Working memory span and receptive vocabulary assessment in Urdu speaking children with speech sound disorder

Emerging evidence suggests that impaired speech may be related to reduced working memory (WM). The current study aimed to validate and compare the influence of articulation, short-term memory (STM), WM, and receptive vocabulary abilities of Pakistani children with speech sound disorder (SSD; N = 50) versus typically developing (TD; N = 30) children aged 7-13 years. Assessments included the Test for Assessment of Articulation and Phonology in Urdu (TAAPU), Peabody Picture Vocabulary Test-4, translated to Urdu (U-PPVT-4), and Digit Memory Test (DMT) used to determine speech articulation, receptive vocabulary, and memory abilities respectively. The percentage correct consonants (PCC) score was used to divide the SSD group further into SSD severity groups. The TD and SSD groups significantly differed in performance on all tasks (p < 0.05). Moreover, the SSD severity groups showed significant differences (p < 0.0001) in performance on different components of TAAPU (total errors and substitution errors) and DMT tasks. However, the SSD severity groups did not show significant differences in performance on the U-PPVT-4. Correlational analyses indicate statistically significant correlations of PCC with STM, WM, and receptive vocabulary. Regression analyses suggested that both WM and STM contribute to speech intelligibility in children with SSD. Our findings in Urdu-speaking children support previous results in English-speaking children suggesting the articulation skills, receptive vocabulary, STM, and WM were less developed in children with SSD than in TD children.