Common test for autism found wanting

By Dr. Liji Thomas, MDMar 5 2020

A new study published in the March 2020 issue of the journal Experimental Results reports that based on data from over 6,500 subjects, the commonly used AQ10 test is not relevant in diagnosing autism. That means a re-examination of the approach used at present to pick up this condition in the population at large is needed. It also means there is a question mark on the validity of research based on this test.

Image Credit: Zahraa Saleh / Shutterstock

The study

The researchers re-examined the Autism-Spectrum Quotient (AQ10) questionnaire, a form which depends on self-reported personality characteristics to diagnose autism. It is just one of many such forms, but it happens to be the one in most common use by GPs and the shortest one too. It is recommended for people aged 12-16 years as well as those above 18 years because they do not take much time, are easy to use, and may be used by the individual without previous training, but with acceptable sensitivity and specificity, according to older reviews.

If adult patients suspect they may have autism, they can take the questionnaire. A score of 6-10 may mean they should go in for more confirmatory tests.

It is recommended by the National Institute for Health and Care Excellence (NICE), which is the UK government's voice in recommending clinical practice measures as well as NHS procedures. NICE supports the use of the AQ10 to screen autism in adults. Such results are used in large-scale studies to understand the prevalence of autistic traits in the population at large. These traits are also linked to the performance of the subjects on other tasks, to help to understand how autism is linked to other social skills and social behavior.

However, the scientists retrieved data from about 6,500 people, all from the society at large, who had taken the AQ10 questionnaire. They aimed to evaluate the effectiveness of the form for assessing autism. Some of the questions include whether the individuals notice small sounds that pass unnoticed by others or find it hard to identify the emotions of others from their faces.

The findings

The study shows that the measure yields unsatisfactory results when the results are analyzed using several commonly used statistical techniques, which means the AQ10 is not a reliable measure of autistic traits. Instead, say the researchers, a new system should be designed to detect the spectrum of autistic traits that manifest in a large population.

The study's senior author Punit Shah says the problem is not about any single question being wrong, but that the test may be picking up findings of more than one mental abnormality and not just one. He admits that it is hard to tell how far this affects patient care.

Shah concludes, "Our findings add further evidence to a growing body of literature indicating that the measures of autism and autistic traits currently used in research are inadequate."

Implications

Other researchers have already pointed out that earlier ASD screening methods were developed before 2013, and therefore do not take into account the newer guidelines of the Diagnostic and Statistical Manual -V (DSM-5). These methods of screening are meant to be used based on clinical diagnosis, which means that when clinical criteria were changed in the DSM-5, the diagnostic decision making within the screening technique must also be altered appropriately. They have concluded that "there is a need to re-examine questions and features within the ASD diagnostic and screening tools in order to comprehensively satisfy the new criteria of the DSM-5."

The danger of using such unreliable tools is that what is currently believed about autism and its management has come from studies based on these very tools which are now being shown to be incapable of fulfilling their intended role. Shah goes on to explain, "If the measure of autism is unreliable, as we suggest, so too are the findings and conclusions. Without reliable measures, it is unclear if the findings from these studies are valid, and may hamper the support we provide for people with autistic personalities or diagnosed autism in society."

A colleague of Shah, Emily Taylor, chimes in: "This is an important finding, which will hopefully initiate a more concerted effort at examining and refining tools used in autism research and clinical practice."

She points out that the current sample is taken from the general population, which has not received appropriate medical diagnoses to countercheck the findings of the study. Therefore, she says, "The next step would be to conduct follow-up studies in equally large clinical samples."

And more importantly, she indicates a general loss of faith in the reliability of mental health assessment tools, not just this single measure of autistic traits. As a result, she says, "We need far more 'basic' science to examine and address these issues in future research towards improving their application in the management of mental health difficulties in society."