Test-retest Reliability of Neurovascular Coupling and Impairment in Epilepsy Measured by fNIRS and EEG.

Simultaneous fNIRS-EEG is a cost efficient, noninvasive, and adaptable multimodal imaging method that measures both the hemodynamics and electrical activity of the brain. Neurovascular coupling (NVC) is an important mechanism in the brain in which increased neuronal activity propels an increase in oxygenated hemoglobin as well as decrease in deoxygenated hemoglobin in the local cerebral blood flow to that specific area. Previous literature has suggested that NVC may be impaired in individuals with epilepsy. The unique approach to measure and quantify NVC via multimodal fNIRS-EEG imaging is an intriguing method to probe the NVC in clinical settings. Therefore, the purpose of the present study is to determine the reliability of NVC in a group of healthy subjects and investigate NVC in a pilot sample of epileptic patients to compare with healthy through a series of auditory tasks using simultaneous fNIRS-EEG. Results showed excellent test-retest reliability agreement in the fNIRS responses and NVC for the healthy control group. Meanwhile, abnormally lower fNIRS and NVC responses were observed in the epileptic patient group. These results provide important data for the reliability of fNIRS-EEG-based NVC testing and show promise that simultaneous fNIRS-EEG imaging can detect impaired NVC in epileptic individuals.