In recent years, researchers studying autism have worked to include more women and girls in their studies. However, despite these efforts, most autism studies consistently recruit small numbers of female subjects or exclude them altogether, according to a new study from MIT.
Researchers have found that a screening test commonly used to determine eligibility for autism studies consistently screens out a much higher percentage of women than men, creating a “leaky pipeline” that results in severe under-reporting. representation of women in autism studies.
This lack of representation makes it harder to develop useful interventions or provide accurate diagnoses for girls and women, researchers say.
“I think the results support a more inclusive approach and a broadening of purpose to end up being less biased in terms of research participation,” says John Gabrieli, Grover Hermann Professor of Health Sciences and Technology and Professor of brain and cognitive. science at MIT. “The more we understand about autism in men and women and non-binary individuals, the better the services and more accurate diagnoses we can provide.”
Gabrieli, who is also a fellow at MIT’s McGovern Institute for Brain Research, is lead author of the study, which appears in the journal autism research. Anila D’Mello, a former MIT postdoc who is now an assistant professor at the University of Texas Southwestern, is the lead author of the paper. MIT Technical Associate Isabelle Frosch, Research Coordinator Cindy Li, and Research Specialist Annie Cardinaux are also the authors of the paper.
Eliminate females
Autism spectrum disorders are diagnosed based on observation of traits such as repetitive behaviors and difficulties with language and social interaction. Doctors can use a variety of screening tests to help them make a diagnosis, but these tests are not required.
For autism research studies, it is common to use a screening test called the Autism Diagnostic Observation Schedule (ADOS) to determine study eligibility. This test, which assesses social interaction, communication, play and repetitive behaviors, provides a quantitative score in each category, and only participants who reach certain scores are eligible to be included in the studies.
In a study exploring how quickly the brains of autistic adults adapt to new events in the environment, scientists in Gabrieli’s lab began to notice that ADOS seemed to have unequal effects on the participation of children. men and women looking. As the study progressed, D’Mello noticed significant brain differences between the male and female study subjects.
To dig deeper into these differences, D’Mello tried to find more female participants using an MIT database of autistic adults who expressed interest in participating in research studies. However, when she sorted the subjects, she found that only about half of the women in the database met the ADOS cut-off scores typically required for inclusion in autism studies, compared to 80% of the men.
“We then realized that there was a gap and that ADOS was essentially weeding out those who ended up participating in the research,” says D’Mello. “We were really surprised at how many men we retained and how many women we lost to ADOS.”
To see if this phenomenon was more widespread, the researchers looked at six publicly available datasets, which include more than 40,000 adults diagnosed with autism. For some of these datasets, participants were screened with ADOS to determine their eligibility to participate in the studies, while for others a “community diagnosis” – diagnosis from a physician or other healthcare provider of health – was enough.
The researchers found that in datasets that required ADOS screening for eligibility, the male-to-female ratio was around 8:1, while in those that only required community diagnosis, the ratios varied d about 2:1 to 1:1.
Previous studies have found differences between behavioral patterns in autistic men and women, but the ADOS test was originally developed using a predominantly male sample, which may explain why it often excludes women from research studies. explains D’Mello.
“There were few females in the sample that was used to create this assessment, so it may not be very good at detecting the female phenotype, which may differ in some respects, mainly in areas like social communication,” she says.
Effects of exclusion
Failure to include more women and girls in autism studies may contribute to gaps in definitions of the disorder, researchers say.
“The way we think about it is that the field may have developed an implicit bias in how autism is defined, and it’s been disproportionately driven by male analysis and male recruitment, and so on,” says Gabrieli. “So the definition doesn’t fit as well, on average, with the different expression of autism that seems to be more common in women.”
This implicit bias has led to documented difficulties in receiving a diagnosis for girls and women, even when their symptoms are the same as those exhibited by autistic boys and men.
“A lot of women could be completely missed in terms of diagnoses, and then our study shows that in the research setting, what’s already a small pelvis shrinks at a much higher rate than men,” says D’Mello. .
Excluding girls and women from this type of research study may lead to treatments not working as well for them, and it contributes to the perception that autism does not affect women as much as men.
“The goal is for research to directly inform treatment, therapies and public perception,” D’Mello says. “If the research indicates that there are no women with autism, or that the brain basis of autism only resembles established patterns in men, then you’re not really helping women as much. than you might be, and you’re not really understanding the truth about what the disorder might be.
The researchers now plan to further explore some of the gender and sex-based differences that appear in autism, and how they arise. They also plan to expand the gender categories they include. In the current study, the surveys each participant completed asked them to choose male or female, but the researchers updated their questionnaire to include non-binary and transgender options.
The research was funded by the Hock E. Tan and K. Lisa Yang Center for Autism Research, the Simons Center for the Social Brain at MIT, and the National Institutes of Mental Health.
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