Gender Differences in Pragmatic Language Features Associated with the Broad Autism Phenotype Among Parents of Children with Autism

Background: Pragmatic language impairment is a primary feature of the broad autism phenotype (BAP), which is characterized by subthreshold personality and language traits that are seen among family members of individuals with autism and reflect underlying genetic susceptibility (Landa et al., 1992; Piven et al., 1997; Ruser et al., 1997). Although a strong gender bias is seen in autism, with a gender ratio of approximately 4:1, it is unclear whether this gender bias exists in the presentation of the BAP in general, and specifically in pragmatic language features of the BAP. Prior reports are conflicting, with some indication that pragmatic language difficulties may be more frequent among mothers than fathers (Piven et al., 1997; Ruser et al., 2007), while other reports have failed to detect gender effects (Landa et al., 1992). Understanding gender bias in the BAP may lead to a more comprehensive characterization of the BAP, and inform potential etiologic mechanisms in the BAP and autism.

Objectives: This study characterized pragmatic language among parents of individuals with autism in order to examine gender differences in the BAP. Additionally, associations between pragmatic language features and personality traits that have been documented as part of the BAP (i.e. aloof, rigid, perfectionistic, and untactful traits) were explored in order to identify features that may be differentially associated with pragmatic language features in males versus females.

Methods: Semi-structured conversational interviews were conducted with fathers (n=39) and mothers (n=49) of individuals with autism. The Pragmatic Rating Scale-Revised (PRS; Landa et al., 1992) was used to assess pragmatic language violations from videotaped interview. Scores were computed for the PRS total score, and for three PRS subscales that had been derived through factor analysis in an independent sample (Losh et al., in review). The Modified Personality Assessment Schedule (M-PAS) was administered to assess aloof, untactful, rigid and perfectionistic personality features as potential correlates of pragmatic language features.

Results: Fathers and mothers of children with autism did not differ on PRS-total score, the PRS-dominating and PRS-suprasegmental subscales. Fathers scored significantly higher than mothers on the PRS-withdrawn subscale (t(86)= 2.56, p=.012), which is characterized primarily by conversation that was vague, terse, and lacking reciprocity. Exploratory correlations showed that aloof personality was significantly associated with the PRS-total score (r=.337, p=.019), the PRS-withdrawn subscale (r=.395, p=.005), and the PRS-suprasegmental subscale (r=.468, p=.001) among mothers, while these relationships did not approach significance among fathers (ps>.412). No other significant associations were detected with personality features.

Conclusions: Fathers of children with autism showed elevated rates of withdrawn communication style as compared to mothers, although overall pragmatic language ability did not differ between these groups. Pragmatic language features were associated with aloof personality style among mothers but not among fathers. Therefore, mechanisms underlying pragmatic language in the BAP may be gender-specific, although it remains unclear as to whether these gender differences are environmentally or biologically mediated. Knowledge of gender differences in BAP can contribute to our understanding of how genetically-linked traits associated with autism are transmitted within families.