Development and validation of immersive hand rehabilitation system using a VR rhythm game with vibrotactile feedback: an fNIRS pilot study

Abstract

Abstract Background Recently, virtual reality (VR) has been widely utilized with rehabilitation to promote user engagement, which has been shown to induce brain plasticity. In particular, contact-free hand tracking technology has been developed as a control input for VR, and there is an increasing demand for patient-specific hand rehabilitation strategies. In this study, we developed a VR-based hand rehabilitation system consisting of a user-specific gesture-controlled rhythm game with vibrotactile feedback and validated the system by measuring brain activation using functional near-infrared spectroscopy (fNIRS). Methods The VR-based hand rehabilitation system provides vibrotactile feedback as the user matches their hand gestures to VR targets customized to their pre-recorded hand gestures that approach according to the rhythm of the music. Cortical activation was measured via fNIRS during 420 seconds of alternating gameplay and rest in 11 healthy subjects and one chronic stroke survivor. Regions of interest (ROI) were the prefrontal cortex (PFC), the premotor cortex & the supplementary motor area (PMC&SMA), the primary sensorimotor cortex (SM1), and the somatosensory association cortex (SAC). Results The mean success rate of gesture matching among healthy subjects was 90% with a standard deviation of 10.7%, and the success rate of the stroke survivor was 79.6%. The oxygenated hemoglobin (HbO) cortical activation maps showed that the hemodynamic responses of HbO increased during the VR-based hand rehabilitation for all ROIs for both groups. Paired t-test analysis showed a significant increase in HbO activation values in 23 out of 51 channels that correspond to all ROIs except the left PFC and PMC&SMA, which showed high subject variability. Conclusion The experimental results indicate that the proposed gesture-controlled VR rhythm game and vibrotactile feedback system successfully activated brain cortical areas related to motor planning and execution, multisensory, and attention. The proposed system is expected to be effective in promoting brain plasticity by inducing brain activation in key areas for stroke rehabilitation.