scholarly journals Respiratory-phase Domain Analysis of Heart Rate Variability Can Accurately Estimate Cardiac Vagal Activity during a Mental Arithmetic Task

2007 ◽  
Vol 46 (03) ◽  
pp. 376-385 ◽  
Author(s):  
M. Tachibana ◽  
K. Takamasu ◽  
K. Kotani

Summary Objectives: The objectives of this paper were to present a method to extract the amplitude of RSA in the respiratory-phase domain, to compare that with subjective or objective indices of the MWL (mental workload), and to compare that with a conventional frequencyanalysis in terms of its accuracy during a mental arithmetic task. Methods: HRV (heart rate variability), ILV (instantaneous lung volume), and motion of the throat were measured under a mental arithmetic experiment and subjective and objective indices were also obtained. The amplitude of RSA was extracted in the respiratory-phase domain, and its correlation with the load level was compared with the results of the frequencydomain analysis, which is the standard analysis of the HRV. Results: The subjective and objective indices decreased as the load level increased, showing that the experimental protocol was appropriate. Then, the amplitude of RSA in the respiratory-phase domain also decreased with the increase in the load level. The results of the correlation analysis showed that the respiratory-phase domain analysis has higher negative correlations, −0.84 and −0.82, with the load level as determined bysimplecorrelation and rankcorrelation, respectively, than does frequencyanalysis, for which the correlations were found to be −0.54 and −0.63, respectively. In addition, it was demonstrated thatthe proposed method could be applied to the short-term extraction of RSA amplitude. Conclusions: We proposed a simple and effective method to extract the amplitude of the respiratory sinus arrhythmia (RSA) in the respiratory-phase domain and the results show that this method can estimate cardiac vagal activity more accurately than frequency analysis.

2007 ◽  
Vol 46 (02) ◽  
pp. 179-185 ◽  
Author(s):  
M. Tachibana ◽  
K. Takamasu ◽  
K. Kotani

Summary Objectives : The objective of our study is to investigate extrinsic influences on heart rate variability using respiratory-phase domain analysis. Swallowing, coughing and vocalization (reading aloud and conversation) are adopted as extrinsic influences. Methods : In this study, an instantaneous R-R interval (RRI) is sampled at each π/10 rad of the respiratory phase and the data is divided into three subsets: a) respiration with event, b) one respiration after the event, and c) normal respiration. Then the mean waveforms of respiratory sinus arrhythmia (RSA) are calculated and compared. Results and Conclusions : It is found that swallowing induces tachycardia that recovers within one respiration. Coughing also induces tachycardia, but it does not recover within one respiration. Vocalization shortens the mean RRI, but the changing respiratory pattern due to vocalization has no statistically significant influence on the amplitude of RSA. Furthermore, it is found that the proposed method is effective for analyzing extrinsic influences on heart rate variability (HRV).


1991 ◽  
Vol 27 (Supplement) ◽  
pp. 58-59
Author(s):  
T Kamada ◽  
S Miyake ◽  
M Kumashiro ◽  
K Inoue

2010 ◽  
Vol 298 (1) ◽  
pp. H202-H209 ◽  
Author(s):  
André E. Aubert ◽  
Bart Verheyden ◽  
Constantin d′Ydewalle ◽  
Frank Beckers ◽  
Omer Van den Bergh

Sustained weightlessness affects all body functions, among these also cardiac autonomic control mechanisms. How this may influence neural response to central stimulation by a mental arithmetic task remains an open question. The hypothesis was tested that microgravity alters cardiovascular neural response to standardized cognitive load stimuli. Beat-to-beat heart rate, brachial blood pressure, and respiratory frequency were collected in five astronauts, taking part in three different short-duration (10 to 11 days) space missions to the International Space Station. Data recording was performed in supine position 1 mo before launch; at days 5 or 8 in space; and on days 1, 4, and 25 after landing. Heart rate variability (HRV) parameters were obtained in the frequency domain. Measurements were performed in the control condition for 10 min and during a 5-min mental arithmetic stress task, consisting of deducting 17 from a four-digit number, read by a colleague, and orally announcing the result. Our results show that over all sessions (pre-, in-, and postflight), mental stress induced an average increase in mean heart rate (Δ7 ± 1 beats/min; P = 0.03) and mean arterial pressure (Δ7 ± 1 mmHg; P = 0.006). A sympathetic excitation during mental stress was shown from HRV parameters: increase of low frequency expressed in normalized units (Δ8.3 ± 1.4; P = 0.004) and low frequency/high frequency (Δ1.6 ± 0.3; P = 0.001) and decrease of high frequency expressed in normalized units (Δ8.9 ± 1.4; P = 0.004). The total power was not influenced by mental stress. No effect of spaceflight was found on baseline heart rate, mean arterial pressure, and HRV parameters. No differences in response to mental stress were found between pre-, in-, and postflight. Our findings confirm that a mental arithmetic task in astronauts elicits sympathovagal shifts toward enhanced sympathetic modulation and reduced vagal modulation. However, these responses are not changed in space during microgravity or after spaceflight.


2018 ◽  
Author(s):  
Vittorio Iacovella ◽  
Luca Faes ◽  
Uri Hasson

AbstractNeuroimaging research has shown that different cognitive tasks induce relatively specific activation patterns, as well as less task-specific deactivation patterns. Here we examined whether individual differences in Autonomic Nervous System (ANS) activity during task performance correlate with the magnitude of task-induced deactivation. In an fMRI study, participants performed a continuous mental arithmetic task in a task/rest block design, while undergoing combined fMRI and heart / respiration rate acquisitions using photoplethysmograph and respiration belt. As expected, task performance increased heart-rate and reduced the RMSSD, a cardiac index related to vagal tone. Across participants, higher heart rate during task was linked to increased activation in fronto-parietal regions, as well as to stronger deactivation in ventromedial prefrontal regions. Respiration frequency during task was associated with similar patterns, but in different regions than those identified for heart-rate. Finally, in a large set of regions, almost exclusively limited to the Default Mode Network, lower RMSSD was associated with greater deactivation, and furthermore, the vast majority of these regions were task-deactivated at the group level. Together, our findings show that inter-individual differences in ANS activity are strongly linked to task-induced deactivation. Importantly, our findings suggest that deactivation is a multifaceted construct potentially linked to ANS control, because distinct ANS measures correlate with deactivation in different regions. We discuss the implications for current theories of cortical control of the ANS and for accounts of deactivation, with particular reference to studies documenting a “failure to deactivate” in multiple clinical states.


2000 ◽  
Vol 14 (3) ◽  
pp. 159-164 ◽  
Author(s):  
Jeffrey L. Goodie ◽  
Kevin T. Larkin ◽  
Scott Schauss

Abstract The Polar Vantage XL heart rate monitor provides an ambulatory, inexpensive method of continuously measuring heart rate. To examine the validity of the Polar monitor for measuring heart rate during resting periods and while engaging in two stressful tasks, 30 students participated in a 1-hour laboratory session. Heart rates were measured simultaneously using the Polar monitor and electrocardiography (ECG) during a hand grip exercise and a mental arithmetic task, each preceded by a 4-min resting period. Within-subject correlations between the two devices were significant (mean r = 0.98, P < .001). All correlations, except for three participants, exceeded r = 0.90. Between-task correlation analyses revealed high correlations (i. e., rs ≥ 0.98) between the Polar monitor and ECG. The Polar monitor obtained readings that were slightly, though significantly higher than readings obtained using ECG. The correspondence between observed mean heart rates from the Polar monitor and ECG suggest that the Polar monitor provides a valid measure of heart rate during stationary laboratory tasks.


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