A Cardiac Hypothesis for the Origin of EEG Alpha

Castillo, Horace T.

doi:10.1109/tbme.1983.325080

Cited by 3 publications

(2 citation statements)

References 5 publications

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“…[34][35][36] Bench-based models that reproduced the effect of the systolic blood pressure wave on the brain found the brain oscillated at 10 Hz, with an amplitude of~10 mmHg. 37 Acute hypoxia, to the levels produced in this study, triggers a~20% increase in cerebral blood flow. [29][30][31] Increased cerebral blood flow could increase the pulsatile mechanical forces acting on the brain, and thus the amplitude of the brain oscillations, to a level detectable by the brain oximeter.…”

Section: Oscillationsmentioning

confidence: 65%

“…These oscillations are believed to arise from intrinsic neural activity; however, a number of studies have demonstrated associations between cerebral blood flow or heart rate and the amplitude of these oscillations, suggesting that brain movement due to the mechanical forces associated with the systolic pressure wave is an alternative mechanism. 37,[42][43][44][45][46]…”

Section: Oscillationsmentioning

confidence: 99%

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<p>Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia</p>

Dixon¹,

MacLeod²

2020

MDER

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Introduction: Research in traumatic brain injury suggests better patient outcomes when invasive oxygen monitoring is used to detect and correct episodes of brain hypoxia. Invasive brain oxygen monitoring is, however, not routinely used due to the risks, costs and technical challengers. We are developing a non-invasive brain oximeter to address these limitations. The monitor uses the principles of pulse oximetry to record a brain photoplethysmographic waveform and oxygen saturations. We undertook a study in volunteers to assess the new monitor. Patients and Methods: We compared the temporal changes in the brain and skin oxygen saturations in six volunteers undergoing progressive hypoxia to reach arterial saturations of 70%. This approach provides a method to discriminate potential contamination of the brain signal by skin oxygen levels, as the responses in brain and skin oxygen saturations are distinct due to the auto-regulation of cerebral blood flow to compensate for hypoxia. Conventional pulse oximetry was used to assess skin oxygen levels. Blood was also collected from the internal jugular vein and correlated with the brain oximeter oxygen levels. Results: At baseline, a photoplethysmographic waveform consistent with that expected from the brain was obtained in five subjects. The signal was adequate to assess oxygen saturations in three subjects. During hypoxia, the brain's oximeter oxygen saturation fell to 74%, while skin saturation fell to 50% (P<0.0001). The brain photoplethysmographic waveform developed a high-frequency oscillation of~7 Hz, which was not present in the skin during hypoxia. A weak correlation between the brain oximeter and proximal internal jugular vein oxygen levels was demonstrated, R 2 =0.24, P=0.01. Conclusion: Brain oximeter oxygen saturations were relatively well preserved compared to the skin during hypoxia. These findings are consistent with the expected physiological responses and suggest skin oxygen levels did not markedly contaminate the brain oximeter signal.

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Section: Oscillationsmentioning

confidence: 65%

Section: Oscillationsmentioning

confidence: 99%

<p>Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia</p>

Dixon¹,

MacLeod²

2020

MDER

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The cerebral origin of the alpha rhythm

Hogan¹,

Fitzpatrick²

1988

Electroencephalography and Clinical Neurophysiology

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The Development of Non-Invasive Optical Brain Pulse Monitoring: A Review

Teo,

Petautschnig,

Chung

et al. 2024

MDER

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Early detection of neurological deterioration in serious acute brain injury is seen as an important goal to reduce death and disability, but monitoring for neurological deterioration remains challenging. Routine methods, such as neurological examination and brain imaging, often identify brain injuries only after they have progressed to an irreversible stage. Alternate approaches such as invasive brain monitoring, are complex, costly and carry inherent risks. The optical brain pulse monitor (OBPM) is a novel, non-invasive, safe, and continuous monitoring device designed to provide earlier detection of neurological deterioration and address the limitations of traditional approaches. This review presents the development, technical aspects, and clinical results from past and ongoing trials over the last five years.

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A Cardiac Hypothesis for the Origin of EEG Alpha

Cited by 3 publications

References 5 publications

<p>Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia</p>

<p>Assessment of a Non Invasive Brain Oximeter in Volunteers Undergoing Acute Hypoxia</p>

The cerebral origin of the alpha rhythm

The Development of Non-Invasive Optical Brain Pulse Monitoring: A Review

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