Frequency analysis of oscillations in cerebral hemodynamics measured by time domain near infrared spectroscopy

Biomed Opt Express. 2019 Jan 23;10(2):761-771. doi: 10.1364/BOE.10.000761. eCollection 2019 Feb 1.

Abstract

In this paper, we propose the application of time-domain near-infrared spectroscopy to the assessment of oscillations in cerebral hemodynamics. These oscillations were observed in the statistical moments of the distributions of time of flight of photons (DTOFs) measured on the head. We analyzed the zeroth and second centralized moments of DTOFs (total number of photons and variance) to obtain their spectra to provide parameters for the frequency components of microcirculation, which differ between the extracerebral and intracerebral layers of the head. Analysis of these moments revealed statistically significant differences between a control group of healthy subjects and a group of patients with severe neurovascular disorders, which is a promising result for the assessment of cerebral microcirculation and cerebral autoregulation mechanisms.