Exploring the Overlap Between Dyslexia and Speech Sound Production Deficits

Purpose Children with dyslexia have speech production deficits in a variety of spoken language contexts. In this article, we discuss the nature of speech production errors in children with dyslexia, including those who have a history of speech sound disorder and those who do not, to familiarize speech-language pathologists with speech production-specific risk factors that may help predict or identify dyslexia in young children. Method In this tutorial, we discuss the role of a phonological deficit in children with dyslexia and how this may manifest as speech production errors, sometimes in conjunction with a speech sound disorder but sometimes not. We also briefly review other factors outside the realm of phonology that may alert the speech-language pathologist to possible dyslexia. Results Speech-language pathologists possess unique knowledge that directly contributes to the identification and remediation of children with dyslexia. We present several clinical recommendations related to speech production deficits in children with dyslexia. We also review what is known about how and when children with speech sound disorder are most at risk for dyslexia. Conclusion Speech-language pathologists have a unique opportunity to assist in the identification of young children who are at risk for dyslexia

Perceptual skills underlying phonological deficits in children: Evidence from behavioral and electrophysiological measures of speech perception

Deficits in phonology, which are related to the organization and retrieval of speech sounds in the mental lexicon are associated with two distinct clinical disorders, dyslexia (DYS) and speech-sound disorder (SSD). Three studies were conducted to identify the relationship between speech perception and phonological functioning in these children. Thirty-eight children (7;6–9;6 years) with DYS, SSD, DYS/SSD and their typically-developing (TD) peers participated in this investigation. The first study presented children with three syllable discrimination tasks to determine their sensitivity to specific acoustic-phonetic contrasts. All children performed discriminated /bα – wα/, an early-developing acoustic contrast, equally well. Children with phonological impairments had more difficulty discriminating a spectro-temporal cue distinguishing place of articulation, /dα – gα/ than TD children. Children with SSD performed poorly discriminating a spectro-temporal cue for a speech production error, /rα – wα/. However, children with DYS/SSD discriminated this same contrast with no difficulty, despite the fact children in both groups exhibited a similar speech production error. The second study evaluated the importance of non-linguistic characteristics of speech on children with phonological deficits and their TD peers during word recognition. All children performed equally well on the word recognition tasks. However, exploratory analysis revealed children with SSD exhibit particular weakness for the processing of fine spectral cues during word recognition. The third study evaluated underlying neural processes during speech identification of three syllable contrasts. Findings showed that children with phonological deficits exhibited electrophysiological processing differences as compared to their TD peers. Children with DYS or SSD exhibited delayed and inefficient neural processing for /dα – gα/, whereas children with DYS/SSD exhibited further delayed and more inefficient neural processing for this same contrast. Children with SSD and DYS/SSD discriminated /rα – wα/ at a significantly later stage of neural processing than their peers. These findings suggest children with disorders of phonology exhibit less efficient and less automatic neural processes for speech perception. Taken together, these studies provide evidence that measures of speech perception distinguish children with differing deficits in phonology. Further research is warranted to determine the utility of these measures for early identification for children at risk for long-term effects of these deficits

Poor Speech Perception Is Not a Core Deficit of Childhood Apraxia of Speech: Preliminary Findings

Purpose Childhood apraxia of speech (CAS) is hypothesized to arise from deficits in speech motor planning and programming, but the influence of abnormal speech perception in CAS on these processes is debated. This study examined speech perception abilities among children with CAS with and without language impairment compared to those with language impairment, speech delay, and typically developing peers. Method Speech perception was measured by discrimination of synthesized speech syllable continua that varied in frequency (/dɑ/–/ɡɑ/). Groups were classified by performance on speech and language assessments and compared on syllable discrimination thresholds. Within-group variability was also evaluated. Results Children with CAS without language impairment did not significantly differ in syllable discrimination compared to typically developing peers. In contrast, those with CAS and language impairment showed significantly poorer syllable discrimination abilities compared to children with CAS only and typically developing peers. Children with speech delay and language impairment also showed significantly poorer discrimination abilities, with appreciable within-group variability. Conclusions These findings suggest that speech perception deficits are not a core feature of CAS but rather occur with co-occurring language impairment in a subset of children with CAS. This study establishes the significance of accounting for language ability in children with CAS