Sex differences in cognitive profiles of autistic people: A systematic review and a research

Background Autistic females are under-diagnosed. Research identified sex-differences in ASD core symptoms and females’ advantage in social abilities. Despite the mutual influence of symptom severity, social-communication skills, and cognitive abilities; cognitive profiles’ sex-differences have been under-investigated and measures used are variable. Objectives The aim of our research is to analyze ASD cognitive profiles’ sex-differences, conducting a subtest-level-depth analysis as, based on our PRISMA review, literature is characterized by a predominance of macro-level-analysis and unbalanced samples. Further, we hypothesized males’ advantage in visuo-spatial non-language-based tasks and, based on clinical practice, females’ advantage in verbal tasks. Methods PRISMA Review Studies eligibility was defined according to PICOS criteria, among these: quantitative research from 01/01/2000, participants aged 0-to-19 years, ASD diagnosis, no comorbidities. N=644 records were screened by two authors. After full-texts assessment, 22 studies were included (%agreement=94,59%; Cohen’s Kappa=0,89). Data extraction was based on “Cochrane Handbook for Systematic Reviews” recommendations. Research Participants Two groups: 72 autistic preschoolers: n=36 females (Mage=55.80m; sd=21.80m), n=36 males (Mage=56.30m; sd=20.40m) 20 autistic children and adolescents: n=10 females (Mage=139.00m; sd=30.60m), n=10 males (Mage=135.00m; sd=29.00m) Measures Participants underwent clinical assessment, including cognitive profiling with Griffiths Mental Development Scales (GMDS-ER, preschoolers) and Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV, school-aged subjects). Behavioral profiles were assessed using ADOS-2. Results PRISMA Review Contrasting result regarding cognitive profiles: no sex-differences using the Mullen Scales of Early Development (MSEL) and WISC (n=5 studies). Males’ advantage in Performance Development Quotient (GMDS) (n=2) and Perceptual Reasoning Index (WISC) (n=2). Both sexes’ profiles are characterized by advantage in visual-reception and performance. Attention to detail: males’ advantage (n=2) Research No significant sex-differences in cognitive profiles. Preschoolers’ profile: Males: Performance DQ advantage and Personal-Social weakness (t(35)=5.01, p<0.001); Females: Performance DQ advantage and Language weakness (t(35)=2,63, p=0,01). Children and adolescents’ profiles: higher scores in Perceptual Reasoning and lower scores in Working Memory (Males:t (9)= 3.63, p=0.006; Females:t(9)= 2.63, p=0.03) and Processing Speed (Males:t (9)= 3.85, p=0.004; Females:t(9)= 2.49, p=0.03). No sex-differences in ADOS-2 scores. Significant sex-difference in Unusual eye-contact score in preschoolers (W=558.00, p=0.02, r=0.27; Males mean=2.00, sd=0.00; Females mean=1.78, sd=0.59). Conclusions Focusing on cognitive aspects is pivotal for diagnostic precision and interventions individualization. Despite contradictory results in literature, we found various studies suggesting absence of cognitive abilities’ sex-differences. Further, both sexes' profiles seem characterized by an advantage in Performance/Perceptual Reasoning, as confirmed by our study. Conversely to what was hypothesized we did not find females’ advantage in verbal abilities; future research should conduct qualitative analysis of verbal tasks’ to individuate potential gender differences, as well as, replicate studies and enhance sample homogeneity.