Evaluating the effectiveness of virtual reality-based therapy as an adjunct to conventional rehabilitation in the management of adolescents with cerebral palsy: An intervention protocol

Abstract

Virtual reality (VR)-based therapy has demonstrated potential in enhancing upper and lower limb functions, postural control, and balance. Despite its growing use, evidence regarding its impact on physical function and quality of life (QoL) in individuals with cerebral palsy (CP) remains scarce. This study protocol outlines a randomized controlled trial (RCT) designed to evaluate the efficacy of VR-based therapy as an adjunct to conventional therapy on physical function and QoL in adolescents with CP, as well as to explore the perceptions of participants and their caregivers regarding the intervention. This RCT will include 56 adolescents with CP, aged 10-17 years, who will be randomly assigned in a 1:1 ratio to either the intervention group (VR-based therapy) or the control group. Both groups will receive their usual conventional therapy, equated between groups. Additionally, the intervention group will receive VR therapy using the Xbox 360 Kinect, delivered twice weekly in 45- to 60-minute sessions for 12 weeks. Outcome measures will include the Gross Motor Function Measure-88, the 6-Minute Walk Test, handheld dynamometry, and the Paediatric Quality of Life Inventory. Assessments will be conducted at baseline, mid-intervention (week 6), and post-intervention (week 12). Qualitative data will be collected through semi-structured interviews with participants and caregivers after the 12-week program. Statistical analyses will be conducted on an intention-to-treat basis. Repeated measures ANOVA will be used to evaluate changes in physical function and QoL over time at baseline, mid- and post-intervention. The qualitative data from interviews will be analyzed using thematic analysis to identify key themes related to the experiences and perceptions of caregivers and participants.

Specifications table

Subject area:	Medicine and Dentistry
More specific subject area:	Rehabilitation
Name of your protocol:	Virtual Reality
Reagents/tools:	GMFM 88- Gross Motor Function Measure 6MWT- six-minute walk test Handheld dynamometer Paediatric Quality of Life Inventory
Experimental design:	This experimental study involves adolescents with cerebral palsy (CP) aged 10-17 and includes semi-structured interviews with their caregivers/parents. Participants (n = 56) will be randomly assigned to either an intervention group receiving virtual reality (VR) therapy (n = 28) or a control group (n = 28). The intervention will consist of VR therapy administered twice weekly for 45-60 minutes per session over 12 weeks. Outcomes will be assessed using the Gross Motor Function Measure-88 (GMFM-88), the 6-Minute Walk Test (6MWT), handheld dynamometry, and the Paediatric Quality of Life Inventory (PedsQL). These measures will be taken at baseline, mid-intervention (week 6), and post-intervention (week 12). Semi-structured interviews with caregivers will be conducted at the end of the 12-week intervention.
Trial registration:	The study protocol is registered with the Australian New Zealand Clinical Trials Registry under ACTRN12622001013752.
Ethics:	The Universiti Kebangsaan Malaysia Ethical Committee has approved the study protocol, with approval number JEP-2022-180.
Value of the Protocol:	Given the inconclusive results from previous studies, this protocol aims to provide essential evidence on the effectiveness of VR therapy by utilizing robust outcome measures, including physical function and QoL, in adolescents with CP. This study protocol will offer valuable guidance for clinicians on incorporating VR therapy into treatment plans for children and adolescents with CP, potentially enhancing therapeutic outcomes and improving patient care.

Background

Cerebral palsy (CP) is a non-progressive neurological disorder arising from brain damage or malformation during early development, which significantly impairs motor function, coordination, and balance [1]. These impairments lead to substantial physical limitations, restricting participation in everyday activities and social interactions, ultimately diminishing the quality of life (QoL) for adolescents with CP [2]. Management of CP primarily involves conventional rehabilitation therapies, particularly physiotherapy, which has demonstrated efficacy in addressing motor deficits. Physiotherapy protocols typically encompass stretching, strengthening exercises, movement facilitation, as well as balance and positioning training [3,4]. However, despite the benefits of these traditional methods, many adolescents with CP experience functional decline and reduced walking capacity as they transition into adulthood, indicating that conventional approaches may be insufficient to sustain long-term improvements [5]. This underscores the need for adjunctive therapies to enhance therapeutic outcomes in this population.

Virtual reality (VR) has emerged as an innovative therapeutic tool in the rehabilitation of CP, due to its widespread availability and affordability [6]. VR is increasingly being integrated into therapy for adolescents with CP, both in clinical settings and home-based interventions [7]. This technology provides an interactive and immersive experience that can stimulate motor areas in the brain, fostering neuroplasticity, which is the brain's ability to reorganize and form new neural pathways. By replicating real-world environments and delivering multisensory stimuli, including visual, auditory, and kinesthetic inputs, VR enhances motor learning, boosts motivation, and improves physical function [8]. The application of VR in therapy, often referred to as virtual rehabilitation, has been used in both physical and cognitive interventions, supporting the rehabilitation process in a controlled and engaging environment [9]. This multisensory engagement, along with real-time feedback, is believed to stimulate cortical reorganization, which leads to improved motor function in children with CP [10]. Early implementations of virtual rehabilitation focused primarily on physical and cognitive therapy, establishing VR as a valuable tool for diagnosis, treatment, and patient education [9,11].

While VR therapy shows theoretical promise, clinical evidence remains limited and inconsistent. Several studies have reported positive effects of VR on balance and gross motor function in children with CP [12]. Meta-analyses have also demonstrated the effectiveness of VR as a complementary treatment for improving upper limb function [13]. For instance, Howard (2017) found that VR rehabilitation programs were more effective than conventional methods in enhancing physical outcomes [6]. However, findings across studies remain inconsistent, particularly concerning VR's impact on gait speed, balance, participation, and QoL in CP and other neurological conditions, highlighting the need for further research [14]. Additionally, acceptance of VR as a therapeutic modality varies, with some advocating for its use as a primary treatment, others endorsing it as a complementary approach, and some questioning its efficacy altogether [15]. Qualitative analysis is therefore crucial to understand parents' perceptions of VR as an adjunct to conventional therapy, as this insight can strengthen the evidence obtained from objective measures [16]. Exploring whether parents' and children's rehabilitation goals were met is essential, as parental perceptions can directly influence their child's engagement in the intervention [17], yet this aspect has been underreported in previous studies.

In summary, the current body of evidence on the use of VR in CP rehabilitation is constrained by methodological limitations, such as small sample sizes and variability in study designs, which have contributed to mixed results. This study seeks to address these gaps by evaluating the effectiveness of VR as an adjunct to conventional therapy in improving physical function and quality of life in adolescents with CP. Furthermore, the study will explore caregivers' perceptions of the intervention, offering valuable insights into its acceptability and impact. The anticipated clinical implications include a clearer understanding of VR's role as a complementary therapy, which could inform future rehabilitation strategies aimed at enhancing outcomes for adolescents with CP.

Description of protocol

Trial design

This study employs a mixed-methods research design, integrating a parallel-group randomized controlled trial (RCT) with qualitative semi-structured interviews. The primary aim is to evaluate the effectiveness of VR-based therapy as an adjunct to conventional therapy for adolescents with CP. The trial protocol has been designed in accordance with the SPIRIT guidelines to ensure methodological rigor and transparency in reporting. Furthermore, the study has been prospectively registered with the Australian New Zealand Clinical Trials Registry under the registration number ACTRN12622001013752.

Trial population

Adolescents with CP will be recruited from the Hospital Pakar Kanak-kanak Universiti Kebangsaan Malaysia (HPKK UKM), a leading tertiary pediatric hospital that provides an optimal setting for this study in Malaysia. Participants will be selected based on specific inclusion and exclusion criteria to ensure the relevance and appropriateness of the sample. The inclusion criteria are as follows: (i) a diagnosis of spastic cerebral palsy, including hemiplegia, diplegia, quadriplegia, dyskinetic, or mixed types; (ii) a Gross Motor Function Classification System (GMFCS) level of I-III; (iii) an age range of 10 to 17 years; (iv) and no current participation in any specific or structured fitness program. Conversely, the exclusion criteria include (i) a diagnosis of ataxic cerebral palsy; (ii) recent treatment with botulinum toxin A or serial casting of the lower limb within six months prior to the start of virtual therapy; and (iii) a history of orthopedic surgery within the six months preceding the initiation of virtual therapy.

Sample size calculation

The sample size for this trial was determined using G*Power Software Version 3.1.9.7 [18]. This trial aims to evaluate the impact of VR therapy on physical functions and QoL in adolescents with cerebral palsy. Data from a previous study utilizing the Gross Motor Function Measure-88 (GMFM-88) [19] were employed to estimate the sample size. The calculation was based on a Cohen's d of 0.2, a 95 % confidence interval, an alpha level (α) of 0.05, and a statistical power of 0.8 [18]. Additionally, accounting for an anticipated dropout rate of 30 %, the required sample size is 56 participants, with 28 participants will be allocated to each group.

Screening, recruitment, and randomization

Adolescents with CP will be screened and recruited from HPKK UKM using a convenience sampling approach, based on predefined inclusion and exclusion criteria. The screening and randomization processes will be conducted by a researcher who is independent of both the intervention and outcome assessments. This separation ensures objectivity and minimizes potential biases in participant selection and data collection [20]. Eligible participants and their guardians will receive comprehensive explanations of the study protocol, both in written and verbal formats. This will include details about the study's aims, procedures, potential risks and benefits, and the expected time commitment. Upon understanding these aspects, participants and their caregivers will be required to sign informed consent forms, while assent forms will be obtained from the adolescents in line with ethical guidelines for minors [20].

A blinded assessor will collect sociodemographic data, anthropometric measurement, and baseline outcome measures using standardized procedures and validated tools to ensure the accuracy and reliability of the data [20]. Participants will be randomized in a 1:1 ratio into either the intervention or control group using a computer-generated randomization sequence. Allocation concealment will be achieved using 56 sealed, opaque, sequentially numbered envelopes, each containing the group assignment (intervention or control) and a unique personal identification number. This process will ensure that group allocation remains concealed until the moment of assignment, thus reducing the risk of selection bias [20].

Group allocation and intervention

Participants in both the intervention and control groups will undergo conventional rehabilitation, individually tailored to their specific needs. These sessions will be conducted twice weekly over a period of 12 consecutive weeks. All conventional rehabilitation sessions will be supervised by qualified physiotherapists from HPKK UKM, who will remain blinded to group allocation to minimize bias.

The conventional rehabilitation program will encompass therapeutic exercises, mobility training, and balance training, administered under physiotherapist supervision and tailored to the needs of individual patients. The therapeutic exercise component will include manual stretching as a warm-up, strengthening and aerobic exercises. Manual stretching targeting both the upper namely shoulder flexor, extensor, abductor, adductor, internal rotator, external rotator, elbow flexor and extensor, and lower limbs such as hip flexor, extensor, abductor, adductor, internal rotator, external rotator, knee flexor, extensor, ankle plantar flexor, dorsiflexor) which sustained for 40-60 seconds and 3 times for each movement [21]. Strengthening will focus on the lower limb muscles comprising hip extensor, hip abductor and knee extensor. Strengthening exercises will be performed in sets of 10 repetitions, with progression based on the guidelines provided by the American College of Sports Medicine 2020 [22]. As for the aerobic exercise, participants will take part in training which aims to keep their heart rates in the appropriate training zone for aerobic benefit [22] such as treadmill walking and motorized cycling for 30 min [23]. Aerobic training will be regulated so that participants do not exceed a Rating of Perceived Exertion (RPE) of 13. Mobility and balance training will involve weight-shifting exercises (particularly on the affected side) with and without reaching activities, elongation exercises on the weight-shifted side, and facilitation of righting, equilibrium, and protective reactions. Equipment such as balance boards, mats, trampolines, and various sizes of exercise balls will be utilized during these exercises. To ensure the safety and effectiveness of the intervention, participants' heart rate, oxygen saturation (SpO2), and RPE will be measured both before and after each exercise session. Sessions will last between 45 and 60 min, including rest periods, and will be conducted twice a week throughout the intervention period. The conventional rehabilitation program will end with a cool-down session in which manual stretching will be repeated.

In addition to conventional rehabilitation, participants in the intervention group will receive VR-based rehabilitation as an adjunct to their usual treatment. The VR program will be conducted using the Xbox 360 Kinect, a device equipped with motion sensors that detect movements without physical contact. The VR exercises will include standing-based activities such as marching, side-stepping, upper limb movements, squatting, and jumping. A qualified physiotherapist researcher will supervise the VR therapy sessions over the 12-week intervention period. Each VR therapy session will be conducted twice weekly, with a duration of 45 to 60 min per session. Participants will perform warm-up and cool-down exercises before and after each session to ensure safety and proper conditioning. During the sessions, the supervising physiotherapist will monitor participants’ heart rates (HR) and RPE. To maintain safe exertion levels, the maximum allowable RPE will be set at ‘13’. If a participant's RPE reaches ‘13,’ rest breaks will be provided. If the RPE remains elevated at ‘13’ after the rest period, the session will be discontinued for that day. Each VR activity will last approximately 3 to 5 min. Participants will be encouraged to progress to the next difficulty level once they have achieved the maximum score in their current level. All participants, regardless of group allocation, will complete outcome questionnaires at baseline, 6 weeks, and 12 weeks. The intervention group will continue to receive their conventional therapy alongside the VR-based rehabilitation. Below is a summary of the VR activities tailored to participants based on their GMFCS level (Table 1):

Table 1.

Types of virtual reality activities using Xbox based on GMFCS levels.

GMFCSa Level	Movements Involved	Virtual Reality Activities
1	Side Stepping, Jumping, Squatting, Upper Limb Movements, Kicking, Marching, Dual Tasks, Agility	Ice Age 4; Kinect Adventures (Reflex Ridge Mover, River Rush); Kinect Sports (Hurdles, Long Jump, Target Kick); Motion Explosion (Balance Beam, Star Hop)
2	Side Stepping, Mild Jumping, Upper Limb Movements, Kicking, Dual Tasks, Marching	Kinect Adventures (Sure Shot, 20,000 Leakage, Space Pop); Dance Central (Poker Face); Kinect Sports (Target Kick, Sprints, Long Jump); Motion Explosion (Balance Beam, Star Hop)
3	Marching, Side Stepping, Upper Limb Movements, Dual Task	Kinect Adventures (Sure Shot, 20,000 Leakage, Space Pop); Dance Central (Poker Face); Kinect Sports (Sprints, Body Ball); Motion Explosion (Balance Beam)

^aGMFCS: Gross Motor Function Classification System.

Outcome measures and assessment intervals

Outcome measures in this trial will be assessed by a blinded assessor at three intervals: baseline, mid-intervention (week 6), and immediately post-intervention (week 12). The primary outcome measures will include the GMFM-88, the 6-Minute Walk Test (6MWT), handheld dynamometry, and the Pediatric Quality of Life Inventory (PedsQoL). Gross motor function will be evaluated using the GMFM-88, a reliable observational tool designed to detect changes in motor function in children with cerebral palsy [24]. This study will focus on dimensions D (standing) and E (walking, running, and jumping) of the GMFM-88, with all items administered in accordance with the manual's guidelines [24].

Walking performance will be assessed using the 6MWT, a validated measure for the CP population [25]. The Minimum Detectable Change (MDC) values have been established based on GMFCS levels: 61.9 m for level I, 64.0 m for level II, and 47.4 m for level III [25]. Prior to the test, participants will wear appropriate footwear and will be seated on a standardized wooden chair with full back and arm support. To minimize variability, participants will be instructed to avoid any vigorous physical activity for at least two hours before the assessment. Baseline heart rate, blood pressure, and SpO2 will be measured. The Borg RPE scale will be administered both pre- and post-test to gauge subjective exertion levels [26]. The 6 MWT will be conducted on a 30-meter indoor walkway, marked with brightly colored tape at the start and end points. Participants will be instructed to walk continuously for six minutes without running or jogging [25]. They may stop or rest at any point during the test, with no verbal encouragement provided to ensure consistency across all assessments.

Isometric muscle strength in the lower limbs will be measured using a validated handheld dynamometer [27]. Testing procedures will follow standardized protocols, assessing hip extensor strength in a prone position, hip abductor strength in a side-lying position, and knee extensor strength in a high sitting position [28]. Measurements will be taken bilaterally to determine maximal voluntary contraction in each muscle group [26]. Quality of life will be assessed using the PedsQoL, which has been validated in the Malay language [28]. This instrument will explore various domains of the child's life, including physical, emotional, and social functioning [29].

Semi-structured interviews

In addition to the quantitative outcome measures, a qualitative component will be incorporated to gather in-depth insights into participants’ VR therapy experiences and perceptions. Semi-structured interviews will be conducted with the caregivers of participants to explore both physical and psychological outcomes associated with the intervention. Key topics will include energy levels, perceived differences between conventional and VR therapy, and the perceived impact of VR therapy on overall health. Sample questions may include: “How would you describe your child's energy levels throughout the day?”, “What are the main differences between conventional therapy and VR therapy?”, and “Do you feel that VR therapy has positively contributed to your child's health? Does your child express a desire to continue with VR therapy?”

These semi-structured interviews will be conducted once participants have completed the 12-week VR program. The interviews will be conducted via phone calls, each expected to last between 20 to 30 min. All interviews will be audio-recorded with the explicit consent of the participants’ caregivers and subsequently transcribed for analysis. The open-ended nature of the interview questions is designed to elicit rich, detailed responses from the caregivers, focusing on their perceptions of the VR treatment, the differences they observe between VR and conventional therapy, and their children's willingness to continue with VR therapy, including the reasons behind these preferences. Fig. 1 illustrates the trial procedures, encompassing the stages of screening, recruitment, randomization, intervention, and outcome assessment.

Fig. 1.

Study flowchart.

Safety and adverse events

The anticipated adverse events during the VR therapy sessions include tripping, which may lead to falls or muscle strains. To mitigate these risks, a qualified physiotherapist will be present during all VR therapy sessions to monitor participants and provide immediate assistance if needed. Additionally, the therapy will be conducted in a controlled environment, ensuring that the intervention space is safe and appropriately prepared according to the VR equipment manufacturer's guidelines. Any incidents or adverse effects will be systematically recorded and closely monitored at each follow-up session. These reports will be reviewed and discussed among the research team during regular progress meetings to ensure participant safety and to address any issues promptly.

Adherence

To enhance adherence to the therapy sessions, several strategies will be implemented, including maintaining a logbook to track participant attendance, conducting courtesy follow-up phone calls, and offering regular encouragement to continue with the intervention. While participation in the study is entirely voluntary, participants are free to withdraw from the study at any stage without any impact on the standard care they receive.

Data monitoring

The proposed trial will not require a data monitoring committee because there are no major safety concerns, unknown risks, long-term follow-up, or double-blind treatment assignment. Each participant's personal data, such as name, will be eliminated and replaced by code to keep the participants' privacy.

Data analysis

Quantitative data will be analyzed using the intention-to-treat principle with SPSS software. To evaluate the effects of the VR intervention compared to the control group, we will employ repeated-measures analysis of variance (ANOVA) to examine changes across three time points: baseline, 6 weeks, and 12 weeks. This analysis will be applied to all outcome variables, including the 6MWT, isometric strength, GMFM, and PedsQoL. Subgroup analyses based on GMFCS levels will be conducted for sensitivity analysis to explore time, group, and interaction effects. Sociodemographic and anthropometric data will be analyzed descriptively and compared between groups to assess baseline equivalence and potential influences on intervention outcomes. In cases of missing data, multiple imputation methods will be used to address incomplete data and preserve statistical power. The magnitude of differences between groups will be assessed using Cohen's d effect size [30]. Effect sizes will be interpreted as follows: small (d = 0.2), medium (d = 0.5), and large (d = 0.8) [30]. The significance level for all analyses will be set at p < 0.05. For qualitative data, thematic analysis will be employed [31]. One researcher will transcribe the recorded interviews, and a second researcher will verify the transcripts against the audio recordings to ensure accuracy. Trustworthiness of the qualitative data will be maintained through this rigorous transcription and verification process [31].

Strengths and limitations

A key strength of this study is the use of multiple outcome measures to assess quantitative results, complemented by semi-structured interviews to capture qualitative insights. This mixed-methods approach will enrich the data and provide a more comprehensive understanding of the findings. However, the study is limited by its single-hospital setting, which restricts the generalizability of the results to a broader population. Additionally, the study utilizes non-immersive VR, meaning the outcomes may not represent other VR formats.

Ethics and dissemination

This study will be conducted in accordance with the Declaration of Helsinki and in compliance with Good Clinical Practice guidelines. Ethical approval has been granted by the Universiti Kebangsaan Malaysia Ethical Committee (JEP-2022-180). We affirm that all necessary regulatory approvals have been obtained for the conduct of this study. The results of this trial will be disseminated through presentations at various national and international scientific forums and published in peer-reviewed journals. Additionally, a summary of the trial findings will be made available on the Clinical Trials Registry of India portal. Upon completion of the trial, each participant will receive personalized feedback regarding their involvement and outcomes.

Protocol validation

This study utilized a randomized control trial to evaluate the effectiveness of VR therapy in adolescents with CP by delivering robust and comprehensive results. In addition, this study pioneers the investigation of parents’ perceptions of their children's experiences concerning physical function and quality of life following a 12-week VR intervention program. Understanding the effects of this therapy may result in targeted therapy and provide physiotherapists with additional options when treating adolescents with CP.

Limitations

None.

CRediT authorship contribution statement

Huda Aliah Mohd Iqbal: Project administration, Writing – original draft, Writing – review & editing. Asfarina Zanudin: Conceptualization, Funding acquisition, Supervision, Writing – review & editing. Ho Wei Sheng: Writing – original draft, Writing – review & editing. Mohd Azzuan Ahmad: Writing – original draft, Writing – review & editing. Nor Azlin Mohd Nordin: Conceptualization, Supervision, Writing – review & editing.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

No data was used for the research described in the article.