Feelings from the heart: Developing HRV decrease-trigger algorithms via multilevel hyperplane simulation to detect psychosocially meaningful episodes in everyday life

Acute fasting modulates autonomic nervous system function and ambulatory cardiac interoception

Intermittent fasting has been associated with diverse physical and psychological health benefits. According to previous research, fasting-induced alterations in psychophysiological functioning should facilitate the accurate detection of an internal bodily signal (like the heart), which is referred to as interoceptive accuracy. In two within-subjects studies we aimed to examine whether an intermittent fasting protocol (i) evokes distinct autonomic nervous system changes in the laboratory and (ii) improves (objectifiable) interoceptive accuracy and sensibility (i.e., the subjective belief in perceiving bodily signals) in everyday life. Study 1 (N = 36) found increasing heart rate variability (precisely, the root mean square of successive differences; RMSSD) accompanied by a more vascular than myocardial response following a 16 h fast. Study 2 (N = 40) applied an ecological momentary assessment design including intermittent fasting (8 h normal eating followed by 16 h fasting) and normal eating (24 h normal eating) for three consecutive days each. Findings suggested a tendency toward higher interoceptive accuracy and sensibility during the fasting regimen, which was particularly pronounced in individuals exhibiting lower RMSSD. Together, findings suggest that (short-term) fasting seems to facilitate momentary attention to organismic cues due to alterations in autonomic nervous system function.

The cardiac correlates of feeling safe in everyday life: A Bayesian replication study

BACKGROUND

Feeling safe and secure has been proposed to dampen autonomic arousal and buffer threat responses. In a previous study, we could show that momentary ratings of subjective safety were associated with elevated heart rate variability (specifically, root mean square of successive differences; RMSSD) and lower heart rate in everyday life, thus suggesting a health-protective role of feeling safe.

METHODS

This study aimed to replicate this effect in a sample of N = 79 adults, applying Bayesian statistics with prior effects of the original study.

RESULTS

Using an ecological momentary assessment (EMA) across three days we could replicate the effect of lower heart rate and higher RMSSD in moments when participants felt more safe. In accordance with the original study, we could also show that the effect on heart rate were independent of RMSSD, thus suggesting a contribution of sympathetic activity to this effect.

CONCLUSION

The findings confirm the connection between momentary feelings of safety and cardiac regulation, thus substantiating research on the health-protective role of psychological safety.

Precise detection and localization of R-peaks from ECG signals

Heart rate variability (HRV) is derived from the R-R interval, which depends on the precise localization of R-peaks within an electrocardiogram (ECG) signal. However, current algorithm assessment methods prioritize the R-peak detection's sensitivity rather than the precision of pinpointing the exact R-peak positions. As a result, it is of great value to develop an R-peak detection algorithm with high-precision R-peak localization. This paper introduces a novel R-peak localization algorithm that involves modifications to the well-established Pan-Tompkins (PT) algorithm. The algorithm was implemented as follows. First, the raw ECG signal $ X\left(i\right) $ was band-pass filtered (5-35 Hz) to obtain a preprocessed signal $ Y\left(i\right) $. Second, $ Y\left(i\right) $ was squared to enhance the QRS complex, followed by a 5 Hz low-pass filter to obtain the QRS envelope, which was transformed into a window signal $ W\left(i\right) $ by dynamic threshold with a minimum width of 200 ms to mark the QRS complex. Third, $ Y\left(i\right) $ was used to generate QRS template $ T\left(n\right) $ automatically, and then the R-peak was identified by a template matching process to find the maximum absolute value of all cross-correlation values between $ T\left(n\right) $ and $ Y\left(i\right) $. The proposed algorithm achieved a sensitivity (SE) of 99.78%, a positive prediction value (PPV) of 99.78% and data error rate (DER) of 0.44% in R-peak localization for the MIT-BIH Arrhythmia database. The annotated-detected error (ADE), which represents the error between the annotated R-peak location and the detected R-peak location, was 8.35 ms for the MIT-BIH Arrhythmia database. These results outperformed the results obtained using the classical Pan-Tompkins algorithm which yielded an SE of 98.87%, a PPV of 99.14%, a DER of 1.98% and an ADE of 21.65 ms for the MIT-BIH Arrhythmia database. It can be concluded that the algorithm can precisely detect the location of R-peaks and may have the potential to enhance clinical applications of HRV analysis.

Dynamic heartbeat tracking beyond the laboratory: Introducing the novel Graz Ambulatory Interoception Task (GRAIT)

We present a novel ambulatory method, the Graz Ambulatory Interoception Task (GRAIT), to assess the accuracy of interoceptive beliefs (AccIB). This method captures both between- and within-person variations of AccIB by having participants counting perceived heartbeats in daily life. Reliability analyses showed high between-person (RkR = 0.99) and moderate within-person reliability (RCn = 0.62). Validity was supported by associations with an established laboratory task (r = 0.87). Within-person associations revealed that interoceptive sensibility, heart rate variability, and states of low arousal coupled with positive affect were linked to AccIB. Study 2 replicated these findings and showed a relationship between AccIB and self-control in everyday life, highlighting the importance of cardiac interoception and its relevance for health.

Multimodal, Idiographic Ambulatory Sensing Will Transform our Understanding of Emotion

Emotions are inherently complex - situated inside the brain while being influenced by conditions inside the body and outside in the world - resulting in substantial variation in experience. Most studies, however, are not designed to sufficiently sample this variation. In this paper, we discuss what could be discovered if emotion were systematically studied within persons 'in the wild', using biologically-triggered experience sampling: a multimodal and deeply idiographic approach to ambulatory sensing that links body and mind across contexts and over time. We outline the rationale for this approach, discuss challenges to its implementation and widespread adoption, and set out opportunities for innovation afforded by emerging technologies. Implementing these innovations will enrich method and theory at the frontier of affective science, propelling the contextually situated study of emotion into the future.

The ambulatory battery of creativity: Additional evidence for reliability and validity

Psychometrically sound instruments that assess temporal dynamics of creative abilities are limited. The Ambulatory Battery of Creativity (ABC) is designed to assess creative ideation performance multiple times in everyday life and was proven to capture the intra-individual dynamic of creative abilities reliably and validly. The present ambulatory study aimed to replicate and extend the psychometric evidence of the novel ABC. Sixty-nine participants worked on the ABC during a 5-day ambulatory assessment protocol. Each day, participants completed six randomly presented items of the verbal and the figural ABC. Matching previous psychometric analyses, the results indicated good between-person (≥0.80) and good within-person (≥0.72) reliability. Furthermore, evidence for between-person and within-person validity of the ABC was obtained. Performance in the verbal and the figural ABC were interrelated and correlated with an independent measure of creative potential. The verbal ABC was further associated with openness, self-reported creative behavior, creative activities, and creative achievements, thus providing additional evidence of construct validity, especially for the verbal ABC. Finally, the verbal and the figural ABC yielded convincing within-person validity: Longer response times and higher subjective originality ratings were associated with more original ideas. This replication and extension of the ABC’s psychometric properties indicates that it enables a reliable and valid assessment of moment-to-moment fluctuations of creative ideation abilities in everyday life, which may facilitate the investigation of exciting new research questions related to dynamic aspects of creative ability.

Physiological stress reactivity and recovery: Some laboratory results transfer to daily life

Stress is a prevalent theme in our daily lives and is related to numerous negative health outcomes. Laboratory research has studied the physiological stress response extensively with objective measures such as vagally-mediated heart rate variability (vmHRV). Recently, the vagal tank theory emerged as a promising approach to predicting adaptive vmHRV levels around stressful events. This study aimed to investigate whether the predictions of the vagal tank theory about vmHRV during stress reactivity and recovery translate into naturalistic stressful events in daily life. Sixty-seven students wore an EcgMove 4 sensor for 4 days to measure vmHRV. Through a combination of device-based and self-report assessment, vmHRV data were segmented into before, during, and after stressful events. VmHRV segments were analyzed with multilevel modeling, accounting for physiological and psychological covariates. VmHRV before stressful events predicted more adaptive vmHRV during the event but not vmHRV recovery afterwards. The results therefore partially support the vagal tank theory's predictions with data from daily life and allow recommendations for future studies of real-world stress reactivity and recovery. The value of intraindividual variations in vmHRV as predictors of adaptive stress response is underscored by these findings and could inform future interventions that seek to increase momentary vmHRV.

Ecological Momentary Assessment of Creative Ideation

Abstract. Creative ideas in daily life show substantial variation in quality. Yet, most studies investigate the creative ideation process in highly controlled laboratory contexts, which challenges the ecological validity of creativity research findings. In this article, we advocate the use of ambulatory assessments of creative ideation to gain deeper insight into the variability of ideation processes (between- and within-subjects) in everyday life. We demonstrate this approach by the example of the ambulatory battery of creativity (ABC), which constitutes a reliable and valid approach to assess divergent thinking ability in the verbal and figural domain in everyday life context. Furthermore, it differentiates between-person and within-person variation of creative ideation performance. The first part of this paper will shortly describe the general approach using ABC as an example. In the second part, we use the 7 C’s heuristic to explore applications and implications of this novel method for creativity research. We focus on four C’s with special relevance for ambulatory assessment: Creator, Creating, Context, and Curricula. To this end, we review the findings of strongly controlled laboratory studies and discuss and illustrate applications of the ambulatory assessment. We conclude that the assessment of creative ideation performance in the field might help move the spotlight of creative ideation research from the laboratory to more naturalistic settings. This would increase the ecological validity of creative ideation research and facilitate fresh or unprecedented perspectives on past and future questions on a person’s creative potential and its moment-to-moment fluctuation.

Feelings from the Heart Part II: Simulation and Validation of Static and Dynamic HRV Decrease-Trigger Algorithms to Detect Stress in Firefighters

Several mobile devices have multiple sensors on board and interact with smartphones. This allows for a complex online evaluation of physiological data, important for interactive psychophysiological assessments, which targets the triggering of psychological states based on physiological data such as heart rate variability (HRV). However, algorithms designed to trigger meaningful physiological processes are rare. One exception is the concept of additional HRV reduction (AddHRVr), which aims to control for metabolic-related changes in cardiac activity. In this study we present an approach, based on data of a previous study, which allows algorithm settings to be derived that could be used to automatically trigger the assessment of psychosocial states by online-analysis of transient HRV changes in a sample of 38 firefighters. Settings of a static and a dynamic AddHRVr algorithm were systematically manipulated and quantified by binary triggers. These triggers were subjected to multilevel models predicting increases of objective stress during a period of 24 h. Effect estimates (i.e., odds) and bootstrap power simulations were calculated to inform about the most robust algorithm settings. This study delivers evidence that a dynamic AddHRVr algorithm can trigger transitions of stress, which should be further validated in future interactive psychophysiological assessments.