Abstract
Background. Video games have become popular in stroke rehabilitation; however, the nature of this intervention is not fully understood. Objectives. To compare the number of (a) purposeful and nonpurposeful repetitions of the weaker upper extremity (UE) and (b) movement accelerations as assessed by accelerometer activity counts of the weaker and stronger UEs of individuals with chronic stroke while playing video games or participating in traditional therapy. Methods. Twenty-nine individuals (mean age 59 years, 1-7 years poststroke) took part in a group intervention of video -games (n = 15) or traditional therapy (n = 14) as part of a randomized controlled trial. During 1 - 2 sessions, participants were video-taped while wearing wrist accelerometers. Assessors counted the number of repetitions and classified movements as purposeful or nonpurposeful using videotapes. The weaker UE motor impairments were correlated to movement accelerations, to determine if participants were using their potential during the sessions. Results. Participants in the video game group performed a median of 271 purposeful movements and 37 970 activity counts compared to 48 purposeful movements and 14 872 activity counts in the traditional group (z = −3.0, P = .001 and z = −1.9, P = .05, respectively). Participants in the traditional group performed a median of 26 nonpurposeful (exercises) compared with 0 in the video game group (z = −4.2, P = .000). Strong significant correlations were found between the motor ability of the weak UE to repetitions of participants in both groups (r = .86, P < .01). Participants with higher motor ability performed more repetitions. Conclusions. Video games elicited more UE purposeful repetitions and higher acceleration of movement compared with traditional therapy in individuals with chronic stroke.
Introduction
Stroke rehabilitation is considered a relearning process in which motor learning mechanisms are operative and interact with spontaneous recovery. 1 The recovery of the weak upper extremity (UE) poststroke is considered limited and unsatisfactory,2-4 while full functional recovery occurs only in 10% to 20% of the individuals poststroke. 3 Despite the recommendation that these individuals move and use their weak UE in order to facilitate its recovery and brain plasticity, 5 many do not use their weaker arm enough, and limited repetitions of movements have been recognized. Lang et al 6 observed inpatients in stroke rehabilitation performing only an average of 39 repetitions of active, 34 repetitions of passive, and 12 repetitions of purposeful (goal-directed) UE movements during a single session of occupational or physical therapy. The amount of daily use of the weak UE of individuals undergoing subacute stroke rehabilitation (quantified by accelerometers) did not increase significantly from rehabilitation admission to discharge, despite significant improvement in their motor and functional ability as assessed by clinical measures. 7 In addition to facilitating more repetitions of UE movements to enhance brain reorganization,8,9 it is recommended that UE movements should be incorporated into meaningful, task-oriented activities.10,11 Since many individuals poststroke have inadequate UE movement, 12 it is often not feasible to perform task-oriented activities, and therefore non-purposeful repetitive movements are practiced. Clinicians are thus tasked with seeking novel methods to increase the number of repetitions of purposeful movements during and following rehabilitation.
Virtual reality (VR) is a novel approach to UE stroke rehabilitation13-15 providing easily controlled and graded UE purposeful tasks that can be practiced in a repetitive manner, and thereby may improve motor function poststroke.16,17 Small sample clinical studies using costly VR systems18-20 as well as video game consoles (eg, Sony PlayStation EyeToy, Nintendo Wii)21-23 have shown improvement in the motor ability of the weak UE. Preliminary findings from studies that quantified the amount of UE movements while playing video games revealed that individuals with stroke and individuals without a disability performed higher acceleration of movements as assessed by wrist accelerometers and were observed to perform more repetitions of active movements while playing EyeToy games as opposed to Wii games.24,25 Video games are becoming a popular tool used in rehabilitation; however, the nature of this intervention in terms of motor demands is not fully understood, hence it is important to characterize this type of intervention and to compare it with traditional therapy by quantifying specific components of the intervention. Based on the literature,21-24 it appears that the use of video games could facilitate repetitions of purposeful movements of individuals during and after stroke rehabilitation. Therefore, our study objectives were to compare the number of (a) purposeful and nonpurposeful repetitions of the weaker UE as observed from video-tapes and (b) movement acceleration and intensity as assessed by accelerometers of the weaker and stronger UEs of individuals with chronic stroke while playing video games or participating in traditional therapy and to correlate these to the motor impairments of the weaker UE, which will determine if participants are using their potential during the sessions.
Methods
This study was a secondary cross-sectional analysis of a subset of data from a larger randomized controlled trial examining the effectiveness of video games compared with traditional therapy among individuals with chronic stroke. For this analysis, data were available for 29 of the 43 participants from the main trial.
Population
Individuals were eligible for the main trial if they were at least 6 months poststroke, aged 18 to 80 years, cognitively intact (score >24 points on the Mini Mental State Examination), had mild to severe weakness of their affected UE (as assessed by scores 4-60/60 points on the Fugl-Meyer Motor Assessment [FMA] 26 [UE subtest]), able to walk at least 10 meters, community dwelling, without other neurological conditions or epilepsy. Individuals were stratified according to the UE motor impairment and then randomly assigned the video game or traditional intervention, both receiving group therapeutic sessions for 3 months (1-hour session × 2 sessions per week). The study was approved by the Hospital Helsinki Committee and all individuals provided written informed consent.
Tools
Upper extremity repetitions were classified and counted according to the observation guide by Lang et al. 6 UE movements were classified as nonpurposeful, active/passive exercises, or active/passive purposeful movements of the affected UE. For example, elbow flexion performed with the weaker UE is an active exercise. If performed by the therapist or by the participant’s stronger UE it was considered a passive exercise. Reaching/rolling/throwing a real/virtual ball are examples of purposeful movements (active if done by the weak UE or passive if self-assisted by stronger hand or therapist).
The movement acceleration and intensity of UE movement was quantified by accelerometers (Actical, Mini-Mitter Co.) worn on each wrist while the participants were video-taped and then the UE repetitions were counted. The Actical accelerometer is a tri-axial small (28 × 27 × 10 mm) and light (17 g) accelerometer, it has a frequency range of 0.3 to 3.0 Hz, is sensitive to 0.05 to 2.0 G-force, and samples at 32 Hz. The accelerometer records, rectifies and integrates acceleration over 15-second epochs as activity counts (AC) and based on regression models to reflect the intensity of movement (0 = sedentary to 3 = vigorous) for each hand. The reliability and validity of these accelerometers for the UE of individuals with stroke has been established. 7
The following tools were used to characterize the population. The UE subtest of the FMA 26 quantified the motor impairment of the weak UE, The Action Research Arm Test 27 assessed the functional ability of the UE. The validly and reliability of these tools have been established. 28 Standing balance was assessed by the Functional Reach Test 29 and the Functional Independence Measure 30 was administered as an interview 31 to determine the independence in basic activities of daily living. Stroke and demographic information was collected as well.
The Group Intervention
Video games were selected based on the participant’s ability and preference. Individuals in the video game group (VGG) played the following consoles (games); XBOX Kinect (Bowling, 20,000 Leaks), Sony PlayStation 2 EyeToy (Kung Foo, Slap Stream), Sony PlayStation 3 MOVE (Start the Party CD), or SeeMe (http://www.virtual-reality-rehabilitation.com/) VR system (Ball, Cleaner), developed specifically for rehabilitation. After a 5-minute warm-up, participants were divided into pairs and played games for 25 minutes, then rotated partners and consoles for the remaining time. Individuals in the traditional group (TG) were instructed to perform movements and functional tasks using therapeutic aids such as balls, blocks, and cones in a group and then in pairs or triads. Participants in both groups were supervised by experienced occupational therapists who tried to minimize compensatory movements. They were encouraged the use weaker UE and if not possible, were instructed to assist the movement with their stronger hand.
Procedure
Group sessions followed a protocol developed specially for the study. Since the motor demands increased gradually during the 3-month program as the participants learned the different exercises/activities (TG) or the different video games (VGG), UE movements were quantified during the last month of the intervention. Participants wearing wrist accelerometers were video-taped while participating in 2 consecutive therapeutic group sessions and the number of repetitions of weak UE movements was classified and counted by an assessor. Four assessors were trained in counting the different types of movements. Interrater reliability (ICC3,1) (95% confidence interval [CI]) between the 4 assessors was 0.98 (0.94-0.99), P < .001. Acceptable significant ICCs [95% CI] were found for all the types of movements (0.81 [0.50-0.93] to 0.93 [0.83-0.97], P < .001) and for the AC (0.77 [0.36-0.92] to 0.89 [0.72-0.96], P = .002] and intensity (0.87 [0.68-0.95] to 0.91 [0.84-0.97], P = .001) for both hands between the 2 consecutive sessions. Considering these values of acceptable consistencies between the 2 sessions, we subsequently included 9 more participants who were recorded only during a single session. After completing the intervention, 1 to 2 weeks following the sessions that were video-taped, the assessments were administered again (FMA scores are presented) and, satisfaction questionnaires inquiring about their level of enjoyment from the intervention were filled in.
Data Analysis
To characterize the study sample, descriptive statistics and frequencies were used. Using Shapiro–Wilks test, the variables were not found to distribute normally, therefore nonparametric tests were used. The mean number of movements, AC and intensity was calculated for participants that had two sessions and the total number of movements, AC and intensity from the single session was used for the remaining participants. The number of repetitions, accelerometer AC and intensity are presented as the median (interquartile range [IQR]), and differences between groups (VGG vs TG) were assessed by the Mann–Whitney U test. For each group, Spearman correlations were assessed between the FMA (as assessed at the end of the intervention) to the number of repetitions and accelerometer AC and intensity. Correlations ranging from 0.25 to 0.49 were considered fair and values of 0.5 to 0.75 were considered moderate to good relationships. 32
Results
The movements of 29 participants (n = 15 VGG, n = 14 TG) age range 29-69 years (VGG) and 42-78 years (TG) were analyzed. They were 1 to 6 years (VGG) and 1 to 7 years (TG) poststroke, walked independently with (n = 9 VGG, 7 TG) or without a walking aid (n = 7 VGG, 6 TG) and the motor impairment of their weak UE ranged considerably (see Table 1). These participants were present in the sessions that were video-taped; their video-tapes were clear so the repetitions could be counted easily and they had full accelerometer data.
Characteristics of Participants in Each Group.
Abbreviations: IQR, interquartile range; FMA, Fugl-Meyer Motor Assessment (UE subtest); MMSE, Mini Mental State Examination; FIM, Functional Independence Measure; UE, upper extremity.
Participants in the VGG did not perform nonpurposeful movements (median of 0 active and 0 passive exercise movements) as opposed to a median (IQR) of 26 (3-122) active and 26 (0-66) passive exercise, nonpurposeful movements in the TG (z = −4.2, P = .000 and z = −3.5, P = .002, respectively). However, participants in the VGG performed a median (IQR) of 271 (157-490) active purposeful movements compared to 48 (3-123) active purposeful movements in the TG (z = −3.0, P = .001). Participants in the VGG performed a similar number of passive purposeful movements as the participants in the TG: median (IQR) = 0 (0-11) and 0 (0-24), respectively (z = −0.1, P = .8).
Higher accelerometer AC were registered for the weaker hand of the participants in the VGG, 37 970 (12 833-67 031), compared with the participants in the TG, 14 872 (9932-23 747) (z = −1.9, P = .05; see Figure 1). Although similar differences were found for the stronger hand, 34 927 (15 505-49 742) AC for the VGG compared with 24 168 (10 866-39 935) AC for the TG, these differences were not significant (z = −1.2, P = .2). The median (IQR) intensity of the weak UE in the VGG was 2.08 (1.8-2.3) (out of a maximum of 3) and 1.8 (1.6-2.0) in the TG, which was significantly different (z = −2.0, P = .04).
Median accelerometer activity counts from the weaker and stronger hands of participants from the video game group (n = 15) and the traditional group (n = 14) (on the left) and from 7 participants (Fugl-Meyer Motor Assessment >41 points) in each group (on the right) while participating in a session.
At the end of the intervention the median (IQR) FMA score for the VGG was 50 (10-58), which was not significantly different (z = −1.4, P = .15) from the FMA scores in the TG, 34 (5-51). These scores were correlated with the repetitions of (active) purposeful movements and accelerometer readings. Strong significant correlations were found between the FMA of the weak UE to repetitions of purposeful movements of participants in the VGG (r = .89, P < .01) and TG (r = .89, P < .01). The higher the FMA score, that is, the more active movement the participants had, the more repetitions of purposeful movements were observed. Interestingly, strong significant correlations between the FMA and the accelerometer AC and intensity were found only for the participants in the VGG (r = .85, P < .01 and r = .84, P < .01, respectively). In other words, participants with more active movement were able to produce higher acceleration and intensity of movement. Significant high and moderate correlations found between the repetitions of purposeful movement to accelerometer AC in the VGG and TG (r = .92, P < .01 and r = .58, P < .05, respectively), but only in the VGG was the number of repetitions of purposeful movement correlated to the intensity of the movement (r = .91, P < .01).
Ninety-two percent of the individuals in the VGG and 77% of the individuals in the TG rated their level of enjoyment from the intervention from “very much” to “extremely.”
Discussion
Counting repetitions of UE movement highlighted the differences between the motor interventions provided to the 2 groups. Participants in the TG performed nonpurposeful, active, and passive exercises while participants in the VGG did not perform simple exercises; all their movements were integrated into purposeful movements aimed at interacting with virtual objects. During 1 hour, participants in the VGG performed a median of 271 purposeful repetitions, which is similar to the repetitions observed for 5 individuals with chronic stroke playing EyeToy games (301 repetitions per 60-minute session) but much higher than observed for 7 individuals playing Wii games (39 repetitions). 25 The median of 271 repetitions of our participants is more than 5 times the repetitions performed during the TG (48 repetitions), 5 times more than the repetitions performed by individuals with subacute stroke (n = 28) counted by Kimberley et al. 33 [mean (SD) = 28.93 (14.50), during 30-minute session and 20 times more repetitions counted in a previous study of that group [a mean (SD) = 12 (12) repetitions], of individuals undergoing stroke rehabilitation. 6
Clinicians have understood the importance of increasing the repetitions performed per session. For example, Birkenmeier et al 11 recently reported a proof-of-concept study of high-repetition doses of UE task–specific training. Thirteen individuals were encouraged to perform 300 repetitions per 1-hour session of supervised functional tasks, defined by the participants as relevant. These participants performed a mean of 322 repetitions per session and rated their fatigue and pain as low. An improvement following a 3-week high-repetition doses intervention was reported. The constraint-induced movement therapy literature also shows that high-intensity training can be achieved. 34 Robot-assisted therapy is another way to increase the number of repetitions. For example, in a recent pilot randomized controlled trial, 35 the effects of intensity in UE robot-assisted therapy was examined. High-intensity therapy (600-800 repetitions) was compared with low-intensity therapy (300-400 repetitions) and conventional therapy. The higher intensity group (n = 6) showed better improvement in motor function and muscle strength compared to the other groups. Combs et al. 36 demonstrated that for 8 participants with chronic stroke, a VR gaming (dance) system, can elicit 800 to 2000 repetitions of goal-oriented reaching movements per 30-minute sessions. In the current study, we also demonstrated that by using inexpensive video games we can facilitate UE repetitions in a fun and motivating manner.
The fact that more participants in the VGG reported enjoyment supports previous studies that found gaming factors to enhance enjoyment and motivation for treatment when using virtual environments. 37 Enjoyment from a task appears to correlate with the time participants are prepared to spend doing a task, which can lead to active participation and functional improvement.38,39 Whereas participants in the TG were sometimes observed resting or stopping their exercise/activity, participants in the VGG did not stop interacting during a virtual game. Since individuals with stroke are recommended to practice UE movements, their internal motivation is important, 39 which can lead to significant improvement in functional ability. 40
The repetitions elicited while playing the video games were translated into a median of 37 970 AC, which is more than double the AC monitored for the participants in the TG (14 872), similar to the number of AC monitored during a whole day of individuals with subacute stroke prior to rehabilitation discharge, median (IQR) = 41 541 (19 340-105 980), and 15 times more than that was produced during a therapeutic in-patient session of occupational or physical therapy, median (IQR) = 2411 (635-6848) and 2744 (927-5960), respectively. 7 This difference is emphasized when focusing on the participants with mild/no UE motor impairment (median 67 031 AC in the VGG compared with a median of 17 873 AC in the TG). More so, the significant high correlations between the accelerometer AC and the number of repetitions found in the VGG and the correlations with the motor impairment (FMA) emphasizes that these individuals maximized their UE potential while playing video games. Therefore, video games have great potential for facilitating UE goal-directed movements of individuals who have active movements who potentially could have a console at home to maintain and improve their UE.
The higher levels of accelerometer AC reflects not only more repetitions but also higher intensity of movements. Playing video games and responding to and interacting with virtual stimulus seems to facilitate individuals to move faster, which may be an effective way of increasing rehabilitation intensity after stroke. 41 Since some of the movements may be of poor quality, it is recommended that participants be periodically supervised while playing. More so, well-established treatment approaches (such as constraint-induced movement therapy 34 ) that focus on repetitive and meaningful activities and less on the quality of movement demonstrate improvement in the functional use of the weaker UE.
The relatively small and heterogeneous sample in each group is a limitation of this study. Thus, differences between games and consoles were not analyzed, so larger studies are needed. Only 29 participants from the main trial were analyzed; however, comparability of the participants between groups was maintained. The assessors were not blind to the study hypothesis. The video games group intervention was compared with traditional state-of-the-art group occupational therapy.
Conclusions
The use of commercial video games facilitates 5 times more repetitions of purposeful movements, and double the accelerometer AC compared with traditional therapy. For individuals with mild/no motor impairment these differences are greater. Therefore, video games can be used as a means of therapy aimed to increase the number of UE repetitions and acceleration of individuals with chronic stroke. Further studies are required to assess the effectiveness of this type of intervention on motor recovery of the weak UE of individuals poststroke.
Footnotes
Acknowledgements
We thank all of the participants.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Funding was provided to DR from the European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement number 277023 titled “Virtual Reality Intervention for Stroke Rehabilitation.”