SENSITIVITY AND SPECIFICITY OF PLATFORM POSTUROGRAPHY FOR IDENTIFYINGPATIENTS WITH VESTIBULAR DYSFUNCTION

Sensitive and specific measures are needed to identify patients with v estibular impairments. The purpose of this clinical perspective is to describe the sensitivity and specificity of dynamic and static platfor m posturography for detecting vestibular disorders. The sensory organi zation test (SOT) of dynamic posturography (EquiTest), the motor ''per turbation'' test, and Romberg's tests on a static (fixed) force platfo rm each had over 90% specificity. This finding means that nearly all o f the subjects who should have tested negative, did test negative on e ach type of assessment. The sensitivity of the SOT was evaluated acros s five studies involving a total of 836 patients with peripheral vesti bular deficits (PVDs). Abnormalities in the SOT were detected in only 40% (n=338) of the cases. Static platform posturography sensitivity wa s evaluated across six studies involving a total of 571 patients with PVDs, and abnormalities were defected in 53% (n=302) of these cases. T ests of spontaneous and positional nystagmus s and the horizontal comp onent of the vestibuloocular reflex (VOR), by comparison, detected PVD s in 48% of 738 patients with suspected vestibular impairment. For pat ients with vestibular deficits associated with central nervous system disease a total of 389 cases were identified in five studies and SOT a bnormalities were found in 54% (n= 209) of these cases. The motor pert urbation test was abnormal in 35% (n= 41) of 119 patients with central vestibular disease. In conclusion the sensitivity of static posturogr aphy appeared to be slightly better than that of dynamic posturography for detecting PVDs, but the level of sensitivity for each posturograp hy test, as well as for tests of horizontal VOR function, was consider ed to be low. Combining either type of posturography with other tests of vestibular function, however, increased the overall sensitivity of detecting vestibular deficits to 61% to 89%. It was concluded that dyn amic and static platform posturography as well as tests of VOR functio n lack adequate sensitivity to detect vestibular impairment when appli ed in isolation. Posturography appears to detect vestibular deficits i n some patients who had normal VOR assessments and, therefore, provide s supplemental rather than redundant information about vestibular dysf unction. [Di Fabio RP. Sensitivity and specificity of platform posturo graphy for identifying patients with vestibular dysfunction. Phys Ther . 1995;75:290-305.]