Clinical Effectiveness of Non-Immersive Virtual Reality Tasks for Post-Stroke Neuro-Rehabilitation of Distal Upper-Extremities: A Case Report

Abstract

A library of non-immersive Virtual Reality (VR) tasks were developed for post-stroke rehabilitation of distal upper extremities. The objective was to evaluate the rehabilitation impact of the developed VR-tasks on a patient with chronic stroke. The study involved a 50-year-old male patient with chronic (13 month) stroke. Twenty VR therapy sessions of 45 min each were given. Clinical scales, cortical-excitability measures, functional MRI (fMRI), and diffusion tensor imaging (DTI) data were acquired pre-and post-therapy to evaluate the motor recovery. Increase in Fugl-Meyer Assessment (wrist/hand) by 2 units, Barthel Index by 5 units, Brunnstrom Stage by 1 unit, Addenbrooke's Cognitive Examination by 3 units, Wrist Active Range of Motion by 5° and decrease in Modified Ashworth Scale by 1 unit were observed. Ipsilesional Motor Evoked Potential (MEP) amplitude (obtained using Transcranial Magnetic Stimulation) was increased by 60.9µV with a decrease in Resting Motor Threshold (RMT) by 7%, and contralesional MEP amplitude was increased by 56.2µV with a decrease in RMT by 7%. The fMRI-derived Laterality Index of Sensorimotor Cortex increased in precentral-gyrus (from 0.28 to 0.33) and in postcentral-gyrus (from 0.07 to 0.3). The DTI-derived FA-asymmetry decreased in precentral-gyrus (from 0.029 to 0.024) and in postcentral-gyrus (from 0.027 to 0.017). Relative reduction in task-specific performance metrics, i.e., time taken to complete the task (31.6%), smoothness of trajectory (76.7%), and relative percentage error (80.7%), were observed from day 1 to day 20 of the VR therapy. VR therapy resulted in improvement in clinical outcomes in a patient with chronic stroke. The research also gives insights to further improve the overall system of rehabilitation.

Keywords: DTI; case report; cortical excitability; distal upper extremities; fMRI; neuro-rehabilitation; stroke; virtual reality.

Figure 1

Timeline with relevant data from the episodes of care and clinical assessment scores obtained at the time of enrollment. * Details in Supplementary Material.

Figure 2

VR therapy setup.

Figure 3

BOLD functional MR images for wrist extension task with voxel level threshold p < 0.05 (FWE corrected) and cluster level threshold of 5 voxels. Talairach-client was used to correlate MNI coordinates with gray and white matter. (a,c) pre-therapy activations and (b,d) post-therapy activations during affected hand trial; (e,g) pre-therapy activations and (f,h) post-therapy activations during unaffected hand trial for the masked regions of sensorimotor cortex (36:8:68 slices) and cerebellum (−54:8:−22 slices).

Figure 4

3D tractography images of CST of both hemispheres (a) pre- and (b) post-therapy. Post-therapy image of affected (right) hemisphere indicating denser and more intact tracts as compared to pre-therapy (indicated by red arrow mark).

Figure 5

Variation in quantitative task-specific performance metrics: (a) TCT, (b) smoothness of trajectory, and (c) relative % error obtained from the patient (P) at day 1, 10, and 20 of VR therapy. A relative decrease in TCT, smoothness of trajectory, and relative % error values was observed from day 1 to day 20. The reference values shown were obtained from the average performance metrics of 40 healthy subjects in our earlier work. (d) shows qualitative trajectory plots for day 1 and 20 obtained from P. At day 1, the trajectory of P was incomplete; it became identical with that of a representative healthy subject (obtained from our previous work) at day 20.