  We present a virtual reality (VR) experience that creates a research-grade
benchmark in assessing patients with active upper-limb tremor, while
simultaneously offering the opportunity for patients to engage with VR
experiences without their pathologic tremor. Accurate and precise use of
handheld motion controllers in VR gaming applications may be limited for
patients with upper limb tremor. In parallel, objective tools measuring tremor
are not in widespread, routine clinical use. We used a commercially available
VR system and designed a challenging virtual-balloon-popping test mimicking a
common nose-to-target pointing task used by medical practitioners to
subjectively evaluate tremor in the exam room. Within our VR experience, we
offer a software mode which uses a low-pass filter to adjust hand position and
pointing orientation over a series of past data points. This digital filter
creates a smoothing function for hand movement which effectively removes the
patient's tremor in the VR representation. While the patient completes trials
of the reaching task, quantitative data on the pathologic tremor is digitally
recorded. With speed, accuracy, and the tremor components computed across three
axes of movement, patients can be evaluated for their tremor amplitudes in a
quantitative, replicable, and enjoyable manner. Removal of tremor in digital
space may allow patients having significant upper limb tremor to have both an
objective clinical measurement of symptoms while providing patients positive
feedback and interaction.
