Virtual Prism Adaptation Therapy: Protocol for Validation in Healthy Adults
February 12th, 2020
This experimental protocol demonstrates the use of virtual prism adaptation therapy (VPAT) in healthy adults and the association between VPAT and functional near infrared spectroscopy to determine the effect of VPAT on cortical activation. Results suggest that VPAT may be feasible and could induce similar behavioral adaptation as conventional prism adaptation therapy.
Our experimental protocol can address whether prism adaptation therapy is effective for patients with hemispatial neglect and whether our virtual prism adaptation therapy system promotes spatial realignment and cortical activation. Virtual prism adaptation therapy was developed to be less costly, quicker to set up, and easier to adjust than conventional prism adaptation. This technique can be used to replace conventional prism therapy in patients with hemispatial neglect because it can mimic the effects of conventional prism adaptation.
This method suggests a potential for using virtual reality for stroke therapy and may give insight into hemispatial neglect rehabilitation within the virtual rehabilitation field. Although the system is based on a virtual reality gaming engine and therefore is easily used. Be sure to take care with preparation.
For functional near infrared spectroscopy measurement setup, have the participant sit in a chair with a straight back and confirm that the participant's hand will not hit the table when reaching out. Next, select the appropriate functional near infrared spectroscopy size according to the participant's head circumference and place the cap on the head of the participant so that the vertex is located at the intersection of the midpoint between the inion and nasion and the midpoint between the left preauricular and right preauricular areas. Display the montage on the screen and connect 15 sources and 24 detectors to the montage.
Use conductive gel to improve the gain from the light source if critical before inserting the optode and place the retaining cap on the participant. To set up the software, run the functional near infrared spectroscopy system software and load the neglect montage. With the montage displayed on the screen, set 15 sources and 24 detectors according to the montage and click calibrate.
To calibrate the virtual prism adaptation therapy system, first mount the virtual reality head mounted display on over the functional near infrared spectroscopy cap taking care to avoid disturbing the cap. When the display is in place, open the virtual prism adaptation therapy software and enter the participant's information. Click start and confirm the visualization of the virtual hand in the display.
Initiate the two-step calibration and instruct the participant to watch the red cross mark in the center of the screen. Then press the R key to calibrate the screen. Instruct the participant to point to the target with the right hand.
Then press the O key to calibrate the hand position. Sufficient space should be provided for calibration in the hand range and the hand should not be stretched too far to set the target position. At the end of the calibration, confirm the participant's readiness to start the experiment and start the system without the prism mode.
Click the start key to initiate an experiment with four phases simultaneously with functional near infrared spectroscopy recording and instruct the participant to point or click with their right index finger within three seconds of the appropriate icon appearing or to rest. In the virtual prism adaptation mode, the set deviation angle results in a virtual hand deviation. The green hand is the actual hand recognized position which is not shown to the user.
The blue hands are deviated hands shown to the user. In deviation mode, the user's hand extends in the left direction in order to keep the user's hand more and more close to the target. For the clicking block, instruct the participant to press the push button.
Each phase will consist of blocks for pointing, clicking, or resting. In this representative graph, the pointing error for four healthy participants is shown with the average of the median value from 10 trials in the subphase of each pointing task lasting 30 seconds. Here, the pointing error for each subject is presented demonstrating an adaptation during the virtual prism adaptation therapy phases and the post prismatic adaptation.
Use screen calibration to place the virtual space in front of the user's visual range and use target distance calibration to place the target within the reach of the user. We have studied healthy adult volunteers, but the technology could be used with clinical patients. In addition, comparison of the data with real prism classes could be meaningful.
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Overview
This experimental protocol demonstrates the use of virtual prism adaptation therapy (VPAT) in healthy adults and its potential to mimic conventional prism adaptation therapy. The study explores the association between VPAT and functional near infrared spectroscopy to assess its effects on cortical activation.
Key Study Components
Area of Science
- Neuroscience
- Rehabilitation
- Virtual Reality
Background
- Prism adaptation therapy is used for patients with hemispatial neglect.
- Virtual prism adaptation therapy aims to be more cost-effective and easier to implement.
- This technique may provide insights into rehabilitation strategies for stroke patients.
- Utilizes a virtual reality gaming engine for accessibility.
Purpose of Study
- To evaluate the effectiveness of VPAT for spatial realignment.
- To determine the impact of VPAT on cortical activation.
- To explore the feasibility of using VPAT as a replacement for conventional therapy.
Methods Used
- Implementation of virtual prism adaptation therapy.
- Functional near infrared spectroscopy to measure cortical activation.
- Comparison of behavioral adaptations between VPAT and conventional therapy.
- Assessment of system setup and user experience.
Main Results
- VPAT may induce similar behavioral adaptations as conventional therapy.
- Feasibility of VPAT was demonstrated in healthy adults.
- Evidence of cortical activation changes associated with VPAT.
- Potential for VPAT to be used in clinical settings for rehabilitation.
Conclusions
- VPAT is a promising alternative to conventional prism adaptation therapy.
- Further research is needed to validate its effectiveness in clinical populations.
- This method could enhance rehabilitation approaches for hemispatial neglect.
Frequently Asked Questions
Executive Industry Relevance
Virtual prism adaptation therapy (VPAT) offers a cost-effective, scalable approach to assess spatial realignment and cortical activation in neurorehabilitation research. By leveraging virtual reality and fNIRS, VPAT enables mechanistic de-risking of therapeutic hypotheses related to visuospatial motor integration. This supports target validation and predictive confidence in early discovery for stroke-related cognitive deficits.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Interrogates therapeutic hypotheses on spatial realignment mechanisms in hemispatial neglect models.
- Operational Value: Enables functional target validation through quantifiable behavioral error reduction and cortical activation patterns.
- Predictive Value: Supports portfolio triage by providing measurable biomarkers of visuospatial adaptation prior to clinical investment.
Screening & Assay Development
- Assay Readiness: Prepares validated neurobehavioral readouts (pointing error, deviation angle) for high-throughput compound or intervention screening.
- Reproducibility: Standardized calibration protocols (screen and hand position) ensure consistent quantitative outputs across operators and sites.
- Scalability: VR-based system allows rapid deployment and adaptation across diverse participant pools without physical prism hardware constraints.
Translational & Preclinical Research
- Translational Continuity: Bridges discovery-phase mechanistic insights with preclinical validity via fNIRS-measured cortical activation in dorsolateral prefrontal and parietal regions.
- Risk-Adjusted Advancement: Enables go/no-go decisions based on convergent behavioral and neurophysiological adaptation thresholds.
- Disease-Relevant System: Models visuospatial dysfunction relevant to stroke-induced hemispatial neglect, supporting biomarker-aligned preclinical validation.
Pipeline & Workflow Integration
VPAT fits within the discovery-to-preclinical continuum by enabling hypothesis-driven assessment of neurorepair mechanisms before lead optimization.
- Discovery Biology: Tests pathway-specific hypotheses involving visuomotor integration and attentional reorienting networks.
- Screening: Delivers standardized, quantitative behavioral readouts (pointing error median) suitable for intervention comparison.
- Analytics: Generates fNIRS-derived cortical activation maps that inform target engagement and mechanistic de-risking.
- Translational Research: Alters with preclinical validity through homologous cortical activation patterns in healthy models predictive of patient response.
- Enterprise Reuse: Platform-agnostic VR/fNIRS framework supports reuse across cognitive motor domains beyond neglect.
Operational & Enterprise Impact
- Scientific Value: Reduces mechanistic ambiguity by linking behavioral adaptation to prefrontal-parietal cortical activation.
- Operational Value: Eliminates physical prism constraints, enabling faster setup, lower cost, and easier parameter adjustment.
- Strategic Value: Improves go/no-go confidence through multimodal validation (behavioral + neuroimaging), reducing late-stage failure risk.
- Portfolio Impact: Facilitates risk-adjusted prioritization of neurorehabilitation candidates using objective neurobehavioral thresholds.
Implementation Considerations
- Requires expertise in VR system calibration, fNIRS montage placement, and neurobehavioral task design.
- Dependent on functional near infrared spectroscopy hardware, VR head-mounted display, and depth-sensing camera integration.
- Necessitates cross-team standardization of calibration protocols (screen and hand position) for reproducible multi-site deployment.
- Adaptation considerations include adjusting deviation angles and target distances for varied motor abilities and visual fields.
- Practical limitation: Current validation limited to healthy adults; clinical translation requires stroke patient data.
