Executive Function
Executive function (EF) is a broad domain that includes skills to guide goal-directed behavior, including the ability to shift tasks, update information into working memory, and inhibit responses.47-48 EF has been well-researched in children with SDB.11,14,16-17,20,21,46 Compared to normative data, most studies report average abilities to plan and monitor tasks,11,17,21 think flexibly,16 problem-solve effectively,20 and sequence tasks.21Other studies reported impairments in these same domains.14,46 One recent study reported that children with SDB fell in the bottom 25% on tasks that measured mental flexibility and problem solving compared to normative data.46 Another study supported these results with findings of reduced problem-solving abilities in children with SDB, compared to normative data.14
Multiple studies that included a control group reported differences in EF capabilities for children with and without SDB. In some studies, SDB groups performed worse than controls in general attention/EF domains,17,19 specific planning and monitoring tasks,9,17 and efficiency tasks.14Other studies found no differences on measures of planning,14,21 organization,14,21and verbal fluency.14 A recent meta-analysis investigated differences in EF between children with SDB and controls. They reported a medium effect size in the domain of generativity.49 No significant differences were found on standardized measures of inhibition, working memory, shifting, or vigilance.49
Studies that investigated the influence of SDB severity level on EF reported more errors on cancellation tasks in children with mild, compared to moderate SDB,16 and greater impairment on problem-solving tasks in individuals with severe compared to moderate or mild SDB.11 Others reported no differences across SDB severity levels for sequencing,21 planning,11,14 and organizing.11,14Therefore, preliminary research suggests that children with all levels of EF severity may demonstrate reduced executive abilities in domains including but not limited to planning, organizing, inhibition, and problem solving.
Numerous studies investigated associations between SDB respiratory parameters and EF deficits. Some studies reported no association between respiratory parameters and EF.5,14 Other studies reported that a higher arousal index was associated with decreased mental flexibility,20 planning,17organization,17 difficulty solving complex tasks,46 and increased reaction time.46 Additional respiratory parameters such as AHI,20 slow wave activity,46 and oxygen desaturation46 have also been related to executive dysfunction in this population. Taken together, the literature indicates that sleep duration and indices of respiratory status are associated with executive dysfunction across multiple domains in children with SDB.
Kaihua et al50 investigated indicators of executive dysfunction in children with SDB using event related potentials (ERP). Using an electroencephalograph (EEG), the authors measured two constituents of ERP (N2 and P3 amplitude and latency) while children were completing a Go/No Go task.50 During the Go task, children with SDB demonstrated elevated amplitude and latency of P3, indicating a higher level of attentional investment and delayed response time compared to controls.50 During the NoGo task, children with SDB demonstrated reduced N2 amplitude and increased P3 latency, indicating reduced impulse inhibition and longer response time compared to controls.50 This suggests that children with SDB require additional time and additional attentional capacity to complete inhibitory tasks, compared to children without SDB.50 The authors conjectured that intermittent sleep and hypoxia might influence neural circuitry in children with SDB, contributing to the increasing amplitude and latency of P3 and decreased amplitude of N2.50
There were large discrepancies in the literature regarding the impact of SDB on EF. These discrepancies were likely influenced by limited sample sizes,16,20,50 a large variety of EF measures, wide ranging discrepancies in SDB definitions and criteria, and lack of control for important covariates including BMI16 and SES.11 In addition, multiple studies recruited participants at-risk for SDB through clinical referrals,14,16,20,46,50 rather than the community.11,17,19