OBJECTIVE: To characterize integrity of fronto-striatal circuitry in chronic traumatic brain injury (TBI). BACKGROUND: Due to both direct and indirect effects, TBI is hypothesized to affect frontal and striatal function. On the basis of elegant animal, lesion, and neuroimaging literatures, oculomotor testing can provide a useful tool for in vivo assessments of neurophysiologic function. The predictive saccade paradigm in oculomotor function is well established to provide assessment of this fronto-striatal circuit. METHODS: Sixty patients with a history of chronic TBI completed 2 specific tests of oculomotor function, including a test of reflexive visually guided saccades to assess basic oculomotor function and a predictive saccade test to assess procedural learning. RESULTS: TBI (mild and moderate/severe) was associated with a decrease in rates of procedural learning, with degree of impairment increasing with injury severity. This was observed as a decrease in the proportion of anticipatory saccades (primary measure of learning). CONCLUSIONS: This abnormal oculomotor performance supports the hypothesis that TBI results in chronic impairment of frontal-striatal functions proportionally to injury severity and demonstrate that oculomotor testing is sensitive to all severities of closed-head injury.
OBJECTIVE: To characterize integrity of fronto-striatal circuitry in chronic traumatic brain injury (TBI). BACKGROUND: Due to both direct and indirect effects, TBI is hypothesized to affect frontal and striatal function. On the basis of elegant animal, lesion, and neuroimaging literatures, oculomotor testing can provide a useful tool for in vivo assessments of neurophysiologic function. The predictive saccade paradigm in oculomotor function is well established to provide assessment of this fronto-striatal circuit. METHODS: Sixty patients with a history of chronic TBI completed 2 specific tests of oculomotor function, including a test of reflexive visually guided saccades to assess basic oculomotor function and a predictive saccade test to assess procedural learning. RESULTS: TBI (mild and moderate/severe) was associated with a decrease in rates of procedural learning, with degree of impairment increasing with injury severity. This was observed as a decrease in the proportion of anticipatory saccades (primary measure of learning). CONCLUSIONS: This abnormal oculomotor performance supports the hypothesis that TBI results in chronic impairment of frontal-striatal functions proportionally to injury severity and demonstrate that oculomotor testing is sensitive to all severities of closed-head injury.
Authors: Priya S Dhawan; Danielle Leong; Lisa Tapsell; Amaal J Starling; Steven L Galetta; Laura J Balcer; Trenton L Overall; Jennifer S Adler; Rashmi B Halker-Singh; Bert B Vargas; David Dodick Journal: Neurol Clin Pract Date: 2017-12