Appraising the need for audiological assessment before autism spectrum disorder referral.

Objectives: Mandatory audiological testing before autism spectrum disorder (ASD) assessment is common practice. Hearing impairment (HI) in the general paediatric population is estimated at 3%; however, hearing impairment prevalence among children with ASD is poorly established. Our objective was to determine which children referred for ASD assessment require preliminary audiological assessment.

Methods: Retrospective chart review of children (n=4,173; 0 to 19 years) referred to British Columbia's Autism Assessment Network (2010 to 2014). We analyzed HI rate, risk factors, and timing of HI diagnosis relative to ASD referral.

Results: ASD was diagnosed in 53.4%. HI rates among ASD referrals was 3.3% and not significantly higher in children with ASD (ASD+; 3.5%) versus No-ASD (3.0%). No significant differences in HI severity or type were found, but more ASD+ females (5.5%) than ASD+ males (3.1%) had HI (P<0.05). Six HI risk factors were significant (problems with intellect, language, vision/eye, ear, genetic abnormalities, and prematurity) and HI was associated with more risk factors (P<0.01). Only 12 children (8.9%) were diagnosed with HI after ASD referral; all males 6 years or younger and only one had no risk factors. ASD+ children with HI were older at ASD referral than No-ASD (P<0.05).

Conclusions: Children with ASD have similar hearing impairment rates to those without ASD. HI may delay referral for ASD assessment. As most children were diagnosed with HI before ASD referral or had at least one risk factor, we suggest that routine testing for HI among ASD referrals should only be required for children with risk factors.