Algorithmic Virtual Reality Reduces Parkinsonian Tremor

Abstract

Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders, affecting approximately 6-7 million patients worldwide. Involuntary hand tremor (IHT), one of the cardinal motor symptoms of PD, is extremely debilitating to patients reducing their quality of life. In this study, we combined neuroscience together with the nascent field of medical virtual reality (VR). Our goals were to 1) generate technology to enable PD patients to leapfrog the real life difficulties of living with IHT by entering VR metaverse worlds in which they are tremor-free and can function at new heights, 2) to determine whether lack of tremors in VR modifies central biofeedback mechanisms to non-invasively reduce tremors in real life. We thus generated algorithms that adjusted the moving average centroid of digital hands to stabilize tremors in VR. We implemented these algorithms in the Oculus Rift VR system and enrolled nine subjects with PD in a trial that yielded several important observations. First, we established the Oculus Rift as a potent measurement device for IHT. Secondly, we determined parkinsonian tremors can be abolished in VR with algorithms that removed up to 99% of tremors from PD subjects' digital hands (76% average reduction). These data suggest PD subjects can enter VR and be asymptomatic of PD IHT. To test whether our algorithms have measurable practical utility, we created a VR painting application, FingerPaint, and tested it against TiltBrush the leading VR painting application. We empirically demonstrate that complex freeform art created in FingerPaint had up to 51% reduction in tremor-associated parkinsonian drawing irregularities (24% average reduction). Lastly, we generated a technical framework wherein movements in the real-world can be measured side-by-side with those in VR. With this framework, we observed real life parkinsonian tremors were significantly reduced by up to 87% in real life when our algorithms abolished digital hand tremors in VR (35% average reduction). This reduction was observed in 78% of subjects and was progressive as subjects had increasingly reduced real life tremors the longer they were in VR.