Does the addition of virtual reality training to a standard program of inpatient rehabilitation improve sitting balance ability and function after stroke? Protocol for a single-blind randomized controlled trial

This is a prospective single-site, stratified, single-blinded, parallel-group study on the addition of supplemental sitting balance exercises, administered via VRT, for the recovery of sitting balance and function in stroke rehabilitation inpatients. Stratification is based on the FIM score, with blocked and balanced randomization.

This research is being performed in accordance with the Declaration of Helsinki. Approval has been obtained from the Élisabeth Bruyère Research Institute (M16-14-019) and University of Ottawa (A01-15-03) Research Ethics Boards. Potential participants are informed of study details, including procedures, risks and benefits, confidentiality and the voluntary nature of participation, before signing the consent form.

Potential participants are being recruited from the inpatient stroke rehabilitation unit of Élisabeth Bruyère Hospital, a tertiary care teaching hospital associated with Bruyère Continuing Care and the University of Ottawa, located in Ottawa, Ontario, Canada. This stroke unit is the largest dedicated inpatient rehabilitation unit for stroke rehabilitation in the Champlain Local Health Integration Network in Eastern Ontario and admits approximately 200 stroke inpatients a year.

Potential participants are eligible if they 1) have had an ischemic or hemorrhagic stroke in the left or right cortical or subcortical region, 2) cannot stand independently for greater than 1 minute or are unable to stand at all, 3) can sit for at least 20 minutes with or without trunk support and can sit for at least 1 minute without trunk support, and 4) can provide informed consent. Potential participants are not eligible if they 1) have an unstable cardiovascular, respiratory, endocrine, orthopedic or neurological condition that precludes exercise of low to moderate intensity, 2) have vestibular deficits or vertigo, or 3) have had seizure activity in the previous 6 months. Aphasia and apraxia of speech are not absolute exclusion criteria, but potential participants must be deemed able to learn VRT in order to participate. Suitable patients are asked by a member of their circle of care (physiatrist, resident, primary care nurse, rehabilitation health care professional) if they are interested in hearing about research studies and if in agreement, are identified to the recruiting member of the research team. Once the study is detailed to the potential participant (by research team members AT-H or LS) and informed consent is obtained, the participant proceeds to the measurement phase followed by the VRT training sessions.

Sample size was estimated from the primary outcome measure [Function In Sitting Test (FIST)] based on the formula for the difference between two independent means using a two-tailed α of 0.05 and a (1-β) of 0.80. We hypothesized that VRT will improve the mean FIST score from the pre-intervention assessment to the post-intervention assessment by a minimum of 6.5 points, which is the minimal clinically important difference (MCID) [23], with a standard deviation (SD) of 9 points. Gorman et al. [23] studied the use of the FIST on 125 individuals with various diagnoses (64 % stroke, 10 % traumatic brain injury, 10 % cancer/tumor resection, 16 % other) attending inpatient rehabilitation. The SD for the FIST in this sample varied between 15.7 on admission and 6.9 at discharge. Because our sample of only stroke patients is more homogeneous we chose a SD of 9.0. This gives appropriate power with a sample size that is reasonable to recruit within two years. While we believe that our experimental intervention of VRT that challenges sitting balance is superior to our control intervention, we cannot rule out that it may be inferior and have conservatively assumed a two-tailed alternative hypothesis. Considering a multivariate repeated-measures design with two groups and three repetitions, the required sample size is 62 participants (31/group). We expect a non-completion rate of 20 % and require each block to have equal numbers; therefore we have set out to recruit 76 participants in total.

Data on demographics (age, weight and height etc.), details about the stroke (location, size etc.) and comorbidities are recorded on each participant, to describe the sample. These characteristics will also be assessed to ascertain if they explain some of the variability in the outcome measures.

A permuted blocked and balanced randomization method stratified by pre-admission FIM score (low [≤59] or high [≥60]) is being used to allocate eligible participants to the experimental or control groups. The randomization process is carried out with a web-based randomization system based at a remote coordinating centre. The research study team member who completes the pre-intervention outcome measures (AT-H) enters information about a participant’s eligibility and FIM score, and an email stating the participant’s randomization category is sent to the research study team member delivering the VRT (LS), who is the only person to know group allocation until the participant has completed the entire protocol. Using this method, the study team member who performs the outcome measures is blinded to the participant’s group allocation. Healthcare providers on the stroke rehabilitation unit are similarly blinded to their patients’ group allocation. While participants may potentially know whether they are in the experimental or control group, they are cautioned not to remark on the VRT exercises that they receive to the research study team member performing the outcome measures or to their healthcare providers. Results from the outcome measures will not be revealed to the participants or to the research study team member delivering the VRT until after all recruitment, treatment and assessments have been performed for all 76 participants.

Participants in both groups perform VRT for 30–45 min daily for 10–12 sessions over 2–3 weeks. This timing does not include breaks, so a typical session lasts for 45–60 min. The number of sessions completed and minutes of game time per session is recorded. VRT is provided in addition to participants’ traditional rehabilitation program, which consists of 4 hours of physical therapy, 3 h of exercise supervised by a rehabilitation assistant and 3 h of occupational therapy a week, and up to 3 h of speech language pathology a week as required. The specific therapy provided is at the discretion of the rehabilitation professionals, based on national guidelines. Neuropsychology and social work support are provided as needed. The VRT laboratory is located on the inpatient stroke ward; therefore participants do not have to leave the unit to participate.

VRT is delivered by a single research study team member (LS); a registered physiotherapist with 22 years of experience; 8 years with stroke. She provides constant supervision and monitoring of the VRT, which is delivered using Jintronix Rehabilitation software (Jintronix, Montreal, PQ) and three-dimensional motion capture technology (Kinect v2, Microsoft Canada Co., Mississauga, ON). A camera captures the movements of the participant and allows him or her to control an avatar, which interacts with a game (Fig. 1). The Jintronix system was originally designed for rehabilitation after stroke, is very user-friendly and provides a selection of games/exercises for training sitting balance. Games for the experimental group challenge sitting balance control, reaching and shifting the base of support. Five games are played: Fish Frenzy, Ball Maze, Garden Grab, Bike Barrier and Kitchen Clean-up (Table 1). The difficulty of the games is monitored such that if a participant can perform a game with ease, the level of the game is increased by requiring more speed, distance and/or accuracy in reaching, to continuously challenge the participant’s sitting balance. The Jintronix system gives feedback related to the participants’ performance after each game. A belt is used to secure the upper arm to the trunk to increase trunk lean if necessary. If the game is too challenging or frustrating with respect to sitting balance, the level is decreased, to ensure safety and some success. A CONFORMat™ pressure mat (Tekscan, Inc., South Boston, MA) is used to monitor centre of pressure changes under the buttocks during the intervention. This information assists the research study team member to determine if the game parameters need to be modified to meet the treatment group goals.

The control group spends the same amount of time performing VRT as the experimental group, in order to equalize the additional time spent per week in an engaging activity for both groups. This will allow us to assess the effect of supplemental sitting balance exercises administered with VRT, rather than the effect of VRT per se, on the recovery of sitting balance and function. Control group participants are strapped into their chair to minimize trunk movement [24] and game parameters are chosen to minimize trunk lean and require only limited arm movements. Five games are played: Fish Frenzy, Space Race, Catch-Carry-Drop, Kitchen Clean-up and Pop-Clap (Table 1). Participants in both groups are encouraged to use their more-affected upper extremity; however their less-affected arm is used if the more-affected arm demonstrates poor recovery, fatigue, or pain.

Outcome measures are performed by a single research study team member (AT-H, also a physiotherapist, with 28 years of experience), blinded to treatment group. Unless mentioned otherwise, outcomes are assessed before the intervention begins (pre-), at the end of the intervention (post-) and one month later (1 month post-) (Fig. 2).

The primary outcome measure is the Function in Sitting Test (FIST) [25], a 14-item comprehensive test of sitting balance ability and function that includes components of sensory, motor, proactive, reactive and static sitting balance. Each item is scored from zero (complete assistance required) to four (independent). Content, construct and concurrent validity of the FIST have been confirmed [23, 25]. Intra-rater [intraclass correlation coefficient (ICC) 0.99 (95 % CI 0.994 – 0.997)],inter-rater [ICC 0.99 (95 % CI 0.988 – 0.994)] and test-retest reliability [ICC 0.97 (95 % CI 0.847 – 0.995 0] are excellent [26]. Responsiveness of the FIST has also been established, with a MCID during inpatient rehabilitation of 6.5 points, sensitivity of 0.93, specificity of 0.47, an effect size of 0.83 and a standard response mean of 1.04 [23].

Secondary outcome measures include the Ottawa Sitting Scale (OSS) [27] and quantitative measures of static sitting balance [28]. The OSS includes 12 items related to sitting balance ability and function, performed with feet on and off of the floor. Each item is scored from zero (unable, falls) to four (independent). The OSS has excellent intra-rater (ICC 0.99) and inter-rater (ICC 0.96 - 0.98) reliability [27].

To assess static sitting balance participants sit on an AMTI force plate (model 0R6-7-1000, Watertown, MA, US) with their feet off of the floor and positioned such that 75 % of the thigh length is on the force plate. The base of support (BoS) is measured as the area between the greater trochanters, from the front of the force plate to the posterior superior iliac spines. They sit quietly on the force plate for four minutes. Centre of pressure (CoP) displacement is quantified through the creation of an ellipse, normalized to each participant’s BoS. The area of this ellipse represents the participant’s postural sway during quiet sitting.

Three outcome measures are used to address sitting balance function performed during reaching and leaning tasks, the Reaching Performance Scale (RPS) [29], the Wolf Motor Function Test (WMFT) [30] and quantitative measures of dynamic sitting balance. The RPS involves reaching to pick up a cone placed on a table at two distances (1 cm and 30 cm from the front edge of a table placed at arm’s length). Aptitudes such as movement smoothness and trunk displacement are each scored on a scale of 0 to 3, for a total out of 36. Concurrent and discriminant validity have been assessed and preliminary intra-rater and inter-rater reliability are moderate to excellent (ICC > 0.80) [29].

The WMFT assesses the ability to perform 15 upper extremity functional tasks, such as placing the hand onto a table, lifting a pencil and turning a key in a lock. Each item is timed and also scored from zero (does not attempt) to five (normal). Two items also involve strength testing. The WMFT shows good to excellent construct and criterion validity, internal consistency and inter-rater (ICC > 0.88) and test-retest (ICC > 0.90) reliability [31‐33]. The minimal detectable change (at the 95 % level, MDC₉₅) is 0.7 s for the WMFT Performance Time score and 0.1 points for the average WMFT Functional Ability Scale [34]. The MCID is 19.0 s (dominant side affected) for the Performance Time score and 1.0 points (dominant side) to 1.2 points (non-dominant side) for the Functional Ability Scale [35].

Dynamic sitting balance is quantified to assess the components of postural control relative to the limits of stability (LoS) in sitting [28]. Participants sit on the force plate as before and are asked to lean as far as possible in 8 directions, three times each. An ellipse representative of the LoS is created and normalized to each participant with respect to their BoS. The area of this ellipse represents the extent that a participant can reach without losing stability.

Motivation to engage in exercise is assessed prior to the intervention (pre-) by asking the question “Over the next 3 weeks, either in the hospital or after you are discharged home, how motivated are you to participate in physical activity for more than 20 minutes for at least 1 day per week?” [36, 37]. The question is repeated with the phrase “… 2 days per week”, etc., up to 7 days per week. Each of the seven versions of the question is scored on a 0 to 6 Likert scale. This measure is reliable (Cronbach’s α 0.92) [38].

The Behavioral Regulation in Exercise Questionnaire (BREQ-2) is also used prior to the intervention (pre-) to assess the quality of motivation for general physical activity [39‐41]. The BREQ-2 is a 19-item scale consisting of five subscales, intrinsic motivation (example question, “I engage in physical activity because it’s fun”), identified regulation, introjected regulation (example question, “I feel guilty when I don’t engage in physical activity”), external regulation and amotivation. Each question is scored from zero (not true for me) to four (very true for me). The BREQ-2 has strong factorial validity, acceptable internal consistency and intra-rater reliability (Cronbach’s α > 0.73) [41].

The 26-item Psychosocial Impact of Assistive Devices Scale (PIADS) is used to measure the effects of assistive devices or technology on “functional independence, well-being and quality of life” [42, 43]. VRT is the technology assessed with this scale, which is administered at the end of the intervention (post-). The PIADS has good internal consistency, construct and predictive validity, high test-retest reliability (Cronbach’s α 0.95) and is responsive to device intervention [42‐44].

Baseline characteristics of the participants in the two treatment arms will be assessed using frequency distributions and univariate descriptive statistics including measures of central tendency and dispersion.

To assess the primary outcome measure for the first study objective, a pair-wise analysis evaluating the pre-post and pre-post 1-month intervention mean differences in the FIST with a 95 % confidence interval will be performed. The unadjusted mean difference will be compared first. In addition, a repeated-measures linear regression model will be used to further elucidate the measure of effect while adjusting for possible confounding variables and repeated measures of the FIST. Covariates such as total FIM score, age, and sex will be added to the model using automated stepwise procedures. Variables will be considered for inclusion into the models if there is sufficient statistical evidence and the interaction has clinical rationale. No specific subgroup analyses will be performed.

Analyses of the pre-post and pre-post 1-month intervention mean difference scores (as appropriate) for the OSS, CoP displacement characteristics of the postural sway and LoS ellipses, RPS and WMFT scores will also be reported using mean differences and 95 % confidence intervals. Linear regression modeling of secondary outcomes to assess the impact of various confounding variables (total FIM score, age, sex) will be performed, as for the FIST, above. Scores for the motivation to exercise question, BREQ-2 and PIADS will be compared between groups using t-tests. Scores for the motivation to exercise question will be compared between groups using a Mann–Whitney U test.