Bedside Assessment of Visual Tracking in Traumatic Brain Injury: Comparing Simple and Predictive Paradigms Using Multiple Oculomotor Markers
Oculomotor function is a sensitive marker of neurological impairment with smooth pursuit deficiencies investigated in various disorders. However, the oculomotor deficits following traumatic brain injury (TBI) have not been fully characterized. In this study, we employed a novel bedside eye-tracking paradigm to assess oculomotor dysfunction in 30 TBI patients and 30 age-matched controls. Our paradigm utilized short, repeated linear tracking segments with head-free recording, enabling the extraction of multiple oculomotor indices, including saccadic pursuit, tracking deviation under occlusion, initial tracking speed, initial saccade latency, pupil response, and vergence instability. TBI patients exhibited widespread deficits across these indices (AUC = 0.71-0.84), which correlated significantly with functional recovery, as measured by the Functional Independence Measure (R = 0.41-0.78, p < 0.001) but not with the initial Glasgow Coma Scale scores. These findings suggest that TBI disrupts multiple components of the oculomotor system, extending to predictive tracking, pupil-linked arousal, and binocular coordination. Additionally, preliminary testing in disorders of consciousness (DOC) patients revealed fragmented tracking, suggesting a potential application for assessing perceptual awareness. Our findings support the use of eye tracking as a promising tool for quantifying brain function in TBI, with potential applications in prognosis, rehabilitation monitoring, and broader neurological assessment.