Evaluation and Diagnosis of Brain Death: a Non-Invasive Pilot Study Using Functional Near-Infrared Spectroscopy (fNIRS)

Brain death is an irreversible event for the brain that the brain and brainstem functions are destroyed. Conventional methods of diagnosing and evaluating brain death are time-consuming, costly and in many cases dangerous. Alternative monitoring systems also have several limitations. The functional near-infrared spectroscopy (fNIRS) can track oxyhemoglobin and deoxyhemoglobin changes of the tissue using scattering and light absorption properties of the brain and blood components. The spatially resolved spectroscopy (SRS) method can additionally measure tissue oxygen index (TOI). We have collected data from several brain death patients using our non-invasive fNIRS portable system. Initially, we have observed that in brain dead patients, oxyhemoglobin and deoxyhemoglobin changes are quasiperiodic. Moreover, their TOI change has a very low standard deviation and was quasi-periodic. These results can be biomarkers for diagnosis, evaluation, and validation of brain death.