The Relationship Between Sensory Processing, Physiological Stress, and Sleep Quality In Children with Autism Spectrum Disorder

Background:  Many children with ASD experience sleep disorders such as frequent night wakening, difficulty getting to sleep¹. They also demonstrate physiological and behavioral responses to sensory stimulation that are different from typical children (TYP)². Atypical sensory processing, specifically sensory sensitivity, has been suggested as a contributing factor to sleep problems in some children³. Both sleep and sensory processing have been linked to overall arousal and the stress hormone cortisol^4,5. Here, we posited that hypersensitivity, high physiological arousal, and high nighttime salivary cortisol would predict sleep problems identified in children with and without ASD.

Objectives:  1) Elucidate the relationship(s) between responses to sensory stimuli and problem sleep behaviors in children with ASD; 2)identify which behavioral, neuroendocrine, and physiological variables best predict good sleepers and poor sleepers.

Methods:  Participants were fifty five children, 6-12 years of age (ASD=27, TYP=28). All children were screened for normal intelligence using the Leiter-R non-verbal scale of intelligence. ASD diagnosis was made by using the ADOS or ADI-R and confirmed through proof of documentation. A cross sectional repeated measures design was used. Statistical analysis included bivariate correlations, multiple analysis of variance (MANCOVA) models, and logistic regression.

The Sensory Challenge Protocol (SCP)⁶, a series of eight sensory stimuli in six sensory domains presented in a laboratory setting while physiological data is collected, was administered. Tonic arousal was measured using baseline electrodermal activity (EDA) and baseline/diurnal salivary cortisol. Electrodermal response magnitude (EDR) and post-challenge salivary cortisol reflected response to SCP. Sensory Profile (SP) quadrant scores (Sensory Sensitivity/SS, Sensory Avoiding/SA, Sensation Seeking/SSk, Low Registration/LR) reflected sensory processing abilities. A sleep index was calculated from questions related to sleep behaviors (nightmares, overtired, sleeps less than most kids, sleeps more than most kids, talks or walks in sleep, and trouble sleeping) on the Child Behavior Checklist.

Results:  Children with ASD had a higher prevalence of atypical sensory responses and sleep disturbances. SA correlated most strongly with sleep problems in children with ASD; SS and SSk behaviors correlated most strongly with sleep difficulties in TYP children. Looking across groups, poor sleepers demonstrated higher afternoon salivary cortisol, greater EDR magnitude, and higher cortisol post-sensory challenge. Cortisol, EDR, and SP measures predicted good sleepers from poor sleepers with 85.7% accuracy.

Conclusions:  Sleep constitutes an area of concern for ASD. This research documents specific sensory processing behaviors linked to sleep disturbances in ASD and TYP, and characterizes poor sleep physiologically. Further examination of a sleep/sensory processing link may inform both intervention and future studies.

References

1. Krakowiak, P., et al. J Sleep Res, 17(197), 206, 2008.

2. Ben-Sasson, A., et al. JADD, 39(1), 1-11, 2009.

3. Milner, C. E., et al. Neuroreport, 20(3), 331-336, 2009

4. Reynolds, S., et al. JAD, doi:10.1177/1087054708329906, 2009.

5. Schoen, S. A., et al. Front  Int Neurosci, 3(29), 2009.

6. Miller, L. J., et al. In Understanding the nature of sensory integration with diverse populations (Schaaf, Smith-Roley, Blanche, eds) (pp. 57-88) Therapy Skill Builders, 2001.