Combining augmented reality with functional electrical stimulation for independent therapy: assessing technology acceptance among individuals with cervical spinal cord injury

Abstract Introduction: Functional electrical stimulation (FES) can improve functional outcomes for individuals with cervical spinal cord injury (cSCI). While wearing augmented reality (AR) headsets, automated hand tracking can be leveraged to automate FES delivery and control stimulation patterns to assist independent hand exercises. The current study assessed the perceived usefulness and feasibility of using a combined AR-FES system for individuals with cSCI. Methods: 12 individuals with cSCI tried a custom AR-FES application for a single 30-minute session in a supervised clinical environment. While wearing the headset, the system compared actual to target hand postures during hand exercises with real objects, with a closed-loop linear scaling of FES amplitudes to help participants achieve correct grasping patterns. Immediately after, participants completed a custom questionnaire, the System Usability Scale (SUS), and a 30-minute semi-structured interview analyzed using a hybrid inductive-deductive thematic analysis informed by the Technology Acceptance Model. Results: Positive usability metrics (i.e., mean SUS = 75; SD = 12) were complemented by three themes: 1) Perceived Ease of Use (subthemes: perceived complexity, technological and physical limitations), 2) Perceived Usefulness (subthemes: potential impact on recovery, addressing limitations of previous therapies, person dependent), and 3) Behavioural Intention to Use (subthemes: attitudes towards use, using the system in different environments and ways). Conclusion: Individuals with cSCI perceived that the AR-FES system was useful toward recovery, potentially feasible for independent use, and provided suggestions to increase both. Thus, the study demonstrates the potential to increase the dosage of neuromodulation-based rehabilitation via independent use of an AR-FES system.