Cerebral control of saccades and neuropsychological test results after head injury.

Abnormalities in the control of saccades have been described in patients with cerebral pathology.(1, 2) We assessed control of visually guided, reflexive and volitional saccades in 16 patients suffering severe traumatic brain injury and 12 controls and related the results to deficits on neuropsychological tests of speed of information processing and goal directed behaviour. All saccadic latencies were prolonged. Suppression of inappropriate saccades was impaired on volitional saccade tests which proved to be more sensitive in identifying impairment of goal directed behaviour than the neuropsychological test results. Patients' self-paced saccade rate was lower than controls' and correlated with performance on several visually mediated neuropsychological test results. Patients' visually guided, reflexive saccades were hypometric; this hypometria correlated with both visual and non-visual neuropsychological test results and with post-traumatic amnesia duration. Hypometria in reflexive saccades may reflect diffuse brain injury. Re-examination after 12 months revealed that the control of volitional saccades improved but there was no improvement in the visually guided reflexive saccade measures. The volitional saccade tests may be useful in documenting both impairment and subsequent recovery.