Oculomotor function in chronic traumatic brain injury

Objective: To characterize oculomotor function using visually guided saccade and antisaccade (AS) tasks in chronic traumatic brain injury (TBI) and assess the relationship to neuropsychologic testing. Background: TBI causes dysfunction of prefrontal cortex, in part by disrupting cortical and subcortical pathways, resulting in specific cognitive impairments. Oculomotor function tests provide a method of assessing the integrity of these pathways. Methods: Twenty mild TBI (MTBI), 17 moderate to severe TBI (M/STBI), and 19 healthy controls underwent oculomotor and neuropsychologic testing. Results: On the visually guided saccade task, the M/STBI showed longer latencies and reduced accuracy. On the AS task, which is more dependent on prefrontal cortex function, both patient groups committed more prosaccade errors than controls. On neuropsychologic testing, only the M/STBI patients were significantly impaired. Correlations were found between AS and neuropsychologic performance. Conclusions: The M/STBI group was impaired on both oculomotor tasks and neuropsychologic testing, consistent with more global neuropathology. The MTBI group showed impaired performance primarily on the AS task, consistent with prefrontal system dysfunction. Hence, oculomotor testing is sensitive to the range of neuropathology in chronic TBI. and importantly, may be more sensitive to neuropathology in MTBI.