B waves: a systematic review of terminology, characteristics, and analysis methods

Martinez-Tejada, Isabel; Arum, Alexander; Wilhjelm, Jens E.; Juhler, Marianne; Andresen, Morten

doi:10.1186/s12987-019-0153-6

Cited by 29 publications

(28 citation statements)

References 126 publications

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“…B‐waves were originally defined as rhythmic oscillations in the ICP signal with an amplitude up to 50 mmHg and with frequencies of 0.5–2 waves/min (Lundberg, 1960). Since then, two types of B‐wave have been described, ramp‐type and sinusoidal, with the latter subdivided into high‐ or low‐amplitude waves depending on whether the amplitude is > or <10 mmHg (Martinez‐Tejada et al., 2019).…”

Section: Introductionmentioning

confidence: 99%

B‐waves are present in patients without intracranial pressure disturbances

Riedel

Martinez-Tejada

Norager

et al. 2020

Journal of Sleep Research

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Intracranial pressure (ICP) B‐waves are defined as short, repeating elevations of ICP of up to 50 mmHg with a frequency of 0.5–2 waves/min. The presence of B‐waves in overnight recordings is regarded as a pathological phenomenon. However, the physiology of B‐waves is still not fully understood and studies with transcranial Doppler, as a surrogate marker for ICP, have suggested that B‐waves could be a normal physiological phenomenon. We present four patients without known structural neurological disease other than a coincidentally found unruptured intracranial aneurysm. One of the patients had experienced well‐controlled epilepsy for several years, but was included because ICP under these conditions is unlikely to be abnormal. Following informed consent, all four patients had a telemetric ICP probe implanted during a prophylactic operation with closure of the aneurysm. They underwent overnight ICP monitoring with simultaneous polysomnography (PSG) sleep studies at 8 weeks after the operation. These patients exhibited nocturnal B‐waves, but did not have major structural brain lesions. Their ICP values were within the normal range. Nocturnal B‐waves occurred in close association with sleep‐disordered breathing (SDB) in rapid eye movement (REM) and non‐REM sleep stages. SDB during REM sleep was associated with ramp‐type B‐waves; SDB during non‐REM sleep was associated with the sinusoidal type of B‐wave. We propose that B‐waves are a physiological phenomenon associated with SDB and that the mechanical changes during respiration could have an essential and previously unrecognised role in the generation of B‐waves.

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Section: Introductionmentioning

confidence: 99%

B‐waves are present in patients without intracranial pressure disturbances

Riedel

Martinez-Tejada

Norager

et al. 2020

Journal of Sleep Research

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“…To further focus our investigation, we interrogate two well-defined vascular oscillatory mechanisms within the lowfrequency range, namely the B wave and the M-wave (which overlaps with the frequency of vasomotion). They are both understudied in the MRI literature, but both have established clinical utility (Julien, 2006;Martinez-Tejada et al, 2019). Such low-frequency oscillations are typically challenging to characterize as it is currently impossible to isolate vascular from neuronally driven oscillations in this frequency range.…”

Section: Discussionmentioning

confidence: 99%

“…• B wave: calculated using PPG: B waves were defined as short repeating elevations in intracranial pressure (ICP) (10-20 mmHg) with a frequency of 0.5-2 waves/min (Lundberg, 1960), which translates to a fairly broad range of 0.008 to 0.03 Hz. One way to subdivide B waves is in terms of symmetrical, asymmetrical and plateau waves, each potentially associated with distinct etiology (Martinez-Tejada et al, 2019). Although clearly visible B waves are typically a feature of disease, the frequency of B waves is immediately overlapping with the range of interest for rs-fMRI, prompting us to study B-wave contribution in the CSF signal.…”

Section: Ppg-derived Vascular Measuresmentioning

confidence: 99%

“…While the generators and pathways of such oscillations are not fully understood, these rhythms have been recognized for their diagnostic significance (Schytz et al, 2010;Spiegelberg et al, 2016). B waves are defined as short repeating elevations in intracranial pressure (Lundberg, 1960;Martinez-Tejada et al, 2019) that can lead to oscillations in arterial blood pressure (Droste and Krauss, 1999), while M waves are interpreted as the magnitude of blood-pressure (BP) oscillations that can translate into blood flow oscillations. An additional complication is that M waves overlap in frequency with vasomotion.…”

Section: Introductionmentioning

confidence: 99%

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Vascular origins of low-frequency oscillations in the cerebrospinal fluid signal in resting-state fMRI: Interpretation using photoplethysmography

Attarpour

Ward

Chen

2020

Preprint

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Slow and rhythmic spontaneous oscillations of cerebral blood flow are well known to have diagnostic utility, notably frequencies of 0.008-0.03 Hz (B-waves) and 0.05-0.15Hz (Mayer waves or M waves). However, intracranial measurements of these oscillations have been difficult. Oscillations in the cerebrospinal fluid (CSF), which are influenced by the cardiac pulse wave, represent a possible avenue for non-invasively tracking these oscillations using resting-state functional MRI (rs-fMRI), and have been used to correct for vascular oscillations in rs-fMRI functional connectivity calculations. However, the relationship between low-frequency CSF and vascular oscillations is unclear. In this study, we investigate this relationship using fast simultaneous multi-slice rs-fMRI coupled with fingertip photoplethysmography (PPG). We not only extract B-wave and M-wave range spectral power from the PPG signal, but also derive the pulse-intensity ratio (PIR, a surrogate of slow blood-pressure oscillations), the second-derivative of the PPG (SDPPG, a surrogate of arterial stiffness) and heart-rate variability (HRV). The main findings of this study are: (1) signals in different CSF regions (ROIs) are not equivalent in their vascular contributions or in their associations with vascular and tissue rs-fMRI signals; (2) the PPG signal contains the highest signal contribution from the M-wave range, while PIR contains the highest signal contribution from the B-wave range; (3) in the low-frequency range, PIR is more strongly associated with rs-fMRI signal in the CSF than PPG itself, and than HRV and SDPPG; (4) PPG-related vascular oscillations only contribute to < 20% of the CSF signal in rs-fMRI, insufficient support for the assumption that low-frequency CSF signal fluctuations directly reflect vascular oscillations. These findings caution the use of CSF as a monolithic region for extracting physiological nuisance regressors in rs-fMRI applications. They also pave the way for using rs-fMRI in the CSF as a potential tool for tracking cerebrovascular health through, for instance the strong relationship between PIR and the CSF signal.

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“…SDPPG, which is included in this study as a commonly cited measure of arterial compliance, is mainly driven by high-frequency vascular oscillations, presumably reflecting beat-to-beat compliance. PIR, as a surrogate measure of SBP, contains the highest percentage of power in the band <0.1 Hz, attesting to the relationship between intracranial and systemic blood pressure (Martinez-Tejada et al, 2019).…”

Section: Potential Implications Of Ppg-derived Signalsmentioning

confidence: 91%

Vascular origins of low‐frequency oscillations in the cerebrospinal fluid signal in resting‐state fMRI: Interpretation using photoplethysmography

Attarpour

Ward

Chen

2021

Human Brain Mapping

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In vivo mapping of cerebrovascular oscillations in the 0.05-0.15 Hz remains difficult.Oscillations in the cerebrospinal fluid (CSF) represent a possible avenue for noninvasively tracking these oscillations using resting-state functional MRI (rs-fMRI), and have been used to correct for vascular oscillations in rs-fMRI functional connectivity. However, the relationship between low-frequency CSF and vascular oscillations remains unclear. In this study, we investigate this relationship using fast simultaneous rs-fMRI and photoplethysmogram (PPG), examining the 0.1 Hz PPG signal, heart-rate variability (HRV), pulse-intensity ratio (PIR), and the second derivative of the PPG (SDPPG). The main findings of this study are: (a) signals in different CSF regions are not equivalent in their associations with vascular and tissue rs-fMRI signals; (b) the PPG signal is maximally coherent with the arterial and CSF signals at the cardiac frequency, but coherent with brain tissue at 0.2 Hz; (c) PIR is maximally coherent with the CSF signal near 0.03 Hz; and (d) PPGrelated vascular oscillations only contribute to 15% of the CSF (and arterial) signal in rs-fMRI. These findings caution against averaging all CSF regions when extracting physiological nuisance regressors in rs-fMRI applications, and indicate the drivers of the CSF signal are more than simply cardiac. Our study is an initial attempt at the refinement and standardization of how the CSF signal in rs-fMRI can be used and interpreted. It also paves the way for using rs-fMRI in the CSF as a potential tool for tracking cerebrovascular health through, for instance, the potential relationship between PIR and the CSF signal.

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B waves: a systematic review of terminology, characteristics, and analysis methods

Cited by 29 publications

References 126 publications

B‐waves are present in patients without intracranial pressure disturbances

B‐waves are present in patients without intracranial pressure disturbances

Vascular origins of low-frequency oscillations in the cerebrospinal fluid signal in resting-state fMRI: Interpretation using photoplethysmography

Vascular origins of low‐frequency oscillations in the cerebrospinal fluid signal in resting‐state fMRI: Interpretation using photoplethysmography

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