Verbal Ability As a Predictor of Sleep and Gastrointestinal Comorbidities in Children with Autism Spectrum Disorder

Background:  Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder with known medical comorbidities.  Associations between ASD, gastrointestinal dysfunction, sleep difficulties, and verbal communication ability have been suggested in previous studies.  It is hypothesized that the ability of ASD patients to communicate verbally influences the ability of parents and physicians to recognize the presence of comorbid conditions.

Objectives:  This study seeks to identify the prevalence of gastrointestinal dysfunction and concurrent sleep difficulties in ASD patients, and subsequently determine if the ability to communicate verbally alters the prevalence of these comorbidities.

Methods:  The Thompson Center for Autism and Neurodevelopmental Disorders’ patient database provided a study population of 338 eligible patients (Autism= 197; Aspergers= 34; PDD-NOS= 107).  Parent-reported questionnaires from individual ASD patients were assessed for:  gastrointestinal dysfunction (constipation, loose stools, other generalized GI complaint), sleep dysfunction (trouble falling asleep, trouble sleeping in one’s own bed, achieving inadequate hours of sleep, nighttime awakening), and verbal communication status (ADOS module 1= nonverbal, ADOS modules 2-4= verbal).  Data was analyzed using Microsoft Excel and SPSS statistics software.

Results:  Of the 338 study patients, 138 (40.8%) reported gastrointestinal dysfunction, and 139 (41.1%) reported problems with sleep.  This study identified an increased prevalence of sleep dysfunction in patients with concomitant gastrointestinal difficulties (42.0%) compared to patients without reported gastrointestinal problems (40.5%).  There was an increased prevalence of gastrointestinal dysfunction in patients with adequate verbal communication skills (73.2%) compared to patients who were classified as non-verbal (26.8%).  In addition, there was an increased prevalence of sleep dysfunction in verbal patients (62.6%) versus non-verbal patients (37.4%).

Conclusions:  This study concludes that the prevalence of sleep difficulties in ASD patients is enhanced by concurrent gastrointestinal dysfunction, while verbal communication status serves as a positive predictor of these ASD comorbidities.  These findings suggest that the diagnosis of gastrointestinal or sleep dysfunction may be overlooked in many nonverbal ASD patients, indicating the need for modification of screening procedures for ASD comorbidities currently used in clinic.  Future analyses of larger patient populations such as that provided by the Autism Treatment Network database, or physician-completed patient data forms rather than parent-reported questionnaires would serve as a strong comparative tool to the findings of this study.