Autism spectrum disorders in adults and the autonomic nervous system: Heart rate variability markers in the diagnostic procedure

The diagnostic assessment of autism spectrum disorders (ASD) in adults is a challenging and time-consuming procedure. In order to address the lack of specialised health-care professionals and improve the waiting time, we aimed to identify specific electrocardiogram (ECG) derived Heart Rate Variability (HRV) parameters that could be used for diagnostic purposes. 152 patients were diagnosed based on a standardised clinical procedure and assigned to one of three groups: ASD (n = 56), any other psychiatric disorder (OD) (n = 72), and patients with no diagnosis (ND) (n = 24). Groups were compared using ANOVA. Discriminative power of biological parameters and the clinical assessment were compared using receiver operating characteristic curves (ROCs). Patients with ASD showed reduced parasympathetic and increased sympathetic activity compared to ND. The accuracy determined by the area under the curve (AUC) of the biological parameters for discrimination between ASD vs. pooled OD/ND was 0.736 (95% CI = 0.652-0.820), compared to .856 (95% CI = 0.795-0.917) for the extensive clinical assessment. Our results confirmed the dysregulation of the autonomic nervous system in ASD with reduced parasympathetic and increased sympathetic activity as compared to ND. The discriminative power of biological markers including HRV was considerable and could supplement less sophisticated clinical assessments.

Is autonomic function during resting-state atypical in Autism: A systematic review of evidence

BACKGROUND

Theories of differences in resting-state arousal in autistic individuals are influential. Differences in arousal during resting-state would impact engagement and adaptation to the environment, having a cascading effect on development of attentional and social skills.

OBJECTIVES

We systematically evaluated the evidence for differences in measures of autonomic arousal (heart rate, pupillometry or electrodermal activity) during resting-state in autistic individuals; to understand whether certain contextual or methodological factors impact reports of such differences.

DATA SOURCES

We searched PsycInfo, MEDLINE and EMBASE databases for papers published until 16th May 2019. Of 1207 titles initially identified, 60 met inclusion criteria.

RESULTS AND CONCLUSIONS

Of the 51 studies that investigated group differences between neurotypical and autistic participants, 60.8 % found evidence of group differences. While findings of hyperarousal were more common, particularly using indices of parasympathetic function, findings of hypo-arousal and autonomic dysregulation were also consistently present. Importantly, experimental context played a role in revealing such differences. The evidence is discussed with regard to important methodological factors and implications for future research are described.

Profiles of Autonomic Activity in Autism Spectrum Disorder with and without Anxiety

Both anxiety and autism spectrum disorder (ASD) are associated with atypical physiological activity. Few studies have systematically assessed the resting physiological activity in ASD with co-occurring anxiety disorders. We tested 75 participants divided in four groups: youth with ASD, with (ASD + Anxiety = 22, 6F, 12.29 ± 2.83 years old) and without co-occurring anxiety (ASD Alone = 15, 6F, 11.59 ± 2.85 years old) and compared their physiological profile with that of matched typically developing controls (TDC) with (Anxiety Alone = 16, 6F, 11.24 ± 3.36 years old) and without co-occurring anxiety disorders (TDC = 22, 8F, 11.88 ± 2.88 years old). Results indicated reduced sympathetic and parasympathetic activity at rest in ASD as compared to TDC youth. ASD + Anxiety and Anxiety Alone groups showed different sympathetic, but similar parasympathetic activity. These findings suggest that autonomic profile-based approaches may advance research, diagnosis, and treatment of ASD and anxiety.