The Relation Between Poor Sleep and Executive Functioning in Children with Autism Spectrum Disorders

Background: Poor sleep has been associated with executive function impairments in clinical and typical populations. Specific effects of sleep among youths with autism spectrum disorders (ASD) are less clear. Cognitive and behavioral rigidity, and working memory weaknesses are aspects of executive function frequently observed in ASD. 

Objectives:  (1)Examine whether poorer sleep is associated with greater impairment in emotional lability, cognitive and behavioral rigidity, working memory, and overall executive function impairment among ASD and Typically Developing Children (TDCs).  (2)Test ASD as a moderator of the association between sleep and executive functions.

Methods:  Participants were 100 youths aged 6 to 17 with ASD (n= 58; 83% male; mean age 9.3±2.8) or TDC (n=42; 62% male; mean age =9.2±2.3). ASD diagnoses were made based on ADOS, ADI-R, and clinical judgment. Youths were administered the DAS II to assess their General Cognitive Abilities (ASD=100.6±19.1; TDC=100.0±11.6).  Parents completed (1) the Behavior Rating Inventory of Executive Function (BRIEF) which yielded a measure of cognitive and behavioral rigidity (Shift Scale; ASD=68.2±13.2; TDC=44.5±8.4), emotional lability (Emotional Control scale; ASD=62.1±11.1; TDC=44.8±8.3), working memory (Working Memory scale; ASD=65.3±10.3; TDC=45.9±8.3) and overall executive function impairment (Global Executive Composite; ASD=67.3±9.3; TDC=44.1±8.6) (higher scores indicated greater impairment); (2) the Children’s Sleep Habits Questionnaire (CSHQ) which yielded a total subscale score (ASD=47.7±11.8; TDC=43.2±12.3; higher score indicated poorer sleep). Hierarchical regression examined “predictors” of specific and overall executive function impairment, by entering control variables of age, sex, and cognitive functioning (Steps 1-3), followed by group (ASD or TDC) (Step 4), CSHQ score (Step 5), and sleepxgroup Interaction term  (Step 6).

Results:  Main effects were found, such that group (ASD) and sleep were both significant independent “predictors” of Emotional Control, Shift, Working Memory, and Global Executive Composite scores (p<.001 for all β’s).  Significant moderations for group were found for Shift, Working Memory, and Global Executive Composite scores.  Posthoc analyses revealed that poorer sleep and higher Shift scores were associated (β=.50, p<.001) for the ASD group but not the TDC group.  Poorer sleep explained 17.1% of variance in working memory among youths with ASD (β=.44, p<.001), but was not significant among TDCs.  Lastly, poorer sleep and greater levels of impairment in Global Executive Composite scores were positively associated with ASD (β=0.55, p<.001) and negatively among TDCs (β=-.04, p<.001).

Conclusions: Poorer sleep and poorer emotional control were associated for all youths. Poorer sleep was not associated with impaired Shift, Working Memory, and Global Executive Composite scores in TDCs.  It is unclear if findings are due to a lack of association, or smaller variance in sleep among the TDC sample.  Poorer sleep was associated with more impaired Shift, Working Memory, and Global Executive Composite scores in the ASD group. These scores reflect functions that are associated with the core deficits in ASD that have a significant impact on academic, community, and social functioning.  We hypothesize that poor sleep causes problems with day-to-day cognitive and emotional control that negatively impacts adaptive functioning and quality of life.  If true, more effort should be devoted to sleep intervention for ASD.