Saccadic eye movement disturbances in whiplash patients with persistent complaints

In order to analyse the possible basis of subjective complaints following w hiplash injury, horizontal eye movements were examined in subjects with per sistent complaints ('symptomatic group') and subjects who had completely re covered ('recovered group'). The results for the symptomatic and recovered groups were compared with those for age-matched, healthy volunteers (contro l group). A battery of different saccade paradigms was employed: two were r eflexive saccade tasks including a gap and an overlap task, and two were in tentional saccade tasks consisting of an antisaccade and a memory-guided sa ccade task. In addition, the symptomatic and recovered groups also underwen t psychiatric evaluation in a structured clinical interview, and all groups were assessed for emotional functioning using the Beck Depression Inventor y (BDI), The recovered group did not differ significantly from the control group in saccade performance and emotional functioning. The symptomatic gro up showed dissociation of their performances of reflexive and intentional s accade tasks: performance in reflexive saccade tasks was normal, but in int entional saccade tasks the symptomatic group showed significantly impaired inhibition of unwanted reflexive saccades, impaired saccade triggering (i.e . increased latency) and a higher percentage error in amplitude in memory-g uided saccades, Based on clinical interviews, no signs of major depression or dysthymia were found in any of the groups. Compared with the other two g roups, the symptomatic group had significantly higher overall BDI scores, b ut these resulted from BDI dimensions that were non-specific to depression, viz, 'physiological manifestations' (e.g. fatigue, sleep disturbance) or ' performance difficulty' (e.g. work inhibition). In summary, in the symptoma tic group the pattern of eye movement disturbances together with normal per formance in reflexive saccade tasks and impaired performance in the intenti onal saccade tasks, especially impaired inhibitory function, suggests dysfu nction of prefrontal and frontal cortical structures.