In children with a Cochlear Implant (CI), constraints on the development of speech perception can arise either from a period a auditory deprivation or from technological limitations in the transmission of the acoustic signals by the implant. Our aim here is to see whether relatively short periods of auditory deprivation (up to the age of 2 or 3 years old) do not modify the architecture of speech perception.
Identification and discrimination data show that the perception of speech sounds by children with CI is not qualitatively different from the one of normal-hearing control children (NH controls). Children with CI present the same degree of ‘categorical perception’, i.e. the same relationship between their discrimination and identification performances (Medina & Serniclaes, 2009; Bouton et al., 2012). Children with CI also present the same ‘lexicality effect’ as NH controls, i.e. the same improvement in the perception of words compared to pseudo-words (Bouton et al., 2011). However, there are quantitative differences between children with CI and NH controls. Children with CI exhibit a precision deficit the identification and discrimination of distinctive features, and such deficit is larger for the nasality feature compared to the other vocalic or consonantic features (mode and place of articulation, voicing and aperture: Bouton et al., 2011; 2012). Such precision deficit probably arises from limitations in the coding of spectral cues by the CI, a hypothesis that might be investigated with a computer simulation of speech perception processes (Serniclaes et al., 1996; 1998).