A Virtual Reality Telerehabilitation System that enables clinicians to assess the wheelchair accessibility of users' built environments from a remote location was developed. This system used commercial software to construct 3D virtualized environments from photographs. We previously performed two reliability analyses on the hardware and software components and a feasibility test. Through these pilot studies, algorithms for constructing 3D models of wheelchair users ' ho me environment s and for assessing the environments' accessibility were developed and we could have confirmed that this system could be an appropriate and useful intervention tool for accessibility assessment of a wheelchair user's home environment. As the last phase of this study, we evaluated the developed system's capability, as compa red to that of the CIP method, in assessing the accessibility of the wheelchair user's built environment . Three houses were assessed for three imaginary subjects via the Conventional In Person (CIP) method by an architect and via the VRTS by another architect . This field evaluation verified the value of the Virtual Reality Telerehabilitation System for a nalyzing a ccessibility of the p hysical e nvironment and showed that it could reduce the reliance on a rehabilitation engineer and an architect and shift to reliance on a less highly trained person, at a consequent lower cost.
3D Model, Accessibility, Home Modification, Telerehabilitaion, Virtual Reality.
Home modification has come to be recognized as an important intervention strategy to manage health care conditions, maintain or improve functioning, ensure safety, and reduce wheelchair user's dependency on others  . However, the availability of skilled professionals with experience in home modifications for accessibility is limited  . A system that enables accurate remote assessments would be an important tool to improve our ability to perform home assessments more easily and at decreased cost.
A Remote Wheelchair Accessibility Assessment System using v irtual r eality(VR) technology  and telerehabilitation concept  was developed in order to enable clinicians to assess the wheelchair accessibility of users' built environments from a remote location. Characteristics of the camera and 3D reconstruction program chosen for the system significantly affect its overall reliability. In this study, we performed two reliability analyses on the hardware and software components: 1) Verification that commercial software can construct sufficiently accurate 3D models by analyzing the accuracy of dimensional measurements in a virtualized environment; 2) comparison of dimensional measurements with four camera settings. Based on these two analyses, we were able to specify a consumer level digital camera and the Photomodeler Pro software for this system [5, 6] . And we then tested the feasibility of the selected software and hardware in an actual environment. The feasibility test of the hardware and software instruments adapted through first and second analyses showed these instruments were appropriate [7, 6] .
Lastly, we performed a field evaluation to test whether this new system is comparable to the traditional method of accessibility assessment to evaluate its ability to assess the accessibility of a wheelchair user's typical built environment.
This study used a repeated measures design. A home physical environment was divided into several problem areas such as entrance, hallway, bathroom, living room. Each problem area was identified by several tasks that can be performed in it. All possible tasks in each area within each home were evaluated using two methods: VRTS and CIP. In this within-subject design, tasks evaluated by the VRTS method would be the experimental group and the same tasks evaluated by the CIP method would be the control group. Evaluators were blinded to each other's assessment. The assessment addresses several problem areas of the home, and each area has a number of associated tasks. Each task was designated as problematic or not, hence, in need of modification or not, by each architect evaluator. In this study, three houses were evaluated for three imaginary subject situations and six problem areas were identified for the evaluation of each house. And a number of tasks (usually about 70) were evaluated in a home evaluation by both evaluators using the same evaluation form. We adapted some of the tasks of the CASPAR TM  as checklist items of our developed evaluation form. In addition to the tasks of the CASPAR TM , we added some features necessary to wheelchair users, such as whether enough space exists to build a ramp or to install a stair glide or a lift.
If an individual requested a home accessibility assessment through the architecture firm Lynch & Associates, the architect then instructed any interested customer to contact the investigator..
Instead of actual clients, three imaginary situations were created through completion of the survey form for three imaginary subjects.
Pictures were then taken of the client's home environment. In this study, three students of the school were recruited as part-time assistants for the image acquisition. When he/she took pictures of a problem area, at least two carpenter's squares were located in the middle of the space. And he/she sketched a rough floor plan of the home environment which showed where each problem area was located.
The architecture firm of Lynch and Associates conducted the Conventional In-Person assessment by visiting their client's home and investigating the physical environment. The architect completed the evaluation form with the information from the on-site investigation and measurement of his/her client's home environment.
A 3D model was made for each problem area, using the 3D modeling software, Photomodeler Pro. Once the model was constructed, the technician measured the dimensions of norm objects (carpenter's squares) in the 3D model in order to determine whether the model was accurate enough to be used for the accessibility assessment.
Another architect from Tusick and Associates then evaluated the accessibility and assessed the modification requirements for each imaginary client's situation, using the virtualized model of each home environment, and referring to 2D photos and preliminary information from the survey form. She also used the evaluation form to evaluate all tasks in all problem areas in an orderly and systematic way.
The investigator compared the data from each evaluation form, completed by the two architect evaluators, to determine the level of agreement between the evaluation results via the VRTS method and the CIP method.
|Category||True Response||Kappa k( p-value)||Odds Ratio [95%CI]||McNemar (p-value)|
|True Positive: Sensitivity||True Negative: Specificity|
205.272 [104.062, 404.921]
We used the Conventional In-Person assessment as the baseline to compar e the VRTS protocol . The proportion of overall agreement was highly observed as 94.1% and the overall sensitivity and specificity was reported as 95.6% and 90.3% respectively. As a significant Kappa coefficient of .857 and the 95% Confidence Interval of Odds rate of [104.062, 404.921] were calculated, a high level of overall agreement rate was shown. And high p-value (.868) of the McNamar test implied that there was no marginal homogeneity, that is, no tendency to identify the task incorrectly in the positive or negative direction.
The results of field trials showed high congruence between the assessments by two methods. Findings suggest ed that the VRTS assessments have the potential to enable specialists to assess pote ntial accessibility problems in built environments regardless of the location of the client, home, or specialist. This study also provided the evidence that a virtual reality telerehabilitation system can be an alternative, cost-effective solution to conventional rehabilitation services. We will improve the system continuously with the state-of-the-science technologies and this progress in this study will provide a means of accessibility assessment for wheelchair users in underserved areas who otherwise would not have access to evaluations of their built environments by professionals. The VRTS can be utilized in both homes and public spaces, and the study shows the potential for applications of virtual reality technology in the area of architectural interior environment, such as in the interior design and home renovation industries.
This work was funded by the Department of Veterans Affairs and the University of Pittsburgh. Opinions expressed are those of the authors and do not necessarily reflect those of the funding agencies.
University of Pittsburgh
Department of Rehabilitation Science and Technology
5044 Forbes Tower
Pittsburgh, PA 15260
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