Estimation of Coherence Between Blood Flow and Spontaneous EEG Activity in Neonates

Simpson, David M.; Rosas, Daniel Alfonso Botero; Infantosi, Antonio Fernando Catelli

doi:10.1109/tbme.2005.845368

Cited by 9 publications

(5 citation statements)

References 29 publications

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“…The frequency coherence function C xy (f) returns a value between 0 and 1, with 1 indicating the same frequency-power characteristics between studied signals [11,35,37,45].…”

Section: Discussionmentioning

confidence: 99%

“…)

C_{x y} false(f false) = \frac{false| P_{x y} {false(f false) |}^{2}}{P_{x y} false(f false) P_{y y} false(f false)}

where C xy ( f ) is the coherence between the input signals x and y , P xy ( f ) is the cross PSD at a given frequency, P xx ( f ) and P yy ( f ) are the PSD of x and y signals at chosen frequency . The frequency coherence function C xy ( f ) returns a value between 0 and 1, with 1 indicating the same frequency‐power characteristics between studied signals .…”

Section: Methodsmentioning

confidence: 99%

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Dynamics of Microvascular Blood Flow and Oxygenation Measured Simultaneously in Human Skin

et al. 2014

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We have evaluated the dynamics of skin microvascular blood flow (BF) and tissue oxygenation parameters (OXY) measured simultaneously at the same site using a combined non-invasive BF+OXY+temperature probe. Skin BF, oxygenated (oxyHb) and deoxygenated (deoxyHb) haemoglobin and mean oxygen saturation (SO 2 ) were measured in 50 healthy volunteers at rest and during perturbation of local blood flow by post-occlusive reactive hyperaemia, sympathetic nervous system-mediated vasoconstriction (deep inspiratory breath-hold) and local skin warming. The relationship between BF and SO 2 over the range of flows investigated was described by a non-linear equation with an asymptote for SO 2 of 84% at BF >50 PU. SO 2 was independently associated with BF, skin temperature, BMI and age, which together identified 59% of the variance in SO 2 (p<0.0001). Fourier analysis revealed periodic low frequency fluctuations in both BF and SO 2 , attributable to endothelial (~0.01 Hz), neurogenic (~0.04 Hz) and myogenic (~0.1Hz) flow motion activity. The frequency coherence between the BF and SO 2 signals was greatest in the endothelial and neurogenic frequency bands. The simultaneous evaluation of microvascular blood flow and oxygenation kinetics in healthy skin provides a platform from which to investigate microvascular impairment in the skin and more generally the pathogenesis of microvascular disease.

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“…The frequency coherence function C xy (f) returns a value between 0 and 1, with 1 indicating the same frequency-power characteristics between studied signals [11,35,37,45].…”

Section: Discussionmentioning

confidence: 99%

“…)

C_{x y} false(f false) = \frac{false| P_{x y} {false(f false) |}^{2}}{P_{x y} false(f false) P_{y y} false(f false)}

Section: Methodsmentioning

confidence: 99%

Dynamics of Microvascular Blood Flow and Oxygenation Measured Simultaneously in Human Skin

et al. 2014

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“…2) and thus parameter estimation methods need to be adapted accordingly. The coefficients of the AR model were estimated by the least squares method applied over the available (remaining) samples (Simpson et al, 2001;Simpson et al, 2005). This may be illustrated for the simple example for a univariate AR model shown in Eq.…”

Section: Coherence Causal Coherence and Autoregressive Modeling With Missing Samplesmentioning

confidence: 99%

Gain and coherence estimates between respiration and heart-rate: Differences between inspiration and expiration

Fonseca

Beda

Sá

et al. 2013

Autonomic Neuroscience

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The interaction of respiration and heart-rate variability (HRV), leading to respiratory sinus arrhythmia (RSA) and, in the inverse direction, cardioventilatory coupling has been subject of much study and controversy. A parametric linear feedback model can be used to study these interactions. In order to investigate differences between inspiratory and expiratory periods, we propose that models are estimated separately for each period, by finding least mean square estimates only over the desired signal segments. This approach was tested in simulated data and heart-rate and respiratory air flow signals recorded from 25 young healthy adults (13 men and 12 women), at rest, breathing spontaneously through a face mask for 5 min. The results show significant differences (p<0.05) between the estimates of coherence obtained from the whole recording, and the inspiration and expiration periods. Simple and causal coherence from respiration to HRV was higher during inspiration than expiration. The estimates of gain also differed significantly in the high frequency (HF) band (0.15-0.5Hz) between those obtained from the whole recording, and the inspiratory and expiratory periods. These results indicate that a single linear model fitted to the whole recording neglects potentially important differences between inspiration and expiration, and the current paper shows how such differences can be estimated, without the need to control breathing.

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“…The magnitude square of the coherence (MSC) between P and V was then estimated as [5]: Finally, the statistical significance of the maximum value of the MSC estimate within a selected frequency band was tested using the Monte Carlo simulation (surrogate data based on the original P and V time series), as described in a previous work [5].…”

Section: Estimating the Magnitude Square Coherence From Signals With Missing Datamentioning

confidence: 99%

“…Recently, we developed a methodology, which can be applied to EEG and CBFV signals with missing samples [4], allowing the estimation of the coherence between the time series of EEG power parameters and of the mean velocity of the CBF [5]. The aim of this work is to contribute to a better understanding of the underlined mechanisms involved, association between the neuronal activity and the Doppler velocimetry of the middle cerebral artery from to term NB.…”

Section: Introductionmentioning

confidence: 99%

Coherence Between Spontaneous Eeg and Doppler Velocimetry of Cerebral Blood Flow in Newborns During Quiet Sleep

Rosas

Infantosi

World Congress on Medical Physics and Biomedical Engineering 2006

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Cerebral blood flow (CBF) changes in the newborns (NB) can lead to brain damage by decrease in the oxygen and glucose supply. Aiming at contributing to a better understanding of the underlined mechanisms involved, association between the electroencephalogram (EEG, right front-temporal EEG derivation) and the Doppler velocimetry of the middle cerebral artery from to term NB has been investigated. These signals were simultaneously collected from 20 NB and then epochs during quiet sleep (QS patterns: Tracé Alternant, TA, and High Voltage Slow, HVS) were selected. EEG power parameters within frequency bands of interest, e.g. power in theta (P within 4-8 Hz) and the velocimetry of CBF were estimated at each second. In order to investigate the association in the frequency domain, firstly the cross correlation function (CCF) with missing samples were estimated and then the magnitude square coherence (MSC) calculated. During TA, CCF between P and V resulted in the maximum value of the median close to 0.24 around -5 s (P anticipated to V) for 84.6% of the NB with p < 0.05 (statistical significance was tested with Monte Carlo simulation). The maximum of the MSC median occurred around 0.10 Hz in 92.3% of the NB (p < 0.05). A distinct behavior was observed for HVS. This could mask the results of TA when both patterns are taken together (QS). These findings indicate a significant association between the neuronal activity and CBF during TA. The high coherence value could be interpreted as TA influencing CBF or the existence of another physiologic variable influencing both, the CBF and the neuronal activity.

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Estimation of Coherence Between Blood Flow and Spontaneous EEG Activity in Neonates

Cited by 9 publications

References 29 publications

Dynamics of Microvascular Blood Flow and Oxygenation Measured Simultaneously in Human Skin

Dynamics of Microvascular Blood Flow and Oxygenation Measured Simultaneously in Human Skin

Gain and coherence estimates between respiration and heart-rate: Differences between inspiration and expiration

Coherence Between Spontaneous Eeg and Doppler Velocimetry of Cerebral Blood Flow in Newborns During Quiet Sleep

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