Abstract
Traumatic brain injury (TBI) is a leading cause of mortality and disability worldwide. A challenge for diagnosing and assessing the severity of TBI, however, is that quantitative biomarkers are lacking. We explored potential functional indicators for TBI by noninvasively monitoring sensory-evoked electrical and hemodynamic activity using a novel hybrid optical and electrophysiological measurement approach. By combining diffuse correlation spectroscopy with co-localized electrophysiological measurements in a mouse model of TBI, we observed concomitant alterations in somatosensory-evoked cerebral blood flow and electrical potentials following controlled cortical impact. Injury acutely reduced the amplitude of stimulus-evoked responses, which mostly recovered to baseline values within 30 min; intertrial variability for these parameters was also acutely altered. The kinetics of recovery, however, varied among specific components of the evoked waveforms, and we observed strong correlations between the two measurement modalities for only a select subset of waveform parameters. Overall, our results identify a novel set of potential biomarkers for TBI and demonstrate the utility of combined, noninvasive optical and electrophysiological measurements for detecting injury-induced abnormalities in neurovascular reactivity.
