Browsing by Author "Gage, Rachel"

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    Indoor Spatial Updating with Impaired Vision-Human Performance Data for 32 Normally Sighted Subjects, 16 Low Vision Subjects and 16 Blind Subjects
    (2016-09-21) Legge, Gordon E; Granquist, Christina; Baek, Yihwa; Gage, Rachel; legge@umn.edu; Legge, Gordon E
    Spatial updating is the ability to keep track of position and orientation while moving through an environment. We asked how normally sighted and visually impaired subjects compare in spatial updating and in estimating room dimensions. Groups of 32 normally sighted, 16 low vision and 16 blind subjects estimated the dimensions of six rectangular rooms. Updating was assessed by guiding the subjects along three-segment paths in the rooms. At the end of each path, they estimated the distance and direction to the starting location, and to a designated target (a bean bag dropped at the first segment of their path). Spatial updating was tested in five conditions ranging from free viewing to full auditory and visual deprivation (see documentation for details). The normal and low-vision groups did not differ in their accuracy for judging room dimensions. Correlations between estimated size and physical size were high. Accuracy of low-vision performance was not correlated with acuity, contrast sensitivity or field status. Accuracy was lower for the blind subjects. The three groups were very similar in spatial-updating performance, and exhibited only weak dependence on the nature of the viewing conditions. Conclusions. People with a wide range of low-vision conditions are able to judge room dimensions as accurately as people with normal vision. Blind subjects have difficulty in judging the dimensions of quiet rooms, but some information is available from echolocation. Vision status has little impact on performance in simple spatial updating; Proprioceptive and vestibular cues are sufficient.
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    Tactile Acuity of Young and Old Pianists [Minnesota Lab for Low-Vision Research, 2019]
    (2019-04-16) Legge, Gordon E; Granquist, Christina; Lubet, Alex; Gage, Rachel; Xiong, Ying-Zi; yingzi@umn.edu; Xiong, Ying-Zi; The Minnesota Laboratory for Low-Vision Research
    A previous study from our lab demonstrated retention of high tactile acuity throughout the lifespan in blind subjects in contrast to the typical decline found for sighted subjects (Legge, Madison, Vaughn, Cheong & Miller, 2008). We hypothesize that preserved tactile acuity in old age is due to lifelong experience with focused attention to touch and not to blindness per se. Proficient pianists devote attention to touch--fingerings and dynamics--over years of practice. To test our hypothesis, we measured tactile acuity in groups of young and old normally sighted pianists and compared their results to the blind and sighted subjects in our 2008 study. The pianists, like the subjects in 2008, were tested on two tactile-acuity charts requiring active touch, one composed of embossed Landolt rings and the other composed of dot patterns similar to braille. For both tests, the pianists performed more like the blind subjects than the sighted subjects from our 2008 study. Our results are consistent with the hypothesis that lifelong experience with focused attention to touch acts to preserve tactile acuity into old age for both blind and sighted subjects. We now release the data we collected in the 2008 study and the new study for sharing and replication purposes.