Intraoperative Cerebral Measurements Using Implantable Cortical Multimodality Probe.

Area of Science:

• Biomedical Engineering
• Neuroscience
• Medical Devices

Background:

• Simultaneous monitoring of brain activity, hemodynamics, and temperature is crucial for understanding neurological conditions.
• Existing methods often lack the capability for chronic, multi-parameter intracranial measurements.

Purpose of the Study:

• To develop and evaluate a novel multimodality probe for simultaneous measurement of electroencephalograms (EEGs), cerebral hemodynamics, and brain surface temperature (BrT).
• To assess the probe's performance in detecting functional changes during abnormal brain activity.

Main Methods:

• Fabrication of a flexible printed circuit board-based probe with six channels, integrating platinum electrodes for EEG, LEDs/photodiodes for near-infrared spectroscopy (NIRS) hemodynamics, and thermistors for BrT.
• Chronic intracranial placement of the probe at a resected brain site for in-vivo measurements.
• Evaluation of probe performance by analyzing simultaneous EEG, hemodynamic (HbT), and BrT data during observed abnormal brain activity.

Main Results:

• The multimodality probe successfully measured EEG, cerebral hemodynamics, and brain surface temperature simultaneously.
• Characteristic epileptogenic abnormal electroencephalograms with polarity reversal were observed at 16 min and 38 s.
• Brain cell oxygen consumption was inferred during abnormal EEG events, despite no noticeable change in total hemoglobin (HbT) values.

Conclusions:

• The developed multimodality probe is capable of chronic intracranial monitoring of multiple physiological parameters.
• The findings suggest that brain cells consume oxygen during epileptogenic activity, even when macro-hemodynamic changes are not apparent.
• This technology offers a promising tool for advancing the study of brain function and neurological disorders.