Friday, May 16, 2008
Champagne Terrace/Bordeaux (Novotel London West)
Background: Restricted, repetitive and stereotyped behaviors, interests and activities (RBs) are diagnostic features of autism spectrum disorders (ASD
), yet their presence varies greatly. Animal research suggests a relationship between the presence of increased motor stereotypies and lower levels of the stress hormone cortisol. Studies of children with Fragile X found that higher cortisol levels are associated with more internalizing behaviors while lower levels are associated with frequent eye-gaze aversion behaviors.
Objectives: Examine the relationship between frequency/severity of RBs and cortisol levels in pre-pubescent children diagnosed with an ASD, while controlling for sleep quality.
Methods: Two groups of ASD children (ages 3 to 9 years) with high (n = 7) vs. low (n = 6) RBs were recruited. Cut-off scores for inclusion were defined by taking the upper and lower quartiles of RBS-R total scores from the lead author’s study of 52 ASD subjects. Caregivers completed the RBS-R prior to collecting salivary cortisol samples from their child four times daily (waking, 30 minutes after waking, before lunch and before dinner) for three days and completed sleep diaries. Child’s current autism diagnostic symptoms, adaptive behaviors, puberty and medication status, full-scale IQ score, and socioeconomic status were also collected.
Results: For each of the four time points, cortisol levels were averaged across three days and these average values were entered into a repeated measures ANOVA. Results of this analysis show a trend towards the high RB group having lower cortisol levels than the low RB group (F(1, 11) = 3.5, p = 0.095).
Conclusions: We hypothesize that the RBs observed in the ASD population are self-soothing. Salivary cortisol may prove helpful in elucidating the etiology of repetitive behaviors and therefore assist in designing appropriate treatments.
Sponsor: Developmental Psychobiology Endowment Fund, University of Colorado of Denver School of Medicine, Denver CO