Frequency-resolved analysis of coherent oscillations of local cerebral blood volume, measured with near-infrared spectroscopy, and systemic arterial pressure in healthy human subjects

• Published in: PloS one Vol. 14; no. 2; p. e0211710
• Main Authors: Tgavalekos, Kristen, Pham, Thao, Krishnamurthy, Nishanth, Sassaroli, Angelo, Fantini, Sergio
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 12.02.2019; Public Library of Science (PLoS)
• Subjects: Adult; Analysis; Arterial Pressure - physiology; Biology and Life Sciences; Biomedical engineering; Blood flow; Blood pressure; Blood volume; Cerebral blood flow; Cerebral Blood Volume - physiology; Cerebrum - blood supply; Cerebrum - chemistry; Cerebrum - physiology; Cuffs; Deflation (Economics); Engineering; Female; Frequency analysis; Glycosylated hemoglobin; Hemodynamics; Hemoglobin; Hemoglobins; Hemoglobins - analysis; Human subjects; Humans; I.R. radiation; Inflation (Economics); Infrared spectra; Infrared spectroscopy; Male; Medicine and Health Sciences; Middle Aged; Near infrared radiation; Near infrared spectroscopy; Oscillations; Parameters; Plethysmography; Prefrontal cortex; Research and Analysis Methods; Spatial variability; Spectroscopic analysis; Spectroscopy; Spectroscopy, Near-Infrared; Spectrum analysis; Time constant; Transfer functions; Variability; Young Adult; United States > US; Massachusetts
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0211710

We report a study on twenty-two healthy human subjects of the dynamic relationship between cerebral hemoglobin concentration ([HbT]), measured with near-infrared spectroscopy (NIRS) in the prefrontal cortex, and systemic arterial blood pressure (ABP), measured with finger plethysmography. [HbT] is a measure of local cerebral blood volume (CBV). We induced hemodynamic oscillations at discrete frequencies in the range 0.04-0.20 Hz with cyclic inflation and deflation of pneumatic cuffs wrapped around the subject's thighs. We modeled the transfer function of ABP and [HbT] in terms of effective arterial (K(a)) and venous (K(v)) compliances, and a cerebral autoregulation time constant (τ(AR)). The mean values (± standard errors) of these parameters across the twenty-two subjects were K(a) = 0.01 ± 0.01 μM/mmHg, K(v) = 0.09 ± 0.05 μM/mmHg, and τ(AR) = 2.2 ± 1.3 s. Spatially resolved measurements in a subset of eight subjects reveal a spatial variability of these parameters that may exceed the inter-subject variability at a set location. This study sheds some light onto the role that ABP and cerebral blood flow (CBF) play in the dynamics of [HbT] measured with NIRS, and paves the way for new non-invasive optical studies of cerebral blood flow and cerebral autoregulation.