Autism Screening

I thought this new study was interesting because it reveals that the instruments ("tests") used to evaluate individuals for autism differ in quality. Some work reasonable well, while others should either be revised or abandoned.

The instruments tested were those administered by caregivers, not researchers or clinicians. That means these are not the battery of instruments used during a neuro-psychological screening. A "level 2" screening is one that parents, educators, or trained caregivers give to determine if more screening is necessary. A level 2 instrument is not definitive and can only, at best, identify individuals who should undergo further evaluation.

Screening Accuracy of Level 2 Autism Spectrum Disorder Rating Scales: A Review of Selected Instruments

Autism, Vol. 14, No. 4, 263-284 (2010)

Megan Norris and Luc Lecavalier
Nisonger Center and Department of Psychology, The Ohio State University

The goal of this review was to examine the state of Level 2, caregiver-completed rating scales for the screening of AutismSpectrum Disorders (ASDs) in individuals above the age of three years. We focused on screening accuracy and paid particular attention to comparison groups. Inclusion criteria required that scales be developed post ICD-10, be ASD-specific, and have published evidence of diagnostic validity in peer-reviewed journals. The five scales reviewed were: the Social Communication Questionnaire (SCQ), Gilliam Autism Rating Scale/Gilliam Autism Rating Scale-SecondEdition (GARS/GARS-2), Social Responsiveness Scale (SRS), Autism Spectrum Screening Questionnaire (ASSQ), and Asperger Syndrome Diagnostic Scale (ASDS). Twenty total studies were located, most examining the SCQ. Research on the other scales was limited. Comparisons between scales were few and available evidence of diagnostic validity is scarce for certain subpopulations (e.g., lower functioning individuals, PDDNOS). Overall, the SCQ performed well, the SRS and ASSQ showed promise, and the GARS/GARS-2 and ASDS demonstrated poor sensitivity. This review indicates that Level 2 ASD caregiver-completed rating scales are in need of much more scientific scrutiny.
I know some schools do use GARS and ASDS to determine program eligibility. Unfortunately, some school counselors (generally not clinicians) do view these as definitive tests. Thankfully, that is rare -- most schools and special programs know any level 2 instrument should only be used to consider a further referral for evaluation.

There are stories of deaf students being diagnosed as autistic in error. Vision problems can also affect student scores on some questionnaires. The worst situation I heard about involved a student with a brain tumor -- which definitely affects the behavior and responsiveness of a child.

If a child has been evaluated with a level 2 instrument and referred to a psychologist or psychiatrist for full evaluation, that does not necessarily mean the child has autism. Remember, autism at early ages can resemble serious neurological conditions. A full screening is important. Always see a specialist and never assume the level 2 instrument is sufficient.

Level 2 exams might help a child obtain services, but they are no match for a medical examination accompanied by a full assessment.

Comments

  1. Its nonsence really because all the tests purport to represent is those things they identify, essentially self created autism.

    Without any clear neuro-biological marker the tests are only as accurate as the raters believe them to be and full of artefact.

    It a bit like a folk test for hot weather according to questions like
    "is it hot enough to turn on the air conditioning? "Is it hot enough to take your shirt off? "Is it hot enough to eat a packet of salted crisps?" All without benefit of a thermometer for any comparison.

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  2. Mental health issues are far more complex and dangerous to base on expression vs. etiology. We know there is a history of abusing mental health diagnoses.

    Level 2 instruments are messy, at best. They exist because schools and caregivers are, whether I like it or not, often involved in qualifying students for support services. It is not an ideal situation. The variances of level 2 results interpreted at the school sites are wide, even varying by state in the U.S. Some states are more likely to label students "autistic" than others, and this does seem to parallel which instruments are used and the biases of the examiners.

    I would need to find the OSEP (Office of Special Education Programs) data, but one report I found showed students moving from California, Oregon, and Minnesota to other states were most likely to "lose" their autism qualification for instructional supports. Likewise, moving into those states increased the odds of a level 2 diagnosis. There was more state-to-state consistency among neurological evaluations, but still some variances.

    I theorize how instruments are applied and evaluated depends on the training of the administrator. If so, then graduates from the same master's or doctoral programs would have similar diagnostic patterns. R. R. Grinker has written about this, as has epidemiologist Michael Frommer.

    My doctoral research included an entire chapter of the problem of defining "autism" and the competing definitions from clinicians, researchers, caregivers, and policy makers. The scientific aim is to define based on etiology, which means we would prefer as narrow a definition to guide research as is possible.

    I'm somewhat conflicted by the use of "autism" for an ever-expanding diagnostic range. When we can identify markers, such as those for Rett Syndrome, it seems knowing the etiology means Rett is distinct and medical, not "autism" but a label for a physical, measurable, condition. (DSM-V will remove Rett as drafted.)

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  3. My Doctoral thesis will include a similar chapter, I shall have to look up yours and cite it :)

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