Visual Scanning Behaviour during a Visual Search Task: An Objective Indicator of White Matter Integrity in Patients with Post-Concussion Syndrome

Post-concussion syndrome (PCS) is associated with incomplete recovery following a mild traumatic brain injury (mTBI). Currently, there is no biomarker to diagnose post-concussion syndrome. Although microstructural damage to white matter tracts is postulated and reported in some studies, there is no diagnostic biomarker available. In this paper, we present preliminary results of a novel and simple-toadminister eye-tracking paradigm that relates visual scanning behaviour to microstructural integrity of the corpus callosum (CC). The novel paradigm is based on the Matching Familiar Figures Test (MFFT). In the MFFT test, a series of slides each containing a familiar standard figure and six variants are presented. Only one of the variants is identical to the standard figure and subjects are instructed to select the matched variant. The normalised number of transitions to the standard figure prior to the first selection (NNTP) is used as an indirect measure of the microstructural integrity of the CC. Microstructural integrity was evaluated by measuring the fractional anisotropy (FA) of the CC derived from tract based spatial statistics on diffusion tensor imaging (DTI). Fifty-five patients with PCS completed the visual scanning paradigm and magnetic resonance imaging. Significant inverse correlation was found between the NNTP and the FA of the CC (r= -0.463, p