Heart Rate Variability and Cognitive Function In Middle-Age Adults: The Coronary Artery Risk Development in Young Adults

The Clinical Role of Heart Rate Variability Assessment in Cognitively Impaired Patients and Its Applicability in Community Care Settings: A Systematic Review of the Literature

Heart rate variability (HRV) correlates well with a person's overall physiological function. Clinically, HRV is successfully used in acute care to identify impending infections, but little is known about its potential in the management of chronic diseases like cognitive decline/dementia. The aim of this study was to identify the best available knowledge about HRV in cognitively impaired populations that might be applied to improve clinical practice in community settings. We conducted a systematic literature search in PubMed, Embase, and Cochrane databases published from January 2009 to August 2022. Eligible studies were selected using Covidence and each study underwent qualitative assessment using the Mixed Method Appraisal Tool. At each stage of selection, each study was reviewed independently by two members of the team, and any disputes were discussed along the way. The literature identified that the brain regions controlling HRV are also those affected by dementias of Alzheimer's type (AD) and Lewy body types (DLB). HRV was impaired in both types, with DLB showing greater impairment in all HRV parameters compared to AD. No studies explored the temporal changes of HRV or its use in the clinical management of people with cognitive impairment (CI). The current lack of standardization of HRV recording and analysis limits its use in clinical practice. HRV may emerge as a potentially useful tool to identify people with early/preclinical memory impairment and help to differentiate AD from DLB. Longitudinal HRV measurement is emerging as a useful way to monitor disease progression and treatment response, and continuous HRV measurement may prove useful in the early identification of sepsis and its complications in patients no longer able to communicate their illness experiences.

The Influence of Kapalabhati on Working Memory and Phasic Heart Rate Variability

BACKGROUND

Cognitive communication abilities, such as working memory (WM), are vital for accomplishing daily activities and are also important for higher-order processes such as planning and problem-solving. The current study investigates the simultaneous effect of kapalabhati (KBH) on WM and phasic heart rate variability (HRV).

METHODS

Twenty participants who fulfilled the inclusion and exclusion criteria, with an average age of 23.65±3.07 years (mean±SD), were recruited for the study. Prior to data collection, the participants underwent a seven-day orientation to maintain uniformity in KBH practice. EKGs were assessed using a 16-channel polygraph system arranged in a standard limb lead II configuration. WM was assessed using E-Prime version 2.0 (Psychology Software Tools, Sharpsburg, PA, USA).

RESULTS

There was a significant increase in accuracy after the immediate KBH practice in all three conditions of the WM task (i.e., n-back task: 0-back, 1-back, and 2-back). However, there was also an increase in reaction time. Repeated measures ANOVA of HRV measures showed statistically significant changes in mean rhythm-to-rhythm (RR) intervals, heart rate (HR), number of adjacent N-N intervals over 50 milliseconds (NN50), percentage of successive normal sinus RR intervals greater than 50 milliseconds (pNN50 RR), low frequency (LF), and high frequency (HF), with HR, NN50, pNN50, LF, and HF all significant at p<0.001 and the LF/HF ratio significant at the p<0.01 level.

CONCLUSION

The results of the current study suggest that KBH practice can modulate vagal tone or parasympathetic activity and improve WM performance. Furthermore, the parasympathetic shift found in the present study may promote better cardioprotective health and longevity.

Loneliness during the post-confinement period: The significance of social living conditions for stress biomarkers and memory

In the aftermath of the COVID-19 lockdown, concerns about the impact of loneliness and reduced social interactions on mental health have arisen. This study explored the repercussions of post-lockdown social restrictions across psychological (loneliness, perceived stress, and depressive symptoms), biological (hair cortisol and cardiovascular activity), and cognitive dimensions (subjective memory complaints and working, declarative, and prospective memory), with a specific emphasis on perceived loneliness and the living situation. The study included 45 students: 23 (mean age = 25.69 years) in the Alone Group (AG), who experienced significant family changes and international relocation, and 22 (mean age = 25.50 years) in the Not Alone Group (NAG), who maintained their nuclear family and did not move from their home country. We assessed heart rate variability (HRV) before, during, and after immediate memory evaluations using time-domain (the square root of the mean, RMSSD) measures. The analysis revealed no significant group differences in telematic contact with family and friends, perceived stress, or depression. However, the AG participants reported fewer face-to-face interactions and greater perceived loneliness compared to the NAG. Additionally, the AG group exhibited slightly higher hair cortisol levels and worse working memory (WM) and prospective memory (PM) performance. Importantly, no significant associations were observed between memory outcomes and stress biomarkers. However, a significant interaction effect of loneliness in the relationship between hair cortisol levels and PM was found. That is, hair cortisol concentrations were negatively related to PM when participants perceived high and moderate loneliness. This interaction was absent in the working and declarative memory domains. In summary, these findings underscore the intricate interplay between loneliness, cortisol, and memory, emphasizing the need for comprehensive research on the complex mechanisms governing these multifaceted relationships.

Blood pressure variability supersedes heart rate variability as a real-world measure of dementia risk

Blood pressure variability (BPV) and heart rate variability (HRV) have been associated with Alzheimer's Disease and Related Dementias (ADRD) in rigorously controlled studies. However, the extent to which BPV and HRV may offer predictive information in real-world, routine clinical care is unclear. In a retrospective cohort study of 48,204 adults (age 54.9 ± 17.5 years, 60% female) receiving continuous care at a single center, we derived BPV and HRV from routinely collected clinical data. We use multivariable Cox models to evaluate the association of BPV and HRV, separately and in combination, with incident ADRD. Over a median 3 [2.4, 3.0] years, there were 443 cases of new-onset ADRD. We found that clinically derived measures of BPV, but not HRV, were consistently associated with incident ADRD. In combined analyses, only patients in both the highest quartile of BPV and lowest quartile of HRV had increased ADRD risk (HR 2.34, 95% CI 1.44-3.81). These results indicate that clinically derived BPV, rather than HRV, offers a consistent and readily available metric for ADRD risk assessment in a real-world patient care setting. Thus, implementation of BPV as a widely accessible tool could allow clinical providers to efficiently identify patients most likely to benefit from comprehensive ADRD screening.

Effects of Aerobic Exercise Combined With Attentional Bias Modification in the Care of Male Patients With a Methamphetamine Use Disorder

OBJECTIVE

It remains unclear which individual or combined strategies are most beneficial for methamphetamine use disorders (MUDs). We compared the effects of aerobic exercise, attentional bias modification, and combined intervention on male patients with MUD.

METHOD

One hundred male patients with MUD were randomly assigned to combined intervention, aerobic exercise, attentional bias modification, or control groups (25 patients per group). The 8-week intervention protocol included three 60-minute sessions of aerobic exercises per week. Primary outcomes included high- and low-frequency heart rate variability, executive function, and cardiorespiratory fitness measured by customized software, computerized tests, and the Harvard step test, respectively. Secondary outcomes included psychiatric symptoms, drug craving, training acceptability, and persistence.

RESULTS

Participant characteristics were matched between groups at baseline. Executive function, heart rate variability, cardiorespiratory fitness, drug craving, and most psychiatric symptoms had significant time-group interactions at posttest (p < .05, η2 = .08-.28). Compared with the attentional bias modification and control groups, the combined intervention and aerobic exercise groups improved significantly in executive function, heart rate variability, cardiorespiratory fitness, and most secondary outcomes. In addition, high-frequency heart rate variability and cardiorespiratory fitness in the aerobic exercise group were significantly higher than those in the combined intervention group.

CONCLUSIONS

Combination strategies showed comparable efficacy to aerobic exercise alone in improving executive function, psychiatric symptoms, and drug craving and significantly exceeded other conditions. For heart rate variability and cardiorespiratory fitness, aerobic exercise alone was the most effective. For acceptability and persistence, combination strategies were preferred over single-domain training and health education intervention.

Autonomic modulation and the risk of dementia in a middle-aged cohort: A 17-year follow-up study

BACKGROUND

Altered autonomic modulation, measured by heart rate variability (HRV), has been found to be associated with dementia risk in the elderly. However, long-term follow-up study evaluating the association between autonomic modulation from middle-age and the incidence of dementia has been limited.

METHODS

This retrospective cohort analyzed data from Taiwan's National Health Insurance Database covering the period from 2001 to 2017, with a linkage to citywide health examinations conducted by Tainan Metropolitan City, Taiwan. We included subjects aged 45-64 years. The mean follow-up period was 15.75 ± 3.40 years. The measurements of HRV included resting heart rate, high frequency (HF), low frequency (LF), standard deviation of normal-to-normal R-R intervals (SDNN), ratio between the 30th and 15th R-R interval after standing up from the supine position (30/15 ratio), ratio between the R-R intervals during expiration and inspiration, and the ratio between the high- and low-frequency components (LF/HF). The main study outcome was the incidence of dementia. We performed multivariable Cox proportional hazard regression models to compare the risk of dementia among different HRV subgroups.

RESULTS

We included 565 participants with a mean age of 53 (SD: 6) years, of whom 44% were male. The risk of dementia was significantly increased in association with lower parasympathetic HRV modulation, including SDNN (HR: 3.23, 95% CI: 1.55-6.73) and 30/15 ratio (HR: 3.52, 95%CI: 1.67-7.42). Moreover, the risk of dementia was increased in subjects with higher LF/HF ratios (HR: 2.05, 95% CI: 1.12-3.72).

CONCLUSIONS

Lower parasympathetic activity and higher sympathetic-vagal imbalance in middle-age were associated with dementia risk.

Autonomic Cardiovascular Control, Psychological Well-Being, and Cognitive Performance in People With Spinal Cord Injury

PURPOSE

To examine associations between parameters of psychological well-being, injury characteristics, cardiovascular autonomic nervous system (ANS) control, and cognitive performance in persons with spinal cord injury (SCI) compared with age-matched uninjured controls. This is an observational, cross-sectional study including a total of 94 participants (52 with SCI and 42 uninjured controls: UIC). Cardiovascular ANS responses were continuously monitored at rest and during administration of the Paced Auditory Serial Addition Test (PASAT). Self-report scores on the SCI-Quality of Life questionnaires are reported for depression, anxiety, fatigue, resilience, and positive affect. Participants with SCI performed significantly more poorly on the PASAT compared with the uninjured controls. Although not statistically significant, participants with SCI tended to report more psychological distress and less well-being than the uninjured controls. In addition, when compared with uninjured controls, the cardiovascular ANS responses to testing were significantly altered in participants with SCI; however, these responses to testing did not predict PASAT performance. Self-reported levels of anxiety were significantly related to PASAT score in the SCI group, but there was no significant relationship between PASAT and the other indices of SCI-Quality of Life. Future investigations should more closely examine the relationship among cardiovascular ANS impairments, psychological disorders, and cognitive dysfunction to better elucidate the underpinnings of these deficits and to guide interventions aimed at improving physiological, psychological, and cognitive health after SCI. Tetraplegia, paraplegia, blood pressure variability, cognitive, mood.

Effects of sleep fragmentation and partial sleep restriction on heart rate variability during night

We developed a cross-over study design with two interventions in randomized order to compare the effects of sleep fragmentation and partial sleep restriction on cardiac autonomic tone. Twenty male subjects (40.6 ± 7.5 years old) underwent overnight polysomnography during 2 weeks, each week containing one undisturbed baseline night, one intervention night (either sleep restriction with 5 h of sleep or sleep fragmentation with awakening every hour) and two undisturbed recovery nights. Parameters of heart rate variability (HRV) were used to assess cardiac autonomic modulation during the nights. Sleep restriction showed significant higher heart rate (p = 0.018) and lower HRV-pNN50 (p = 0.012) during sleep stage N1 and lower HRV-SDNN (p = 0.009) during wakefulness compared to the respective baseline. For HR and SDNN there were recovery effects. There was no significant difference comparing fragmentation night and its baseline. Comparing both intervention nights, sleep restriction had lower HRV high frequency (HF) components in stage N1 (p = 0.018) and stage N2 (p = 0.012), lower HRV low frequency (LF) (p = 0.007) regarding the entire night and lower SDNN (p = 0.033) during WASO during sleep. Sleep restriction increases sympathetic tone and decreases vagal tone during night causing increased autonomic stress, while fragmented sleep does not affect cardiac autonomic parameters in our sample.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

High vagally mediated resting-state heart rate variability is associated with superior working memory function

Background

Heart rate variability (HRV), a cardiac vagal tone indicator, has been proven to predict performance on some cognitive tasks that rely on the prefrontal cortex. However, the relationship between vagal tone and working memory remains understudied. This study explores the link between vagal tone and working memory function, combined with behavioral tasks and functional near-infrared spectroscopy (fNIRS).

Methods

A total of 42 undergraduate students were tested for 5-min resting-state HRV to obtain the root mean square of successive differences (rMSSD) data, and then divided into high and low vagal tone groups according to the median of rMSSD data. The two groups underwent the n-back test, and fNIRS was used to measure the neural activity in the test state. ANOVA and the independent sample t-test were performed to compare group mean differences, and the Pearson correlation coefficient was used for correlation analysis.

Results

The high vagal tone group had a shorter reaction time, higher accuracy, lower inverse efficiency score, and lower oxy-Hb concentration in the bilateral prefrontal cortex in the working memory tasks state. Furthermore, there were associations between behavioral performance, oxy-Hb concentration, and resting-state rMSSD.

Conclusion

Our findings suggest that high vagally mediated resting-state HRV is associated with working memory performance. High vagal tone means a higher efficiency of neural resources, beneficial to presenting a better working memory function.

Psychophysiological Stress Response of Novel Students in Chemical Laboratory Practices

Abstract. The aim of the present study was to analyze the psychophysiological stress response of novel pharmacy and biotechnology students in chemistry laboratory practices. Autonomic stress response was analyzed in 66 students by considering heart rate variability (HRV) values before, during, and after their first laboratory practice, as well as their distress perception before and after this activity. In the laboratory practice, students had to deal with toxic products, sharp objects, or irritating substances while being examined by the teachers. Consistent with a large anticipatory anxiety response at the beginning of the practice, results showed low HRV values, generally related to a typical sympathetic modulation. This sympathetic effect persisted during the entire laboratory practice. Moreover, just after the end of the practice, there was an attenuation of the sympathetic activation and a takeover by the parasympathetic system, as revealed by the increase of HRV parameters. Laboratory practices performed by novel Pharmacy and Biotechnology students did not produce the expected habituation response at psychophysiological level since, in addition to an anticipatory anxiety response observed prior to the laboratory practice, a high sympathetic autonomic activation was observed during the whole practice. In brief, using HRV parameters could be a useful tool to analyze stress responses in students and to help them with new strategies to improve routine evaluation procedures.

Understanding the roles of central and autonomic activity during sleep in the improvement of working memory and episodic memory

The last decade has seen significant progress in identifying sleep mechanisms that support cognition. Most of these studies focus on the link between electrophysiological events of the central nervous system during sleep and improvements in different cognitive domains, while the dynamic shifts of the autonomic nervous system across sleep have been largely overlooked. Recent studies, however, have identified significant contributions of autonomic inputs during sleep to cognition. Yet, there remain considerable gaps in understanding how central and autonomic systems work together during sleep to facilitate cognitive improvement. In this article we examine the evidence for the independent and interactive roles of central and autonomic activities during sleep and wake in cognitive processing. We specifically focus on the prefrontal-subcortical structures supporting working memory and mechanisms underlying the formation of hippocampal-dependent episodic memory. Our Slow Oscillation Switch Model identifies separate and competing underlying mechanisms supporting the two memory domains at the synaptic, systems, and behavioral levels. We propose that sleep is a competitive arena in which both memory domains vie for limited resources, experimentally demonstrated when boosting one system leads to a functional trade-off in electrophysiological and behavioral outcomes. As these findings inevitably lead to further questions, we suggest areas of future research to better understand how the brain and body interact to support a wide range of cognitive domains during a single sleep episode.

Physical activity trajectories, autonomic balance and cognitive function: The Coronary Artery Risk Development in Young Adults (CARDIA) study

Physical activity (PA) plays an important role in cognitive health. However, the underlying mechanisms are not fully understood. Cardiac autonomic balance is influenced by PA and implicated in dementia pathogenesis. We examined whether autonomic balance mediates the association between PA and cognitive function. The sample included 1939 participants from the Coronary Artery Risk Development in Young Adults study who completed cognitive testing after 30-year follow-up (baseline: mean age 25.2 ± 3.5y; 58% women; 43% Black). Moderate to vigorous intensity PA (MVPA) was obtained in 7 consecutive examinations over 20 years (Year 0-Year 20). Cardiac autonomic balance was assessed at Year 20 via resting heart rate (RHR), standard deviation normal to normal (SDNN) and root mean square of successive differences (RMSSD). We used group-based trajectory modeling to identify homogenous MVPA trajectory groups, and formal mediation analysis to test whether autonomic function indices mediate the association between MVPA trajectories and cognition. We identified three distinct PA trajectory patterns: (1) Below MVPA guidelines (n = 1122; 57.9%); (2) Meeting MVPA guidelines (n = 652; 33.6%); and (3) Exceeding MVPA guidelines (n = 165; 8.5%). Meeting and exceeding MVPA guidelines were related to better autonomic balance overall, and to improved semantic fluency performance. Statistically, the association between higher MVPA level and verbal ability was mediated by SDNN and RMSSD, but not by RHR. In our sample of young and middle-aged adults, higher MVPA levels over time were associated with better cardiac autonomic function, which explained some of the associations between PA trajectories and better cognition.

Autonomic function predicts cognitive decline in mild cognitive impairment: Evidence from power spectral analysis of heart rate variability in a longitudinal study

Background

Despite the emerging clinical relevance of heart rate variability (HRV) as a potential biomarker of cognitive decline and as a candidate target for intervention, there is a dearth of research on the prospective relationship between HRV and cognitive change. In particular, no study has addressed this issue in subjects with a diagnosis of cognitive status including cognitive impairment.

Objective

To investigate HRV as a predictor of cognitive decline in subjects with normal cognition (NC) or Mild Cognitive Impairment (MCI). Specifically, we tested the literature-based hypothesis that the HRV response to different physical challenges would predict decline in different cognitive domains.

Methods

This longitudinal study represents the approximately 3-year follow-up of a previous cross-sectional study enrolling 80 older outpatients (aged ≥ 65). At baseline, power spectral analysis of HRV was performed on five-minute electrocardiographic recordings at rest and during a sympathetic (active standing) and a parasympathetic (paced breathing) challenge. We focused on normalized HRV measures [normalized low frequency power (LFn) and the low frequency to high frequency power ratio (LF/HF)] and on their dynamic response from rest to challenge (Δ HRV). Extensive neuropsychological testing was used to diagnose cognitive status at baseline and to evaluate cognitive change over the follow-up via annualized changes in cognitive Z-scores. The association between Δ HRV and cognitive change was explored by means of linear regression, unadjusted and adjusted for potential confounders.

Results

In subjects diagnosed with MCI at baseline a greater response to a sympathetic challenge predicted a greater decline in episodic memory [adjusted model: Δ LFn, standardized regression coefficient (β) = −0.528, p = 0.019; Δ LF/HF, β = −0.643, p = 0.001] whereas a greater response to a parasympathetic challenge predicted a lesser decline in executive functioning (adjusted model: Δ LFn, β = −0.716, p < 0.001; Δ LF/HF, β = −0.935, p < 0.001).

Conclusion

Our findings provide novel insight into the link between HRV and cognition in MCI. They contribute to a better understanding of the heart-brain connection, but will require replication in larger cohorts.

Sympathetic Vagal Balance and Cognitive Performance in Young Adults during the NIH Cognitive Test

Compromised cognitive function is associated with increased mortality and increased healthcare costs. Autonomic nervous system arousal, as measured by an electrocardiogram (ECG), has received recent attention because of its association with the blood perfusion of brain regions involved with cognitive function. The purposes of this study were to determine whether the ECG HR variation, as measured by the standard deviation of the heart rate N-to-N intervals (SDNN), and sympathetic vagal tone, as estimated by the low-frequency/high-frequency ratio (LF/HF), are increased with cognitive performance during the NIH Cognitive Test (Picture Sequence, Dimensional Change Card Sort, Flanker, and List Sorting). A total of 62 young people without cognitive impairment participated in this study. We discovered that the ECG LF/HF ratio was increased in the top 50% of participants who could: (1) inhibit information and stay attentive to a desired task during the Flanker Test; (U = 329, p = 0.03; R² = 0.76); and (2) promote cognitive function flexibility during the DCCS Test; (U = 55, p = 0.007; R² = 0.98). Taken together, these findings support that the arousal level influences performance during a cognitive test.

Examining the Autonomic Nervous System in the Relationship among Heart Rate Variability, Stress Coping, and Cognitive Ability in Individuals with Psychiatric Disorders

Depression is one of the most severe psychiatric disorders and affects patients on emotional, physical, and cognitive levels. Comorbid somatic conditions, such as cardiovascular diseases, are frequent and affect the quality of life, as well as mortality. Underlying maladaptive autonomic nervous system regulation influences emotional and cognitive processes. This study, thus, aimed to investigate the relationship among heart rate variability (HRV), self-reported coping strategies, executive function, and inhibition in individuals with psychiatric disorders. Data of 97 patients treated in a multi-professional psychiatric rehabilitation center for 6 weeks were analyzed. Subjects underwent psychological tests (Stress Coping Style Questionnaire, Emotional Competence Questionnaire, and Becks Depression Inventory-II), a cognitive test (Color-Word Interference Test), and a 24 h electrocardiogram to record HRV. Patients with higher depression scores had significantly lower HRVs and decreased self-reported abilities for stress coping. Depression severity did not affect cognitive inhibitory abilities. HRV was related to neither coping strategies nor cognitive inhibition abilities. However, lower HRV was related to higher values of Negative Stress Coping (β = −0.21, p < 0.05). This relationship was fully mediated by depression severity (−4.79, 95% CI: −8.72, −0.72). HRV is not related to quantitative cognitive inhibition, but to the self-reported ability to cope with negative emotions in individuals with psychiatric disorders.

Analysis of Heart Rate Variability and Game Performance in Normal and Cognitively Impaired Elderly Subjects Using Serious Games

Cognitive decline is one of the primary concerns in the elderly population. Serious games have been used for different purposes related to elderly care, such as physical therapy, cognitive training and mood management. There has been scientific evidence regarding the relationship between cognition and the autonomic nervous system (ANS) through heart rate variability (HRV). This paper explores the changes in the ANS among elderly people of normal and impaired cognition through measured HRV. Forty-eight subjects were classified into two groups: normal cognition (NC) (n = 24) and mild cognitive impairment (MCI) (n = 24). The subjects went through the following experiment flow: rest for 3 min (Rest 1), play a cognitive aptitude game (Game 1), rest for another 3 min (Rest 2), then play two reaction-time games (Game 2&3). Ten HRV features were extracted from measured electrocardiography (ECG) signals. Based on statistical analysis, there was no significant difference on the HRV between the two groups, but the experiment sessions do have a significant effect. There was no significant interaction between sessions and cognitive status. This implies that the HRV between the two groups have no significant difference, and they will experience similar changes in their HRV regardless of their cognitive status. Based on the game performance, there was a significant difference between the two groups of elderly people. Tree-based pipeline optimization tool (TPOT) was used for generating a machine learning pipeline for classification. Classification accuracy of 68.75% was achieved using HRV features, but higher accuracies of 83.33% and 81.20% were achieved using game performance or both HRV and game performance features, respectively. These results show that HRV has the potential to be used for detection of mild cognition impairment, but game performance can yield better accuracy. Thus, serious games have the potential to be used for assessing cognitive decline among the elderly.

Heart Disease and Stroke Statistics-2022 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update. The 2022 Statistical Update is the product of a full year's worth of effort by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. This year's edition includes data on the monitoring and benefits of cardiovascular health in the population and an enhanced focus on social determinants of health, adverse pregnancy outcomes, vascular contributions to brain health, and the global burden of cardiovascular disease and healthy life expectancy.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Decreased nocturnal heart rate variability and potentially related brain regions in arteriosclerotic cerebral small vessel disease

Background

To assess heart rate variability (HRV) among patients with arteriosclerotic cerebral small vessel disease (CSVD) by comparing with control subjects, and to determine whether HRV parameters were related to structural alterations in brain regions involved in autonomic regulation among CSVD patients.

Methods

We consecutively recruited subjects aged between 50 and 80 years who visited the Stroke Prevention Clinic of our hospital and have completed brain magnetic resonance imaging examination from September 1, 2018 to August 31, 2019. Polysomnography and synchronous analyses of HRV were then performed in all participants. Multivariable binary logistic regression was used to identify the relationship between HRV parameters and CSVD. Participants were invited to further undergo three-dimensional brain volume scan, and the voxel based morphometry (VBM) analysis was used to identify gray matter atrophy.

Results

Among 109 participants enrolled in this study, 63 were assigned to the arteriosclerotic CSVD group and 46 to the control group. Lower standard deviation of normal-to-normal intervals (SDNN, OR = 0.943, 95% CI 0.903 to 0.985, P = 0.009) and higher ratio of low to high frequency power (LF/HF, OR = 4.372, 95% CI 1.033 to 18.508, P = 0.045) during the sleep period were associated with CSVD, independent of traditional cerebrovascular risk factors and sleep disordered breathing. A number of 24 CSVD patients and 21 controls further underwent three-dimensional brain volume scan and VBM analysis. Based on VBM results, SDNN during the awake time (β = 0.544, 95% CI 0.211 to 0.877, P = 0.001) and the sleep period (β = 0.532, 95% CI 0.202 to 0.862, P = 0.001) were both positively related with gray matter volume within the right inferior frontal gyrus only among CSVD patients.

Conclusions

Decreased nocturnal HRV is associated with arteriosclerotic CSVD independent of traditional cerebrovascular risk factors and sleep disordered breathing. The structural atrophy of some brain regions associated with cardiac autonomic regulation sheds light on the potential relationship.

Trial registration

Trial registration number: ChiCTR1800017902. Date of registration: 20 Aug 2018.

The Association Between Heart Rate Variability and 90-Day Prognosis in Patients With Transient Ischemic Attack and Minor Stroke

Background: Low heart rate variability (HRV) is known to be associated with increased all-cause, cardiovascular, and cerebrovascular mortality but its association with clinical outcomes in patients with transient ischemic attack (TIA) or minor stroke is unclear.

Methods: We selected TIA and minor stroke patients from a prospective registration study. From each continuous electrocardiograph (ECG) record, each QRS complex was detected and normal-to-normal (N-N) intervals were determined. The standard deviation of all N-N intervals (SDNN) and the square root of the mean squared differences of successive N-N intervals (RMSSD) were calculated. Logistic regression analysis and Cox regression analysis were performed to assess the outcomes of patients at 90 days, and the odds and risk ratios (OR/HR) of each index quartile were compared.

Results: Compared with SDNN patients in the lowest quartile, neurological disability was significantly reduced in other quartile groups at 90 days, with significant differences [OR of group Q2 was 0.659; 95% confidence interval (CI), 0.482–0.900; p = 0.0088; OR of group Q3 was 0.662; 95% CI, 0.478–0.916; p = 0.0127; OR of group Q4 was 0.441; 95% CI, 0.305–0.639; p <0.0001]. Compared with the lowest quartile, the recurrence rate of TIA or minor stroke in patients of the two higher quartiles (Q3 and Q4) of SDNN was significantly reduced at 90 days (HR of Q3 group was 0.732; 95% CI, 0.539–0.995; p = 0.0461; HR of Q4 group was 0.528; 95% CI, 0.374–0.745; p = 0.0003).

Conclusions: Based on our findings, autonomic dysfunction is an adverse indicator for neurological function prognosis and stroke recurrence 90 days after TIA or minor stroke.

Positive Effect of Cognitive Reserve on Episodic Memory, Executive and Attentional Functions Taking Into Account Amyloid-Beta, Tau, and Apolipoprotein E Status

Studies exploring the simultaneous influence of several physiological and environmental factors on domain-specific cognition in late middle-age remain scarce. Therefore, our objective was to determine the respective contribution of modifiable risk/protective factors (cognitive reserve and allostatic load) on specific cognitive domains (episodic memory, executive functions, and attention), taking into account non-modifiable factors [sex, age, and genetic risk for Alzheimer's disease (AD)] and AD-related biomarker amount (amyloid-beta and tau/neuroinflammation) in a healthy late-middle-aged population. One hundred and one healthy participants (59.4 ± 5 years; 68 women) were evaluated for episodic memory, executive and attentional functioning via neuropsychological test battery. Cognitive reserve was determined by the National Adult Reading Test. The allostatic load consisted of measures of lipid metabolism and sympathetic nervous system functioning. The amyloid-beta level was assessed using positron emission tomography in all participants, whereas tau/neuroinflammation positron emission tomography scans and apolipoprotein E genotype were available for 58 participants. Higher cognitive reserve was the main correlate of better cognitive performance across all domains. Moreover, age was negatively associated with attentional functioning, whereas sex was a significant predictor for episodic memory, with women having better performance than men. Finally, our results did not show clear significant associations between performance over any cognitive domain and apolipoprotein E genotype and AD biomarkers. This suggests that domain-specific cognition in late healthy midlife is mainly determined by a combination of modifiable (cognitive reserve) and non-modifiable factors (sex and age) rather than by AD biomarkers and genetic risk for AD.

Different Impact of Heart Rate Variability in the Deep Cerebral and Central Hemodynamics at Rest: An in silico Investigation

Background: Heart rate variability (HRV), defined as the variability between consecutive heartbeats, is a surrogate measure of cardiac vagal tone. It is widely accepted that a decreased HRV is associated to several risk factors and cardiovascular diseases. However, a possible association between HRV and altered cerebral hemodynamics is still debated, suffering from HRV short-term measures and the paucity of high-resolution deep cerebral data. We propose a computational approach to evaluate the deep cerebral and central hemodynamics subject to physiological alterations of HRV in an ideal young healthy patient at rest.

Methods: The cardiovascular-cerebral model is composed by electrical components able to reproduce the response of the different cardiovascular regions and their features. The model was validated over more than thirty studies and recently exploited to understand the hemodynamic mechanisms between cardiac arrythmia and cognitive deficit. Three configurations (baseline, increased HRV, and decreased HRV) are built based on the standard deviation (SDNN) of RR beats. For each configuration, 5,000 RR beats are simulated to investigate the occurrence of extreme values, alteration of the regular hemodynamics pattern, and variation of mean perfusion/pressure levels.

Results: In the cerebral circulation, our results show that HRV has overall a stronger impact on pressure than flow rate mean values but similarly alters pressure and flow rate in terms of extreme events. By comparing reduced and increased HRV, this latter induces a higher probability of altered mean and extreme values, and is therefore more detrimental at distal cerebral level. On the contrary, at central level a decreased HRV induces a higher cardiac effort without improving the mechano-contractile performance, thus overall reducing the heart efficiency.

Conclusions: Present results suggest that: (i) the increase of HRV per se does not seem to be sufficient to trigger a better cerebral hemodynamic response; (ii) by accounting for both central and cerebral circulations, the optimal HRV configuration is found at baseline. Given the relation inversely linking HRV and HR, the presence of this optimal condition can contribute to explain why the mean HR of the general population settles around the baseline value (70 bpm).

Associations between 20-year lipid variability throughout young adulthood and midlife cognitive function and brain integrity

BACKGROUND

Little is known about long-term lipid variability in young adulthood in relation to cognitive function and brain integrity in midlife.

METHODS

We studied 3,328 adults from the Coronary Artery Risk Development in Young Adults. We defined low- and high- density lipoprotein (LDL, HDL) variability as the intra-individual standard deviation of lipid measurements over 20 years of young adulthood (1985-2005). Cognitive tests were administered in 2010. Brain scans were performed in 2010 on 714 participants. To facilitate comparison, cognitive tests and brain metrics were z-scored.

RESULTS

Mean age at baseline was 25.4 years. Higher 20-year LDL variability was associated with worse verbal memory in midlife (β=-0.25, 95% CI [-0.42, -0.08]), adjusted for important covariates. Higher 20-year HDL variability was associated with worse processing speed in midlife (β=-0.80, 95% CI [-1.18, -0.41]) and brain integrity, e.g. smaller total brain volume (β=-0.58, 95% CI [-0.82, -0.34]) and worse total brain fractional anisotropy (β=-1.13, 95% CI [-1.87, -0.39]).

CONCLUSIONS

Higher long-term lipid variability in adulthood was associated with worse cognition and brain integrity in midlife, in a relatively young cohort.

Phasic heart rate variability and the association with cognitive performance: A cross-sectional study in a healthy population setting

Introduction

Sympathovagal balance measured by heart rate variability is a core component of psychophysiological research. Through the close link of physiological and psychological aspects, often a reduced heart rate variability is associated with impaired cognitive function. A better understanding of the associations between cognitive and cardiovascular dysfunctions is necessary to prevent the manifestation of diseases. Therefore, this study investigated phasic heart rate variability using rest, anticipatory, stress, and recovery periods and the association with high and low cognitive performance in a generally healthy population setting.

Methods

114 healthy individuals (40 males, 74 females) aged 20 to 70 participated in the cross-sectional study. The heart rate variability based on standard deviation of NN intervals (SDNN), and the root means square of successive differences (RMSSD), low frequency (LF), high frequency (HF) and LF/HF ratio and its association with high and low cognitive performance measured by the California Verbal Learning Task II were examined.

Results

The results of this study indicate that the paradigm was successful in producing stress and showed a significant association between phasic heart rate variability (SDNN) and verbal episodic memory performance, irrespective of age and sex.

Discussion

The results of this study suggest that a reduced heart rate variability is associated with reduced cognitive function regardless of age and sex and seem to be an early indicator of sympathovagal disbalance.

Conclusion

This leads to the conclusion that differences between high and low cognitive performance might show differences in heart rate variability at an early stage, where no diseases are yet manifest.

Vascular contributions to cognitive impairment and dementia (VCID): A report from the 2018 National Heart, Lung, and Blood Institute and National Institute of Neurological Disorders and Stroke Workshop

Vascular contributions to cognitive impairment and dementia (VCID) are characterized by the aging neurovascular unit being confronted with and failing to cope with biological insults due to systemic and cerebral vascular disease, proteinopathy including Alzheimer's biology, metabolic disease, or immune response, resulting in cognitive decline. This report summarizes the discussion and recommendations from a working group convened by the National Heart, Lung, and Blood Institute and the National Institute of Neurological Disorders and Stroke to evaluate the state of the field in VCID research, identify research priorities, and foster collaborations. As discussed in this report, advances in understanding the biological mechanisms of VCID across the wide spectrum of pathologies, chronic systemic comorbidities, and other risk factors may lead to potential prevention and new treatment strategies to decrease the burden of dementia. Better understanding of the social determinants of health that affect risks for both vascular disease and VCID could provide insight into strategies to reduce racial and ethnic disparities in VCID.

Inverse associations between parasympathetic activity and cognitive flexibility in African Americans: Preliminary findings

Previous research suggests that vagal activity and executive function (EF) are positively associated. However, existing data exploring the relationship between HRV and EF remains limited. Though Blacks may have higher HRV, they remain underrepresented in previous research examining HRV and EF. The current study aimed to determine the relationship between EF and HRV in a sample of 92 Black undergraduates (Mean age = 20.32, SD = 2.28). Participants wore an 6‑lead ambulatory electrocardiographic impedance monitoring system to obtain the root mean square of interbeat interval differences (rMSSD) and Cardiac Sympathetic Index. After baseline autonomic activity assessment, participants completed the Berg Card Sorting Test. Utilizing hierarchical regression analyses, HRV was negatively associated with correct responses (Beta = -0.40, SE = 0.04, p=0.01) and categories experienced (Beta = -0.37, SE = 0.01, p=0.01), and positively associated with total errors (Beta = 0.39, SE =0.04, p=0.01). To further elucidate these findings, participants were assigned to coinhibition (n = 12), parasympathetically dominant (n = 34), sympathetically dominant (n = 35), or coactivation (n = 11) autonomic space subgroups. Participants in the sympathetically dominant subgroup completed more categories (M = 6.86, SD = 2.13) and committed fewer errors (M = 30.63, SD = 11.53) than their parasympathetic counterparts (M = 5.74, SD = 2.44; M = 43.29, SD = 18.83, respectively). This study suggests that a state of sympathetic arousal immediately prior to the administration of an EF task, may aid in better task performance.

Parasympathetic and sympathetic nervous systems interactively predict change in cognitive functioning in midlife adults

The two branches of the autonomic nervous system (ANS) have been individually linked to changes in cognitive functioning: The parasympathetic nervous system (PNS) has been associated with healthy cognitive aging, whereas excessive sympathetic nervous system (SNS) activity has been linked to heightened cognitive decline. Despite these separate findings and despite the integrative nature of the ANS, little work has examined the two branches simultaneously to better understand their interactive effects on changes in cognitive functioning in midlife adults. We examined cognitive change in two waves of the Midlife in the United States (MIDUS) study cognitive project and indexed PNS and SNS activity from heart rate variability and epinephrine levels, respectively, from the MIDUS biomarker project (minimum n = 843, 57.9% female, mean age at first wave = 53.8 years). Our findings indicate that greater PNS responsivity (i.e., greater withdrawal and greater recovery) in response to cognitive challenge is associated with attenuated cognitive decline, but only among individuals with low SNS levels; at higher SNS levels, the effects of the PNS on cognitive decline are attenuated. These results suggest that future research targeting the ANS and cognitive aging should consider both ANS branch's effects simultaneously.

Association of Heart Rate Variability With Cognitive Performance: The Multi-Ethnic Study of Atherosclerosis

Background Heart rate variability (HRV) is associated with vascular risk factors for dementia, but whether HRV is associated with specific domains of cognitive performance is unclear. Methods and Results In the Multi-Ethnic Study of Atherosclerosis (N=3018; mean age 59.3±9.2 years), we assessed the relationship of 10-second HRV to scores on tests of global cognitive performance (Cognitive Abilities Screening Instrument), processing speed (Digit Symbol Coding), and working memory (Digit Span). HRV was computed as the SD of normal-normal intervals (SDNN) and root mean square of successive differences (RMSSD) at Exam 1 (2000-2002) and Exam 5 (2010-2012). Cognitive tests were administered at Exam 5. We report regression coefficients (β [95% CI]) representing cognitive test score change per 2-fold increase in HRV. After adjustment for age, race/ethnicity, sex, education, apolipoprotein E genotype, and cardiovascular risk factors and incident disease, higher Exam 1 (β=0.37 [0.06, 0.67]) and Exam 5 (β=0.31 [0.04, 0.59]) SDNN were associated with better Cognitive Abilities Screening Instrument performance. Higher Exam 1 (β=0.80 [0.17, 1.43]) and Exam 5 (β=0.63 [0.06, 1.20]) SDNN, and Exam 5 RMSSD (β=0.54 [0.01, 1.08]) were associated with better Digit Symbol Coding performance. Finally, higher Exam 5 SDNN was associated with better Digit Span performance (β=0.17 [0.01, 0.33]). Associations were attenuated after adjustment for resting heart rate. Conclusions Higher HRV is generally associated with better cognitive performance in this multi-ethnic cohort of aging adults, and further study of the relationship of autonomic function to cognition is warranted.

Use of a pooled cohort to impute cardiovascular disease risk factors across the adult life course

BACKGROUND

In designing prevention strategies, it may be useful to understand how early and midlife cardiovascular disease risk factor (CVDRF) exposures affect outcomes that primarily occur in mid to late life. Few single US cohorts have followed participants from early adulthood to late life.

METHODS

We pooled four prospective cohorts that represent segments of the adult life course, and studied 15 001 White and Black adults aged 18 to 95 years at enrollment. We imputed early and midlife exposure to body mass index (BMI), glucose, lipids and blood pressure (BP). CVDRF trajectories were estimated using linear mixed models. Using the best linear unbiased predictions, we obtained person-specific estimates of CVDRF trajectories beginning at age 20 until each participant's end of follow-up. We then calculated for each CVDRF, summary measures of early and midlife exposure as time-weighted averages (TWAs).

RESULTS

In the pooled cohort, 33.7% were Black and 54.8% were female. CVDRF summary measures worsened in midlife compared with early life and varied by sex and race. In particular, systolic and diastolic BP were consistently higher over the adult life course among men, and BMI was higher among Blacks, particularly Black women. Simulation studies suggested acceptable imputation accuracy, especially for the younger cohorts. Correlations of true and imputed CVDRF summary measures ranged from 0.53 to 0.99, and agreement ranged from 67% to 99%.

CONCLUSIONS

These results suggest that imputed CVDRFs may be accurate enough to be useful in assessing the effects of early and midlife exposures on later life outcomes.

Cognitive efficiency in late midlife is linked to lifestyle characteristics and allostatic load

We investigated whether cognitive fitness in late midlife is associated with physiological and psychological factors linked to increased risk of age-related cognitive decline. Eighty-one healthy late middle-aged participants (mean age: 59.4 y; range: 50-69 y) were included. Cognitive fitness consisted of a composite score known to be sensitive to early subtle cognitive change. Lifestyle factors (referenced below as cognitive reserve factors; CRF) and affective state were determined through questionnaires, and sleep-wake quality was also assessed through actimetry. Allostatic load (AL) was determined through a large range of objective health measures. Generalized linear mixed models, controlling for sex and age, revealed that higher cognitive reserve and lower allostatic load are related to better cognitive efficiency. Crystallized intelligence, sympathetic nervous system functioning and lipid metabolism were the only sub-fields of CRF and AL to be significantly associated with cognition. These results show that previous lifestyle characteristics and current physiological status are simultaneously explaining variability in cognitive abilities in late midlife. Results further encourage early multimodal prevention programs acting on both of these modifiable factors to preserve cognition during the aging process.

Influence of Slow-Paced Breathing on Inhibition After Physical Exertion

This research aims to investigate whether slow-paced breathing (SPB) improves adaptation to psychological stress, and specifically inhibition, when it is performed before or after physical exertion (PE). According to the resonance model, SPB is expected to increase cardiac vagal activity (CVA). Further, according to the neurovisceral integration model, CVA is positively linked to executive cognitive performance, and would thus play a role in the adaptation to psychological stress. We hypothesized that SPB, in comparison to a control condition, will induce a better adaptation to psychological stress, measured via better inhibitory performance. Two within-subject experiments were conducted with athletes: in the first experiment (N = 60) SPB (or control – neutral TV documentary) was realized before PE (“relax before PE”), and in the second experiment (N = 60) SPB (or the watching TV control) was realized after PE (“relax after PE”). PE consisted of 5 min Burpees, a physical exercise involving the whole body. In both experiments the adaptation to psychological stress was investigated with a Stroop task, a measure of inhibition, which followed PE. Perceived stress increased during PE (partial η² = 0.63) and during the Stroop task (partial η² = 0.08), and decreased during relaxation (partial η² = 0.15), however, no effect of condition was found. At the physiological level PE significantly increased HR, RF, and decreased CVA [operationalized in this research via the root mean square of successive differences (RMSSD)] in both experiments. Further, the number of errors in the incongruent category (Stroop interference accuracy) was found to be lower in the SPB condition in comparison to the control condition, however, these results were not mediated by RMSSD. Additionally, the Stroop interference [reaction times (RTs)] was found to be lower overall in “relax before PE,” however, no effect was found regarding SPB and Stroop interference (RTs). Overall, our results suggest that SPB realized before or after PE has a positive effect regarding adaptation to psychological stress and specifically inhibition, however, the underlying mechanisms require further investigation.

Heart Rate Variability and Cognitive Function: A Systematic Review

Background: Autonomic dysfunctions may precede the development of cognitive impairment, but the connection between these dimensions is unclear. This systematic review aims to analyze the relationship between heart rate variability (HRV) and cognitive functions.

Methods: The review process was conducted according to the PRISMA-Statement. Restrictions were made, selecting the studies in English and published in peer-review journals, including at least one cognitive measure and presenting the measurement of HRV. Studies that included participants with medical conditions, dementia, psychiatric disorders, strokes, and traumatic brain injury were excluded. Twenty studies were selected, with a total of 19,431 participants. The results were divided into different cognitive domains determined a priori: global cognitive functioning, attention, processing speed, executive functions, memory, language and visuospatial skills.

Results: Both increased sympathetic activity and decreased parasympathetic activity seem to be associated with a worse performance in the cognitive domains considered, in the absence of dementia and severe cardiovascular diseases or other medical and psychiatric diseases.

Conclusion: The results highlight the influence of the autonomic nervous system (ANS) in cognitive functioning. However, the marked interest facing toward a specific domain, i.e., the executive functions, and the relatively small number of the studies on this topic do not allow understanding better this relationship. Despite these limits, HRV could be considered a promising early biomarker of cognitive impairment in populations without dementia or stroke. This index should be evaluated within a preventative perspective to minimize the risk of developing cognitive impairment.

Anti-aging effects of long-term space missions, estimated by heart rate variability

Reports that aging slows down in space prompted this investigation of anti-aging effects in humans by analyzing astronauts' heart rate variability (HRV). Ambulatory 48-hour electrocardiograms from 7 astronauts (42.1 ± 6.8 years; 6 men) 20.6 ± 2.7 days (ISS01) and 138.6 ± 21.8 days (ISS02) after launch were divided into 24-hour spans of relative lower or higher magnetic disturbance, based on geomagnetic measures in Tromso, Norway. Magnetic disturbances were significantly higher on disturbed than on quiet days (ISS01: 72.01 ± 33.82 versus 33.96 ± 17.90 nT, P = 0.0307; ISS02: 71.06 ± 51.52 versus 32.53 ± 27.27 nT, P = 0.0308). SDNNIDX was increased on disturbed days (by 5.5% during ISS01, P = 0.0110), as were other HRV indices during ISS02 (SDANN, 12.5%, P = 0.0243; Triangular Index, 8.4%, P = 0.0469; and TF-component, 17.2%, P = 0.0054), suggesting the action of an anti-aging or longevity effect. The effect on TF was stronger during light (12:00-17:00) than during darkness (0:00-05:00) (P = 0.0268). The brain default mode network (DMN) was activated, gauged by increases in the LF-band (9.7%, P = 0.0730) and MF1-band (9.9%, P = 0.0281). Magnetic changes in the magnetosphere can affect and enhance HRV indices in space, involving an anti-aging or longevity effect, probably in association with the brain DMN, in a light-dependent manner and/or with help from the circadian clock.

Heart Rate Variability and Performance of Commercial Airline Pilots during Flight Simulations

Pilots undergo a variety of stressors that may affect their performance during all phases of flight. Heart rate variability (HRV) has been considered as a reliable indicator of the parasympathetic and sympathetic activities of human autonomic nervous system, which can be used to characterize the sympathetic stress response of pilots during flight. In this study, thirty active commercial airline pilots were recruited to fly three flight segments in a Federal Aviation Administration (FAA)-certified A320 flight simulator with each segment at a different carbon dioxide (CO₂) concentration on the flight deck. The pilots performed a series of maneuvers of varying difficulty, and their performance was evaluated by FAA designated pilot examiners. The HRV metrics (SDNN, RMSSD and LF/HF ratio) of each pilot both before and during flight simulations were measured with a Movisens EcgMove3 sensor. The average SDNN, RMSSD and LF/HF ratio of the pilots during flight simulations were 34.1 ± 12.7 ms, 23.8 ± 10.2 ms and 5.7 ± 2.8 respectively. Decreased HRV was associated with aging, obesity and performing difficult maneuvers. Both CO₂ exposure and HRV had an independent effect on the pilot performance, while their interaction was not significant. The generalized additive mixed effect model results showed that a pilot performed better on a maneuver when his stress response was lower, as indicated by higher SDNN and RMSSD and lower LF/HF ratio. An interquartile range (IQR) increase in SDNN (21.97 ms) and RMSSD (16.00 ms) and an IQR decrease in LF/HF ratio (4.69) was associated with an increase in the odds of passing a maneuver by 37%, 22% and 20%, respectively.

Early differentiation of dementia with Lewy bodies and Alzheimer's disease: Heart rate variability at mild cognitive impairment stage

OBJECTIVE

Our study aimed to investigate whether heart rate variability (HRV) could be a useful diagnostic screening tool at MCI (mild cognitive impairment) stage of Dementia with Lewy bodies (DLB) from Alzheimer's disease (AD).

METHODS

This retrospective study used a selected sample from Ajou neurological registry. We identified MCI patients who underwent HRV testing at baseline, and who developed probable DLB (MCI-DLB: n = 23) or AD (MCI-AD: n = 32).

RESULTS

The MCI-DLB group exhibited significantly lower levels of almost all HRV parameters compared with the MCI-AD group. Fronto-executive function and visuospatial abilities were poorer in the MCI-DLB group, whereas the extent of verbal memory impairment was greater in the MCI-AD. Verbal memory score was negatively correlated with overall HRV parameters, and visuospatial function was positively correlated with the frequency domain of HRV. Receiver operating curve area under the curve (AUC) analysis revealed that the low frequency component was the best potential diagnostic marker (AUC = 0.88).

CONCLUSION

MCI-DLB patients exhibited greater cardiac autonomic dysfunction (as measured by HRV) and greater fronto-executive and visuospatial deficit compared with MCI-AD patients.

SIGNIFICANCE

HRV may be useful method to differentiate DLB from AD in patients with MCI; this would facilitate early disease-specific intervention.