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Michael Richards, Herbert Goltz, Agnes Wong; Audiovisual integration and the temporal ventriloquism effect in amblyopia. Journal of Vision 2017;17(10):1354. doi: 10.1167/17.10.1354.
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© ARVO (1962-2015); The Authors (2016-present)
Introduction: Amblyopia is a developmental visual disorder increasingly recognized to affect multisensory integration. Previously, our lab reported that amblyopic individuals perceive audiovisual simultaneity over an extended range of signal onset asynchronies (SOA). While the reason for the broadened simultaneity window is unknown, it may represent impaired temporal integration. To test this hypothesis, we examined the temporal ventriloquism effect – a phenomenon in which visual temporal order judgment (TOJ) is normally enhanced by lagging auditory clicks. Methods: Viewing with both eyes, amblyopic (n = 8) and visually normal (n = 9) participants judged which of two vertically separated lights appeared first. SOA between the lights varied from -144 (bottom first) to 144 ms (top first) in 14 increments. Paired clicks accompanied the onset of the lights such that the first click preceded the first light, or second click lagged the second light, by 100, 200, 300, or 450 ms. A baseline condition with synchronous clicks and a unisensory visual condition were also included. Psychometric functions were fit to the data, and just noticeable difference (JND) values were calculated for the visual TOJ task. Results: In the amblyopia group, visual TOJ performance (mean JND = 47 ms) was enhanced over baseline (mean JND = 62 ms) when the second click lagged the second light by 100 ms (RM ANOVA, p = 0.025, Bonferroni adjustment). Performance was not significantly different between groups for any click condition, including baseline or unisensory visual conditions (mixed design ANOVA, p = 0.581) Conclusion: Participants with amblyopia demonstrate 1) enhanced visual TOJ performance consistent with the temporal ventriloquism effect and 2) unisensory visual TOJ performance equivalent to normal individuals. These findings suggest that the widened audiovisual simultaneity window in amblyopia is not the result of impaired capacity for temporal audiovisual integration or reduced visual temporal resolution.
Meeting abstract presented at VSS 2017
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