Introduction: The so-called whiplash injury of the cervical spine is a benign condition with a lack of identifiable physical or neurological damage and a fair rate of recovery. However, different previous studies reported impaired cognitive performance in a segment of patients who suffered whiplash injury. Patients after whiplash frequently complain of dizziness, continuous neck-pain, headache, and poor concentration, origin of which still remains unclear. Previous eye movement studies in whiplash patients testing visually-guided saccades, vestibulo-ocular reflex and smooth pursuit, were unconvincing. The aim of actual study was to examine whiplash patients with more behaviourally relevant saccade tasks.

Subjects and Methods: Three groups of individuals were examined:

1. a symptomatic group (11 subjects) complaining of continuous neck-pain, headache, dizziness and poor concentration at the moment of examination;
2. a recovered group (10 subjects) who had suffered whiplash injury, but did no longer complain of trauma-related symptoms;
3. a healthy control group (16 subjects).

The following paradigms were tested in all three groups: reflexive visually guided saccades with or without gap, antisaccades, and memory-guided saccades.

Results: In the antisaccade task, the percentage of errors (i.e. failure to suppress saccades to a peripheral target) was significantly increased in the symptomatic group (mean: 42%; range 10 - 80%) compared with the control group (17%; range 0 - 27% p < 0.002). The percentage of errors in the recovered whiplash group was not increased (16%; range: 10 - 23%). In the memory saccade task, a significant difference of unwanted reflexive saccades toward the flashed target (18%, range 3 - 30% p < 0.0001) compared to the control group (6%, range 0 - 17%) was found. Furthermore, the symptomatic group showed significantly longer latencies (mean: 477 ±144 ms vs. 382 ±100 ms; p < 0.02) and significantly reduced accuracy of memory-guided saccades (0.31 ±0.16 vs. 0.21 ±0.07; p < 0.019) compared with the control group. The recovered whiplash group showed no significant differences for all these parameters. In the visually guided saccade paradigms (gap and overlap task) there were no significant differences in the performance between all three groups.

Conclusions: This study shows that:

1. in whiplash patients with complaints a typical constellation of eye movement disorders may be found. Whiplash patients seem to be impaired in prefrontal functions such as the suppressing unwanted reflexive saccades (in the antisaccade task and in the memory-guided saccade task) and the triggering of intentional saccades. On the other hand, they show no disturbances in reflexive visually-guided saccades suggesting intact parietal functions;
2. whiplash patients without actual complaints performed the saccade tasks without restrictions, compared to a control group. Therefore, the observed eye movements disorders seem to be an further objective indicator for a functional disturbance of prefrontal functions in whiplash patients, and are in agreement with recent functional imaging studies showing prefrontal dysfunction in whiplash patients.