Abstract
We previously showed training to recover multiple visual discrimination abilities at trained locations in cortically blind (CB) fields (Huxlin, et al., 2009, Das et al., 2014). Here, we asked whether such training also decreases the size of the visual deficit, and whether this is impacted by number of training sessions, locations trained, time since stroke and patient age. Humphrey Visual Fields (HVF) were collected in 19 CB subjects – 5 untrained controls and 14 subjects trained on static orientation and/or global direction discrimination tasks (see Huxlin et al., 2009; Das et al., 2014). After recovering normal performance at a minimum of one blind field location, or after an interval of 1-13 months in the controls, HVFs were re-measured. Pre- and post-training maps of luminance sensitivity were generated by convolving 24-2 and 10-2 HVFs in each eye, averaging the two eyes, and interpolating between sampled locations. Only changes > 6dB were considered significant. Without training, both increases and decreases in sensitivity were observed (over 16 ± 5 deg2 and 9 ± 5 deg2 of the HVF, respectively). Training increased luminance sensitivity over an area 84 ± 16 deg2 in size; no decreases in sensitivity were observed. Curiously, improvements were not restricted to trained locations, but extended in a band 5 ± 1° wide along the pre-training blind field border. Improvement area was significantly correlated with number of training sessions and locations trained, but not with time since stroke or patient age. Finally, quality of life was assessed pre- and post-training using the National Eye Institute's VFQ-25 questionnaire. Training caused significant improvements in near and distance activities, and in the mean vision-related score. Thus, visual discrimination training in CB fields recovered luminance sensitivity over much of the blind field border, an improvement that appeared sufficient to increase visual functioning and quality of life.
Meeting abstract presented at VSS 2016