Wednesday, 10 February 2016

Autism and the 'female camouflage effect'

Two papers provide some blogging fodder today. The first is from Agnieszka Rynkiewicz and colleagues [1] (open-access available here) who introduces a concept that many people with an interest in autism might have considered: a 'female camouflage effect' in autism. The second paper is by C Ellie Wilson and colleagues [2] and continues the idea that sex/gender differences present in autism might have some important implications for diagnostic evaluation.

Both these papers entertain the idea that although the history of autism has been very 'male-dominated' in light of the sex ratio for the label for example (see here), science and clinical practice is coming round to the idea that there may be important sex/gender differences in the presentation of core issues (see here) that might mean quite a few females have been 'over-looked' or 'under-identified' when it comes to autism. It's of increasing interest.

Rynkiewicz et al set about to present "an innovative computerized technique to objectively evaluate the non-verbal modality of communication (gestures) during two demonstration tasks of ADOS-2 (Autism Diagnostic Observation Schedule, Second Edition)." ADOS, by the way, is one of the gold-standard assessment instruments designed with autism in mind (see here). As part of their really interesting report on "automated coding of non-verbal mode of communication (gestures)" and computation of a "Gesture Index (GI)" they compared results from boys and girls ("high-functioning" as they describe them) and whether "females with autism had a higher GI compared to males with autism."

After data were crunched and the like, the authors concluded that: "High-functioning females with autism might present better on non-verbal (gestures) mode of communication than boys with autism." Further: "This may be because they are effective at camouflaging other diagnostic features." Potentially very important information indeed.

The second paper by Wilson et al continues the theme that sex/gender might have a part to play on the manifestation of autism and onwards diagnostic evaluation. With the aim of reporting "sex differences in clinical outcomes for 1244 adults (935 males and 309 females) referred for autism spectrum disorder assessment", researchers found among other things that: "Males had significantly more repetitive behaviours/restricted interests than females." Onwards: "The sexes may present with different manifestations of the autism spectrum disorder phenotype and differences vary by diagnostic subtype."

Variation in the presentation of repetitive and/or restricted behaviours/interests by sex has been talked about in the peer-reviewed research before [3]. As part of a wider suggestion of a specific female phenotype of autism potentially emerging (see here) (being careful with those generalisations) I'd like to think that a greater awareness of such issues could notably enhance the whole diagnostic system especially for females. Indeed, one area that I think would substantially benefit from a little more inspection of a potential 'female camouflage effect' in autism is that of the 'diagnosis' (although not formally noted in standardised texts) of pathological demand avoidance (PDA). At least one person has talked about female autism and the overlap with PDA (see here) and I'm minded to suggest that they might be on to something rather important.

Oh, and since I'm on the topic of sex/gender and autism, I'm minded to bring in the paper by Katarzyna Chawarska and colleagues [4] talking about infant 'at-risk for autism' girls and social attention potentially pertinent to discussions on any female camouflage effect...


[1] Rynkiewicz A. et al. An investigation of the 'female camouflage effect' in autism using a computerized ADOS-2 and a test of sex/gender differences. Mol Autism. 2016 Jan 21;7:10.

[2] Wilson CE. et al. Does sex influence the diagnostic evaluation of autism spectrum disorder in adults? Autism. 2016. Jan 22.

[3] Van Wijngaarden-Cremers PJ. et al. Gender and age differences in the core triad of impairments in autism spectrum disorders: a systematic review and meta-analysis. J Autism Dev Disord. 2014 Mar;44(3):627-35.

[4] Chawarska K. et al. Enhanced Social Attention in Female Infant Siblings at Risk for Autism. Journal of the American Academy of Child & Adolescent Psychiatry. 2015. Dec 17.

---------- Rynkiewicz, A., Schuller, B., Marchi, E., Piana, S., Camurri, A., Lassalle, A., & Baron-Cohen, S. (2016). An investigation of the ‘female camouflage effect’ in autism using a computerized ADOS-2 and a test of sex/gender differences Molecular Autism, 7 (1) DOI: 10.1186/s13229-016-0073-0 Wilson CE, Murphy CM, McAlonan G, Robertson DM, Spain D, Hayward H, Woodhouse E, Deeley PQ, Gillan N, Ohlsen JC, Zinkstok J, Stoencheva V, Faulkner J, Yildiran H, Bell V, Hammond N, Craig MC, & Murphy DG (2016). Does sex influence the diagnostic evaluation of autism spectrum disorder in adults? Autism : the international journal of research and practice PMID: 26802113