Virtual reality-based treatment for regaining upper extremity function induces cortex grey matter changes in persons with acquired brain injury

Abstract

Background: Individuals with acquired brain injuries (ABI) are in need of neurorehabilitation and neurorepair. Virtual anatomical interactivity (VAI) presents a digital game-like format in which ABI survivors with upper limb paresis use an unaffected limb to control a standard input device and a commonplace computer mouse to control virtual limb movements and tasks in a virtual world.

Methods: In a prospective cohort study, 35 ambulatory survivors of ABI (25/71% stroke, 10/29% traumatic brain injury) were enrolled. The subjects were divided into three groups: group A received VAI therapy only, group B received VAI and physical/occupational therapy (P/OT), and group C received P/OT only. Motor skills were evaluated by muscle strength (hand key pinch strength, grasp, and three-jaw chuck pinch) and active range of motion (AROM) of the shoulder, elbow, and wrist. Changes were analyzed by ANOVA, ANCOVA, and one-tailed Pearson correlation analysis. MRI data was acquired for group A, and volumetric changes in grey matter were analyzed using voxel-based morphometry (VBM) and correlated with quantified motor skills.

Results: AROM of the shoulder, elbow, and wrist improved in all three groups. VBM revealed grey matter increases in five brain areas: the tail of the hippocampus, the left caudate, the rostral cingulate zone, the depth of the central sulcus, and the visual cortex. A positive correlation between the grey matter volumes in three cortical regions (motor and premotor and supplementary motor areas) and motor test results (power and AROM) was detected.

Conclusions: Our findings suggest that the VAI rehabilitation program significantly improved motor function and skills in the affected upper extremities of subjects with acquired brain injuries. Significant increases in grey matter volume in the motor and premotor regions of affected hemisphere and correlations of motor skills and volume in nonaffected brain regions were present, suggesting marked changes in structural brain plasticity.

Trial registration: The trial "Limitations of motor brain activity - use of virtual reality for simulation of therapeutic interventions" has been registered under reference number ISRCTN11757651 .

Keywords: Acquired brain injury (ABI); Brain plasticity; Magnetic resonance imaging (MRI); Rehabilitation; Stroke; Therapeutic games; Traumatic brain injury (TBI); Video-observation-feedback therapy; Virtual anatomical interactivity (VAI); Virtual world.

Conflict of interest statement

In the present study, 3DPreMotorSkill Technologies, LLC contributed financial support to nearly all of the study components, including stipends to survivor-participants in group A and charges for MRI services. 3DPreMotorSkill Technologies, LLC is a research and development (R&D) company. It has never sold anything and it has never earned revenue from any source other than R&D grants. Significant contributions of financial support was given by the military endowment fund REGIBASE and the Kladruby Rehabilitation Center to Jakub Pětioký. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest.

Figures

Fig. 1

Examples of VAI games: multi-finger actions to pick up a spoon and drop it into a cup, tapping actions using the index and middle fingers on a remote control, removing a light bulb and reinserting it into another fixture designated by a letter of the alphabet, choosing letters of the alphabet to form words and phrases. All actions are performed by clicking and draging mouse on the appropriate body part

Fig. 2

Motor achievements: a grip strengths before and after intervention. In parts b–d, estimated marginal means of gains are presented for b grip strengths, c shoulder abduction, and d shoulder flexion. In graphs b, c, and d the covariates appearing in the model are evaluated at the following values: therapy hours = 152.2466

Fig. 3

Results of voxel-based morphometry, nonstationary smoothness corrected p < 0.005, cluster size > 200. Neurological convention (left side of the brain is on the left side of the picture). Grey matter (GM) volume increased in the left postcentral gyrus (a), tail of the left hippocampus (b), left visual cortex and left prefrontal areas 8 and 32 (c), and left caudate (d)