Upper Extremity Biomechanics in Immersive Virtual Reality After Spinal Cord Injury

Date of Award

8-1-2024

Degree Name

M.S. in Mechanical Engineering

Department

Department of Mechanical and Aerospace Engineering

Advisor/Chair

Megan Reissman

Abstract

Injuries to the spinal cord can be debilitating to the function of the upper extremity. Many people with spinal cord injuries (SCIs) undergo rigorous therapies to help preserve range of motion and strength. Task specific training has been shown to offer benefits in upper extremity rehabilitation. In recent years, virtual reality has gained popularity for its ability to offer task specific training in an engaging and immersive environment. This study explores therapeutic virtual reality gaming for people with spinal cord injuries. The first aim of the study is to compare the kinematic performance of individuals with spinal cord injuries to healthy controls. This study’s second aim is to characterize the qualities of the movement task, such as movement direction and block position, that generate maximum kinematic responses in the SCI group. Finally, the third study aim is to compare the effects of different movement types on overall kinematic performance. Individuals with spinal cord injuries (n=7) and healthy, age-matched, sex-matched controls (n=7) were asked to play Beat Saber in an immersive virtual reality environment. Participants were equipped with upper extremity motion capture markers, virtual reality trackers, and the virtual reality headset/controllers. Custom levels were created in Beat Saber that had different movement directions (UP, DOWN, IN, OUT) and different block positions (HIGH, LOW, MED, LAT). Trials were composed of either movements with one hand (UNI), movements mirrored about the midline (MIR), or movements in opposing directions about the midline (OPP). Participants completed six randomized trials, repeating each of these movement types twice. Results showed that the joint profiles of the participants with SCIs used less overall shoulder and elbow joint motion to accomplish the tasks, compared to the healthy controls. At the wrist, SCI participants were able to use comparable or greater wrist radial/ulnar deviation than the controls. SCI participants also demonstrated rounded joint velocity profiles and minimal energy expenditure. This is consistent with other research indicating that people with SCIs will optimize their endpoint accuracy while reducing the metabolic cost. HIGH block positions often generated more joint motion, with the exception of wrist radial/ulnar deviation which is greatest with the LOW block position. MED block positioning promoted increased shoulder horizontal adduction/ abduction while HIGH block positioning promoted increased shoulder adduction/abduction. UNI movement types generated the highest joint range of motion overall. This is likely because MIR and OPP movement types are more cognitively demanding and require more enhanced motor planning skills. This study has demonstrated the efficacy of using motion capture technology to establish gold-standard kinematics for people with SCIs while playing a therapeutic virtual reality game. Further research is needed to understand the motor control impacts of different gaming designs, as well as more individuals with SCIs need to be recruited for us to make any statements about the kinematic performance as relating to the level of injury.

Keywords

Biomechanics; Upper Extremity Biomechanics; Virtual Reality; Spinal Cord Injury, Beat Saber

Rights Statement

Copyright © 2024, author.

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