Comparing DDK rate variability in typically developing children in central Scotland

This study investigated the variability of diadokochinesis (DDK) rates among 5-6, 7-8, and 9-10 year old school children to determine how it changes across different ages. Previous research on DDK with typically developing children has identified a developmental trajectory of increased DDK rate with age. However, considerable variability within age groups has also been noted, posing challenges in establishing normative ranges of speech motor performance, beneficial for diagnosing motor speech disorders.
DDK data was collected from 77 children attending Scottish primary schools aged 5 to 10 (mean = 7 years; 9 months, SD= 1.75). The DDK task was conducted and recorded through an iPad and included repetitions of /pɛ/, /tɛ/, /kɛ/ single syllables and the trisyllable /pɛtɛkɛ/ sounds. Acoustic and derived measures, including mean syllable duration and DDK rate, were analysed.
Results show significant differences in DDK rates and syllable durations across age groups, with 7-8-, and 9-10 years olds showing faster DDK performances than 5-6 year old children. The study highlights greater variability in DDK rates of 9–10-year-old children compared to younger age groups, which emphasizes the need for further investigation of the role of variability in determining children’s development of articulatory stability.