Diadochokinetic skills: normal and atypical performance in children aged 3-5 years.

Although diadochokinetic (DDK) tasks are a popular assessment tool in clinical practice, the interpretation of their results is often limited and obscure. This paper examines the development of DDK skills in normally developing children (age range 3-5 years) for comparison with three case studies of children with specific speech difficulties. The results are presented in terms of accuracy, rate and consistency of response. The normally-developing children increased the accuracy and consistency but not the rate of their responses between the ages of 3 and 5 years. The three case study children (matched on severity of speech difficulty) not only performed differently from control children on some of the measures but also performed differently from each other. The diagnostic value of a developmental DDK profile is discussed.