Envelope Enhancement as a method to normalize speech perception by children with dyslexia

Van Hirtum, T. 1, 2 , Ghesquière, P. 2 & Wouters, J. 1

1 KU Leuven - University of Leuven, Dept. of Neurosciences, ExpORL
2 KU Leuven - University of Leuven, Faculty of Psychology and Educational Sciences, Parenting and Special Education Research Unit

It has been hypothesized that the phonological deficits, typically observed in dyslexic readers, are preceded by poor speech perception. Recent theories attribute impaired speech perception in dyslexia to altered processing of dynamic features of the speech envelope. Therefore, if speech perception deficits in dyslexia indeed stem from faulty speech envelope tracking, then consequently enhancing the envelope might improve speech perception by persons with dyslexia.
In this study, we implemented an envelope enhancement strategy (EE) to amplify specific amplitude transitions and reinforce the temporal structure of the speech envelope. We tested sixty-three children, aged 9 to 12 years, with and without dyslexia using a sentence repetition task in a speech weighted noise. We tested speech perception in four different conditions: natural speech, vocoded speech and their enhanced versions. These conditions were used to assess both the nature of the speech perception deficit and the effect of the EE-algorithm on speech perception.
Results showed atypical speech-in-noise-perception in children with dyslexia. However, EE-implementation instantaneously improved and even normalized speech perception thresholds for children with dyslexia. These results, and the effect of multiple cognitive tests and children?s characteristics (e.g. age, family risk, speech therapy) on these results will be discussed at the conference.