Assessment of verbal and nonverbal cognitive abilities in children with stuttering using 5th edition Stanford Binet

Stuttering is a speech disorder disrupting fluency with implications that could affect psychological, educational, social, and occupational aspects of life. Cognitive functions include mental processes that allows for execution of goal-directed responses in different situations. They are usually referred to as executive functions (EF) which consists of three main components, working memory, cognitive flexibility, and inhibitory control. The Stanford Binet 5th edition (SB5) is an intelligence scale designed to assess various cognitive skills by measuring five main domains that require the administration of these executive skills. Recent research has focused on executive functions skills among children with stuttering (CWS), and how it might affect stuttering development and severity.

The aim of this study was to compare the cognitive verbal and nonverbal skills using the Stanford Binet intelligence quotient test 5th edition (SB5) between children with stuttering (CWS) and children with no stuttering (CWNS) and to assess which of these skills affected stuttering severity among CWS.

A total of 70 children, 40 CWS and 30 CWNS, were assessed using the SB5 test. Further assessment of the CWS was done using the stuttering severity index (SSI) to determine the degree of stuttering. Statistical analysis and comparison were used to determine results and differences in cognitive skills, and regressive analysis was used to determine the most predicative factor in stuttering development and severity.

Showed that CWS performed lower scores than CWNS in all SB5 domains except in non-verbal domain, where the two groups did not differ significantly in their performance. Working memory was the weakest skill among CWS and stood out as the only significant predicative factor in stuttering. Children with severe stuttering performed higher in their total IQ, nonverbal IQ, knowledge, and fluid reasoning than moderate stutterers, having the strongest performance in non-verbal IQ, still none of these domains turned out to be of a predicative significance in severity.

Findings suggest that working memory is the weakest executive skill in CWS as well as other executive functions related to cognitive flexibility compared to fluent controls. Working memory skills are significantly lower in CWS but does not correlate with its severity; whereas the strongest skills, among CWS compared to fluent controls, are in the nonverbal domains.