Mild traumatic brain injury (TBI) is common and associated with a spectrum of symptoms, which usually resolve within 3 months. But 5%–15% of patients are left with chronic disabling symptoms which challenge the current construct of mTBI. Increasingly mTBI has been a common subject of legal cases where neu- rologists have been ensnared.

The main reason for such legal challenges is the lack of clarity in mTBI definition and prognosis. The current mTBI construct is heavily dependent on the Mayo classification of Brain Injury Assessment, where Post-traumatic amnesia (PTA) is often taken as the principal index of severity, without attention to other relevant phenomena. Unfortunately, PTA is an unreliable indicator for the whole spectrum of brain injury and there is an urgent need for a better diagnostic construct, specifically utilizing the recent advances in TBI-pathophysiology (neurovascular cascade and cone of vulnerability).

We propose 1) evaluation for all brain injuries using multimodal imaging (MRI/fNIRS) protocol to capture the dynamic neurovascular changes seen in the entire spectrum of TBI severity. 2)Explore the relation between neuroimaging changes to the clinical symptoms occurring in various TBI stages by correlat- ing the comprehensive imaging data to the structured clinical assessments. 3) We will develop a novel clinical scoring system of injury severity across the spectrum of TBI by integrating the clinical outcome data with radiological (microvascular & macroscopic) and molecular biomarkers (Salivary RNA) for use in routine clinical practice.