Eliciting Constant and Prominent Waves n34–p44 of Vestibular-evoked Myogenic Potentials

Abstract

Objective —The serial peaks of vestibular-evoked myogenic potentials (VEMPs) have been labeled p13, n23, n34 and p44 according to their latency. Waves p13–n23 have been shown to be of saccular origin, whereas the origin of waves n34–p44 is still unknown. In order to improve the clinical applicability of waves n34–p44, we examine the use of different patterns of acoustic stimuli to evoke constant and prominent VEMPs, especially waves n34–p44.

Material and Methods —In this prospective study 27 healthy volunteers (54 ears) underwent VEMP tests. Three kinds of click intensity (85, 95 and 105 dB nHL) were presented in a random order to evoke 85-VEMP, 95-VEMP and 105-VEMP, respectively. The response rate, latency of each peak, peak-to-peak interval and amplitude of waves p13–n23 and n34–p44 were measured and analyzed.

Results —The response rates of waves p13–n23 in 85-VEMP, 95-VEMP and 105-VEMP were 26% (14/54), 89% (48/54) and 98% (53/54), respectively. Significant differences in the response rate existed between 85-VEMP and both 95-VEMP and 105-VEMP (p<0.01), whereas there was a non-significant difference between 95-VEMP and 105-VEMP (p>0.05). In contrast, the response rates for eliciting waves n34–p44 were 19% (10/54), 63% (34/54) and 89% (48/54), using 85, 95 and 105 dB acoustic stimuli, respectively. A significantly higher response rate for waves n34–p44 occurred when the intensity of the stimuli increased (p<0.01). Although neither latencies nor interval exhibited a significant difference between 95-VEMP and 105-VEMP, the amplitude of 105-VEMP was significantly greater than that of 95-VEMP for both waves p13–n23 and n34–p44.

Conclusion —An acoustic stimulus intensity of 105 dB nHL is required to reliably elicit waves n34–p44 in subjects with normal hearing.

• click
• intensity
• vestibular-evoked myogenic potential
• wave n34–p44
• wave p13–n23

Huang T-W, Young Y-H, Cheng P-W. Eliciting constant and prominent waves n34–p44 of vestibular-evoked myogenic potentials. Acta Otolaryngol 2004; 124: 1022–1027.

Huang T-W, Young Y-H, Cheng P-W. Eliciting constant and prominent waves n34–p44 of vestibular-evoked myogenic potentials. Acta Otolaryngol 2004; 124: 1022–1027.