Purpose: Focusing on individuals with visual impairment, this study investigated the effects of spatial learning using tactile maps on orientation accuracy by path integration in physical and mental imagery walking scenarios.
Materials and methods: Twelve blindfolded sighted people learned nonlooping routes with two corners using tactile maps composed of volumetric raised-line elements, then navigated the routes physically and mentally. At four orientation points along the route-the starting point, Corner A, Corner B, and the endpoint-participants indicated the direction of the other points by aligning a raised, tapered rectangle attached to a horizontal digital protractor.
Results and discussion: During the physical and mental walking tasks, the participants' mean orientation error values, representing the error in angle from the correct orientation, approximated zero for all orientation directions. However, the mean absolute error, i.e. the absolute value of the orientation error, ranged from 12.5° to 32.5° across different orientation points and tasks. As the participants followed the route, the absolute error relative to the next direction of travel increased, and the absolute errors for orientation points they had passed were substantially large. These results indicate that although tactile maps do not always enable precise orientation, they provide navigators with a surveyed spatial understanding that assists orientation through path integration. Furthermore, the mean difference in orientation error between mental and walking tasks measured on the same route for all directions was not significantly different from zero. This suggests that mental imagery walking with the tactile map helps predict orientation performance by path integration in navigators without vision.
Keywords: Tactile map; mental map; mental walking; orientation and mobility; path integration; spatial learning; visual impairment.
Learning routes using a tactile map is a useful approach for facilitating orientation based on path integration, even though it does not completely eliminate orientation-related errors.The orientation task, which uses a tactile map to perform the mental walking task, has potential as a new evaluation method for orientation ability through path integration in people with visual impairment.