Electrophysiological Markers of Visuospatial Attention Recovery after Mild Traumatic Brain Injury

Abstract

Objective: Attentional problems are amongst the most commonly reported complaints following mild traumatic brain injury (mTBI), including difficulties 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 affected 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.

A Pilot Investigation of Visual Pathways in Patients with Mild Traumatic Brain Injury

“…Human studies featuring VEP analysis of mTBI instances have included decreased amplitudes and increased latencies of the P3b component after mTBI [ 37 ]. In concussed athletes that were symptomatic, significant reductions in visual P3 amplitude were reported compared to recently concussed, but asymptomatic, boxing and soccer athletes and never concussed athletes [ 38 , 39 ].…”

“…There have been instances during rehabilitation where the brain may undergo sensory reorganization by recruiting multisensory neurons after progressive degenerative visual conditions [ 32 , 37 , 38 ]. Additionally, it is conceivable that internal sensory reorganization may be an adjunct method for internal repair in instances of induced visual cortical injury.…”

From Correlational Signs to Markers. Current Trends in Neuroelectric Research on Visual Attentional Processing

“…The study by Julie Bolduc-Teasdale, Pierre Jolicoeur, and Michelle McKerral [ 49 ] adds original findings on different forms of mild traumatic brain injury (mTBI) compared to uninjured controls by means of a novel and sensitive as well as rigorous ERP task implemented at the diagnostic and follow-up levels. Thanks to this task, the authors were able to show that both earlier VEPs (P1, N1) and visuospatial-attention orienting-related N2pc as well as encoding in visual short-term memory (vSTM), at later stages of brain processing, were as a whole comparable between mTBI and controls.…”