scholarly journals Cardiorespiratory Dynamic Response to Mental Stress: A Multivariate Time-Frequency Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Devy Widjaja ◽  
Michele Orini ◽  
Elke Vlemincx ◽  
Sabine Van Huffel
Keyword(s):  
Dynamic Response ◽  
Mental Stress ◽  
Mental Arithmetic ◽  
Autonomic Response ◽  
Vagal Activity ◽  
Simulation Studies ◽  
Time Frequency ◽  
Rr Interval ◽  
Time Varying Parameters ◽  
Cardiorespiratory Coupling

Mental stress is a growing problem in our society. In order to deal with this, it is important to understand the underlying stress mechanisms. In this study, we aim to determine how the cardiorespiratory interactions are affected by mental arithmetic stress and attention. We conduct cross time-frequency (TF) analyses to assess the cardiorespiratory coupling. In addition, we introduce partial TF spectra to separate variations in the RR interval series that are linearly related to respiration from RR interval variations (RRV) that are not related to respiration. The performance of partial spectra is evaluated in two simulation studies. Time-varying parameters, such as instantaneous powers and frequencies, are derived from the computed spectra. Statistical analysis is carried out continuously in time to evaluate the dynamic response to mental stress and attention. The results show an increased heart and respiratory rate during stress and attention, compared to a resting condition. Also a fast reduction in vagal activity is noted. The partial TF analysis reveals a faster reduction of RRV power related to (3 s) than unrelated to (30 s) respiration, demonstrating that the autonomic response to mental stress is driven by mechanisms characterized by different temporal scales.

scholarly journals EEG Mental Stress Assessment Using Hybrid Multi-Domain Feature Sets of Functional Connectivity Network and Time-Frequency Features

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6300
Author(s):  
Ala Hag ◽  
Dini Handayani ◽  
Thulasyammal Pillai ◽  
Teddy Mantoro ◽  
Mun Hou Kit ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Mental Stress ◽  
Mental Arithmetic ◽  
Support Vector ◽  
Svm Classifier ◽  
Amylase Level ◽  
Negative Consequences ◽  
Eeg Signals ◽  
Arithmetic Task ◽  
Time Frequency

Exposure to mental stress for long period leads to serious accidents and health problems. To avoid negative consequences on health and safety, it is very important to detect mental stress at its early stages, i.e., when it is still limited to acute or episodic stress. In this study, we developed an experimental protocol to induce two different levels of stress by utilizing a mental arithmetic task with time pressure and negative feedback as the stressors. We assessed the levels of stress on 22 healthy subjects using frontal electroencephalogram (EEG) signals, salivary alpha-amylase level (AAL), and multiple machine learning (ML) classifiers. The EEG signals were analyzed using a fusion of functional connectivity networks estimated by the Phase Locking Value (PLV) and temporal and spectral domain features. A total of 210 different features were extracted from all domains. Only the optimum multi-domain features were used for classification. We then quantified stress levels using statistical analysis and seven ML classifiers. Our result showed that the AAL level was significantly increased (p < 0.01) under stress condition in all subjects. Likewise, the functional connectivity network demonstrated a significant decrease under stress, p < 0.05. Moreover, we achieved the highest stress classification accuracy of 93.2% using the Support Vector Machine (SVM) classifier. Other classifiers produced relatively similar results.

scholarly journals Cardiovascular Autonomic Response to Amlodipine in Primary Hypertension

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Youssouf Radjab ◽  
Souad Aboudrar ◽  
Fatima Zahra Milouk ◽  
Hanan Rkain ◽  
Mustapha EL Bakkali ◽  
...  
Keyword(s):  
Oral Administration ◽  
Mental Stress ◽  
Stress Test ◽  
Primary Hypertension ◽  
Autonomic Response ◽  
Vagal Activity ◽  
Deep Breathing ◽  
Stress Tests ◽  
Hand Grip ◽  
Before And After

Sympathetic hyperactivity may be involved in primary hypertension. The purpose of this study was to evaluate both sympathetic and vagal activity responses in patients receiving amlodipine as antihypertensive agent. Patients and Methods. This prospective study included a group of primary hypertensive patients (N=32, mean age 54.6±7.6 years). The cardiovascular autonomic tests performed in this group, before and after 3 months of daily oral administration of amlodipine, included deep breathing, hand-grip, and mental stress tests. Statistical analysis was done using the Student’s t-test. Results. Cardiovascular autonomic reflexes responses before and after 3 months of amlodipine oral administration were as follows: the mental stress test stimulation method produced a central alpha adrenergic response of 23.9±8.7% versus 11.2±2.0% (P<0.05), a central beta sympathetic response of 16.7±9.2% versus 10.4±1.3% (P<0.05), a blood pressure increase in response to hand grip test of 20.5±7.3% versus 10.7±2.4% (P<0.05), vagal response to deep breathing test was 21.2±6.5% versus 30.8±2.9%, (P<0.05). Conclusion. The results attest that amlodipine may have an anti-sympathetic effect.

scholarly journals Cardiovascular Sympathetic Arousal in Response to Different Mental Stressors

2015 ◽  
pp. S585-S594 ◽  
Author(s):  
M. MESTANIK ◽  
A. MESTANIKOVA ◽  
Z. VISNOVCOVA ◽  
A. CALKOVSKA ◽  
I. TONHAJZEROVA
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Mental Stress ◽  
Mental Arithmetic ◽  
Real Life ◽  
Stroop Test ◽  
Autonomic Response ◽  
Central Processing ◽  
Mental Stressors ◽  
Sympathetic Arousal

The altered regulation of autonomic response to mental stress can result in increased cardiovascular risk. The laboratory tests used to simulate the autonomic responses to real-life stressors do not necessarily induce generalized sympathetic activation; therefore, the assessment of regulatory outputs to different effector organs could be important. We aimed to study the cardiovascular sympathetic arousal in response to different mental stressors (Stroop test, mental arithmetic test) in 20 healthy students. The conceivable sympathetic vascular index – spectral power of low frequency band of systolic arterial pressure variability (LF-SAP) and novel potential cardio-sympathetic index – symbolic dynamics heart rate variability index 0V% were evaluated. The heart and vessels responded differently to mental stress – while Stroop test induced increase of both 0V% and LF-SAP indices suggesting complex sympathetic arousal, mental arithmetic test evoked only 0V% increase compared to baseline (p<0.01, p<0.001, p<0.01, respectively). Significantly greater reactivity of LF-SAP, 0V%, heart rate (HR) and mean arterial pressure (MAP) were found in response to Stroop test compared to mental arithmetic test potentially indicating the effect of different central processing (0V%, LF-SAP: p<0.001; HR, MAP: p<0.01). The different effectors’ sympathetic responses to cognitive stressors could provide novel important information regarding potential pathomechanisms of stress-related diseases.

scholarly journals Automatic ECG Classification Using Continuous Wavelet Transform and Convolutional Neural Network

Entropy ◽  
2021 ◽  
Vol 23 (1) ◽  
pp. 119
Author(s):  
Tao Wang ◽  
Changhua Lu ◽  
Yining Sun ◽  
Mei Yang ◽  
Chun Liu ◽  
...  
Keyword(s):  
Neural Network ◽  
Wavelet Transform ◽  
Convolutional Neural Network ◽  
Continuous Wavelet Transform ◽  
Continuous Wavelet ◽  
Time Frequency ◽  
Ecg Signals ◽  
Rr Interval ◽  
Frequency Components ◽  
Fully Connected

Early detection of arrhythmia and effective treatment can prevent deaths caused by cardiovascular disease (CVD). In clinical practice, the diagnosis is made by checking the electrocardiogram (ECG) beat-by-beat, but this is usually time-consuming and laborious. In the paper, we propose an automatic ECG classification method based on Continuous Wavelet Transform (CWT) and Convolutional Neural Network (CNN). CWT is used to decompose ECG signals to obtain different time-frequency components, and CNN is used to extract features from the 2D-scalogram composed of the above time-frequency components. Considering the surrounding R peak interval (also called RR interval) is also useful for the diagnosis of arrhythmia, four RR interval features are extracted and combined with the CNN features to input into a fully connected layer for ECG classification. By testing in the MIT-BIH arrhythmia database, our method achieves an overall performance of 70.75%, 67.47%, 68.76%, and 98.74% for positive predictive value, sensitivity, F1-score, and accuracy, respectively. Compared with existing methods, the overall F1-score of our method is increased by 4.75~16.85%. Because our method is simple and highly accurate, it can potentially be used as a clinical auxiliary diagnostic tool.

Effect of short-term mental stress on time- domain indices of heart rate variability in obese individuals – A case- control study

Biomedicine ◽  
2021 ◽  
Vol 41 (2) ◽  
pp. 274-277
Author(s):  
Priya S.A. ◽  
R. Rajalakshmi
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Neuronal Activity ◽  
Time Domain ◽  
Mental Stress ◽  
Mental Arithmetic ◽  
High Body Mass Index ◽  
Control Group ◽  
Stress Task ◽  
The Individual

  Introduction and Aim: Mental stress may impact dramatically on dynamic autonomic control on heart. Many studies have demonstrated association of high body mass index (BMI) with greater risk for cardiovascular disease with disturbance in autonomic neuronal activity. Analysis of Heart rate variability (HRV)during acute mental stress assesses the autonomic status of the individual. Hence, we aimed to study the effect of acute mental stress on time domain measures in obese adults.   Materials and Methods:Sixty male volunteers of 30 each in study group (obese individuals) and control group (non-obese individuals) were recruited for the study. A basal recording of ECG in lead II was done on all the individuals. Then they underwent mental arithmetic stress task for 5 minutes during which again ECG was recorded. The change in time domain measures of HRV during rest and stress task was analyzed and compared between both the groups.   Results: Analysis of time domain measures of HRV revealed a statistically significant increase (p ? 0.001) in mean heart rate in both obese and non-obese individuals, while rMSSD(root mean square differences of successive RR interval) and SDNN (standard deviation of all NN intervals) showed a statistically significant (p? 0.001) decrease in obese individuals and non-obese individuals did not show any statistically significant change during the mental stress task.   Conclusion: In response to acute mental stress there was increased heart rate in both the groups. But the autonomic neuronal activity differed by way of sympathetic dominance in non-obese individuals and parasympathetic withdrawal in obese individuals.  

Mental stress and cognitive performance do not increase overall level of cerebral O2 uptake in humans

1992 ◽  
Vol 73 (2) ◽  
pp. 420-426 ◽  
Author(s):  
P. L. Madsen ◽  
J. F. Schmidt ◽  
S. Holm ◽  
H. Jorgensen ◽  
G. Wildschiodtz ◽  
...  
Keyword(s):  
Mental Stress ◽  
Mental Arithmetic ◽  
Statistical Significance ◽  
Plasma Catecholamines ◽  
Synaptic Activity ◽  
Large Individual ◽  
Cerebral Metabolic Rate ◽  
Mental Activation ◽  
Individual Variations ◽  
Lactate Output

We measured cerebral metabolic rate of oxygen (CMRO2), cerebral blood flow (CBF), and cerebral lactate output during rest, during the execution of mental arithmetic, and during mental stress induced by physical and psychological annoyance. Measurements were performed in healthy volunteers by use of the Kety-Schmidt technique with 133Xe as the inert gas. Electroencephalographic desynchronization and highly significant increases in plasma catecholamines and heart rate verified that the test measurements were performed during conditions differing distinctly from the resting state. In accordance with an earlier study (Sokoloff et al. J. Clin. Invest. 34: 1101–1108, 1985), a minimal and nonsignificant 1% reduction of global CMRO2 during mental arithmetic was observed, signifying that this form of mental activation was unassociated with any detectable increase in overall cerebral synaptic activity. Mental stress induced a slight but highly significant (P less than 0.002) 6% reduction in global CMRO2. This finding is in contrast to results from earlier investigations and contradicts the generally accepted notion of an association between mental arousal and a diffuse upregulation of cerebral synaptic activity. During mental arithmetic and mental stress, cerebral lactate output increased by 207 and 344%, respectively, but because of large individual variations in the measured responses, the elevations reached statistical significance only during mental arithmetic.

scholarly journals Emergence of Heartbeat Frailty in Advanced Age: Perspectives from Life-Long EKG Recordings in Mice

2022 ◽  
Author(s):  
Jack M Moen ◽  
Christopher H Morrell ◽  
Ismayil Ahmet ◽  
Michael G Matt ◽  
Moran Davoodi ◽  
...  
Keyword(s):  
Sinus Bradycardia ◽  
Progressive Increase ◽  
Advanced Age ◽  
Whole Body ◽  
Energetic Efficiency ◽  
Cross Sectional ◽  
Time Frequency ◽  
Cell Dysfunction ◽  
Rr Interval ◽  
The Mean

SAN failure, aka sick-sinus syndrome, which features sinus bradycardia, SAN impulse pauses, and irregularity of RR interval rhythms are manifestations of SAN cell dysfunction that increases exponentially with advanced age, i.e., SAN frailty. Abnormalities in intrinsic RR interval variability may be the earliest signatures of SAN cell dysfunction leading to SAN frailty in late life. We measured RR interval variability within EKG time-series prior to and during double autonomic blockade in long-lived C57/BL6 mice at 3 month intervals from 6 months of age until the end of life. Long-lived mice (those that achieved the median cohort lifespan of 24 months and beyond) displayed relatively minor changes in intrinsic RR interval variability prior to 21 months of age. Between 21 and 30 months of age, marked changes in intrinsic RR interval variability signatures in time, frequency, non-linear, and fragmentation domains result in a marked increase in the mean intrinsic RR interval. The effects of autonomic input partially compensated for the prolongation of the mean RR interval by impacting the age-associated deterioration in the RR interval variability signatures toward a youthful pattern. Cross-sectional analyses of other subsets of mice at ages at or beyond the median life span of our longitudinal cohort demonstrated increased non-cardiac, constitutional, whole body frailty, a decrease in energetic efficiency, and an increase in respiratory exchange ratio. In this context, we interpret the progressive increase in intrinsic RR interval variability beyond 21 months of age to be an indication of heartbeat frailty.

scholarly journals Monitoring the structural dynamic response of a masonry tower: comparing classical and time-frequency analyses

2012 ◽  
Vol 10 (4) ◽  
pp. 1221-1235 ◽  
Author(s):  
Rocco Ditommaso ◽  
Marco Mucciarelli ◽  
Stefano Parolai ◽  
Matteo Picozzi
Keyword(s):  
Dynamic Response ◽  
Structural Dynamic ◽  
Time Frequency ◽  
Masonry Tower

Time-frequency equivalence using chirp signals for frequency response analysis

2021 ◽  
Author(s):  
Resmi Suresh ◽  
Raghunathan Rengaswamy
Keyword(s):  
Frequency Response ◽  
Electrochemical Impedance ◽  
Response Analysis ◽  
Chirp Signal ◽  
Simulation Studies ◽  
Frequency Response Analysis ◽  
Time Frequency ◽  
Input Signals ◽  
Chirp Signals ◽  
Potential Impact

Abstract Frequency response analysis (FRA) of systems is a well-researched area. For years, FRA has been performed using input signals, which are a series of sinusoids or a sum of sinusoids. This results in large experimentation time, particularly when the system has to be probed at lower frequencies. In this work, we describe a previously unknown time-frequency duality for linear systems when probed through chirp signals. We show that the entire frequency response can be extracted with a single chirp signal by extending the notion of instantaneous frequency to both the input and output signals. It is surprising that this powerful result had not been uncovered given that FRA has been used in multiple disciplines for more than hundred years. This result has the possibility of completely revolutionizing methods used for frequency response analysis. Simulation studies that support the main result are described. While this result is of relevance in multiple areas, we demonstrate the potential impact of this result in electrochemical impedance spectroscopy.

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