Consciously postural sway and cervical vertigo after whiplash injury

Study Design. Cross-sectional study of whiplash injury patients with vertigo and healthy volunteers consciously pretending to have postural sway as in malingering. Objective. The aim of this study was to evaluate the postural sway in malingerers by posturography. Summary of Background Data. Malingering is not a problem in the majority of cases with whiplash injury and diagnosis should be made carefully. However, some patients with whiplash injury might exaggerate their symptoms or be malingerers because of the potential gain associated with insurance claims. We designed a diagnostic study to screen putative malingerers. Methods. Subjects were 20 healthy volunteers who were tested under standing condition (normal group), consciously swaying the body under standing condition like malingerers (pseudomalingering group) and 32 patients who complained of neck pain with vertigo or dizziness after whiplash injury with WAD (whiplash-associated disorders) grade I and II (WAD group). The movement of the center of pressure (COP) was measured using a force platform to quantify postural sway. Static posturography was performed under open and closed eyes. We analyzed (1) total envelop area per unit of time (E-AREA), (2) shifting length per second (LNG/TIME), (3) sway pattern, and (4) Romberg rate representing total shifting length under eyes-closed/eyes-open. Results. In open eyes condition, the values of E-AREA and LNG/TIME were significant higher under pseudomalingering than both of the control and WAD groups (P < 0.05). The Romberg rate was 1.30 +/- 0.17, 1.13 +/- 0.19, and 1.83 +/- 0.94 in control, pseudo-malingering, and WAD group, respectively, and was less than 1.0 in 45% of pseudomalingering. There were significant differences in the E-AREA, LEN/TIME, and Romberg rate between pseudomalingering and the other 2 groups (P < 0.05). Conclusion. Our results suggest that compared with normal subjects and WAD patients, malingerers are more likely to exhibit a wide E-AREA, a long sway length per second, and a low Romberg rate. Malingering must be diagnosed carefully and posturography could be a helpful supplementary tool for differentiating whiplash-associated vertigo from malingering.