Relationship Between Sleep and Behavior in Autism Spectrum Disorder: Exploring the Impact of Sleep Variability

Abstract

Objective: The relationship between sleep (caregiver-reported and actigraphy-measured) and other caregiver-reported behaviors in children and adults with autism spectrum disorder (ASD) was examined, including the use of machine learning to identify sleep variables important in predicting anxiety in ASD.

Methods: Caregivers of ASD (n = 144) and typically developing (TD) (n = 41) participants reported on sleep and other behaviors. ASD participants wore an actigraphy device at nighttime during an 8 or 10-week non-interventional study. Mean and variability of actigraphy measures for ASD participants in the week preceding midpoint and endpoint were calculated and compared with caregiver-reported and clinician-reported symptoms using a mixed effects model. An elastic-net model was developed to examine which sleep measures may drive prediction of anxiety.

Results: Prevalence of caregiver-reported sleep difficulties in ASD was approximately 70% and correlated significantly (p < 0.05) with sleep efficiency measured by actigraphy. Mean and variability of actigraphy measures like sleep efficiency and number of awakenings were related significantly (p < 0.05) to ASD symptom severity, hyperactivity and anxiety. In the elastic net model, caregiver-reported sleep, and variability of sleep efficiency and awakenings were amongst the important predictors of anxiety.

Conclusion: Caregivers report problems with sleep in the majority of children and adults with ASD. Reported problems and actigraphy measures of sleep, particularly variability, are related to parent reported behaviors. Measuring variability in sleep may prove useful in understanding the relationship between sleep problems and behavior in individuals with ASD. These findings may have implications for both intervention and monitoring outcomes in ASD.

Keywords: ASD; actigraphy; anxiety; hyperactivity; irritability; sleep; variability.

FIGURE 1

Sample ABI web-based format to capture ASD symptoms. ABI, Autism Behavior Inventory; ASD, autism spectrum disorder.

FIGURE 2

Cumulative Distribution Frequency (CDF) of ABI SR sleep for TD and ASD participants at baseline. The CDF plot for ASD (or TD) indicates the proportion of ASD (or TD) participants with less than or equal to a given value of ABI sleep item. For example, approximately 57% of ASD (or 91% of TD) participants have ABI Sleep score less than or equal to a value of 3. ABI, Autism Behavior Inventory; ASD, autism spectrum disorder; TD, typically developing.

FIGURE 3

Variance inflation factor of features after they were corrected for multicollinearity and near zero variance. ADOS CSS, Autism Diagnostic Observation Schedule calibrated severity score; CV, coefficient of variation; IQ, intelligence quotient; SD, standard deviation.

FIGURE 4

Elastic net model construction and evaluation for anxiety prediction. Model used pre-processed actigraphy measures and ABI sleep items from midpoint and endpoint visits, in addition to age, sex, IQ and ADOS CSS total scores. ABI, Autism Behavior Inventory; ADOS CSS, Autism Diagnostic Observation Schedule calibrated severity score; CV, coefficient of variation; IQ, intelligence quotient; minMSE, minimum cross-validated mean squared error; MSE, mean squared error.

FIGURE 5

Cross-validated MSE for the best model at various levels of regularization. Green circle and dashed line denote λ with minimum cross-validated MSE. Blue circle and dashed line denote λ with minimum cross-validated MSE plus one standard deviation. α = 1 was obtained for this model. minMSE, minimum cross-validated mean squared error; MSE, mean squared error.

FIGURE 6

Normalized importance of features on anxiety prediction. Each feature was assigned an importance score from predictions obtained from 100 test sets. ABI sleep item and standard deviation of sleep efficiency were found to be dominant predictors of CASI Total. ABI, Autism Behavior Inventory; ADOS CSS, Autism Diagnostic Observation Schedule calibrated severity score; CASI, Child Adolescent Symptom Inventory; CV, coefficient of variation; IQ, intelligence quotient; SD, standard deviation.