Crossmodal synesthetic congruency improves visual timing in dyslexic children

• Dyslexic children preserved intact crossmodal matching between visual-size and auditory-pitch as did in typical developing peer.
• Dyslexic children employed audiovisual synesthetic correspondence to improve their performance of visual temporal order judgment with temporal ventriloquism paradigm.
• Dyslexic children had general deficits in temporal processing and crossmodal integration.
• The multisensory facilitation for timing performance is correlated with the reading ability and indicates a potential educational intervention for dyslexic children.

Consistent with the temporal ventriloquism effect, synesthetic correspondence between the features of visual size and auditory pitch has been shown to modulate the performance of visual temporal order judgment (TOJ) in typical adults. Here in the two main experiments we recruited seventeen dyslexic children and twenty typically developing children to perform a visual TOJ task and measured their ability of synesthetic correspondence between visual size and auditory pitch. In Experiment 1, participants were shown two consecutively presented visual discs that were temporally flanked by two synesthetic congruent or incongruent auditory beeps. In Experiment 2, participants received a crossmodal matching test (visual-size vs. auditory pitch). The results showed that compared to the typically developing group, dyslexic children benefited more from cross-modal synesthetic correspondence to partially compensate for their deficiency in visual TOJ task. The multisensory facilitation for timing performance was correlated with reading ability (Exp.1). Moreover, dyslexic children formed intact “congruent” matching of visually larger shapes to lower auditory pitch, and visually smaller shapes to higher auditory pitch, as did their typically developing peers (Exp 2). The results of our present study suggested general deficits of temporal processing in dyslexic children, However, with relatively intact ability of auditory pitch-visual size matching, dyslexic children could separate visual events using auditory cues. The current study also indicates a feasible way to improve the reading ability by exploiting temporal ventriloquism effect, modulated by appropriate crossmodal synesthetic associations.

The upper figure showed the experimental stimuli and an example trial. (A) Large or small flashes were combined with high- or low-pitched tones in a synaesthetically congruent (low-large, high-small) or incongruent (low-small, high-large) fashion. (B) Stimuli sequence for the visual temporal order test. Participants judged which side of visual stimulus came first, two visual stimuli (V1 and V2, synchronous or with intervals of 33, 66, 100,166, 233 ms) were accompanied by two auditory beeps (A1 and A2). The stimulus onset asynchronies (SOAs) between A1 and V1, between A2 and V2 were fixed at 150 ms.The lower figure indicated the just noticeable differences (JNDs) in control group and dyslexia group for performance in visual temporal order judgment, with the audiovisual congruent, incongruent and baseline (visual-only) conditions.Figure optionsDownload as PowerPoint slide