Visual Scanning Behaviour during a visual search task: an objective indicator for 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). Often, PCS is characterised by microstructural damage to white matter tracts in the brain. Currently, there is no biomarker to screen for such damage. In this paper we present preliminary result for a novel and simple to administer paradigm that can be used to test the microstructural integrity of the corpus callosum. 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 for the microstructural integrity of the corpus callosum (CC). Microstructural integrity was evaluated directly by measuring the fractional anisotropy of the CC in images obtain by diffusion tensor imaging (DTI) technology. Fifty five patients with PCS completed the new visual scanning paradigm and the DTI procedure. Significant correlation was found between the NNTP and the FA of the corpus callosum (r=-0.463, p=0.000365). Mediation analysis showed that damage to the CC can affect NNTP directly or through processes that affect attention, somatic and cognitive symptoms. The results suggest that VSB during the MFFT task is a multifactorial cognitive and behavioural process that provides an indirect measure of the structural integrity of the CC."