[Tap-hammer elicited vestibular-evoked myogenic potentials system: its design and preliminary application]

Objective: The aim of this study was to design and perform "Tap-hammer"system that can be used to elicit vestibular evoked myogenic potentials (VEMP) in normal adults and to report the preliminary results of this system. Methods: A triggered Tap-hammer was designed, made and connected with an electric recording system, to form as a system for Tap-VEMP recording. Twenty healthy adult volunteers (7 males and 13 females, aged 20 to 37 years, 40 ears in total) were recruited for air-conducted sound VEMP (ACS-VEMP) and Tap-VEMP examinations. Waveforms and parameters of both VEMPs were recorded and analyzed. SPSS 22.0 software was used for statistical analysis. Results: The response rates of ACS-, Tap-ocular VEMP (oVEMP) and ACS-, Tap-cervical VEMP (cVEMP) were both 100% (40/40). The mean±SD n1 latency, p1 latency, n1-p1 interval, amplitude, and asymmetry ratio (AR%) of Tap-oVEMP were (9.80±2.51)ms, (13.90±3.26)ms, (4.09±1.43)ms, (16.43±9.61)μV, (22.68±17.35)% respectively. The mean±SD p1 latency, n1 latency, p1-n1 interval, amplitude, and asymmetry ratio (AR%) of Tap-cVEMP were (13.26±2.07)ms, (21.84±2.89)ms, (8.58±2.10)ms, (457.65±274.94)μV, (20.42±13.46)% respectively. Both n1 latency and p1 latency of Tap-VEMPs were shorter than those in ACS-VEMPs (P<0.05). No statistical difference could be found between the two stimulation methods in the parameters of n1-p1 interval, amplitude, and asymmetry ratio(P>0.05). Conclusion: The Tap-hammer system can elicit VEMP responses in healthy young people. This system can be used as an alternative stimulation method for bone conduction VEMP.