-QOM	60.1±7.8	63.75±7.4	–8.04	0.001
Group 2	WMFT-Time	249.8±80.3	216.0±80.8	23.9	0.001
	WMFT-FAS	33.3±3.4	40.8±3.49	–16.54	0.001
	MAL-AOU	63.8±9.0	68.3±9.7	–9.9	0.001
	MAL-QOM	61.7±8.2	64.8±9.1	–6.7	0.001

WMFT-Time = Wolf Motor Function test (Time in seconds); WMFT-FAS = Wolf Motor Function test - Functional Ability Scale; MAL-AOU = Motor Activity Log- Amount of Use; MAL-QOM = Motor Activity Log - Quality of Movement.

Fig.5

Comparison within groups before and after training. WMFT-Wolf motor function test (time, FAS).

Fig.6

Comparison within groups before and after training. WMFT-Wolf motor function test (time, FAS).

Fig.7

Comparison within groups before and after training. MAL Motor activity log.

Fig.8

Comparison within groups before and after training. MAL Motor activity log.

4 Discussion

This study aimed to compare the effectiveness of voluntary constraint and hand mitt use in Modified CIMT in people with chronic stroke. The results indicate that modified CIMT with voluntary restriction of the unaffected arm is useful in improving the motor control of the affected upper extremity in stroke patients. It is already reported that modified CIMT is an effective treatment with restriction of the unaffected upper limb during training [15, 16]. The mechanism that is thought to be responsible for the improvements seen in CIMT is overcoming learned non-use, adapted task practice (also called shaping) and repetitive task practice, in which functional activities performed on a continuous basis for 15–20 minutes [17]. Increased neural activity in the motor system is known to trigger functional reorganization, and there is some evidence that CIMT draws on neuroplasticity mechanisms to mediate enhanced motor control and the relearning of movements with the hemiparetic limb. The combination of unaffected arm restriction and affected arm training further increases neural activity in the motor system [18]. The results obtained reveal that participants in both the groups showed significant improvement in hand function. But there was no significant difference between both groups.

Page et al. [8] previously reported that patients could become fatigued when wearing the mitt and had difficulty with adherence to the treatment technique. Both therapists and stroke patients had concerns over the use of the restrictive device schedule, in that it might compromise function. It has been suggested that the restrictive device along with continuous supervised training schedules may result in those with stroke not willing to be part of such treatment protocols [16]. The results demonstrated in the current study support previous work. Sterr and Freivogel [19] for example, used a 3-week protocol, during which patients received shaping training of the affected arm for 90 minutes each day with no constraint. Their results showed an increased use of the affected limb in everyday situations, Both Sterr and Freivogel [19] and the current study demonstrated some clinical benefits without physical restriction of the affected limb. This could be explained as voluntary (cortical) inhibition of the unaffected arm during therapy, which seems to be a strong stimuli for changing behavior, in comparison to passive constraints used to prevent activity of the less affected hand while practicing with the affected arm [19]. Functional improvements gained by our patients were similar to those reported in another constraint-induced movement therapy trial by Krawczyk et al. [10]. It seems to be the case that a shorter shaping session can reduce the therapy time required to achieve a clinical outcome. These data suggest that intensity and mode of training has an important role to play rather than the mitt alone in improving hand function for patients with chronic stroke.

The standard constrain used may have some safety implications for patients hence the voluntary restrain can be an alternative option to consider in clinical practice. The exercise programme and the equipment used in the programme outlined are simple and can be used in home environment. This current study demonstrated that task practice is as important as restrain of the affected limb for the recovery process. The duration of the restraint used in the study was in accordance with that previously reported as effective [20].

This study had some limitations in that the sample size was relatively small and the participants were not followed up beyond the intervention period. The adherence to exercise protocol at home was based on the reports of caregiver which was another limitation of the study. Future studies should use larger sample sizes and longer follow up.

5 Conclusion

The voluntary restraint can be an effective mode of constrain technique for use in mCIMT to improve the hand function of affected arm in people with stroke.

Conflict of interest

We hereby declare that there is no conflict of interest involved in this study.

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