The Relationship between Verbal Fluency, Language and Executive Musical Working Memory in Children with Autism Spectrum Disorder

Background: Verbal fluency requires the ability to generate semantic responses to a target category. Studies have found both intact and impaired verbal fluency skills in children with autism spectrum disorder (ASD). Yet, deficits in executive functioning, social communication and often receptive and expressive language are well documented. Language skills may play a role in verbal fluency and executive functioning. However, the role of language proficiency in the relationship between verbal fluency and executive functioning in children with ASD is not well known. Language skills and executive functioning in children with typical development (TD) show improvement following musical training. Given musical strengths of children with ASD, we study the relationship between verbal fluency and executive function as used when playing music, i.e., executive musical working memory.

Objectives: To examine the relationship between verbal fluency and executive musical working memory of children with ASD with low and high levels of language skill.

Methods: Children with ASD (N=30) ages 8 to 12 years old participated in the study. They completed the Verbal Comprehension Index (VCI) of the Weschler Intelligence Scale for Children (WISC-V), and were divided into low ( VCI <75, n=16) or high VCI groups (VCI > 75, n=14). Within each group, we examined the relationship between verbal fluency, as measured on the Delis-Kaplan Executive Function System (DKEFS) Category Fluency condition, and executive functioning, as measured by performance on an executive musical working memory task, measured as the total of their combined performance when judging whether 2 consecutive sequences of musical pitches were the same or different (calculated as Hits minus False Alarms ratio).

Results: DKEFS Category Fluency raw scores in the ASD group with lower VCI were significantly related to performance on the executive musical working memory task F(2,13)=6.032, p=.014, when accounting for age, with higher scores on one task associated with higher scores on the other task. In contrast, DFEKS Category Fluency in the ASD group with higher VCI was not significantly related to performance on the executive musical working memory task F(2,11)=.881, p=.442. We repeated analyses dividing groups with a cut-off VCI at 70 instead of 75 and found the same pattern of results.

Conclusions: These results suggest that language levels (VCI) influence the relationship between verbal fluency and executive functioning (executive musical working memory) in children with ASD, such that this relationship is stronger for children with ASD with language impairments (lower VCI levels) than those without language impairments. Findings shed light on the debate over verbal fluency abilities in children with ASD, suggesting that VCI and executive functioning skills should be considered when assessing verbal fluency, given the observed variation according to language levels. Finally, these results have implications for treatment for language and social communication in children with ASD and language impairments. Children with ASD and lower levels of VCI, as opposed to higher levels of VCI, may benefit more from musical training, known to improve verbal skills and auditory working memory in children with TD, to enhance their verbal fluency and social communication abilities.