Abstracts

Rationale: Relative to lexical skills (e.g., confrontation naming, word retrieval), little is known about pragmatic language in people with epilepsy (PWE). This requires adapting language to social and environmental contexts, which is vital for social functioning. Poor pragmatic language is a hallmark of autism spectrum disorder (ASD), and if present in PWE, may be caused by shared mechanisms underlying comorbid epilepsy and ASD.To examine the nature and causes of poor pragmatic language in PWE, we aimed to 1) compare the prevalence of lexical and pragmatic language difficulties, 2) phenotype pragmatic language, and 3) examine its association with lexical skills, social cognition (i.e., theory of mind), epilepsy variables (e.g., age at seizure onset), and the Broader Autism Phenotype (BAP).  Methods: Language skills were assessed using the Pragmatic Rating Scale, Boston Naming Test-2, and Controlled Oral Word Association Test, in 103 consecutively recruited adults with epilepsy (Mage = 37.4 years, SD = 12.5; MIQ = 104.0, SD = 12.4; 55 females; 51 TLE, 40 GGE, 12 other focal or unknown) and 58 local community members (Mage = 39.6 years, SD = 14.6; MIQ = 113.0, SD = 11.6; 38 females). Theory of mind was assessed using the Faux Pas Task. Full expression of the BAP was classified using the Broader Autism Phenotype Questionnaire and Autism Endophenotype Interview. Results: Pragmatic language deficits were significantly more common in PWE (45%) than confrontation naming (18%, p < .05) and word retrieval deficits (8%; p < .001; Figure 1). Using cluster analysis, we identified three distinct pragmatic language phenotypes in PWE: reduced verbal output (n = 59), overly talkative (n = 30), and confusing communication (n = 14). Discriminant function analysis with follow-up ANCOVAs indicated that age was the only significant predictor of the phenotype expressed by PWE. PWE with reduced verbal output were younger than those with the other two phenotypes (p < .001), while PWE with confusing communication were older (p = .002). Lower IQ and confrontation naming were associated with more severe pragmatic language difficulties in the reduced verbal output phenotype (IQ: r(57) = - .41, p = .001; Confrontation naming: r(58) = - .39, p = .002). BAP status and epilepsy variables did not predict the language phenotype.Across the three phenotypes, PWE with and without the BAP had similar severity of pragmatic language difficulties (Reduced verbal output: p = .65; Overly talkative: p = .47; Confusing communication: p = .94). PWE and the BAP also had similar pragmatic language difficulties to community members with the BAP (p = .87), suggesting that seizures do not interact with the BAP to cause more severe difficulties. Conclusions: In a heterogeneous sample of PWE, 45% had pragmatic language difficulties versus 8-18% with lexical deficits. Neither epilepsy variables nor BAP status affected the pragmatic language phenotype. Given that epilepsy and ASD share mechanisms, similar pragmatic language profiles in PWE with and without the BAP, suggests that these shared mechanisms underpin poor pragmatic language in PWE, regardless of BAP status. This may ultimately have implications for clinical management of these difficulties.  Funding: The study was supported by the National Health and Medical Research Council of Australia Project grants APP1044175, 2013-2016 and APP1098255, 2016-2021 and Practitioner Fellowship (APP1104831), and an Australian Postgraduate Award.