For some children with Childhood Apraxia of Speech (CAS), intervention does not result in significant improvements in articulatory accuracy. Recent literature has proposed that speech consistency may be a valuable alternative outcome measure to demonstrate the efficacy of intervention for these children. The purpose of the study was to investigate the impact of the Nuffield Dyspraxia Programme (NDP-3) on speech consistency as measured by token-to-token and phonemic measures of speech consistency. Two novel phonemic measures of speech consistency were used – the modified Inconsistency Severity Percentage (mISP) and the mISP with consonant clusters (mISPc). The mISP and mISPc were developed to account for all phonemes in a speech sample (i.e., singleton consonants, consonants in clusters, vowels).

Secondary statistical analyses were conducted on data collected from the 14 participants aged 4-12 years old who participated in the McKechnie et al., (2020) RCT. Data pertaining to speech consistency (i.e., Diagnostic Evaluation of Articulation and Phonology (DEAP) – Inconsistency subtest, Goldman-Fristoe Test of Articulation – Second Edition; GFTA-2) were compared between pre-treatment and 1-month post-treatment time points. Correlations between changes in speech consistency and other variables (i.e., age, CAS severity, articulatory accuracy) were calculated.

Significant improvements in speech consistency were present when measured by the Inconsistency Severity Percentage (ISP) and the mISPc. The group of participants who did not improve in articulatory accuracy significantly improved in speech consistency as measured by the ISP. Statistically significant correlations were observed between changes in speech consistency (i.e., mISP and mISPc) and changes in articulatory accuracy (i.e., Percentage of Phonemes Correct).

NDP-3 therapy is associated with some improvements in speech consistency for children with CAS. Phonemic measures best captured such improvements. Speech consistency shows promise as a primary outcome measure of CAS. Future research should continue to investigate the relationship between speech consistency and articulatory accuracy.

At the conclusion of my presentation attendees will take away
1. The relationship between speech consistency and articulatory accuracy should be further investigated, due to its possible clinical implications
2. Speech consistency may improve, even when articulatory accuracy does not
3. Phonemic measures best measure changes in speech consistency