Exploring childhood apraxia of speech : speech and language profiles in 5-year-olds with suspected apraxia of speech or cleft palate

Abstract

Introduction and aims: Childhood apraxia of speech (CAS) is a speech sound disorder (SSD) lacking a quantifiable measure discriminating all cases of CAS from other SSDs. This project aimed at exploring CAS using different perspectives when examining speech and language difficulties commonly seen in 5-year-old children with suspected CAS or children with repaired cleft palate (CP±L). Children with CP±L were added to broaden and differentiate the knowledge base on CAS and to search for factors explaining unfavorable speech outcome in this group.

Material and methods: In study I, a questionnaire was constructed and used, anonymously surveying Swedish SLPs (n=178) knowledge and praxis about CAS features and assessment. Findings were compared to earlier survey findings from English contexts. Study II examined articulation proficiency and orofacial function of children with CP±L (n=52) based on SLP examination and parental interview. For measurement of intelligibility, both parent reports and SLP ratings were compared. Study III included children with CP±L and disordered speech (n=19) and children with suspected CAS (n=15). Phonetic transcription and CAS diagnostics were based on audio-recordings of single word naming. The diagnosis was built on judgement of presence or absence of speech features using a checklist constructed for English speakers. The cross-linguistic applicability of the operationalized features and checklist was tested. In study IV language competence of children with CAS and CP±L was directly assessed, and parental ratings of everyday life communication were added, and results compared.

Results: Swedish SLP’s views on typical speech characteristic of CAS, surveyed in study I, corresponded in large with reports of SLP’s from English-speaking contexts. The top seven characteristics were inconsistent speech production, sequencing difficulties, oro-motor deficits, vowel errors, voicing errors, consonant cluster deletion and prosodic disturbance. In study II, 37% of children with CP±L were found to have orofacial dysfunction; however, this was not an explanatory factor for speech outcome for these children. A distinct CAS profile, found in study III, included the five features: phonemic speech inconsistency for consonants and vowels plus vowel error, voicing error, difficulty achieving initial articulatory configurations or transitionary movement gestures and stress errors. In study IV, expressive language disorder was found in 67% of children with CAS. Receptive language ability was significantly better than expressive language in all children with CAS. No such difference was observed in the group of children without CAS (non-CAS SSD). Parent ratings of communication skills reflected an increased burden on communication in everyday life when difficulties within both speech and language domains were present.

Conclusions: Despite relevant theoretical and/or clinical knowledge about CAS, Swedish SLPs reported a need for further education. Swedish-speaking 5-year-olds with CAS shared a distinct speech profile including five features, with prosodic impairment almost exclusively seen in children with CAS. Findings supported cross-linguistic applicability of CAS speech feature operationalization between English and Swedish speakers. In children with CP±L and SSD, a heightened cooccurrence of CAS, compared to clinical prevalence, should be anticipated. Expressive language ability in children with CAS was worse than receptive language ability. Poor articulation proficiency in children with CP±L did not correlate with orofacial dysfunction. Parental ratings of communication abilities in everyday life added ecological validity and confirmed validity of the clinical assessment procedures.