Vestibular evoked myogenic potential in unilateral vestibular hypofunction

CONCLUSION: The patients with unilateral chronic vestibular hypofunction detected by caloric test demonstrated at least some sort of altered vestibular evoked myogenic potential (VEMP) in 63.63% of the cases. The VEMP altered side was the same as the unilateral vestibular hypofunction side in 54.54% of the cases and was the opposite side in 24.24%. The VEMP test improved functional vestibular assessment in patients with unilateral caloric hypofunction. OBJECTIVES: To analyze VEMP in patients with chronic dizziness and unilateral vestibular hypofunction and verify findings according to the side and structures involved. METHODS: This was an observational study. In all, 66 subjects were evaluated by VEMP (tone bursts/1000 Hz/100 dBnHL/bandpass filtered 10-1500 Hz/4.3 Hz rate), 33 with unilateral vestibular hypofunction, detected by caloric test and clinical data, and 33 control subjects, matched by gender and age. Amplitude of the p13-n23, asymmetry index of the amplitude, p13 and n23 latencies, p13 and n23 interaural difference and threshold were analyzed. Simple descriptive analysis was carried out using the t test, Shapiro-Wilks test, and Mann-Whitney test, p < 0.05. RESULTS: VEMP was altered in patients with unilateral vestibular hypofunction in 63.63% of cases. Thirteen of them were ipsilateral to the vestibular hypofunction and three were contralateral to the vestibular hypofunction. In five cases, VEMP were bilaterally altered.