Heart rate variability as a biomarker in health and affective disorders: A perspective on neuroimaging studies.

The dynamic embodiment of psychological processes is evident in the association of health outcomes, behavioural traits and psychological functioning with Heart Rate Variability (HRV). The dominant high-frequency component of HRV is an index of the central neural control of heart rhythm, mediated via the parasympathetic vagus nerve. HRV provides a potential objective measure of action policies for the adaptive and predictive allostatic regulation of homeostasis within the cardiovascular system. In its support, a network of brain regions (referred to as the 'central autonomic network') maps internal state, and controls autonomic responses. This network includes regions of prefrontal cortex, anterior cingulate cortex, insula, amygdala, periaqueductal grey, pons and medulla. Human neuroimaging studies of neural activation and functional connectivity broadly endorse this architecture, and its link with cardiac regulation at rest and dysregulation in clinical states that include affective disorders. In this review, we appraise neuroimaging research and related evidence for HRV as an informative marker of autonomic integration with affect and cognition, taking a perspective on function and organisation. We consider evidence for the utility of HRV as a metric to inform targeted interventions to improve autonomic and affective dysregulation, and suggest research questions for further investigation.

Interoceptive training to target anxiety in autistic adults (ADIE): A single-center, superiority randomized controlled trial.

BACKGROUND: This trial tested if a novel therapy, Aligning Dimensions of Interoceptive Experience (ADIE), reduces anxiety in autistic adults. ADIE targets the association of anxiety with mismatch between subjective and behavioral measures of an individual's interoceptive sensitivity to bodily signals, including heartbeats. METHODS: In this superiority randomized controlled trial, autistic adults (18-65 years) from clinical and community settings in Southern England were randomly assigned (1:1) to receive six sessions of ADIE or an active 'exteroceptive' control therapy (emotional prosody identification). Researchers conducting outcome assessments were blind to allocation. ADIE combines two modified heartbeat detection tasks with performance feedback and physical activity manipulation that transiently increases cardiac arousal. Participants were followed-up one-week (T1) and 3-months post-intervention (T2). The primary outcome was Spielberger Trait Anxiety Score (STAI-T) at T2. Outcomes were assessed on an intention-to-treat basis using multiple imputation for dealing with missing values. This trial was registered at International Standard Randomized Controlled Trial Registry, ISRCTN14848787. FINDINGS: Between July 01, 2017, and December 31, 2019, 121 participants were randomly allocated to ADIE (n = 61) or prosody (n = 60) intervention groups. Data at T1 was provided by 85 (70%) participants (46 [75%] ADIE; 39 [65%] prosody). Data at T2 was provided by 61 (50%) participants (36 [59%] ADIE; 25 [42%] prosody). One adverse event (cardiac anxiety following ADIE) was recorded. A statistically significant group effect of ADIE on trait anxiety continued at T2 (estimated mean difference 3•23 [95% CI 1•13 to 5•29]; d = 0•30 [95% CI 0•09 to 0•51]; p = 0•005) with 31% of ADIE group participants meeting trial criteria for recovery (compared to 16% in the control group). INTERPRETATION: ADIE can reduce anxiety in autistic adults, putatively improving regulatory control over internal stimuli. With little reliance on language and emotional insight, ADIE may constitute an inclusive intervention. FUNDING MQ: Transforming Mental Health PsyImpact Grant.

Interoceptive awareness mitigates deficits in emotional prosody recognition in Autism.

The sensing of internal bodily signals, a process known as interoception, contributes to subjective emotional feeling states that can guide empathic understanding of the emotions of others. Individuals with Autism Spectrum Conditions (ASC) typically show an attenuated intuitive capacity to recognise and interpret other peoples' emotional signals. Here we test directly if differences in interoceptive processing relate to the ability to perceive emotional signals from the intonation of speech (affective prosody) in ASC adults. We employed a novel prosody paradigm to compare emotional prosody recognition in ASC individuals and a group of neurotypical controls. Then, in a larger group of ASC individuals, we tested how recognition of affective prosody related to objective, subjective and metacognitive (awareness) psychological dimensions of interoception. ASC individuals showed reduced recognition of affective prosody compared to controls. Deficits in performance on the prosody task were mitigated by greater interoceptive awareness, so that ASC individuals were better able to judge the prosodic emotion if they had better insight into their own interoceptive abilities. This data links the ability to access interoceptive representations consciously to the recognition of emotional expression in others, suggesting a crossmodal target for interventions to enhance interpersonal skills.