Why do we need better diagnostics for ASD?

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Zafer Elcik looks at the gender bias in the diagnosis of ASD and highlights recent research which indicates presentation of ASD in girls may be different, and therefore missed by normal diagnostic methods.

Autism Spectrum Disorders (ASD) are difficult to diagnose because there is no definitive test – like a blood test – to conclusively confirm that a person has this condition. ASD presents differently in each individual, so although there are diagnostic tools and guides that clinicians use to observe for certain markers of the disorder, the diagnosis can still be missed depending on how a clinician approaches the condition.

Currently, one in 44 children in the US is identified with an ASD. When it comes to sex breakdown, boys are diagnosed four times as frequently compared to girls. When ASD was first described by Leo Kanner, MD in 1943, he noticed social and communication deficits and that boys were affected four times more frequently than girls. This, in turn, caused most of the autism research conducted to focus only on how the disorder presents in males. There is also an obvious effect of the description of the condition on later diagnostic methods.

ASD is a big diagnosis. When parents get the diagnosis, they then have to figure out which services they need to provide their kids in terms of healthcare and educational support. When there appears to be a barrier for girls and women in terms of getting this diagnosis and accessing the subsequent support that is needed, we have to ask ourselves: what’s missing in the diagnostic process?

Today, researchers and clinicians are more aware of this discrepancy, that the current diagnostics, criteria, approaches, and interventions are not developed with autistic girls and women in mind. We have to get over the perception that autism is a “male condition” that also affects females.

One of the reasons there is a persistent difference between boys and girls relies on that first description, based on the presentation in boys and men. The estimations are calculated with a bias of the condition. This revelation prompted researchers to decrease or eliminate this bias, and they found that the ratio of gender difference in prevalence of ASD could be as low as 1.8 to 1.

Building diagnostics upon male-centric deductions and descriptions affects many steps before getting a diagnosis. Even when suspected of having the condition and referred, girls are still being diagnosed late. Moreover, it causes parents and caregivers to miss symptoms or interpret them differently, and so not mention their concerns during their first visits to the doctor.

A recent study published on February 15, 2022 suggests that we need to think differently about the diagnostic methods. Researchers analysed MRI scans of a total of 773 children, 637 of which were boys and 136 were girls. Even during the study, researchers were challenged with including a sizable number of girls in the study.

When the researchers tried to analyse the images through existing and traditional methods, they found that these relied on the number of groups to be roughly equal. However, when there is a four-fold difference between the sizes of the group, the algorithm would again point to “male autism.” Then a new statistical approach by Tengyu Ma, PhD at Stanford, also a co-author on the study, was applied to the data.

This newly developed algorithm could distinguish between boys and girls with a high accuracy rate of 86%. When tested on the images of the brains of typically developing boys and girls, the algorithm could not make a distinction, showing that the difference found between the sexes is in fact unique to autism.

The results researchers found were compelling: autistic girls were found to have different patterns of connectivity compared to boys. These different patterns were observed in various brain centres like language, motor, and visuospatial attention systems. Also, the largest difference between the sexes among autistic children was found in a group of motor areas, including the primary motor cortex, where a signal is sent for the production of skilled movements of the muscles and the body.

Researchers also found a link between the severity of the motor symptoms marking autism in girls with the differences in motor centres. This means that the brain patterns observed in autistic girls that were most similar to autistic boys tended to present the most pronounced motor symptoms. The language areas were also found to be different between boys and girls with autism.

For decades, we have assumed that autism is more prevalent in boys than in girls. This hypothesis, that stemmed from the initial description of the condition, has been further perpetuated by following studies that focused on boys or did not accurately represent girls. The data may have been analysed with a bias towards autism being a male condition.

Today, we realize that sex ratio estimation may not be entirely accurate. There are many factors at play, and bias in diagnostics is one of them. The differences that are laid out in front of our eyes through this recent study confirm that the differences seen in the brain regions are linked to the clinical symptoms of autism.

All in all, there need to be different tests for autistic girls, and we need a shift in perspective when it comes to identifying the hallmark symptoms of autism spectrum disorder. The findings of this study, and hopefully more studies to be conducted later on to increase our understanding, should be a guide for the entire medical community to improve and better the diagnostics that are in use today, as well as the treatment and intervention options available for girls and women to account for the behavioural and neurological differences between the two sexes.

Zafer Elcik
Author: Zafer Elcik

Zafer Elcik
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Zafer Elcik is the CEO and co-founder of Otsimo, an EdTech company that focuses on developing special education apps with the aim of democratising special education
by making it affordable and accessible for everyone.

Website: otsimo.com/en/ Twitter: @Otsimo Facebook: @Otsimo

 

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