Clinical Usefulness of the VEMP Test in Vestibular Diagnosis

Abstract

Objective 1) Assess the clinical usefulness of the VEMP test in identifying vestibular disease. 2) Evaluate the criteria used for a positive VEMP test. Methods We prospectively evaluated 166 consecutive patients complaining of dizziness with a neurotologic examination including spontaneous nystagmus, head-shake testing, gaze testing, and Hallpike maneuver. ENG testing and MRI scanning were done when indicated. All underwent VEMP testing. We considered 30% and 40% amplitude asymmetry criteria as abnormal for peripheral, and 17 msec latency abnormal for central disease and compared these with the complete clinical evaluation. Results 44 patients had no VEMP response and were excluded. Analysis of the remaining 122 patients showed that 47% of patients with a peripheral vestibular disorder had an abnormal VEMP, using the 30% amplitude asymmetry criterion (p<0.001) (Fisher Exact Test), and 29% had an abnormal VEMP using the 40% criterion (p<0.001). The likelihood of a false positive was very low (3%, p<0.001). 42% of patients diagnosed with central vestibular dysfunction had delayed latency responses and the false positive rate was 2% (p<0.001). Conclusions The very low false positive rate (high specificity) indicates that an abnormal VEMP test is a good predictor of the presence of vestibular dysfunction, but a normal VEMP test does not exclude it. More patients with vestibular disease are identified (47% vs. 29%) just as accurately using a 30% rather than 40% criterion for a positive test. VEMP testing appears to be a valuable addition to the vestibular test battery and should be considered in the evaluation of dizzy patients.