*Article* **Electrophysiological Markers of Visuospatial Attention Recovery after Mild Traumatic Brain Injury**

#### **Julie Bolduc-Teasdale 1,2, Pierre Jolicoeur 2 and Michelle McKerral 1,2,\***


Received: 21 October 2019; Accepted: 22 November 2019; Published: 27 November 2019

**Abstract:** Objective: Attentional problems are amongs<sup>t</sup> the most commonly reported complaints following mild traumatic brain injury (mTBI), including di fficulties orienting and disengaging attention, sustaining it over time, and dividing attentional resources across multiple simultaneous demands. The objective of this study was to track, using a single novel electrophysiological task, various components associated with the deployment of visuospatial selective attention. Methods: A paradigm was designed to evoke earlier visual evoked potentials (VEPs), as well as attention-related and visuocognitive ERPs. Data from 36 individuals with mTBI (19 subacute, 17 chronic) and 22 uninjured controls are presented. Postconcussion symptoms (PCS), anxiety (BAI), depression (BDI-II) and visual attention (TEA Map Search, DKEFS Trail Making Test) were also assessed. Results: Earlier VEPs (P1, N1), as well as processes related to visuospatial orientation (N2pc) and encoding in visual short-term memory (SPCN), appear comparable in mTBI and control participants. However, there appears to be a disruption in the spatiotemporal dynamics of attention (N2pc-Ptc, P2) in subacute mTBI, which recovers within six months. This is also reflected in altered neuropsychological performance (information processing speed, attentional shifting). Furthermore, orientation of attention (P3a) and working memory processes (P3b) are also a ffected and remain as such in the chronic post-mTBI period, in co-occurrence with persisting postconcussion symptomatology. Conclusions: This study adds original findings indicating that such a sensitive and rigorous ERP task implemented at diagnostic and follow-up levels could allow for the identification of subtle but complex brain activation and connectivity deficits that can occur following mTBI.

**Keywords:** mTBI; event-related potentials; visual–attentional processing; brain connectivity; neuropsychological measures; postconcussion symptoms
