To characterize integrity of fronto-striatal circuitry in chronic traumatic brain injury (TBI).
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.
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.
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).
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.
*Center for Cognitive Medicine and Department of Psychiatry
†Department of Neurology, University of Illinois College of Medicine
‡Center for Stroke Research
§Departments of Ophthalmology and Psychology, University of Illinois at Chicago, Chicago, IL
Supported by NIH grant K23 MH068787 from the National Institute of Mental Health, and The Marshall Goldberg Traumatic Brain Injury Research Fund.
The contents of this paper are solely the responsibility of the authors and do not necessarily represent the official views of the University of Illinois at Chicago or the National Institute of Mental Health.
The authors report no conflicts of interest.
Reprints: Marilyn F. Kraus, MD, Center for Cognitive Medicine, University of Illinois, 912 S Wood Street MC 913, Chicago, IL 60612 (e-mail: firstname.lastname@example.org).
Received June 18, 2009
Accepted December 6, 2009