AUTHOR=Owens Andrew P. , Mathias Christopher J. , Iodice Valeria 

TITLE=Autonomic Dysfunction in Autism Spectrum Disorder

JOURNAL=Frontiers in Integrative Neuroscience

VOLUME=Volume 15 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/integrative-neuroscience/articles/10.3389/fnint.2021.787037

DOI=10.3389/fnint.2021.787037

ISSN=1662-5145

ABSTRACT=Background
There have been previous reports of enhanced sympathoexcitation in autism spectrum disorder (ASD). However, no study has yet formally investigated the potential presence of autonomic disorders or dysfunction in ASD using appropriate autonomic investigations. The joint hypermobile form of Ehlers-Danlos syndrome (hE-DS), a heritable rheumatological condition, appears overrepresented in autonomic disorders causing orthostatic intolerance. This study examined the comorbidity of ASD, autonomic disorders and joint hypermobility in two UK autonomic national referral centres. 

Methods
Clinical data from 28 referrals with a confirmed diagnosis of ASD over a 10-year period were compared with 19 age-matched healthy controls. Autonomic function was determined using methods established in the centres previously described. 

Results
20/28 ASD had diagnosable autonomic disorders; 9 postural tachycardia syndrome (PoTS), 4 PoTS and vasovagal syncope (VVS), 3 experienced presyncope, 1 essential hyperhidrosis, 1 orthostatic hypotension, 1 VVS alone and 1 a combination of PoTS, VVS and essential hyperhidrosis. 16/20 ASD with autonomic dysfunction had hE-DS. In ASD, basal heart rate and responses to orthostatic tests of autonomic function were exaggerated, supporting previous findings of increased sympathoexcitation. However, sympathetic vasoconstriction was impaired in ASD.

Conclusions
Intermittent neurocardiovascular autonomic dysfunction affecting heart rate and blood pressure function, and thermoregulatory dysfunction was over-represented in ASD. There is a strong association with hE-DS. Autonomic dysfunction may further impair quality of life in ASD, particularly in those unable to adequately express their experiencing of autonomic symptoms.