Corinne Ammann-Reiffer, Urs Keller, Andrina Kläy, Lea Meier, Hubertus J. A. van Hedel
Swiss Children's Rehab - Research Department, University Children's Hospital Zurich, Affoltern am Albis, Switzerland.
DOI: 10.2340/20030711-1000072

Objective: To evaluate the usability of 2 head-mounted displays in youths undergoing neurorehabilitation; a mixed reality head-mounted display and a virtual reality head-mounted display.
Design: Observational cross-sectional study.
Patients: Thirteen youths (age range 7. 8–16. 5 years) with neuromotor disorder.
Methods: Youths wore a mixed reality or a virtual reality head-mounted display while being verbally guided through a scene with virtual objects. Differences between the 2 systems, regarding usability, user experience, and acceptability, were evaluated using standardized questions for the youths and their therapists. System preferences and symptoms of cybersickness were noted.
Results: Both head-mounted displays were easy to mount and adjust to the children's heads, but the mixed reality system was unstable in 40% of the youths. Participants stated that they could move naturally with both devices. Object appearance scored higher with the virtual reality system, while therapists rated youths' movement execution and needed additional support in favour of the mixed reality system. Most youths preferred the virtual reality device, mainly due to the more distinct appearance of objects and the objects' richer colours. Therapists' preferences were balanced. Two children reported minimal signs of cybersickness.
Conclusion: Youths and therapists accepted both systems well, with advantages regarding usability, user experience, and preference for the virtual reality, and acceptability for the mixed reality head-mounted display.

Many essential walking activities in daily life, such as crossing a street or stepping over an obstacle, can be challenging or tedious to practice in conventional rehabilitation settings. Extended reality applications can create a safe and attractive training environment; therefore we evaluated the usability of 2 head-mounted displays in children and adolescents with a neuromotor impairment. Thirteen youths used a mixed and a virtual reality head-mounted display and were verbally guided through a scene with virtual objects. Both headsets were easy to mount and adjust to the children's heads, but the mixed reality device was unstable in 40% of the youths. Most youths preferred the virtual reality device, mainly due to the more distinct appearance of objects. Therapists' preferences were balanced. Two children reported minimal signs of cybersickness. This study demonstrates the usability of head-mounted displays for youths undergoing rehabilitation, offering exciting possibilities for therapy and training in this field.