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Iliya V. Ivanov, Anna Krumm, Stephan Küster, Manja Company, Martin Staudt, Angelika Cordey, Claudia Gehrlich, Susanne Trauzettel-Klosinski; Effect of Explorative Saccadic Training (EST) to scanning eye movements in children with Homonymous Hemianopia (HH). Invest. Ophthalmol. Vis. Sci. 2016;57(12):4582. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
HH in children is mostly caused by pre- and perinatal brain damage, trauma, tumor, or as result of brain surgery and leads to orientation difficulties in everyday-life. The present study investigates whether a kids-adapted computer-based EST is beneficial in children with HH and helps to develop new compensatory strategies.
22 children with left (9) or right (13) HH participated in an EST to learn explorative saccades in their blind hemifield and to utilize their whole field of gaze. A group of 18 children with normal vision served as control. During eye movement recording, observers were presented full-color photographs (62x46 deg of visual angle) of real-world scenes. A set of images with similar complexities were selected in a free-viewing task. During a visual-search task, subjects had to search for a sinusoidal luminance-modulated Gabor grating embedded in a different set of images with similar overall complexity. Gabor patches ensured that the target location could not be predicted by local or global scene content. Eye positions were sampled at 1000 Hz before (T1), directly after 6 weeks of EST (T2) and 6 weeks (T3) after end of EST. Healthy control subjects did not participate in EST and had eye-movement recorded in both tasks at T1 and T2 only. From the eye position recordings, main parameters analyzed were: Number of Fixations (NF), Reaction Time (RT), Fixation Duration (FD) and number of saccades (to the left, right, seeing and non- seeing side) per trial.
Patient performance improved only in the visual-search task: we found shorter RTs at T2 (234.2 sec) compared to T1 (351 sec). The significant improvement in RTs was sustained for 6 weeks at T3. Comparing patient and healthy control groups at T2 showed no significantly different performance after training. At the same time, there was no significant difference in the healthy control group between T1 and T2.
Our results show that children benefited from the training, indicated by the shorter RTs after training and the maintained improvement in RTs. At the same time, there was no significant difference in the control group, which shows that their performance did not change by just repeating the search task. The finding that the patient performance after training was as good as the healthy control, highlights the significance of EST in HH.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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