Rheoencephalography

McHenry, Lawrence C.

doi:10.1212/wnl.15.6.507

Cited by 25 publications

(20 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our REG results are consistent with published literature [13][14][15]. Data were not evaluated for failed tests (Table 2), which include those with no results or where data could not be evaluated due to artifacts, which occurred for all modalities (with variability; among the modalities, REG was the most sensitive to artifacts).…”

Section: Discussionsupporting

confidence: 88%

Comparison of cerebrovascular reactivity tests: a pilot human study

Bodó

Mahon

Razumovsky³

et al. 2017

Journal of Electrical Bioimpedance

View full text Add to dashboard Cite

In neurosurgery intensive care units, cerebrovascular reactivity tests for neuromonitoring are used to evaluate the status of cerebral blood flow autoregulation; lack of autoregulation indicates a poor patient outcome. The goal of neuromonitoring is to prevent secondary injuries following a primary central nervous system injury, when the brain is vulnerable to further compromise due to hypoxia, ischemia and disturbances in cerebral blood flow and intracranial pressure. Ideally, neuromonitoring would be noninvasive and continuous. This study compares cerebrovascular reactivity monitored by rheoencephalography, a noninvasive continuous monitoring modality, to cerebrovascular reactivity measured by currently used neuromonitoring modalities: transcranial Doppler, near infrared spectroscopy and laser Doppler flowmetry. Fourteen healthy volunteer subjects were measured. The tests used for comparison of cerebrovascular reactivity were breath-holding, hyperventilation, CO2 inhalation, the Valsalva maneuver, and the Trendelenburg and reverse Trendelenburg positions. Data for all modalities measured were recorded by computers and processed off line. All measured modalities reflected cerebrovascular reactivity with variabilities. Breath-holding, CO2 inhalation, and the Valsalva maneuver caused CO2 increase and consequent brain vasodilatation; hyperventilation caused CO2 decrease and brain vasoconstriction. The Trendelenburg and reverse Trendelenburg positions caused extracranial blood volume changes, which masked intracranial cerebrovascular reactivity. The hyperventilation test proved ineffective for measuring cerebrovascular reactivity with rheoencephalography due to respiratory artifacts. Some discrepancies among the various modalities tested were observed. Further validation studies are under preparation to test the applicability of rheoencephalography for noninvasive continuous brain monitoring, including enhanced computational methods, animal studies and clinical monitoring studies of humans.

show abstract

Section: Discussionsupporting

confidence: 88%

Comparison of cerebrovascular reactivity tests: a pilot human study

Bodó

Mahon

Razumovsky³

et al. 2017

Journal of Electrical Bioimpedance

View full text Add to dashboard Cite

show abstract

“…At the same time, these changes can cause an increase in intracranial pressure and a resulting decrease in CBF. In studies of REG conducted earlier, REG was determined to be useful for detecting elevated ICP and arteriosclerosis [15]. An overview of REG can be found elsewhere [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31], however the relationship between REG and CBF AR was missing [8,9,11,12].…”

Section: Medical Basicsmentioning

confidence: 99%

Studies in Rheoencephalography (REG)

Bodó

2010

Journal of Electrical Bioimpedance

View full text Add to dashboard Cite

This article presents an overview of rheoencephalography (REG) -electrical impedance measurements of the brain -and summarizes past and ongoing research to develop medical applications of REG for neuro-critical care and for primary prevention of stroke and cardiovascular disease. The availability of advanced electronics and computation has opened up the potential for use of REG technology as a noninvasive, continuous and inexpensive brain monitor for military and civilian applications. The clinical background information presented here introduces physiological and clinical environments where REG has potential for use in research and clinical settings.REG studies over the past three decades have involved in vitro and in vivo groups (animal and human), including more than 1500 measurements and related electronic and computational results and practical applications. In vitro studies helped researchers understand the flow/volume relationship between Doppler ultrasound and electrical impedance signals and supported development of REG data processing methods. In animal studies, REG was used to monitor the lower limit of cerebral blood flow (CBF) autoregulation (AR) using a newly developed algorithm. These animal studies also confirmed correlations between REG and measurements of carotid flow (CF) and intracranial pressure (ICP). Human studies confirmed the applicability of REG for detecting cerebrovascular alteration, demonstrating the usefulness of REG in the field of stroke/cardio-vascular disease prevention. In these studies, REG was compared to known stroke risk factors and to results obtained using carotid ultrasound measurements. An intelligent REG system (Cerberus) has been developed for primary stroke prevention. In these studies, the biologically relevant variables of the REG signal were pulse amplitude (minimummaximum distance) and duration of the anacrotic (rising) portion of the REG pulse wave.The principal limitation of REG for clinical application is the lack of pathological and physiological correlations. The studies presented here have initiated such inquiries, but many clinical questions about the pathophysiological background of REG remain unanswered.These results demonstrate that REG development is a multidisciplinary subject with relevance for medicine (vascular neurology and neurosurgery intensive care); electronic engineering; mathematics, and computer science (data processing). It is hoped that information presented in this article will provide assistance to those involved in REG research, particularly in development and clinical applications.

show abstract

“…Their statement that the imped ance values for the surface electrode-to-electrolyte interface exceeded the under lying tissue resistance of the brain has been challenged by Kinnen (1969a, b) and the model constructed by Seipel (1967) further refutes this. Finally it has been claimed that some examples of intracerebral pathology are not always revealed by rheoencephalography (Perez-Borja and Meyer, 1964;Waltz and Ray, 1967;Masucci et al, 1970) but there have been successful efforts to do so (McHenry, 1965;Seipel, 1967;Hadjiev, \912\Jacquy et al, 1974). Seipel (1967) found this to be the case for 95% of his 136 REG recordings, while Hadjiev (1972) has reviewed the world literature covering a large number of such investigations.…”

Section: Discussionmentioning

confidence: 99%

The Diagnostic Potential of Rheoencephalography in Psychiatry

Dixon¹,

Doust²

1978

Psychopathology

View full text Add to dashboard Cite

A 3 electrode monopolar rheoencephalograph was employed to produce a 15 min record of electrical impedance plethysmographic pulse-volume waves in 139 healthy subjects and 782 patients belonging to 15 psychiatric syndromes. Parameters of amplitude, percent rise time and average inflow angle were hand-measured and their means obtained for 30 waveforms throughout each record. Results obtained depended significantly upon chronological age and in some cases on gender. Mental health was found clearly distinguishable from psychiatric disability, but psychiatric syndromes could not be differentiated from one another. A low percent rise time coupled with a high average inflow angle were typical of youth and mental health.

show abstract

Rheoencephalography

Cited by 25 publications

References 0 publications

Comparison of cerebrovascular reactivity tests: a pilot human study

Comparison of cerebrovascular reactivity tests: a pilot human study

Studies in Rheoencephalography (REG)

The Diagnostic Potential of Rheoencephalography in Psychiatry

Contact Info

Product

Resources

About