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Many essential walking activities in daily life, such as crossing a street, are challenging to practice in conventional therapeutic settings. Virtual environments (VEs) delivered through a virtual reality (VR) head-mounted display (HMD) would allow training such activities in a safe and attractive environment. Furthermore, the game-like character and high degree of immersion in these applications might help maintain or increase children’s motivation and active participation during the rehabilitation process.
This study aimed to investigate the usability, user experience, and acceptability of an immersive VE experienced through a VR HMD to train everyday life walking activities in pediatric neurorehabilitation.
In a cross-sectional study, 21 youths (median age 12.1 years; range 6.8-17.7 years) with a neuromotor impairment undergoing inpatient or outpatient neurorehabilitation tested a VE experienced through the VR HMD Oculus Quest. The participants, accompanied by their physiotherapists, moved freely around a 4.4 by 10-meter VE, displaying a magical forest and featuring various gamified everyday activities in different game designs. Using their hands, represented in the VE, the participants could interact with the virtual objects placed throughout the VE and trigger visual and auditory feedback. Symptoms of cybersickness were checked, and usability, user experience, and acceptability were evaluated using customized questionnaires with a visual analog scale for youths and a 5-point Likert scale for their therapists.
None of the participants reported any signs of cybersickness after 20 minutes of VR HMD exposure time. They rated comfort (median 10/10) and movement ability (median 10/10) with the VR HMD as high. The VE was perceived as being really there by the majority (median 8/10), and the participants had a strong feeling of spatial presence in the VE (median 9.5/10). They enjoyed exploring the virtual world (median 10/10) and liked this new therapy approach (median 10/10). Therapists’ acceptance of the VR HMD was high (4/5). There were 5 patients that needed more support than usual, mainly for supervision, when moving around with the VR HMD. Otherwise, therapists felt that the VR HMD hardly affected their patients’ movement behavior (median 4.75/5), whereas it seemed to increase their level of therapy engagement (median 4/5) compared to conventional physiotherapy sessions.
This study demonstrates the usability of an immersive VE delivered through a VR HMD to engage youths in the training of everyday walking activities. The participants’ and therapists’ positive ratings on user experience and acceptance further support the promising application of this technology as a future therapeutic tool in pediatric neurorehabilitation.
Pediatric neurorehabilitation strives to provide patients with the greatest possible degree of independence in everyday life [
In recent years, computer technology applications that create virtual environments (VEs) have emerged more and more in the field of rehabilitation [
VEs differ regarding the display device, level of immersion, and type of interaction and can be delivered by custom-built systems as well as affordable off-the-shelf options [
VR HMDs have already been shown to be feasible for balance or gait training in the older population [
Children and adolescents aged 6 to 18 years with a neuromotor impairment and undergoing inpatient or outpatient rehabilitation at the Swiss Children’s Rehab (SCR) of the University Children’s Hospital Zurich were eligible. We aimed to have a diverse group of participants in terms of age, diagnosis, mobility level, visual acuity level, and cognitive abilities to test the VR HMD in a heterogeneous group representing the patient composition at the SCR. Exclusion criteria were inability to follow verbal instructions, uncorrectable severe visual impairment, and a history of seizures or taking anticonvulsant medication. Written informed consent and assent was obtained from the legal representatives and participating children and adolescents.
The VE, representing a magical forest (
The participants experienced the VE through a commercially available VR HMD, the Oculus Quest 1 (Facebook Technologies). The Oculus Quest is a stand-alone device with 6 degrees of freedom and 4 integrated cameras, which enable room and hand tracking. The chosen visual design considered the performance of the Oculus Quest and the fact that a cartoon-like style is often appealing to children. The participants could freely move around the 4.4 by 10-meter VE (determined by the available space of our room and maximal given play zone of the Oculus Quest). We did not use the standard Oculus controllers as input devices, as holding or operating the controllers may have been difficult for some of our patients due to limited finger motor skills or reliance on a mobility aid. Therefore, we used the Oculus hand tracking that allows the participants to use their hands, which are displayed in a realistic and size-adapted manner in the VE, intuitively for interactions with the virtual objects. Possibilities for such interactions were placed throughout the VE and triggered auditory and visual feedback to motivate the participants to move around as much as possible.
The magical forest VE featured a
A video of pediatric neurorehabilitation patients experiencing and interacting with the immersive virtual environment is shown in
Virtual environment with (A) a magic forest, (B) the orientation game, (C) the apple game, and (D) the scoring game.
The ethics committee of the Canton Zurich confirmed through a clarification of responsibility that approval for this cross-sectional study, which took place in the gait laboratory of the SCR, was not needed (Req-2020-00757).
After the participants were informed about the test procedure, the VR HMD was adjusted to their heads, and its optimal position was checked. The participants then started with the
Participant characteristics were retrieved from the patients’ medical records. Their functional level of mobility was rated by the physiotherapists with the Gillette Functional Assessment Questionnaire walking scale (FAQ) and the Functional Mobility Scale (FMS) [
Besides the VRSQ, the investigator used a customized questionnaire covering the aspects of comfort, fun, presence in the VE, and immersion to ask the participants about their experience with the VE and VR HMD. The questions mainly consisted of a subset of items from the Comfort Rating Scale [
The physiotherapists’ questionnaire assessed the acceptability of the VR HMD as a therapeutic tool for their patient. Questions included their ratings of the participants’ movement behavior, level of support needed, and engagement during the VR session on a 5-point Likert scale. They were also asked about their opinion on using a VR HMD as a therapy tool and the advantages, disadvantages, and potential problems of using a VR HMD with their patients.
Furthermore, the absolute position of the VR HMD in the room was logged with a sampling rate of 50 Hz. Based on this data, the covered horizontal and vertical distance per gaming condition and participant was calculated.
Participants’ characteristics and covered horizontal and vertical distances are presented using descriptive statistics. Questionnaire responses are illustrated with frequencies, medians, and IQRs. To quantify potential differences between the 3 games, we tested the horizontal and vertical distances covered during the 3 gaming conditions for normal distribution and performed repeated measures ANOVA with Bonferroni-corrected post hoc tests. Calculated effect sizes were based on the
In total, 21 children and adolescents with a median age of 12.1 (IQR 5.5) years, of which two-thirds had a congenital neuromotor disorder, participated in this study (
Ratings on the usability of the VR HMD, user experience, and acceptability of the immersive VE are described in the following paragraphs.
Descriptive characteristics of the study participants (N=21).
ID | Sex | Age (year) | Height (cm) | Diagnosisa | Glasses | FMSb | FAQc | Mobility aidd |
1 | Fe | 8.2 | 120 | Bilateral spastic-dystonic CPf (II) | Yes | 6, 6, 5 | 9 | None |
2 | Mg | 12.3 | 152 | Stroke | No | 6, 6, 6 | 10 | None |
3 | F | 11.5 | 147 | Bilateral spastic CP (III) with lower limb surgery | No | 1, 1, 1 | 4 | Wheelchair |
4 | M | 15.2 | 167 | Bilateral spastic CP (II) | No | 5, 5, 5 | 8 | None |
5 | M | 9.0 | 121 | Meningomyelocele with lower limb surgery | No | 5, 2, 2 | 8 | Posterior walker |
6 | F | 9.4 | 147 | Cerebral encephalopathy | No | 6, 6, 6 | 9 | None |
7 | M | 17.7 | 183 | Stroke | No | 5, 5, 5 | 7 | None |
8 | M | 11.6 | 146 | Traumatic brain injury | No | 6, 6, 6 | 10 | None |
9 | M | 7.3 | 129 | Stroke | No | 3, 3, 3 | 8 | Crutches |
10 | F | 14.6 | 169 | Traumatic brain injury | Yes | 5, 5, NAh | 6 | None |
11 | F | 10.6 | 127 | Unclear, superimposed disease with spastic-dystonic gait disorder | Yes | 5, 5, 5 | 9 | None |
12 | M | 6.8 | 114 | Meningomyelocele with lower limb surgery | Yes | 2, 1, 1 | 4 | Posterior walker |
13 | M | 12.1 | 150 | Status post septic shock with ischemic cerebral lesions | Yes | 5, 3, 2 | 7 | None |
14 | M | 9.1 | 140 | Bilateral spastic CP (II) with lower limb surgery | Yes | 2, 2, 1 | 7 | Posterior walker |
15 | M | 14.6 | 160 | Meningomyelocele with lower limb surgery | Yes | 2, 2, 1 | 6 | Posterior walker |
16 | M | 14.4 | 167 | Bilateral spastic CP (III) with lower limb surgery | No | 2, 1, 1 | 3 | Wheelchair |
17 | F | 16.0 | 168 | Friedreich ataxia with spondylodesis T4-L3 | No | 2, 2, NA | 6 | Anterior walker |
18 | F | 12.4 | 162 | Meningomyelocele | Yes | 6, 6, 6 | 10 | None |
19 | F | 15.5 | 161 | Bilateral spastic CP (II) with lower limb surgery | No | 5, 3, 3 | 7 | Crutches |
20 | F | 7.9 | 122 | Unilateral spastic CP (I) with lower limb surgery | Yes | 6, 6, 6 | 10 | None |
21 | F | 13.0 | 172 | Congenital ataxia | No | 5, 5, 5 | 9 | None |
aIn children and adolescents diagnosed with cerebral palsy, the Gross Motor Classification System Level is given in parentheses.
bFMS: Functional Mobility Scale at 5, 50, and 500 m.
cFAQ: Gillette Functional Assessment Questionnaire walking scale.
dMobility aid used during virtual reality head-mounted display testing.
eF: female.
fCP: cerebral palsy.
gM: male.
hNA: not assessed.
The participants rated the comfort of the VR HMD after 20 minutes of exposure time almost exclusively as positive. Only 3 patients reported that the VR HMD caused uncomfortable pressure on the back of the head (ID 14) or nose (IDs 16 and 17). Only 1 participant (ID 17) stated that not seeing her own body while moving around was a problem. None of the participants regarded it as unfavorable that the VR HMD blocked their view of the natural environment. Consequently, the youths did not feel hindered in their movement abilities by the VR HMD, except for 2 patients (IDs 5 and 13), who reported that grasping and manipulating the virtual objects was somewhat difficult for them.
The majority (90%, 19/21) of the participants felt that the VE and objects they saw were real (ie, really present). They also rated their feeling of being present in the VE as very high (median 9.5, IQR 1.5;
Youths’ and therapists’ ratings of various parameters regarding the usability of the virtual reality head-mounted display, the user experience, and the acceptability of the immersive virtual environment. VR: virtual reality.
According to the physiotherapists, 5 patients needed more support than usual when moving around with the VR HMD, mainly in the form of supervision (IDs 7, 17, and 20) or assistance with their mobility aids (IDs 3 and 9). Otherwise, the VR HMD hardly affected the participants’ movement behavior. The physiotherapists rated their patients’ level of engagement during the VR session higher than in conventional physiotherapy (62%, 13/21;
They considered the immersive VE a valuable complement to conventional therapy methods for training everyday walking tasks in all but 3 participants (IDs 1, 12, and 21). Increased motivation, movement variations, repetitions, concentration level, playfulness, sense of achievement, joy of discovery, competition possibility with games, dual-task training, and reduced fear of movement were favorable factors mentioned by the physiotherapists. Potential problems or disadvantages identified by the therapists were the increased difficulty in handling the mobility aids when reaching for virtual objects, difficulty to work on gait quality, lack of haptic feedback, nonvisibility of the feet, weight of the VR HMD, and the VE not being challenging enough for some patients.
The
The
Overview of the 4 application modes by participant preferences and distance covered in the horizontal and vertical plane.
We explored an immersive VE with different game conditions experienced through a VR HMD to train everyday life walking activities in a pediatric neurorehabilitation setting. The participants’ and therapists’ ratings regarding usability, user experience, and acceptability were very positive. The youths enjoyed moving around in the VE and experienced enormous fun—regardless of their age. Almost all participants felt comfortable with the VR HMD, and they did not notice any restrictions in their freedom of movement.
The participants reported a high sense of presence, indicating that they felt like being physically and spatially located in the VE. The sense of presence is a crucial feature of a VR application, as it directly influences users’ enjoyment during a VR game [
From the physiotherapists’ point of view, the VR HMD hardly affected their patients’ movements, neither with respect to walking or crossing obstacles nor regarding movement transitions, using the upper extremities, or dealing with their walking devices. This finding is essential since a negative influence of the VR HMD on the patients’ movement execution would be unfavorable for efforts to validate its future clinical application. Furthermore, in contrast to our first study [
Similar to the youths’ feedback, the therapists’ reported that their patients were more dedicated than during regular therapy sessions, for example, by being more interested and focused on the tasks or showing more perseverance. Further, they moved around without additional external motivation and did not seem to lose interest during the 20-minute test session. As motivation is an indispensable factor for active participation during the therapy, these findings are another indication of the promising option of immersive VR as a tool for movement therapy. Additionally, our results align with the findings of other studies that uniformly report the fun and enjoyment of various pediatric [
Despite the relatively high weight of the VR HMD, our patients could wear it for 20 minutes with almost no problems. Furthermore, we observed that the VR HMD is also suitable for different activities, such as walking, stooping, kneeling, crawling, or even running. This is new information, as in pediatric populations, the usability and acceptance of VR HMDs have so far only been tested in static situations [
Whether a VR HMD is a helpful complement to conventional gait therapy methods depends on the patient’s individual abilities, preferences, and the specific therapy goals. Although the missing haptic feedback of not successfully mastering obstacles or the nonvisibility of the feet can make training on gait quality more difficult for some children and adolescents, this absence could help others increase their concentration on their proprioceptive input. Additionally, the possibility to train all activities on even ground might be helpful for some patients. However, the challenge could be too small for others because of an absent uneven terrain. According to the therapists, the patients often seemed to stay more concentrated for longer time periods and demonstrated more endurance and perseverance in the VE than in conventional therapy sessions. In the study of Lai et al [
The mobility level of our participants was at a high level, with 15 being community walkers with an FAQ level of at least 7. The comments of the physiotherapists, who considered our VE not to be the right approach to address some of these patients’ therapeutic goals, indicate that the VE was not challenging enough for patients who can master uneven grounds without any assistance (FAQ≥9), which applied to 8 participants of our study population. The introduction of various difficulty levels, dual-task training, and other VEs with more challenging tasks are possible future solutions to provide an adequate training level for these patients with higher functioning. As we did not compare the visual design of the current VE to others, we cannot comment on the effect of our particular visual design or VE choices.
Although we randomized the order of the 3 games, this was not the case for the
Our participant group was substantially heterogeneous in terms of age and motor abilities. Although it would have been interesting to analyze the impact of these characteristics, our sample size precluded forming any subgroups for further analyses. Additionally, as the study was cross-sectional, we cannot draw any conclusions about the impact of our VR HMD approach on the change in patients’ functional walking abilities or how their motivation would develop over the long term. Further, the assessment of the participants’ qualitative movement behavior was solely based on the subjective ratings of the youths themselves and their therapists.
Consequently, in a current study, we use 3D gait analysis to record spatiotemporal and kinematic parameters to compare the patients’ movements when performing similar activities in real environments and VEs. Furthermore, we aim to develop and implement a foot tracking option in the VE. This option would provide patients with visual feedback on their feet’s position and create further interaction possibilities, which would further help improve the VR experience. Last, the implementation of a movement therapy using a VR HMD is required in a clinical setting to evaluate its value and effect on patients’ motivation and movement skills.
This study demonstrates the usability of an immersive VE delivered through a VR HMD in children and adolescents with neuromotor impairments performing everyday life walking activities. Furthermore, participants’ and therapists’ ratings regarding user experience and acceptability and the application’s high motivational impact support its development as a future tool for movement therapy in pediatric neurorehabilitation. However, in the light of the current generation’s rich gaming experience, choices, variation, difficulty levels, and other typical gaming features seem to be indispensable properties for successfully implementing the VR HMD as a therapy tool.
Video of pediatric neurorehabilitation patients experiencing and interacting with the immersive virtual environment.
Gillette Functional Assessment Questionnaire walking scale
Functional Mobility Scale
head-mounted display
Swiss Children’s Rehab
virtual environment
virtual reality
Virtual Reality Sickness Questionnaire
We are grateful to the children, adolescents, and therapists for the time and effort they dedicated to this project. Further, we thank Augment IT by Netcetera for the valuable collaboration and their efforts and support in the development of the virtual environment. This project was supported by the J&K Wonderland Foundation, Steinhausen, Switzerland; and the Promedica Foundation Chur, Switzerland. We also acknowledge the Children’s Research Center of the University Children’s Hospital Zurich.
CAR contributed to conceptualization, methodology, investigation, formal analysis, and project coordination and wrote the original draft. AK contributed to conceptualization, methodology, investigation, formal analysis, reviewing, and editing. UK contributed to conceptualization, methodology, investigation, writing, reviewing, and editing.
None declared.