Age of Diagnosis of Autism Spectrum Disorders in Children with Hearing Loss

Background:  Upwards 4% of children who are deaf/hard of hearing have co-existing autism spectrum disorder (ASD).  Children with the hearing loss (HL) tend to receive diagnoses of ASD at older ages than hearing children.¹    This disparity likely relates to the complexities of determining whether speech/language and social delays can be accounted for by their HL, or whether they  might be indicative of a comorbid ASD diagnosis.  With universal newborn hearing screening, the age of identification of HL has decreased, making early language acquisition for deaf/hard of hearing children approaching hearing children’s developmental trajectory.²  This advance has relevance to potentially decreasing the age of ASD diagnosis in these children.

Objectives: Investigate age of ASD diagnosis among children with HL; Explore factors associated with later diagnosis.

Methods: Children with dual diagnosis of hearing loss and ASD were identified from a clinical developmental pediatric database of >600 children with any degree of permanent HL.  Children completed a comprehensive evaluation for an ASD using standardized autism evaluations (Autism Diagnostic Observation Schedule, language and psychological  testing).  As evaluation tools have not been validated on children with HL, a team of professionals representing expertise in ASD and expertise in HL arrived at a consensus opinion for the diagnosis of ASD.  Descriptive statistics included medians with ranges and frequencies with percentages. This study was approved by the Institutional Review Board at Cincinnati Children’s Hospital Medical Center.

Results: Among 23 children with ASD and HL, 74% were male.  Most (65%) had profound HL, 14 (61%) children had a cochlear implant, and 3 children had no amplification for HL. The etiology of HL was syndrome or CMV for 30% of children and unknown for 30%. The median non-verbal IQ was 77 (range 27-97).  The ADOS was administered to 19 of the 23 children.  Most children who required Module 1 had profound HL (12/16).  The median age of diagnosis of HL was 14 months (range 1-71) while the median age of ASD diagnosis was 57.5 months (range 33-106).  Only 23% (n=6) children were diagnosed with ASD <48 months of age and 55% <6 years.  Cognitive levels were not correlated with age of ASD diagnosis (Spearman rho=-0.004).  The median time between identification of HL and ASD diagnosis was 40 months (range 6-101) with the diagnosis of ASD occurring after the identification of HL in every child.  Children with cochlear implants appeared to be identified with ASD at earlier ages than those with hearing aids (54 vs. 78 months, p=0.17), though not statistically significant.

Conclusions: Children with HL and a co-existing ASD are challenging to evaluate and tend to receive a diagnosis of ASD at older ages.  This late diagnosis may impact access to early and appropriate interventions for the ASD.  In addition, children who received cochlear implants completed a multidisciplinary evaluation including a developmental pediatrician, which may have provided closer monitoring of speech and language progression and subsequently led to an earlier ASD diagnosis.  Future studies on the validity of autism-specific screening and assessments for children with hearing loss are warranted.