Virtual Reality Testing of Power Wheelchair Driving Skills

• Performance on the Power Mobility Road Test of real world driving skills [ Time Frame: Baseline and 2 week follow up ] [ Designated as safety issue: No ]
• Performance on the computer-based assessment of driving skills [ Time Frame: Baseline and 2 week follow up ] [ Designated as safety issue: No ]
• Performance on the virtual based assessment of driving skills [ Time Frame: Baseline and 2 week follow up ] [ Designated as safety issue: No ]

The purpose of this research study is to examine whether computer based or virtual reality tests are as useful as real power wheelchair driving tests in measuring driving performance and whether they may be useful in helping to identify the problems that some individuals may have with driving power wheelchairs. The specific aims are as follows:

Specific Aim 1: To develop computer-based and VR wheelchair driving assessments for both drivers and non-drivers that correspond to an accepted real-world driving assessment (Power Mobility Road Test) and compare them to the real-world assessment and to each other.

Specific Aim 2: To develop additional features of the computer-based and VR assessments that present dynamic tasks and determine whether skills on these tasks correlate with functional motor abilities.

This study has an experimental, repeated measures design with validity and reliability testing. In Phase 1 of the study, we will design and develop the software needed to create the computer-based and VR testing environments. In Phase 2 of the study, we will recruit and begin testing of subjects.

Subject Assessment and Positioning:

Subjects will complete a brief questionnaire that asks questions about demographic information, general information about health and previous experience with wheelchairs and assistive technology use. This questionnaire will take a maximum of hour to complete. An investigator will perform a brief neurological history and examination on each subject. Using examination and consultation with the subject, the investigator will determine which arm(s) or leg(s) will operate the interface.

All subjects will undergo a real-world power wheelchair assessment with the Power Mobility Road Test (PMRT), the 2D computer-based driving test, and the virtual reality (VR) test in random order. Subjects will be allowed to rest between sessions. Feedback from the subjects will be elicited during and after trials to attempt to identify the most difficult portions of the assessments. We estimate testing of subjects will take approximately 3-4 hours per visit.

Power Mobility Road Test (PMRT):

The PMRT contains two domains: Structured Elements/Tasks and Unstructured Skilled Driving. The first domains contain 16 tasks that include activities such as passing through standard width doorways, turning a ninety-degree turn, and turning 180 degrees. In both domains, each task is scored from 1 to 4, depending on speed and the number of collisions that occur with obstacles. A total score for the entire test is calculated out of a possible 64 points, and the final score on the test reflects the percentage of total points acquired. A passing score is a percentage of > 95%.

Subjects will be tested in their own EPWs when possible. If they do not have their own power wheelchair, one will be provided and the seating configuration will be optimized by the ATP. The PMRT will be administered in our Driving Activities Laboratory, under the supervision of the ATP who will terminate the experimental protocol if any aspect of driving is unsafe. Our laboratory is a modular environment with movable obstacles that can be arranged to create a safe driving environment, allowing for collisions with obstacles that are soft or that collapse when struck. Previous work has documented safe wheelchair mobility, even with unfamiliar equipment, in this laboratory. Subjects who score < 95% on the PMRT but who are actual power wheelchair drivers will still be considered to have failing scores.

To ensure subject safety, any subject who is a power wheelchair user who scores below 95% on the PMRT will be given a referral to an ATP for a full mobility assessment.

Computer-Based Test:

We will create a computer-based version of the PMRT that contains 2D representations of the same tasks contained in the PMRT and which contains a simulated wheelchair and driving course that are scaled to the actual PMRT course measurements. The subject will sit in front of a computer screen in the test wheelchair and maneuver a simulated wheelchair on the screen using a standard joystick or switch control. Subjects will see the environment from their own perspective. The control interface will not be connected to the wheelchair motor but rather to the computer via a serial or USB cable and will directly control the on-screen simulated wheelchair. This will allow testing of participants who do not use power wheelchairs. Subjects will be allowed to practice before testing. Tasks will be scored similarly to the real-world PMRT.

The computer-based test will also contain a second feature that includes hallways and doorways that progressively change widths. Subject scores on these tasks will be determined by the minimum hallway or doorway width that is negotiated without collision. In addition, a series of moving objects of a spectrum of speeds will be presented in random order and the minimum warning time needed to avoid collision will be calculated.

Virtual Reality (VR) Test:

We will also create a VR environment that is scaled to the PMRT. We will use large screens that create a large field of view and that recreate the same tasks contained in the PMRT. Subjects will sit in the center of the screen display and will view a similar image as in the computer-based simulation, but the large field of view will surround subjects. The subject will be allowed to practice before testing commences. Tasks will be scored similarly to the computer-based PMRT.

The VR Test will, like the computer-based test, also contain a second feature that includes a progressively narrowing hallway and doorways. Subject scores on these tasks will be determined by the minimum hallway or doorway width that is negotiated without collision. In addition, moving objects of various speeds will be presented and the minimum warning time needed to avoid collision will be calculated.

Repeat Testing:

Subjects will undergo all three testing scenarios twice, returning on a second visit in no earlier than 2 weeks.

• Other: Power Mobility Road Test (PMRT)
  All subjects will undergo the "real world" power mobility evaluation via the PMRT.
• Other: Computer-Based Test
  All subjects will undergo the computer-based evaluation designed to simulate real world driving in a 2D environment.
• Other: Virtual Reality Test
  All subjects will undergo the virtual-based evaluation designed to simulate real world driving in a 3D environment.

Inclusion Criteria:

1. Subjects must be between 18 to 80 years old.
2. Subjects must have a diagnosis of SCI, spina bifida, syringomyelia, spinal stenosis, transverse myelitis, ALS, spinal cord disease, multiple sclerosis, stroke, polytraumatic injury, or TBI with residual motor, sensory, or cognitive impairments that impair mobility.
3. Subjects must use a power wheelchair or an attendant propelled manual wheelchair for all or part of their mobility.
4. Subjects must be able to provide informed consent.
5. Subjects must have very basic cognitive, visual, and motor skills to interact with an interface.

Exclusion Criteria:

1. Subjects who have active pelvic or thigh wounds. (They may be worsened by prolonged sitting).
2. Subjects with a history of seizures in the last 90 days. (A computer screen task has the potential to induce seizures).
3. Subjects who do not pass the screening protocol.