The Clinical Utility of Vestibular Evoked Myogenic Potentials in Patients of Benign Paroxysmal Positional Vertigo.

Context: Vestibular Evoked Myogenic Potentials (VEMP) is an emerging tool to diagnose Benign Paroxysmal Positional Vertigo (BPPV). The clinical utility of VEMP has been reported only in small accord in Indian literature.

Aim: To study the latency and amplitude of VEMP in patients with BPPV and compare it with that of normal subjects.

Settings And Design: The study included two groups. Group one (control group) were 18 normal subjects. Group two (test group) were 15 subjects with unilateral BPPV.

Materials And Methods: Those subjects who fulfilled the selection criteria based on case history and audiological assessment were taken for the VEMP recording. The VEMP response consist of positive and negative successive waves (pI-nI), with latency values in adults about 13 and 23 milliseconds respectively.

Statistical Analysis: Data was analysed using Statistical Package for Social Sciences (SPSS) version 12 (Chicago, IL, USA). Unpaired t-test was employed to measure the statistical difference between control group and test group.

Results: The difference in n23 and the peak to peak amplitude between the ipsilateral and contralateral ears of the test group were statistically significant, whereas such a difference in the p13 latency turned out to be statistically insignificant. It should be noted that, out of 15 patients in the test group, five patients showed only artifact tracer recordings in both the ears which is considered as no response. The heterogeneity of the results extended from absence of VEMP to prolongation of both p13, n23; prolongation of p13 alone; and even side to side variations.

Conclusion: Absent response from the ipsilateral ear, prolonged latency of n23 and decreased peak to peak amplitude (p13, n23), indicates the disease pathology. However, large sample size is required to draw further conclusions and to consolidate the usage of VEMP in the diagnosis of BPPV.