JMIR Publications

ABSTRACT

Childhood apraxia of speech (CAS) is a motor-based speech sound disorder with a core impairment in planning and/or programming of spatiotemporal parameters of speech movement sequences. CAS may cause deficits in both segmental and suprasegmental components of speech, and it can severely affect children’s ability to speak intelligibly and communicate effectively, and impact their quality of life. Assessment tasks, such as the Maximum Performance Tasks (MPT) and the Syllable Repetition Task (SRT), examine children’s segmental sequencing skills to assist with the diagnosis of CAS. Suprasegmentally, lexical stress errors have been reported as a core feature and aid diagnosis of CAS. However, there are challenges in diagnosing CAS in children who speak tonal languages like Cantonese. In Hong Kong, although MPT and SRT have been used clinically to diagnose CAS in Cantonese-speaking children, their validity in assessing segmental sequencing skills in Cantonese-speaking children with CAS has not been reported. There is an urgent need of such investigations. Suprasegmentally, even though lexical stress is not found in Cantonese, a recent study has reported lexical tone errors in Cantonese-speaking children with CAS. Furthermore, deficits in pitch-variation skills were found in Cantonese-speaking children with CAS using a tone sequencing task (TST). It is hypothesised that there is a universal deficit in pitch-variation skills among speakers with CAS of tonal and non-tonal languages. Pitch-variation skill presents in Cantonese lexical tones and English lexical stress patterns. Further investigations on pitch-variation skills using TST in Cantonese-speaking children with CAS may shed light on suprasegmental deficits in tonal languages, as well as contribute to development of a valid diagnostic tool for CAS in children who speak tonal languages, such as Vietnamese, Thai, and Mandarin. This study aims to examine the diagnostic potential of the MPT, SRT and TST in diagnosing Cantonese-speaking children with CAS, and to investigate pitch-variation skills in Cantonese-speaking children with and without CAS. Thirty children with CAS and three groups of age-and-gender-matched controls (speech sound disorders [SSD] group, non-CAS SSD co-occurring with language impairment [S&LI] group, and typical development [TD] group) will be recruited. All participants will perform MPT, SRT, and TST. Their performance on these measures will be perceptually judged and acoustically measured. It is anticipated that Cantonese-speaking children with CAS will have poorer pitch-variation skills than the control groups, while MPT, SRT and TST will be appropriate diagnostic tools for identifying CAS in Cantonese-speaking children.