EYE-TRAC: monitoring attention and utility for mTBI

Abstract

Attention is a core function in cognition and also the most prevalent cognitive deficit in mild traumatic brain injury (mTBI). Predictive timing is an essential element of attention functioning because sensory processing and execution of goal-oriented behavior are facilitated by temporally accurate prediction. It is hypothesized that impaired synchronization between prediction and external events accounts for the attention deficit in mTBI. Other cognitive and somatic or affective symptoms associated with mTBI may be explained as secondary consequences of impaired predictive timing. Eye-Tracking Rapid Attention Computation (EYE-TRAC) is the quantification of predictive timing with indices of dynamic visuo-motor synchronization (DVS) between the gaze and the target during continuous predictive visual tracking. Such quantification allows for cognitive performance monitoring in comparison to the overall population as well as within individuals over time. We report preliminary results of normative data and data collected from subjects with a history of mTBI within 2 weeks of injury and post-concussive symptoms at the time of recruitment. A substantial proportion of mTBI subjects demonstrated DVS scores worse than 95% of normal subjects. In addition, longitudinal monitoring of acute mTBI subjects showed that initially abnormal DVS scores were followed by improvement toward the normal range. In summary, EYE-TRAC provides fast and objective indices of DVS that allow comparison of attention performance to a normative standard and monitoring of within-individual changes.

Detecting Eye Movement Abnormalities from Concussion

“…Still, the visual tracking performance of a group of acute concussion patients with postconcussive symptoms was found to be worse than that of a normal control group ( fig. 5) [11]. In addition, when the patients were retested 1 month after the injury, most showed improvement, contrasting with Patient Normal Fig.…”

“…The solid vertical line running through the histogram indicates the median, and the dotted vertical line separates the worst 5% of the normal population from the rest. Adapted from [11].…”

“…The myriad cognitive impairments and symptoms associated with concussion are postulated to be secondary consequences of a primary deficit in attention, specifically in the ability to synchronize with external events [3,10,11]. Sensorimotor synchronization is quantified best by visual tracking of a predictably moving target; thus, we have focused on characterizing eye movements during predictive visual tracking.…”

“…performance stability observed in normal individuals [11]. Thus, both group and interindividual comparisons are useful for monitoring progress after concussion.…”

“…The patient was a 16-year-old student athlete who was injured 8 days prior to testing. Adapted from [11].…”