Rapid detection and monitoring of brain injury using sensory-evoked responses

Abstract

There is currently a dearth of quantitative biomarkers for traumatic brain injury (TBI) that can be rapidly acquired and interpreted in active field environments. Clinical imaging, via computed tomography (CT) scan or magnetic resonance imaging (MRI), in combination with a clinical examination, is currently the “gold standard” for diagnosing TBI. These technologies, however, require extended imaging sessions and are rarely available during the peak therapeutic window following injury. Moreover, mild TBI (mTBI) often does not present with structural damage that can be detected by CT or MRI imaging. Techniques that probe neurophysiological function, however, present an opportunity to directly and rapidly assess brain health following head impact. One of the most basic roles of the CNS is to register and parse sensory stimuli from the environment. This process relies on an intricate feedback network that involves a multitude of widely distributed brain structures, and subtle perturbation in brain health can have a dramatic effect on afferent relay and processing of sensory information. In this chapter, we describe recent preclinical approaches for rapidly detecting and monitoring TBI using sensory-evoked physiological biomarkers, particularly somatosensory-evoked electrophysiological and hemodynamic responses. With an eye toward clinical implementation, we focus our discussion on measurements that can be achieved noninvasively.