Early middle ear disease in children with Autistic Spectrum Disorder

Background: The aetiology of the autistic spectrum disorders (ASD) is largely unknown.

Objectives: To assess whether signs and symptoms related to common health problems in childhood are associated with ASD.

Methods: The Avon Longitudinal Study of Parents and Children (ALSPAC; n=14000) started in early pregnancy.  Data collected on the child during the first years of life included signs and symptoms of the infant/child.  A 10% subsample underwent tympanometry which identifies middle ear disease (9 occasions) and word recognition tests (2 occasions) from 8-61 months.

Results: Only two of the 9 signs and symptoms in the first 42 months were consistently reported more often by mothers of ASD children. Associations of ‘ear discharge comprising pus not wax’ with ASD were observed after 6 months (P<0.05). Mothers also reported failure of their ASD children to react to noise from 18 months (P<0.001).  By age 38 months, 80% of ASD children had been suspected of having a hearing deficit. The frequency of normal tympanograms up to 61 months was inversely associated with ASD (OR zero occurrences=25 [95% CI 2.58, 242]; OR for one or two occurrences=4.14 [0.34,50.46]; P trend=0.003). Hearing tests involving speech showed significant impairment at 43 and 61 months (P<0.01). By 7 years of age however ASD children had normal tympanometry and normal audiograms.

Conclusions: We have shown that the only common sign or symptom associated with ASD related to middle ear disease. Objective tympanograms confirmed the association. Affected children showed signs of hearing loss during these early years and were shown to be less able to distinguish speech. This suggests that affected children are less able to hear speech distinctly in early life, and raises the hypothesis that inability to hear during a key period of development may result in the development of traits associated with ASD in susceptible children.