Measurement of eye and arm movement deficits following mild closed head injury

Diffuse axonal injury caused by mild closed head injury (CHI) is likely to damage the extensive neural networks concerned with oculomotor and visuomotor control. We hypothesized that infra-red oculography and computerized tests of visuomotor function would be able to measure the resulting motor deficits. We compared 37 patients with mainly mild closed head injury (CHI, 36 mild and 1 moderate) and 37 controls (matched for age, gender, years of education) at 1 week, 3 months and 6 months post injury on measures of saccades, oculomotor smooth pursuit, and upper-limb visuomotor function. At 1 week, the CHI group demonstrated prolonged saccade latencies, increased directional errors and decreased saccade accuracy in combination with increased arm movement reaction time, decreased arm movement speed, and decreased motor accuracy in the visuomotor tests. Fast oculomotor smooth pursuit was mildly impaired. At 3 months, several oculomotor and visuomotor deficits remained. At 6 months, no deficits were found on any of the motor tests. Our results show that multiple motor systems can be impaired up to several months following mild CHI. These findings indicate that quantitative tests of oculomotor and upper-limb visuomotor function can provide sensitive markers of neurophysiological dysfunction and supports the possible use of such tests to supplement patient assessment following non-severe CHI.