End-tidal CO2: An important parameter for a correct interpretation in functional brain studies using speech tasks

Scholkmann, Felix; Gerber, Ursina; Wolf, M.; Wolf, Ursula

doi:10.1016/j.neuroimage.2012.10.025

Cited by 108 publications

(109 citation statements)

References 136 publications

(180 reference statements)

Supporting

Mentioning

105

Contrasting

Order By: Relevance

“…We hypothesized that this effect might be the result of a decrease in the partial pressure of carbon dioxide in the arterial blood (PaCO2) during speaking [5,6]. This hypothesis was confirmed in a subsequent study [4]: we found significant changes in end-tidal CO2 (PETCO2), a reliable and accurate estimate of PaCO2 [7], during all recitation tasks and even during the control task (mental arithmetic). We concluded that changes in breathing (hyperventilation) during the tasks are mainly to account for the measured changes in hemodynamics and oxygenation mediated by hypocapnia.…”

Section: Introductionmentioning

confidence: 62%

“…As already indicated in [4], in order to explain the results obtained from speech studies, one should be aware that the measured changes of NIRS-derived hemodynamic and oxygenation signals are the result of at least two major physiological effects. One the one hand, increased neuronal activity leads to an increase in the cerebral metabolic rate of O2 (CMRO2) which is accompanied by an increase of the cerebral blood flow (CBF) and thus volume (CBV) (neurovascular coupling) [9].…”

Section: Discussionmentioning

confidence: 99%

“…In previous studies, we showed that guided rhythmic speech exercises in the context of arts speech therapy (AST) cause changes in heart rate variability [1,2], cardiorespiratory interactions [3], as well as hemodynamics and oxygenation in the brain and muscle [4][5][6]. In particular, we demonstrated that during speech exercises, a decrease in cerebral hemodynamics and oxygenation occurred.…”

Section: Introductionmentioning

confidence: 91%

See 2 more Smart Citations

The Effect of Inner Speech on Arterial CO2 and Cerebral Hemodynamics and Oxygenation: A Functional NIRS Study

Scholkmann

Wolf²,

Wolf

2013

Oxygen Transport to Tissue XXXV

View full text Add to dashboard Cite

The aim of the present study was (i) to investigate the effect of inner speech on cerebral hemodynamics and oxygenation, and (ii) to analyze if these changes could be the result of alternations of the arterial carbon dioxide pressure (PaCO2). To this end, in seven adult volunteers, we measured changes of cerebral absolute [O2Hb], [HHb], [tHb] concentrations and tissue oxygen saturation (StO2) (over the left and right anterior prefrontal cortex (PFC)), as well as changes in end-tidal CO2 (PETCO2), a reliable and accurate estimate of PaCO2. Each subject performed three different tasks (inner recitation of hexameter (IRH) or prose (IRP) verses) and a control task (mental arithmetic (MA)) on different days according to a randomized crossover design. Statistical analysis was applied to the differences between pre-baseline, two tasks, and four post-baseline periods. The two brain hemispheres and three tasks were tested separately. During the tasks, we found (i) PETCO2 decreased significantly (p < 0.05) during the IRH ( 3 mmHg) and MA ( 0.5 mmHg) task. (ii) [O2Hb] and StO2 decreased significantly during IRH ( 1.5 M; 2 %), IRP ( 1 M; 1.5 %), and MA ( 1 M; 1.5 %) tasks. During the post-baseline period, [O2Hb] and [tHb] of the left PFC decreased significantly after the IRP and MA task ( 1 M and 2 M, respectively). In conclusion, the study showed that inner speech affects PaCO2, probably due to changes in respiration. Although a decrease in PaCO2 is causing cerebral vasoconstriction and could potentially explain the decreases of [O2Hb] and StO2 during inner speech, the changes in PaCO2 were significantly different between the three tasks (no change in PaCO2 for MA) but led to very similar changes in [O2Hb] and StO2. Thus, the cerebral changes cannot solely be explained by PaCO2. Abstract: The aim of the present study was (i) to investigate the effect of inner speech on cerebral hemodynamics and oxygenation, and (ii) to analyze if these changes could be the result of alternations of the arterial carbon dioxide pressure (Pa-CO2). To this end, in seven adult volunteers, we measured changes of cerebral absolute [O2Hb], [HHb], [tHb] concentrations and tissue oxygen saturation (StO2) (over the left and right anterior prefrontal cortex (PFC)), as well as changes in end-tidal CO2 (PETCO2), a reliable and accurate estimate of PaCO2. Each subject performed three different tasks (inner recitation of hexameter (IRH) or prose (IRP) verses) and a control task (mental arithmetic (MA)) on different days according to a randomized crossover design. Statistical analysis was applied to the differences between pre-baseline, two tasks, and four postbaseline periods. The two brain hemispheres and three tasks were tested separately. During the tasks, we found (i) PETCO2 decreased significantly (p < 0.05) during the IRH (~3 mmHg) and MA (~0.5 mmHg) task. (ii) [O2Hb] and StO2 decreased significantly during IRH (~1.5 μM; ~2 %), IRP (~1 μM; ~1.5 %), and MA (~1 μM; ~1.5 %) tasks. During the post-baseline period, [O2Hb] and [tHb] of t...

show abstract

Section: Introductionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 91%

See 1 more Smart Citation

The Effect of Inner Speech on Arterial CO2 and Cerebral Hemodynamics and Oxygenation: A Functional NIRS Study

Scholkmann

Wolf²,

Wolf

2013

Oxygen Transport to Tissue XXXV

View full text Add to dashboard Cite

show abstract

“…a decrease in PaCO 2 (hypocapnia) leads to a reduction in CBF and CBV by vasoconstriction (Poeppel et al, 2007;Szabo et al, 2011). How PaCO 2 affects fNIRI signals was reviewed by Scholkmann et al (2013) and how to model the coupling between PaCO 2 , blood pressure (BP) and cerebral hemodynamics/oxygenation can be found in (Payne et al, 2011). Durduran et al (2010) demonstrated that PaCO 2 changes affect the cerebral and extracerebral compartment differently, i.e.…”

Section: Classification Of Signal Componentsmentioning

confidence: 99%

“…an increase in PaCO 2 (hypercapnia) led to a significant increase in CBF, but only to a negligible increase in scalp blood flow (SBF). Scholkmann et al (2013) showed that PaCO 2 changes were evoked by speech and mathematical tasks, and strongly affected the fNIRI signals. Task execution may also lead to significant changes in BP during certain experimental tasks such as arm-rising (Minati et al, 2011), anagram task (Tachtsidis et al, 2008a(Tachtsidis et al, ,c, 2009), word generation and constructional puzzle task (Moody et al, 2005), semantic continuous performance task (Jelzow et al, 2011), or emotional picture presentation (Minati et al, 2009).…”

Section: Classification Of Signal Componentsmentioning

confidence: 99%

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Scholkmann¹,

Kleiser²,

Metz³

et al. 2014

NeuroImage

1,418

1,394

View full text Add to dashboard Cite

This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. This year marks the 20th anniversary of functional near-infrared spectroscopy and imaging (fNIRS/fNIRI). As the vast majority of commercial instruments developed until now are based on continuous wave technology, the aim of this publication is to review the current state of instrumentation and methodology of continuous wave fNIRI. For this purpose we provide an overview of the commercially available instruments and address instrumental aspects such as light sources, detectors and sensor arrangements. Methodological aspects, algorithms to calculate the concentrations of oxy-and deoxyhemoglobin and approaches for data analysis are also reviewed. From the single-location measurements of the early years, instrumentation has progressed to imaging initially in two dimensions (topography) and then three (tomography). The methods of analysis have also changed tremendously, from the simple modified Beer-Lambert law to sophisticated image reconstruction and data analysis methods used today. Due to these advances, fNIRI has become a modality that is widely used in neuroscience research and several manufacturers provide commercial instrumentation. It seems likely that fNIRI will become a clinical tool in the foreseeable future, which will enable diagnosis in single subjects. Contents

show abstract

Miniaturized Battery‐Free Wireless Systems for Wearable Pulse Oximetry

Kim

Gutruf

Chiarelli

et al. 2016

Adv Funct Materials

259

242

View full text Add to dashboard Cite

Development of unconventional technologies for wireless collection, storage and analysis of quantitative, clinically relevant information on physiological status is of growing interest. Soft, biocompatible systems are widely regarded as important because they facilitate mounting on external (e.g. skin) and internal (e.g. heart, brain) surfaces of the body. Ultra-miniaturized, lightweight and battery-free devices have the potential to establish complementary options in bio-integration, where chronic interfaces (i.e. months) are possible on hard surfaces such as the fingernails and the teeth, with negligible risk for irritation or discomfort. Here we report materials and device concepts for flexible platforms that incorporate advanced optoelectronic functionality for applications in wireless capture and transmission of photoplethysmograms, including quantitative information on blood oxygenation, heart rate and heart rate variability. Specifically, reflectance pulse oximetry in conjunction with near-field communication (NFC) capabilities enables operation in thin, miniaturized flexible devices. Studies of the material aspects associated with the body interface, together with investigations of the radio frequency characteristics, the optoelectronic data acquisition approaches and the analysis methods capture all of the relevant engineering considerations. Demonstrations of operation on various locations of the body and quantitative comparisons to clinical gold standards establish the versatility and the measurement accuracy of these systems, respectively.

show abstract

End-tidal CO2: An important parameter for a correct interpretation in functional brain studies using speech tasks

Cited by 108 publications

References 136 publications

The Effect of Inner Speech on Arterial CO2 and Cerebral Hemodynamics and Oxygenation: A Functional NIRS Study

The Effect of Inner Speech on Arterial CO2 and Cerebral Hemodynamics and Oxygenation: A Functional NIRS Study

A review on continuous wave functional near-infrared spectroscopy and imaging instrumentation and methodology

Miniaturized Battery‐Free Wireless Systems for Wearable Pulse Oximetry

Contact Info

Product

Resources

About