Monday, May 7, 2018

Applying an Integrative Framework of Executive Function to Preschoolers with Specific Language Impairment

Executive functions refer to those cognitive processes needed to concentrate and pay attention. Core executive functions include inhibition, working memory, and cognitive flexibility. Inhibition refers to the ability to stop paying attention to distractions. Working memory involves the holding and manipulation of information in memory. Cognitive flexibility (or switching) is the ability to flexibly shift between tasks and stimuli, and involves the coordination of multiple executive functions. These abilities support the ability to focus and sustain attention. All of these components are considered interrelated, but separable. Executive functions are important in complex, goal-driven tasks such as school learning.

Executive functions are associated with language learning. Consistent with this notion are findings that children with Developmental Language Disorder (DLD), also known as Specific Language Impairment (SLI), score poorly on some measures of executive functions. Nevertheless, poor scores on executive functions in children with DLD could be due to their poor verbal skills, as many executive functions tasks tap verbal ability. This study addressed this issue by comparing performance of preschool children with DLD on verbal and nonverbal measures of executive functions. A second purpose of the study was to examine a possible hierarchical relationship amongst executive functions with sustained attention underlying working and inhibition, both of which support shifting.

In this study, 26 4- and 5-year-olds diagnosed with DLD and 26 typically developing age-and sex-matched peers completed verbal and nonverbal measures of the following four specific executive function components: sustained selective attention, working memory, inhibition, and shifting. Lower scores for the DLD than typical group were observed on both verbal and nonverbal measures of sustained selective attention and working memory, the verbal inhibition task, and the nonverbal shifting task. These results provided evidence for executive function deficits in preschoolers that are not limited to the verbal domain. A linear relationship was noted however not in the order expected with largest group differences observed for the sustained attention tasks, and smallest for working memory.

Findings of executive function deficits in children with DLD continue to point to the need to investigate impacts for assessment and intervention.

Blogger: Ren Lohmann is an MA student in Linguistics, supervised by Dr. Lisa Archibald.

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