Automated respiratory sinus arrhythmia measurement: Demonstration using executive function assessment

Effects of adverse childhood experience on physiological regulation are moderated by evolved developmental niche history

Childhood experiences of early life stress and adversity can lead to long-term detrimental outcomes across the lifespan. Recent evidence suggests avoiding stressors is not enough for species-typical development. Nurturing and responsive care are needed to both buffer adverse experiences as well as promote healthy development, but little is known regarding the interaction between species-typical environmental support in childhood, Evolved Developmental Niche history (EDN-history), and adversity on physiological regulation in adult women. To investigate the interaction between species-typical nurturing and adversity (ACEs, adverse childhood experiences), women (N = 113) were asked to report on EDN-history and ACEs. Physiological regulation was measured using respiratory sinus arrhythmia (RSA) across three conditions that included stress and relaxation. Applying latent basis coefficient modeling, EDN-history moderated vagal withdrawal from baseline to stress and supported vagal activation from stress to recovery, suggesting a link between EDN-history and vagal adaptability. EDN-history acted as a buffer against ACEs on physiological regulation supporting women's vagal adaptability across differing conditions. Physiological adaptability is a key component of physical and psychological wellbeing and resilience. Experiences of the EDN in childhood may not only buffer adversity but also support the physiological building blocks of health and resilience.

Cardiac-based detection of seizures in children with epilepsy

INTRODUCTION

We evaluated a multi-parametric approach to seizure detection using cardiac and activity features to detect a wide range of seizures across different people using the same model.

METHODS

Electrocardiogram (ECG) and accelerometer data were collected from a chest-worn sensor from 62 children aged 2-17 years undergoing video-electroencephalogram monitoring for clinical care. ECG data from 5 adults aged 31-48 years who experienced focal seizures were also analyzed from the PhysioNet database. A detection algorithm was developed based on a combination of multiple heart rhythm and motion parameters.

RESULTS

Excluding patients with multiple seizures per hour and myoclonic jerks, 25 seizures were captured from 18 children. Using cardiac parameters only, 11/12 generalized seizures with clonic or tonic activity were detected as well as 7/13 focal seizures without generalization. Separately, cardiac parameters were evaluated using electrocardiogram data from 10 complex partial seizures in the PhysioNet database of which 7 were detected. False alarms averaged one per day. Movement-based parameters did not identify any seizures missed by cardiac parameters, but did improve detection time for 4 of the generalized seizures.

CONCLUSION

Our data suggest that cardiac measures can detect seizures with bilateral motor features with high sensitivity, while detection of focal seizures depends on seizure duration and localization and may require customization of parameter thresholds.

Assessing stress variations in children during the strange situation procedure: comparison of three widely used respiratory sinus arrhythmia estimation methods

Objective.The respiratory sinus arrhythmia (RSA) is a well-known marker of vagal activity that can be exploited to measure stress changes. RSA is usually estimated from heart rate variability (HRV). This study aims to compare the RSA obtained with three widely adopted methods showing their strengths and potential pitfalls.Approach.The three methods are tested on 69 healthy preschoolers undergoing a stressful protocol, the strange situation procedure (SSP). We compare the RSA estimated by the Porges method, the univariate autoregressive (AR) spectral analysis of the HRV signal, and the bivariate AR spectral analysis of HRV and respirogram signals. We examine RSA differences detected across the SSP episodes and correlation between the estimates provided by each method.Main results.The Porges and the bivariate AR approaches both detected significant differences (i.e. stress variations) in the RSA measured across the SSP. However, the latter method showed higher sensitivity to stress changes induced by the procedure, with the mean RSA variation between baseline and first separation from the mother (the most stressful condition) being significantly different among methods: Porges, -17.5%; univariate AR, -18.3%; bivariate AR, -23.7%. Moreover, the performances of the Porges algorithm were found strictly dependent on the applied preprocessing.Significance.Our findings confirm the bivariate AR analysis of the HRV and respiratory signals as a robust stress assessment tool that does not require any population-specific preprocessing of the signals and warn about using RSA estimates that neglect breath information in more natural experiments, such as those involving children, in which respiratory frequency changes are extremely likely.

Feasibility of Mild Traumatic Brain Injury Assessment Based on Cardiovascular Response to Postural Change

OBJECTIVE

To determine the feasibility of short-term cardiovascular responses to postural change as a screening tool for mild traumatic brain injury (mTBI), using heart rate metrics that can be measured with a wearable electrocardiogram sensor.

SETTING

Military TBI clinic.

DESIGN

Data collected from active-duty service members who had sustained a medically diagnosed mTBI within the prior 72 hours and from age- and sex-matched controls. Cardiac data collected while participants performed a sequence of postural changes.

MAIN MEASURES

Model classification compared with clinical mTBI diagnosis.

RESULTS

Cardiac biomarkers of mTBI were identified and logistic regression classifiers for mTBI were developed from different subsets of biomarkers. The best model achieved 90% sensitivity and 69% specificity using data from 2 different postural changes.

CONCLUSION

Noninvasive measurement of cardiovascular response to postural change is a promising approach for field-deployable post-mTBI screening.

GABAergic contribution to the muscle mechanoreflex-mediated heart rate responses at the onset of exercise in humans

Previous studies have indicated that central GABAergic mechanisms are involved in the heart rate (HR) responses at the onset of exercise. On the basis of previous research that showed similar increases in HR during passive and active cycling, we reasoned that the GABAergic mechanisms involved in the HR responses at the exercise onset are primarily mediated by muscle mechanoreceptor afferents. Therefore, in this study, we sought to determine whether central GABA mechanisms are involved in the muscle mechanoreflex-mediated HR responses at the onset of exercise in humans. Twenty-eight healthy subjects (14 men and 14 women) aged between 18 and 35 yr randomly performed three bouts of 5-s passive and active cycling under placebo and after oral administration of diazepam (10 mg), a benzodiazepine that produces an enhancement in GABA_A activity. Beat-to-beat HR (electrocardiography) and arterial blood pressure (finger photopletysmography) were continuously measured. Electromyography of the vastus lateralis was obtained to confirm no electrical activity during passive trials. HR increased from rest under placebo and further increased after administration of diazepam in both passive (change: 12 ± 1 vs. 17 ± 1 beats/min, P < 0.01) and active (change: 14 ± 1 vs. 18 ± 1 beats/min, P < 0.01) cycling. Arterial blood pressure increased from rest similarly during all conditions ( P > 0.05). Importantly, no sex-related differences were found in any variables during experiments. These findings demonstrate, for the first time, that the GABAergic mechanisms significantly contribute to the muscle mechanoreflex-mediated HR responses at the onset of exercise in humans. NEW & NOTEWORTHY We found that passive and voluntary cycling evokes similar increases in heart rate and that these responses were enhanced after diazepam administration, a benzodiazepine that enhances GABA_A activity. These findings suggest that the GABAergic system may contribute to the muscle mechanoreflex-mediated vagal withdrawal at the onset of exercise in humans.