Objectives: The current study examined the sex specific clinical profiles of toddlers who received an ASD evaluation based on M-CHAT screen positive status in order to explore potential differences that may contribute to the differential PPV of the M-CHAT in boys and girls.
Methods: The sample included 218 males and 102 females (mean age=25.6 months, SD=5.3) who were evaluated based on screen positive status on the M-CHAT, a parent questionnaire administered at pediatric well-visits. Evaluations included autism diagnostic measures (ADOS, ADI-R, CARS), a developmental measure (Mullen Scales of Early Learning; Mullen), and parent report of history. Clinical judgment incorporated all data collected into a DSM-IV symptom count and final diagnosis. 156 toddlers were diagnosed with and ASD (121 males) and 164 toddlers were not (97 males). 72% of toddlers not diagnosed with ASD were diagnosed with another developmental delay.
Results: ANOVAs were conducted with sex and ASD status (ASD vs. non-ASD) as fixed factors and Mullen scores as dependent factors. Scores on the Fine Motor (FM) and Receptive Language (RL) scales were lower (p’s<.05) in the ASD group compared to the non-ASD group. Scores on the Visual Reception (VR) and Expressive Language (EL) scales did not differ by sex in the non-ASD group; however, girls with ASD demonstrated lower (p’s<.05) scores on these scales than boys with ASD. Scores on the Gross Motor (GM) scale were lower (p<.05) for girls than boys in the non-ASD group, and this effect was larger in the ASD group. ANOVAs were also conducted with sex and ASD status as fixed factors, and ASD symptom outcomes as dependent factors. Although there were no sex by ASD status interactions, there was a main effect (p<.05), of sex on the number of DSM-IV symptoms within the repetitive and restricted patterns of behavior domain (girls<boys).
Conclusions: This distinct pattern of findings suggests that there are differences in the clinical profiles of boys and girls considered at risk for ASD based on the M-CHAT. Generally, toddlers with ASD demonstrated lower scores on developmental outcomes than toddlers who were non-ASD. Girls with ASD demonstrated lower scores on the Mullen VR and EL scales than boys with ASD. Additionally, girls demonstrated lower Mullen GM scores and fewer DSM-IV symptoms within the repetitive restricted patterns of behavior domain than boys, despite ASD status. Future research will examine how these differences may be used in the development of sex-specific scoring algorithms to increase the PPV of the M-CHAT.
See more of: Clinical Phenotype
See more of: Symptoms, Diagnosis & Phenotype