The study was conducted in accordance with international standards of Good Clinical Practice. Ethics approval was obtained from the institutional ethical committee at Shri Dharmasthala Manjunatheshwara University, Dharwad, Karnataka, India (approval number: 2021/Physiotherapy/MPT/07). The study was registered with the Clinical Trials Registry - India (CTRI/2021/07/034903) before the onset of participant enrollment. Both parents and children were provided with a clear explanation of the study’s objectives and methods. Written consent was acquired from the parents, while the children provided their assent to participate. All participants were informed of their right to opt out at any point without any repercussions. To ensure confidentiality, all data were anonymized, and no identifying information was published without explicit consent. No financial compensation was offered to the participants, and no images of the participants were included in the paper or any supplementary materials.

Children diagnosed with CP were recruited for this single-blind randomized clinical trial with an active control arm. For the full CONSORT-EHEALTH (Consolidated Standards of Reporting Trials of Electronic and Mobile Health Applications and Online Telehealth) V1.6 checklist, see Multimedia Appendix 1. Participants were recruited from the Pediatric Physiotherapy Outpatient Department of SDM College of Medical Sciences & Hospital.

Inclusion criteria included (1) children with a confirmed medical diagnosis of CP, a neurodevelopmental disorder, by a medical practitioner or pediatrician; (2) age 4-10 years; (3) Gross Motor Function Classification System (GMFCS) from levels 1 to 3 [42]; (4) Manual Ability Classification System (MACS) from levels 1 to 3 [43]; (5) Modified Ashworth Scale indicating spasticity in finger and wrist flexors rated from 1 to 1+ [44]; and (6) the pediatric version of the Mini Mental State Examination scored 17 and above [45].

Exclusion criteria included (1) visual or auditory impairment, such that they cannot see and interact with the computer; (2) secondary orthopedic complications due to the neurodevelopment disorder like fixed deformities of upper extremities; (3) recent botulinum toxin therapy (less than 6 months); (4) recent surgical intervention of upper extremity; (5) moderate or severe spasticity, that is, Modified Ashworth score of grade 2 and higher; (6) cognitive impairment; and (7) uncontrolled seizures.

All parents and children were informed about the purpose and protocol of the study before enrollment; written informed consent was obtained from parents and assent from the children. Successfully screened participants were randomized to the experimental group (XG) or the control group (CG) by choosing 1 sealed opaque envelope containing a letter signifying the group assignment. A graduate student not involved in the study produced the envelopes, which contained a letter for either the XG or CG. The envelopes were thoroughly shuffled before each selection.

Participants attended 24 treatment sessions, 3 times a week for 8 weeks, at a university clinical rehabilitation research facility. Each session lasted 45 minutes.

The following outcome measures were obtained prior to and following the 8-week intervention.

Upon completion of the 8-week exercise program, parents and children enrolled in the XG were invited to participate in an interview. The following open-ended questions were asked of all participants, and their responses were recorded: (1) When you agreed to participate, how did you hope your child would benefit from the therapy program? (2) What did you like about the therapy program? (3) What was challenging about implementing the therapy program for your child and you? (4) What did you think about the exercises or games or RMD your child was asked to perform? (5) How did your child respond to the exercises or games? Was there any exercise that your child did not seem to enjoy? (6) Would you want your child to continue with the same type of therapy program? Why or why not?

Parents and children who participated in the interviews were requested to share their ideas, thoughts, opinions, and personal experiences. The inductive analytical framework of interpretive description was used for qualitative analysis [17,48].

A staff physiotherapist who was blinded to the intervention conducted all the interviews. Interviews were conducted in the local preferred language (Kannada or English), and audio recordings were later transcribed into a written format. Transcripts were translated professionally, and then one researcher developed the thematic system by coding and categorizing the written transcripts of each interview. A second researcher reviewed the categorized data, identified any additional unique responses, and finalized the codes organized into final themes and subthemes.

Descriptive statistics, including means, 95% CIs, and percentages, were used to summarize demographic variables and outcome measures. The Shapiro-Wilk test was used to assess the normality of the data [49]. Comparisons between groups were evaluated using the independent samples 2-tailed t test for continuous variables and the chi-square test for categorical variables. To analyze the effects of time (pre- to postintervention), group (XG and CG), and the time×group interaction on the CUE assessment, PDMS-2 grasping, and VMI, a mixed model ANOVA with repeated measures was used. Effect sizes for the ANOVA were computed using η², with the thresholds for small, moderate, and large effects defined as 0.01, 0.06, and ≥0.14, respectively, following Cohen guidelines [50]. All statistical analyses were conducted using SPSS (version 24; IBM Corp).

The recruitment target of 34 children was achieved within 8 months. All enrolled children completed both pre- and postassessments and attended all exercise sessions, resulting in a compliance rate of 100%. There were no adverse events or technological issues reported during the exercise programs. These findings demonstrate excellent feasibility. Figure 3 presents the CONSORT (Consolidated Standards of Reporting Trials) diagram, illustrating the participant flow throughout the study.

Table 1 presents demographic and clinical data categorized by group. The data were normally distributed, and there were no significant differences between groups at baseline in terms of age, sex, height, weight, GMFCS or MACS level, or treated hand. The majority of children were classified as GMFCS level II and MACS level II. The XG exhibited significantly higher scores in PDMS-2 grasping and VMI compared to the CG.

Tables 2 and 3 present the ANOVA results for success rate and movement error, respectively, analyzing the effects of time, group, and the time×group interaction. Figure 4 illustrates line plots of group means and 95% CIs before and after the intervention for success rate and movement error. Significant time and group effects were observed with moderate to large effect sizes across all 4 object manipulation tasks. Figure 4 highlights greater improvements in success rate and movement error for the XG compared to the CG, particularly evidenced by significant interaction terms in 3 of 4 object manipulation tasks for success rate and 2 of 4 tasks for movement error.

Table 4 displays ANOVA results for the grasping and VMI subtest scores, examining time, group, and the time×group interaction effects. Significant effects of time, group, and the time×group interaction were observed for both PDMS-2 grasping and VMI test scores. Figure 5 depicts line plots of group means and 95% CIs before and after the intervention for these scores. It illustrates significantly greater improvements in PDMS-2 test scores for the XG compared to the CG, accompanied by moderate to large effect sizes indicating substantial improvements from pre- to postintervention assessments.

This study demonstrated the feasibility and therapeutic benefits of a game-based RMD for improving manual dexterity in children with CP. Both the XG and the CG showed significant improvements in the PDMS-2 subtests and the CUE assessment of manual dexterity. In addition, the XG outperformed the CG, with greater improvements in PDMS-2 grasping and VMI as well as higher success rates and fewer movement errors in the CUE assessment. Additionally, parents reported an increase in their children’s independence in daily tasks, reflecting the positive impact of the game-based exercise program on functional hand use.

The RMD’s design and functionality are crucial to achieving the observed therapeutic benefits. Various handles of different sizes and shapes were used, which could be handled with a 2-finger grip, 3-finger grip, or whole-hand grasp, and manipulated during gameplay using thumb-finger motion, wrist motion, or a combination of elbow and shoulder motions. Both the types of handle motions and the choice of computer games have specific therapeutic value. Many inexpensive commercial computer games that can be played with the RMD require different levels of movement amplitude and precision, that is, speed and accuracy. Regular introduction of new games and progression through difficulty levels are crucial to maintain the interest and participation of the children.

Several researchers and clinicians emphasize the importance of high repetition and task-specific training in facilitating the recovery of hand function [12,51,52]. One main feature of the RMD game–assisted exercise program was to increase the number of repetitions of goal-directed movements, that is, graded speed and accuracy. Each game was played for 2-3 minutes, with each game event lasting approximately 2 seconds, resulting in 60-90 goal-directed game movement responses per game. Typically, each child played several computer games for 30 minutes. Thus, during each exercise session, the children made several hundred game movement responses. This high number of repetitions involved goal-directed, precision movements with random directions, variable amplitudes, and speeds. Additionally, visual feedback of the game paddle relative to various moving game objects was always available. Continuous visual feedback guided the position and motion of the game paddle or sprite rather than the object being manipulated. This type of practice promotes implicit learning of eye-hand coordination [53,54].

Initially, children with severe impairments succeeded in games that involved slow movements and low precision, such as large paddle sizes, large game target objects, few distractor objects, and limited cognitive demands. Children with moderate to mild impairment could engage in a larger variety of games that had faster movement speeds, greater movement precision, and added cognitive demands.

There are no published reports that have calculated the minimal clinically important difference (MCID) for either grasping or VMI subtests. However, the MCID for the total motor quotient has been reported to be 8.3% [55]. In this study, the percentage improvement in grasping and VMI subtests for the XG was 12% and 9.3%, respectively, exceeding the MCID reported for the total motor quotient. The improvements observed for the XG were significantly greater than those observed for the CG, that is, 4% for grasping and 2% for VMI. In the previous study [3], a randomized clinical trial evaluated the effects of a game-based exercise program using an IB computer mouse on manual dexterity in young children with CP aged 4-10 years. The CG received task-specific training similar to that used in constraint-induced movement therapy. Each group received 16 weeks of therapy, 3 times per week. They observed an 18% improvement in PDMS-2 grasping and a 12% improvement in PDMS-2 VMI for the group that received the game-based exercise program. Improvement in the CG was 12% for PDMS-2 grasping and 9% for PDMS-2 VMI. In the previous study [3], the intervention lasted 16 weeks, twice as long as the duration of this study. This discrepancy likely explains the variation in percentage improvement observed in grasping and VMI between the 2 studies: 18% versus 12% for PDMS-2 grasping and 12% versus 9.3% for PDMS-2 VMI.

The PDMS-2 grasping measures daily activities involving the fingers of both hands, such as picking up small objects, buttoning and unbuttoning, stringing beads, and using hand tools. Significant improvements in PDMS-2 grasping were observed despite these tasks not being practiced during the game-based manipulation exercise program. The PDMS-2 VMI assesses an individual’s ability to use visual perceptual skills for various eye-hand coordination tasks, including stacking blocks and drawing figures. In this study, the RMD game tasks required precise movements based on visual feedback from the moving game objects. This requirement is reflected in the substantial improvements seen in both the PDMS-2 tasks and the CUE object manipulation tasks.

Most parents expressed their willingness to join the trial because therapy focused on manual dexterity and addressed the lack of eye-hand coordination in their children. Both the XG and CG showed significant improvements in success rate and a decrease in movement error in all 4 object manipulation tasks, with moderate to large effect sizes. There was a significant time×group interaction, demonstrating that improvements in success rate were significantly greater for XG compared to CG.

The improvements observed in the CUE assessment of function, as well as in both the PDMS-2 grasping and VMI, were consistent with the quantitative data. Parents reported positive changes in their child’s hand function, eye-hand coordination, overall level of participation in daily activities, and concentration levels. They agreed that the addition of computer games was motivating and encouraged their children to actively participate and have fun during exercise sessions. Most parents from the XG commented that the game-based exercises were challenging yet engaging and that their children enjoyed playing them. During the initial stages of the protocol, some parents observed reluctance due to a lack of understanding of the computer games and difficulty with producing precision movements. However, after 2-3 sessions, most parents felt that the computer game–based platform provided a promising way to improve children’s compliance with the therapy program. Other studies incorporating computer games in therapy have also reported that children enjoyed the games used in their exercise programs [13,15,34,35].

The unidirectional force mode, while assisting movement in 1 direction, does not ensure that the handle movements will successfully interact with the target game objects. Additionally, 1 movement direction may receive resistive force, which may not be desirable. A real-time intelligent control scheme is under development, involving communication between the manipulandum and the RTP game. The controller will receive the coordinates of both the game targets and the game paddle. This knowledge about movement directions and amplitudes will be used to determine the direction and magnitude of the force required to rotate the handle and assist the subject in moving the game paddle as needed to interact effectively with the game target objects. This closed-loop assistance can be provided in both movement directions during gameplay, amplifying limited and small voluntary movements of those severely affected while allowing opportunities for progression with increased movement demands.

It is also common for children with paralysis to experience sudden, uncontrolled movements and difficulty managing their strength. To address this, a design change was made after the study to allow the device to be securely attached to a table, preventing unwanted movement during use. The modified device can now be easily attached to a table, providing greater stability and control during gameplay.

The results of this feasibility study demonstrate the feasibility, acceptability, and positive outcomes of the RMD game–based exercise program for the rehabilitation of hand function in children with CP. The findings indicate that computer game–assisted exercise programs can improve manual dexterity in children with CP. The results support further research and development related to the effects of computer game–assisted rehabilitation technology. The long-term effects of computer game–based training on hand function will need to be confirmed in future RCTs.