Heart Rate Variability Research Articles

Changes in physiological signal entropy in patients with obstructive sleep apnoea: a systematic review

Background and Objective Obstructive sleep apnoea (OSA) affects an estimated 936 million people worldwide, yet only 15% receive a definitive diagnosis. Diagnosis of OSA poses challenges due to the dynamic nature of physiological signals such as oxygen saturation (SpO2) and heart rate variability (HRV). Linear analysis methods may not fully capture the irregularities present in these signals. The application of entropy of routine physiological signals offers a promising method to better measure variabilities in dynamic biological data. This review aims to explore entropy changes in physiological signals among individuals with OSA.
Methods Keyword and title searches were performed on Medline, Embase, Scopus, and CINAHL databases. Studies had to analyse physiological signals in OSA using entropy. Quality assessment used the Newcastle-Ottawa Scale. Evidence was qualitatively synthesized, considering entropy signals, entropy type, and time-series length.
Main results Twenty-two studies were included. Multiple physiological signals related to OSA, including SpO2, HRV, and the oxygen desaturation index (ODI), have been investigated using entropy. Results revealed a significant decrease in HRV entropy in those with OSA compared to control groups. Conversely, SpO2 and ODI entropy values were increased in OSA. Despite variations in entropy types, time scales, and data extraction devices, studies using receiver operating characteristic (ROC) curves demonstrated a high discriminative accuracy (>80% AUC) in distinguishing OSA patients from control groups. 
Conclusions This review highlights the potential of SpO2 entropy analysis in developing new diagnostic indices for patients with OSA. Further investigation is needed before applying this technique clinically.
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P098 CARDIAC REMODELING IN MICE TREATED WITH SODIUM OXALATE AND AORTIC STENOSIS

Background: Cardiovascular Diseases are one of the main global public health problems, with increasing mortality due to population aging and Hypertension (HTN). HTN is a risk factor for other diseases, such as aortic stenosis, renal dysfunction, and cardiac hypertrophy (CH). The hemodynamic overload caused by HTN affects the heart and kidneys, but the exact mechanisms of these alterations are not fully understood. Experimental models help study these mechanisms; however, a well-established model of CH with cardiorenal dysfunction does not yet exist. Objective: to evaluate whether the combination of cardiac hypertrophy, induced by transverse aortic constriction (TAC), and renal injury, induced by soluble sodium oxalate (OXA), can be a new model of CH with cardiorenal dysfunction. Methods: Male C57BL mice were randomized as follows: SHAM, receiving saline or OXA solution, and TAC, receiving saline or OXA solution. Echocardiography, direct blood pressure (BP) recording, metabolic cage, histology were performed to evaluate cardiac and renal function, hemodynamics, autonomic modulation, and baroreflex. Results: The TAC+OXA group showed the highest systolic BP(SBP) (SBP: SHAM: 122±5.24 vs. TAC+OXA: 160±5.24 mmHg, p<0.01), increased double product (DP) (DP: SHAM: 64.65±4.76 mmHg/bpm vs. TAC: 89.53±5.85 mmHg/bpm, p=0.02), significant reduction in autonomic modulation (RMSSD: OXA: 12.5±1.8 vs. TAC+OXA: 2.8±0.2 ms, p<0.01) and reflex tachycardia, eccentric hypertrophy, and worse renal function. The TAC group showed eccentric hypertrophy, increased BP variability (SD-SBP: SHAM: 2.97±0.07 mmHg vs. TAC: 5.63±0.57 mmHg, p≤0.01), diastolic dysfunction, and dilated left ventricle in diastole. The OXA group showed increased autonomic modulation and heart rate variability, renal damage characterized by inflammation, proximal tubule damage, and interstitial fibrosis when associated with TAC. All treated groups showed a significant reduction in reflex tachycardia. Conclusion: Transverse aortic constriction combined with OXA gavage is a model of CH with renal dysfunction, as the combination caused more significant renal damage, systemic hypertension, decreased autonomic modulation and baroreflex sensitivity, and eccentric hypertrophy with subsequent LV diastolic dysfunction.

Influencing factors and physiological parameters of psychological hurdle and motivation immediately prior to exercise.

To obtain the benefits of exercise as physical inactivity becomes a global concern, managing psychological hurdles to exercise implementation is important. This study examined troublesomeness, motivation, and physiological parameters immediately before exhaustive exercise. Thirty-one healthy university students (mean age 19.87±2.21 years, 19 female) performed two conditions on separate days: performing push-ups to exhaustion (PE condition) and performing push-ups of the 30% count of the PE condition (P30 condition). Before the push-ups, the participants sat at rest for 5 minutes and were asked about their psychological states; after the first 2 minutes, PE or P30 conditions to be performed that day were disclosed to prepare them psychologically. During the rest, changes in the heart rate variability (HRV), pupil diameter, and front polar area (FPA) neural activity were measured before and after disclosure. Troublesomeness and FPA neural activities were significantly higher in the PE than in the P30 (P<0.001, P=0.04, P=0.01). Correlation analysis revealed correlations between motivation and pupil diameter (P=0.002), and negative correlations between total physical activity (TPA) and negative image of exercise (P=0.01). FPA activity could reflect the psychological hurdle to exhaustive exercise, pupil diameter could reflect the motivational arousal to exercise, and TPA could modulate the psychological hurdle.

Association between instantaneous heart rate sequence during the awake period and cardiovascular events: a study based on Sleep Heart Health Study.

Heart rate variability (HRV) has been reported to be associated with cardiovascular diseases (CVD), while few studies focused on the instantaneous heart rate (IHR). This study aimed to establish models to predict the occurrence of cardiovascular events based on the IHR sequence. A total of 2977 participants with useful electrocardiogram (ECG) data and free of CVD events at baseline from the Sleep Heart Health Study (SHHS) database were included in this retrospective cohort study. All IHR indicators were measured during the awake period before sleep. The logistic regression, random forest, and XGBoost methods were used to develop the predictive models. The model performance was quantified by calculating the area under the curve (AUC). Of theses 2977 participants, 1460 (49.04%) participants had CVD events during the 15-year follow-up. Higher standard deviation of IHR (SDHR) (OR=0.906; 95% CI, 0.832-0.986), coefficient of variation of IHR (CVHR) (OR=0.910; 95% CI, 0.835-0.990), power in low frequency (LF) (OR=0.896; 95% CI, 0.822-0.975), power in high frequency (HF) (OR=0.872; 95% CI, 0.796-0.955), and total power (TP) (OR=0.887; 95% CI, 0.813-0.967) were associated with the lower risk of CVD events, while ratio of semi-minor axis and semi-major axis in Poincare plot (SDratio) (OR=1.105; 95% CI, 1.012-1.206) was related to the higher risk of CVD events. The AUCs of the logistic regression, random forest, and the XGBoost models were 0.734 (95% CI, 0.701-0.767), 0.794 (95% CI, 0.764-0.823) and 0.828 (95% CI, 0.801-0.855) in the testing set, respectively. IHR sequences were important predictors of cardiovascular events. The IHR indicators should be paid more attention to in future clinical researches on CVD.

3M: Measuring Vital Signs With Markov-Gauss Model.

Measuring vital signs (VS) contained in the echoes is crucial to the analyses of breathing and heartbeat signals using medical radar. Although many advanced signal processing algorithms have been developed for radar-based VS measurement and make some improved progress, existing schemes cannot achieve a good estimation of echo phases modulated by the respiratory and cardiac activities with high accuracy or low computation, and thus resulting in serious performance degradation on the subsequent separation of breathing and heartbeat patterns as well as the assessment of breathing rate (BR), heart rate (HR), and heart rate variability (HRV). In this paper, we propose a simple yet effective method to measure VS for medical radar, named 3M method. Specifically, our method firstly introduces the Markov-Gauss model to obtain the recursive expression of the echo phases carrying VS, and secondly derive a simple observation equation (SOE) to reflect the relationship between the observed signal and VS of radar measurement. Thirdly, the aforementioned Markov-Gauss model and SOE are fused by Kalman filter to measure VS with accurate estimation. The 3M method demonstrates an elegant structure, low complexity and excellent features introduced by Kalman filter. Simulation results show the superiority of 3M over other methods. Then, we conduct extensive experiments with insightful visualizations to validate the effectiveness of the 3M method. Comparative results on different scenarios illustrate that the 3M method not only achieves state-of-the-art VS measurement performance but also expresses robust properties to HRV analysis.

Safety and Effectiveness of Acute Intermittent Hypoxia during a Single Treatment at Different Hypoxic Severities

PurposeExamine the cardiovascular, muscular function, cognitive, and neural plastic responses to determine the safety and effectiveness of acute Intermittent hypoxia (AIH) at a low, high, and control fractional inspired oxygen (FiO2) dosage MethodsThirteen human participants performed 30-min of AIH in 60-s intervals at FiO2’s of 0.21 (AIH21), 0.15 (AIH15), and 0.09 (AIH9). Heart rate variability (root mean squared of successive differences; RMSSD), heart rate, oxygen saturation (SpO2), blood pressure, muscular strength, neuromuscular activation, cerebral hemodynamic responses, cognition, symptomology, and brain-derived neurotrophic factor (BDNF) responses were measured before (Pre-AIH), after (post-AIH), and at 20-min of recovery (Recovery-AIH) ResultsThere were no differences between AIH protocols for heart rate, RMSSD, blood pressure, or SpO2. Muscular strength improved Post-AIH for AIH15 (10%) and AIH9 (14%) and remained elevated (6%) at Recovery-AIH. Neuromuscular activation increased Pre-AIH to Post-AIH for AIH15 (10%) and AIH9 (11%). Cerebral hemodynamic responses were not impacted between conditions. Both AIH15 and AIH9 increased BDNF Post-AIH (62%) and Recovery-AIH (63%) ConclusionAcute intermittent hypoxia is generally safe and effective at producing neural plastic responses, but further examination of co-occurring cardiovascular diseases is needed. This study provides safety focused findings which will widen the adoption and refinement of AIH protocols

Approach to Aircraft Handling Qualities Prediction

For the decades that followed the publication of the Cooper–Harper report that formalized a standard and universally recognized handling qualities pilot rating scale, researchers have sought to correlate pilot compensation—as well as physical and mental workload—with the assigned rating. A quantitative correlation remains elusive. In recent years, new physiological measurement devices have been developed that, together with software processing tools, can provide accurate measures of psychophysiological measures, including cognitive workload, distraction, and high/low engagement, based on electroencephalogram and electrocardiogram measures (i.e., brain waves and heart rate variability). The pilot compensation referred to in the Cooper–Harper scale is also a function of task performance measures that reflect aircraft characteristics and inceptor activity that reflects upon physical workload. Using a new piloted simulation test database generated in Manned Flight Simulator’s containerized rotary-wing simulator with 10 experienced test pilots, a machine-learning-based software algorithm that integrates a disparate mix of pilot–vehicle system, physiological, and task performance measures was used to further develop an approach to predict handling qualities levels and ratings.

Neuromodulation of Cardiovascular Risks Associated With Cardiotoxic Chemotherapy: A First-in-Human Randomized Pilot Study. Neuromodulation in Cancer Study (NCAN).

Cardiotoxic chemotherapy is used to treat malignancies such as breast cancer and lymphoma. These treatments predispose patients to cardiotoxicity that can lead to cancer treatment-related cardiac dysfunction (CTRCD). The use of high doses of anthracyclines or in combination with human epidermal growth factor receptor 2 antagonists is associated with a progressively higher risk of CTRCD. CTRCD is preceded by increased activation of the sympathetic nervous system and abnormal left ventricular mechanical deformation as measured by abnormal global longitudinal strain (GLS). Low-level tragus stimulation (LLTS) is a new, safe, noninvasive technique that offers great potential to reduce increased sympathetic activation and improve GLS. Here, we describe a study method to examine the effects of LLTS on autonomic balance and cardiac function in breast cancer or lymphoma patients treated with anthracyclines. A first-in-human pilot, randomized, double-blind feasibility study will evaluate 104 patients (age >50y) with breast cancer or lymphoma who receive anthracyclines with one additional CTRCD risk factor. Patients undergo 2 weeks of LLTS daily (1 h/d). Autonomic balance will be measured using heart rate variability metrics. Strain imaging using GLS will be performed pre and post-LLTS. Endothelial inflammation and oxidative stress measures will be performed using in vitro assays at baseline and after 2 weeks. We hypothesize that LLTS stabilizes sympathovagal imbalance and improves cardiac performance in anthracycline-treated patients with breast cancer or lymphoma.

ER-GET: Emotion Recognition Based on Global ECG Trajectory.

In recent years, the recognition of human emotions based on electrocardiogram (ECG) signals has been considered a novel area of study among researchers. Despite the challenge of extracting latent emotion information from ECG signals, existing methods are able to recognize emotions by calculating the heart rate variability (HRV) features. However, such local features have drawbacks, as they do not provide a comprehensive description of ECG signals, leading to suboptimal recognition performance. For the first time, we propose a new strategy to extract hidden emotional information from the global ECG trajectory for emotion recognition. Specifically, a period of ECG signals is decomposed into sub-signals of different frequency bands through ensemble empirical mode decomposition (EEMD), and a series of multi-sequence trajectory graphs is constructed by orthogonally combining these sub-signals to extract latent emotional information. Additionally, to better utilize these graph features, a network has been designed that includes self-supervised graph representation learning and ensemble learning for classification. This approach surpasses recent notable works, achieving outstanding results, with an accuracy of 95.08% in arousal and 95.90% in valence detection. Additionally, this global feature is compared and discussed in relation to HRV features, with the intention of providing inspiration for subsequent research.

The dynamic role of the left dlPFC in neurovisceral integration: Differential effects of theta burst stimulation on vagally mediated heart rate variability and cognitive-affective processing.

Adapting to the ever-changing demands of the environment requires a complex interplay between cognitive-affective, neuronal, and autonomic processes. Vagally mediated heart rate variability (vmHRV) is positively associated with both cognitive-affective functioning and prefrontal cortex (PFC) activity. Accordingly, the Neurovisceral Integration Model has posited a shared role of the PFC in the regulation of cognitive-affective processes and autonomic nervous system (ANS) activity. While there are numerous correlational findings in this regard, no study so far has investigated whether the manipulation of PFC activity induces changes in vmHRV and cognitive-affective processing in an inter-dependent manner. In a sample of 64 participants, we examined the effects of continuous (cTBS; n = 21) and intermittent theta-burst stimulation (iTBS; n = 20) compared to sham stimulation (n = 23) over the left dorsolateral PFC (dlPFC) on vmHRV and cognitive-affective processing within an emotional stop-signal task (ESST). Our results revealed that both resting vmHRV and vmHRV reactivity predicted cognitive-affective processing. Furthermore, we found a dampening effect of cTBS on resting and on-task vmHRV, as well as an enhancing effect of iTBS on ESST performance. Our results show no direct association between vmHRV changes and ESST performance alterations following stimulation. We interpret our results in the light of a hierarchical model of neurovisceral integration, suggesting a dynamical situation-dependent recruitment of higher-order cortical areas like the dlPFC in the regulation of the ANS. In conclusion, our results highlight the complex interplay between PFC activity, autonomic regulation, and cognitive-affective processing, emphasizing the need for further research to understand the causal dynamics of the underlying neural mechanisms.

Osteopathische herzfokussierte Palpation und Herzfrequenzvariabilität: Teil 1 – Ziele, Material und Methoden der randomisierten, kontrollierten Pilotstudie

Does osteopathic heart-focused palpation change heart rate variability in people with musculoskeletal pain who are under stress? Part 1 of this two-part article describes the aims, material, methods and participants of the randomized, controlled pilot study; part 2 in the following issue will present the results.Heart rate variability (HRV) describes fluctuations in time intervals between heartbeats and reflects autonomic activity. HRV is reduced in stressed patients with musculoskeletal pain and improved after osteopathic manipulative treatment and mind–body interventions. Heart-focused palpation (HFP) combines manual and mind–body approaches to facilitate relaxation. This randomised controlled pilot study investigated the feasibility and sample size for a future randomised controlled trial and the effect of a single treatment with HFP or sham HFP (SHAM) on short-term HRV. A total of 33 adults with stress and musculoskeletal pain completed the trial.

THE RELATIONSHIP BETWEEN CARDIOINTERVALOGRAPHY INDICATORS AND PSYCHOLOGICAL COMPONENTS OF THE ADAPTIVE POTENTIAL OF CADETS IN THE FIRST YEAR OF STUDY

Military service is a very specific type of activity, during which the human body can be exposed to a whole range of unfavorable factors of various etiologies. The most difficult period in military service is the initial adaptation period, when the physiological and psychological restructuring of the soldier's body occurs, his adaptation to life and everyday life, to the requirements of the military environment. Adaptation of military personnel to military activities affects the success of this activity, as well as the preservation of the health of military personnel. The study of the features of the process of adaptation to military service seems important for organizing high-quality training of personnel and achieving the ability of military personnel to withstand significant physical and neuropsychic stress. All this also applies to students of military educational institutions. In this case, motivation will be understood as a time-limited psychophysiological process that controls the behavior of an individual, setting its direction, organization, activity and stability; the ability of a person to actively satisfy his needs, while further acting in the interests of the state and society. One of the important areas of this work, which has great practical significance, is the study, assessment and forecasting of the adaptive capabilities of the cadets' body. Most often, psychological diagnostic methods are used to determine the level of adaptation, but recently instrumental research methods, in particular, heart rate variability analysis, have become increasingly widespread.

Intrathecal Dexmedetomidine as an Adjuvant to Low Dose Hyperbaric 0.5% Bupivacaine on Haemodynamic Parameters in Patients Undergoing Transurethral Resection of Prostate.

To determine the role of dexmedetomidine in potentiating the local anaesthetic efficacy of a low dose of bupivacaine when used as an adjuvant. A prospective, double-blind, randomised study. Place and Duration of the Study: Department of Anaesthesia, Sindh Institute of Urology and Transplantation, Karachi, Pakistan, from July 2021 to February 2022. One hundred and eight patients of ASA physical class I-III undergoing transurethral resection of the prostate (TURP) under sub-arachnoid block (SAB) were enroled and distributed into two equal groups. Group BUPIPURE (BP) was given 7.5 mg of pure 0.5% hyperbaric bupivacain whereas group BUPIDEX (BD) was given 6 mg of 0.5% hyperbaric bupivacain with 3 μg dexmedetomidine intrathecally. The effects in Both groups were compared using chi-square and unpaired t-tests. A significance level of p <0.05 was used to evaluate the statistical significance. Both groups demonstrated a steady decrease in mean heart rate (mean HR 98.9-62.7 per minute as compared to 79.1-59.4 per minute in groups BP and BD, respectively), however, no patient reached to HR <50/min. Group BP had a higher HR variability than group BD. The two groups' median peak sensory levels were similar. However, a statistically significant difference was revealed in the time taken for 2-segment regression (87.5 ± 11.3 min vs. 115.5 ± 6.2 min p <0.001 in BP and BD), as well as the time to reach T10 sensory level (13.56 ± 2.5 min vs. 10.9 ± 3.0 min p <0.001). In patients having TURP, intrathecal dexmedetomidine combined with low-dose bupivacaine results in a quicker start, extended sensory and motor block, and a decreased need for rescue analgesics. Adjuvants, Dexmedetomidine, Spinal anaesthesia, Transurethral Resection of Prostate.

Pupillometry and autonomic nervous system responses to cognitive load and false feedback: an unsupervised machine learning approach.

Pupil dilation is controlled both by sympathetic and parasympathetic nervous system branches. We hypothesized that the dynamic of pupil size changes under cognitive load with additional false feedback can predict individual behavior along with heart rate variability (HRV) patterns and eye movements reflecting specific adaptability to cognitive stress. To test this, we employed an unsupervised machine learning approach to recognize groups of individuals distinguished by pupil dilation dynamics and then compared their autonomic nervous system (ANS) responses along with time, performance, and self-esteem indicators in cognitive tasks. Cohort of 70 participants were exposed to tasks with increasing cognitive load and deception, with measurements of pupillary dynamics, HRV, eye movements, and cognitive performance and behavioral data. Utilizing machine learning k-means clustering algorithm, pupillometry data were segmented to distinct responses to increasing cognitive load and deceit. Further analysis compared clusters, focusing on how physiological (HRV, eye movements) and cognitive metrics (time, mistakes, self-esteem) varied across two clusters of different pupillary response patterns, investigating the relationship between pupil dynamics and autonomic reactions. Cluster analysis of pupillometry data identified two distinct groups with statistically significant varying physiological and behavioral responses. Cluster 0 showed elevated HRV, alongside larger initial pupil sizes. Cluster 1 participants presented lower HRV but demonstrated increased and pronounced oculomotor activity. Behavioral differences included reporting more errors and lower self-esteem in Cluster 0, and faster response times with more precise reactions to deception demonstrated by Cluster 1. Lifestyle variations such as smoking habits and differences in Epworth Sleepiness Scale scores were significant between the clusters. The differentiation in pupillary dynamics and related metrics between the clusters underlines the complex interplay between autonomic regulation, cognitive load, and behavioral responses to cognitive load and deceptive feedback. These findings underscore the potential of pupillometry combined with machine learning in identifying individual differences in stress resilience and cognitive performance. Our research on pupillary dynamics and ANS patterns can lead to the development of remote diagnostic tools for real-time cognitive stress monitoring and performance optimization, applicable in clinical, educational, and occupational settings.

The relationship between emotions and HRV under the stimulation of bra images

It is a stressful ordeal in general to buy bras online aimlessly. The wise approach for eCommerce platform is to use emotion recognition to effectively assess consumers’ needs through the bra images, which can quickly close their preferences and accurately recommend them suitable bras. However, the significant physiological features that can be used for emotion recognition in fashion are still in the exploratory stage. This study focuses on the relationship between cardiac activity and emotional responses (the different levels of Satisfaction (S) and Attractiveness (A) under the stimulation of bra images. Firstly, we labelled 96 bra images in the dimensions and selected 45 bra images to make three groups of emotional stimuli using k-means clustering analysis. Then, we collected Photoplethysmogram (PPG) signals from 46 subjects consisting of 11 males and 35 females simulated by three groups of the stimuli, extracted 10 metrics of heart rate variability (HRV), and then analyzed the relationships between HRV and emotions based on their subjective evaluation. The males and females have different cardiac activity patterns under the same emotion, that the parasympathetic of males are more active than females. In a non-neutral emotion, the parasympathetic nervous system would keep an activated state. However, it is dominated by the parasympathetic nervous system whether in high or low satisfaction. While high and low attractiveness are respectively dominated by the sympathetic and parasympathetic nerves. The results of this study have certain significance for understanding the physiological phenomenon of emotions and further help to explore emotion recognition technology which can be used in product development to enhance the competitiveness of enterprises.

The effect of age on heart rate variability indices during and following high-intensity continuous exercise in masters and young cyclists.

This study compared heart rate variability (HRV) parameters of cardiovascular autonomic regulation between well-trained masters and young cyclists at rest, during and following a continuous cycle (CTS) protocol. Ten masters (age = 56 ± 5years) and eight young (age = 26 ± 3years) cyclists completed a 100min experimental protocol consisting of a 60min CTS cycling bout at 95% of Ventilatory Threshold 2 followed by 40min of supine recovery. Beat-to-beat heart rate was measured continuously, and HRV parameters analysed at standardised 5min intervals during rest, exercise and recovery. The root mean square of the successive differences (RMSSD), low-frequency power and high-frequency power parameters were corrected by division of the R-R interval (time domain), or R-R interval squared (frequency domain). Further, the RMSSD and RMSSD:RR for successive 60-s R-R intervals at the onset (0-10min) and offset (60-70min) of CTS exercise were analysed over 10-min periods. The natural logarithm (Ln) of skewed parameters was taken for analysis. Significant interaction effects (P < 0.05) for 5min segments were found for (LnRMSSD, LnRMSSD:RR, LnHF and LnHF:RR2. Masters cyclists demonstrated lower values of parasympathetic activity at rest and during recovery (15-20min and 35-40min) compared to younger cyclists. However, similar HRV responses were observed during exercise, including throughout the acute onset and offset periods (P > 0.05). This data shows that cardiac autonomic regulation during, or immediately following CTS exercise may not be influenced by age, but masters athletes may exhibit a lower baseline for parasympathetic activity.

Effects of Biofeedback Training on Shooters' Performance, Stress Levels, and HRV

This study aimed to explore the impact of a 12-week biofeedback training on shooters' performance, stress levels, and heart rate variability (HRV). Thirty-six shooters aged 18-24 (18 subjects in each group) participated. The experimental group underwent 12 weeks of biofeedback and shooting training, while the control group only received shooting training. Results showed significant improvements in performance, stress levels, and HRV parameters in the experimental group, reflecting enhanced parasympathetic activity. It was further revealed that TP value was negatively correlated with stress level and positively correlated with performance, and stress level was negatively correlated with performance.

Multidimensional analysis of heart rate variability and burden of illness in bipolar disorder

IntroductionPatients with bipolar disorder (BD) face disproportionate rates of cardiovascular disease. While several mechanisms have been proposed for this association, both are multifactorial and heterogeneous illnesses, and it is unlikely that any individual factor can account for a significant portion of their association. Potential mediators have been mostly studied in isolation even though they are interrelated. Furthermore, few studies have accounted for baseline cardiovascular functioning or burden of illness. MethodsWe sought to analyze the association between burden of illness, phase of the illness (e.g., depressive) and heart rate variability (HRV) in 48 patients diagnosed with BD using canonical correlation analysis. We hypothesized that the association between burden of illness and HRV measures would be different depending on the clinical phase (i.e., euthymia, depression or (hypo)mania). ResultsA longer duration of (hypo)manic episodes was associated with higher rates of hypertension and increased sympathetic activation, along with lower rates of migraine and family history of suicide. In the second canonical variable, a later age at onset of (hypo)manic episodes was associated with higher parasympathetic activity. LimitationsSmall sample size; while the magnitudes of correlations for these top functions were large, none of the models were statistically significant. ConclusionsThere are different dimensions to the association between burden of illness and HRV in BD. The first dimension could comprise higher sympathetic activation in the context of longer (hypo)manic episodes, with lower rates for clinical variables that have been associated with a predominant depressive polarity (e.g., family history of suicide and migraine).

Horses’ Cardiovascular and Glucocorticoid Responses to Equine-Assisted Therapy with Women with Intellectual Disability: An Exploratory Study

ABSTRACT Research on equine-assisted therapy (EAT) has primarily been centered on human health. Relatively few studies have addressed the impact of EAT on horses. This study sought to monitor four experienced therapy horses’ cardiovascular and glucocorticoid activity over the course of standardized EAT sessions designed to support women with intellectual disability. In the control condition, horses completed the EAT protocol solely with the therapist, thereby resembling a training session. Descriptive data analysis revealed higher levels of heart rate during an experimental EAT session and increased salivary cortisol when horses were navigated by the client through an obstacle course during the “challenge” phase of the protocol, pointing at a greater physical demand due to the recipient on horseback. Given the parasympathetic activity and overall heart rate variability across experimental EAT sessions and the cortisol recovery after the sessions, the findings do not give rise to any acute animal welfare concerns. For a more holistic interpretation of the present research results, further investigation into the horse perception of EAT, based on a bigger sample size and additional markers of welfare, is needed.

Acute stress does not influence the learning of a precise manual task: A randomized clinical trial

Acute stress is frequent in sports and rehabilitation contexts and can impact cognitive processes essential for motor learning. This study aimed to investigate the influence of induced acute stress on the learning of a precise manual task, examining its effect on five key parameters of fine motor control: trajectory error, trajectory error direction, time error, tracing accuracy, and task accuracy. A double-masked, randomized clinical trial with 62 participants (average age 20.65 ± 2.54 years; 39 females; 23 males) was conducted. To examine the effects of stress, participants were assigned to either a stress or a control group through stratified randomization by sex. Initially, all participants underwent the Maastricht Acute Stress Test (in its acute stress and control versions, respectively). Subsequently, they performed the precise manual task on a graphic tablet at three stages of the learning process: acquisition, short-term retrieval, and long-term retrieval. Electrodermal activity and heart rate variability were recorded to assess stress induction. Data analysis from 30 stress group participants and 25 control group participants revealed no statistically significant differences between groups in any of the variables studied at the three learning stages. Both groups exhibited statistically significant improvements in time error, trajectory error direction, and tracing accuracy during both short-term and long-term retrieval compared to acquisition. Our findings suggest that acute physical and psychological stress does not markedly impair learning a precise manual task of adhering to a specific trajectory and pace among young adults.