Uncovered p1 and p2 waves preceding the N3 vestibular evoked neurogenic potential in profound sensorineural hearing loss.

BACKGROUND

The N3 wave is a vestibular evoked neurogenic potential detected in some patients with profound sensorineural hearing loss (PSNHL) during brainstem auditory evoked potential (BAEP) analysis. In 1998, Kato et al. mentioned two electropositive waves preceding N3, which we named p1-p2, but no further description was given.

OBJECTIVE

We sought to demonstrate the reproducibility of these waves and hypothesize on their anatomic origin.

METHODS

We used two cohorts of patients with PSNHL. The first cohort comprised 10 patients with N3, allowing us to establish a new test with adequate electrophysiological conditions headed to detect p1-p2 waves (PN3EP). The second cohort consisted of two groups: group A comprised 10 patients in whom N3 was not detected; and group B comprised 20 patients presenting N3. PN3EP was performed in both groups, of which 50% had cervical myogenic vestibular evoked potentials (cVEMPs).

RESULTS

Only group B presented p1-p2. The PN3EP facilitated the identification of p1-p2 over BAEP analysis, and their presence correlated well with cVEMPs.

CONCLUSIONS

P1-p2 may be covered due to inadequate BAEP setting conditions, and could be generated in the distal neural path that generates the N3 wave.