Effects of environmental explanation using three-dimensional tactile maps for orientation and mobility training

We developed a new kit to assemble three-dimensional (3D) tactile maps for orientation and mobility (O&M) training provided to persons with visual impairments. This study evaluated the effects of verbal explanations combined with 3D tactile map kits in improving understanding, recall, and walking along an unfamiliar route in comparison with the effects of only verbal explanation. The 3D tactile maps provided participants having severe visual impairments and little experience with tactile maps with a better understanding and recall of the environmental information concerning the route and landmarks. Participants who used the 3D tactile maps could find specific landmarks set as tasks more accurately and arrive at the destination alone getting lost less frequently. Tactile maps composed of 3D points, lines, and areal parts are useful as a support aid for O&M training because they have high tactile readability and can provide the environmental information that individuals with visual impairment require.

Discriminable Height Differences of Raised Lines

Introduction:

The purpose of this study was to determine the discriminable height differences of raised lines printed on paper, as assessed by people who are blind, with or without years of tactile experience.

Methods:

Ten younger and 10 older tactile readers with blindness and with rich tactile experience; and 10 blindfolded, older, sighted participants with little tactile experience discriminated paired raised-line stimuli of different heights using the fingers of their preferred hand by active touch in a psychophysical experiment.

Results:

There was a significant main effect of the height of the stimulus, F(2, 54) = 56.446, MS = .060, p < .001, [Formula: see text] = .676, [Formula: see text] = .341, and participant group, F(2, 27) = 13.717, MS = .064, p < .001, [Formula: see text] = .504, [Formula: see text] = .357; however, there was no significant main effect of the width of the lines, or any interactions. The younger and older tactile readers had virtually similar thresholds and Weber fractions, and they could discriminate paired stimuli more accurately and efficiently than the older, sighted participants. We provided the discriminable height data of the raised lines based on the mean and 95th percentile values of the Weber fractions.

Discussion:

The results indicate the importance of tactile experiences for height discrimination in active touch. For older persons with recently developed blindness, raised lines with larger height differences should be used.

Information for practitioners:

These data will be helpful for developing new braille embossers that can print raised-line graphics for people with visual impairments, with or without years of tactile experience.

Influences of tactile-dot height and tip radius of curvature on the operational performance of cellular phones

Tactile dots located on operation keys of consumer products such as cellular phones contribute to improving accessibility for older people and people with visual impairment. The Japanese Standards Association (2000) and the International Organization for Standardization (2011) standardized tactile dots. However, reliable data on the appropriate sizes and the shapes was not necessarily available. The purpose of this study is to evaluate influences of the height (0.1, 0.3, 0.55, and 0.75 mm) and the tip radius of curvature (0.1, 0.3, 0.5, 0.7, and 0.9 mm) of tactile dots on the operational performance of cellular phones in younger and older people. Sighted younger and older participants, whose hand was covered by a curtain, operated cellular phones with a tactile dot on its key 5 and without a tactile dot. As the result, both participants performed better at a particular height with larger tip radius of curvature. Furthermore, older participants operated better at high dots like 0.55-0.75 mm. In contrast, younger participants performed better at 0.3 mm and relatively poorly at 0.1 mm and 0.75 mm. Thus, comparatively high tactile dots are useful for improving the accessibility of products for the older and there is an appropriate height range for the younger.