Journal of Autism and Developmental Disorders

, Volume 49, Issue 1, pp 197–208 | Cite as

Vagal Tone as a Putative Mechanism for Pragmatic Competence: An Investigation of Carriers of the FMR1 Premutation

  • Jessica KlusekEmail author
  • Amanda J. Fairchild
  • Jane E. Roberts
Original Paper


Pragmatic language skills exist across a continuum in typical and clinical populations, and are impaired in many neurodevelopmental disorders, most notably autism. The mechanisms underlying pragmatic impairment are poorly understood, although theory suggests dampened vagal tone plays a role. This study investigated the FMR1 premutation as a genetic model that may lend insight into the relationship between vagal function and pragmatic ability. Participants included 38 women with the FMR1 premutation and 23 controls. Vagal tone accounted for significant variance in pragmatics across both groups and statistically mediated the effect of FMR1 premutation status on pragmatic ability. Results support vagal tone as a biophysiological correlate of pragmatic ability, which informs potential mechanistic underpinnings and could have implications for targeted treatment.


Fragile X carrier HRV RSA Social communication Social (Pragmatic) Communication Disorder 



We would like to thank the women who participated in this study.

Author Contributions

JK conceived the study, led the data collection, analysis, interpretation, and drafted the manuscript. AJF provided consultation on the statistical models. JER provided guidance on the study design, data collection, and interpretation. All authors contributed to the interpretation of results and critical revising of the manuscript. All authors read and approved the final manuscript.


This study was funded by the National Institutes of Health (F32DC013934; R01MH090194; R01HD024356; U54HD079125, R01HD02274), the Research Participant Registry Core of the Carolina Institute for Developmental Disabilities (P30HD03110), and an ASPIRE grant from the Office of the Vice President for Research at the University of South Carolina.

Compliance with Ethical Standards

Conflict of interest

The authors declare that they have no conflict of interest.

Ethical Approval

All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and with the 1964 Helsinki declaration and its later amendments.

Informed Consent

Informed consent was obtained from all individual participants included in the study.


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Authors and Affiliations

  1. 1.Department of Communication Sciences and DisordersUniversity of South CarolinaColumbiaUSA
  2. 2.Department of Psychology, Barnwell CollegeUniversity of South CarolinaColumbiaUSA

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