delayed diagnoses: the risk of being overlooked

Authors: Wae Man Chan, Veronica du Plessis, & Liv Mace

Our recent discussion focused on an article titled “Diagnostic Overshadowing: A Delayed Diagnosis of Autism Spectrum Disorder in a Child who is Deaf,” which highlighted the concern of how similar and overlapping traits between autism and hearing loss can lead to a delay in accurate diagnoses. When clinicians attribute behaviors to only hearing impairment, characteristics of autism can be overlooked, leading to the missed opportunity for early support and intervention. 
 
Why Diagnostic Overshadowing Happens: 
Diagnostic overshadowing can occur when symptoms of a pre-existing diagnosis actually reflect a separate condition. In healthcare, this can often affect individuals that present complex symptoms, such as co-occurring developmental delays, seizures, or sensory impairments. Clinicians may focus more on the most urgent or visible symptoms, such as hearing loss or seizure activity, rather than evenly assessing all the symptoms.  

In addition, not all diagnostic tools are adapted for people with multiple disabilities. For instance, standard assessments for autism spectrum disorder (ASD) may not accurately consider those that may be deaf or use sign language, since many assume spoken communication is the norm. Social cues in sign language, such as facial expression and eye contact, may carry different meanings than in spoken language, yet these distinctions are often unaccounted for in standardized tools like the Autism Diagnostic Observation Schedule (ADOS).
 
Overlapping Signs of Autism versus Hearing Loss: 
Some traits of ASD and children who are deaf or hard of hearing (DHH) can be similarly presented. For example, differences in prosody, the pattern of rhythm or melody of speech, are common in both groups. This means that an individual who is deaf or hard of hearing may verbally communicate using a “deaf accent,” which might be mistaken for a speech pattern consistent with autism. 

Traditional diagnostic tools present another barrier. Assessments like the ADOS were developed with the assumption that those being evaluated did not have any hearing issues. They rarely consider sign language, interpreters, or alternative forms of communication. This lack of adaptation can lead to inaccurate evaluations and contribute to a lack of understanding of varying forms of social communication.  

The Impact of a Delayed Diagnosis: 
​A delayed diagnosis of autism can socially, academically, and emotionally affect a child in almost every aspect of life. Without the recognition of their autistic traits, a child may feel misunderstood when in reality they need accommodation and support. Early identification allows families and educators to personalize interventions, including sensory supports and structured learning environments, further supporting autistic children to succeed and feel understood.  

How to Move Toward Better Diagnosis and Care: 
To work on reducing diagnostic overshadowing, clinicians need more inclusive diagnostic tools and broader training. Assessments must be adapted to account for co-occurring conditions, especially when differences in communication can play a significant role. Collaborations between audiologists, psychologists, and educators will help contribute to an integrated and coordinated approach that assesses the child as a whole person rather than a collection of varying symptoms.  

Lastly, education is equally important as clinicians must be trained to recognize the diversity of neurodevelopmental changes and how they can be presented across a spectrum. Clinicians should remain curious, reflective, and open to learning. Ultimately, collaboration is key in leading to better outcomes for many individuals.  

References: 
Dang, Q.-C., Hoffman, M., & St. John, R. (2024). Diagnostic overshadowing: A delayed diagnosis of Autism Spectrum Disorder in a deaf child. Journal of Early Hearing Detection and Intervention, 9(1), 17–21. https://doi.org/10.26077/ed17-2a01