[PS-1.9] Amplitude rise-time processing: A risk factor for dyslexia?

Hakvoort, B. 1 , van der Leij, A. 1 , Maassen, B. 2 & van Zuijen, T. L. 1

1 University of Amsterdam
2 Rijksuniversiteit Groningen

In the longitudinal Dutch Dyslexia Programme (DDP), controls and children with a familial risk of dyslexia (FR) have been followed their entire pre- and primary school period. Over time the FR group has been divided into two groups; a group of familial risk non-dyslexic (FRnondys), and a group of familial risk dyslexic (FRdys) children, allowing us to discern factors that relate to reading and not merely relate to being at risk for dyslexia. The current study investigated whether more proficient basic auditory processing is related to reading fluency. We specifically address differences in amplitude rise-time (art) processing, as a diminished sensitivity to differences in art processing has been previously connected to reading fluency. Participants? sensitivity to amplitude rise time, intensity and frequency processing was measured with event-related potentials (ERPs). The ERP component of interest is the mismatch negativity (MMN), which reflects change detection. Our preliminary results indicate that controls, FRdys and FRnondys children do have an MMN to changes in art. No differences are found between groups. On intensity, only controls had an MMN. On frequency, we find a smaller MMN for FRdys and FRnondys compared to controls. Contrary to previous findings our preliminary results suggest that art processing is not related to reading fluency at all. Furthermore, our results imply that diminished sensitivity to changes in intensity and frequency should be regarded as risk factors for dyslexia that do not directly relate to reading fluency.