Department of Special Education and Communication Disorders



Kelly Farquharson

Tiffany P. Hogan

Date of this Version



Published in International Journal of Speech-Language Pathology 20 (2018), pp 422–433 doi: 10.1080/17549507.2017.1293159


Copyright © 2017 The Speech Pathology Association of Australia Limited. Published by Informa UK Limited, trading as Taylor & Francis Group. Used by permission.


Purpose: The aim of this study was to explore the role of working memory processes as a possible cognitive underpinning of persistent speech sound disorders (SSD).

Method: Forty school-aged children were enrolled; 20 children with persistent SSD (P-SSD) and 20 typically developing children. Children participated in three working memory tasks – one to target each of the components in Baddeley’s working memory model: phonological loop, visual spatial sketchpad and central executive.

Result: Children with P-SSD performed poorly only on the phonological loop tasks compared to their typically developing age-matched peers. However, mediation analyses revealed that the relation between working memory and a P-SSD was reliant upon nonverbal intelligence.

Conclusion: These results suggest that co-morbid low-average nonverbal intelligence are linked to poor working memory in children with P-SSD. Theoretical and clinical implications are discussed.