25732
Anxiety, Language, and Heart Rate Variability in Autism Spectrum Disorders
Anxiety concerns are commonly experienced in children with Autism Spectrum Disorder (ASD) (Kerns et al., 2014). Despite this, those with both ASD and language difficulties are reported to experience less anxiety than those with less language difficulty (Kerns et al., 2014). Using objectively measurable biomarkers of anxiety (e.g., reduced heart rate variability; HRV) that do not rely on language ability may provide a way to improve anxiety assessment in Minimally-Verbal ASD (MV-ASD), but first more must be known about the relationship between HRV, anxiety and language. Social Engagement Systems theory, a sub-portion of the Polyvagal Theory, suggests that children with ASD experience deficits in a “social communication circuit” (Porges, 2007). Additionally, it has been shown that, much like anxiety, receptive language can be predictive of lower HRV (Patriquin, Scarpa, Friedman, & Porges, 2013). These studies provide a framework for the relationship of language or anxiety to HRV individually however few studies have looked at the interactions between HRV, language and anxiety.
Objectives:
In a sample of children with ASD it was hypothesized that RSA would be predicted by anxiety and receptive language abilities such that more anxiety and higher receptive ability will result in lower RSA.
Methods:
Participants consisted of 23 children (18 males) age ranged from 51 months to 95 months (mean = 68.70, SD = 14.07). Anxiety was measured by parent report using the Developmental Behavior Checklist, Parent Version- Anxiety Subscale (DBC-P; Einfeld & Tonge, 1992, 1995, 2002). Receptive language was measured using the Peabody Picture Vocabulary Test, Third Edition (PPVT-III; Dunn & Dunn, 1997), which was administered to children during the study visit. Additionally, children watched a 3-minute baseline video, which allowed for the measurement of baseline HRV via LifeShirt! (Vivometrics).
Results:
The model tested the prediction of parent-reported anxiety (DBC-P) and receptive language ability (PPVT-III) and their interaction with HRV (as measured by RSA). Child demographic variables such as age and gender were not correlated to RSA and therefore no covariates were included in the regression analysis. As shown in previous studies, PPVT-III was uniquely and positively related to RSA (β = .545, p = .011). However, neither anxiety nor the interaction term was significant (β = .072, p = .713, β = -.170, p = .075 respectively). The full model with the interaction term was not significant (p = .052); however, the model with level 1 predictors explain 31.6% of the variance in RSA (F(2,19) = 4.390, p = .027).
Conclusions:
These findings indicate that, consistent with the Polyvagal Theory of the Social Engagement System (Porges, 2007) and previous studies (Patriquin, Scarpa, Friedman, & Porges, 2013) receptive language seems indicative of lower RSA. However, anxiety does not seem indicative of lowered RSA in this population, and the relationship between anxiety and RSA also does not appear to be moderated by language. This finding is surprising given the existing research on anxiety and HRV. These results may be due to parent-report not being an accurate reflection of child anxiety.