Depth-sensitive cerebral blood flow and low-frequency oscillations for consciousness assessment using time-domain...

Area of Science:

• Neuroscience
• Biomedical Engineering
• Medical Physics

Background:

• Continuous monitoring of cerebral blood flow (CBF) and neurovascular dynamics is crucial for brain injury assessment.
• Existing neuroimaging lacks portability and depth specificity for neurocritical care.
• Traumatic brain injury (TBI) and disorders of consciousness (DOC) require advanced monitoring tools.

Purpose of the Study:

• To evaluate time-domain diffuse correlation spectroscopy (TD-DCS) for depth-sensitive CBF and low-frequency oscillation (LFO) monitoring.
• To assess TD-DCS feasibility in healthy individuals and patients with DOC.
• To explore TD-DCS for detecting altered brain function in neurocritical care settings.

Main Methods:

• A 1064-nm TD-DCS system with superconducting nanowire single-photon detectors (SNSPDs) was employed.
• Resting-state measurements were acquired from 25 healthy adults and 5 TBI patients with DOC.
• Temporal gating separated superficial and cortical signals; LFOs analyzed via power spectral density and task-evoked responses.

Main Results:

• Disorders of consciousness patients showed altered resting-state LFO amplitude and spectral distribution compared to controls.
• A shift toward slower oscillatory components was observed in DOC patients.
• Task-evoked hemodynamic responses were attenuated and transient in DOC patients versus healthy participants.

Conclusions:

• TD-DCS is a noninvasive, depth-resolved method for monitoring cerebral hemodynamics and spontaneous brain activity.
• The technology shows potential as a portable bedside tool for neurocritical care.
• TD-DCS can assess cerebrovascular dynamics and residual cortical responsiveness in patients with brain injuries.