What question did this study set out to answer?

The aim is to compare different bone-conduction transducers for oVEMP testing to identify effective excitation methods.

April 16, 20260 citationsOpen Access

Ocular VEMP using bone conduction stimuli at the forehead : a pilot study comparing B250, minishaker and tendon hammer with vibrometry validation

BHBo HåkanssonChalmers University of Technology KJKarl-Johan Fredén JanssonChalmers University of Technology LVLuca VerrecchiaKarolinska University Hospital

Key Points

The aim is to compare different bone-conduction transducers for oVEMP testing to identify effective excitation methods.
Ocular VEMPs were measured using three transducers: B250, Minishaker, and Tendon hammer.
Stimuli were applied at forehead Fz/AFz with a 250 Hz single sinus cycle.
Mastoid velocity was measured using a laser Doppler vibrometer.
B250 and Minishaker produced dual oVEMP peaks with early n1 (mean latency: 8.8 ms) and late n2 responses.
The Tendon hammer had response latencies in between those of B250 and Minishaker.
Laser Doppler vibrometry showed multiple positive peaks for B250 and a single peak for Minishaker.

Abstract

Background: Bone-conduction stimuli in oVEMP testing offer lower stimulus levels and independence of conductive hearing loss but lack a clinically suitable transducer for excitation. A new bone-conduction transducer (B250) has been developed which is easy to attach and can be directly connected to test stations. Objective: To compare, in a pilot investigation B250, Minishaker and Tendon hammer excitation, used for oVEMP and mastoid vibration measurements. Methods: oVEMPs in three subjects were measured using transducers driven by a 250 Hz condensation single sinus cycle and with a Tendon hammer, all applied at forehead Fz/AFz. Corresponding mastoid velocity was measured using a laser Doppler vibrometer (LDV). Results: B250 and Minishaker often produced dual oVEMP peaks with an early n1 (mean latency: 8.8 ms) and a late n2 response (B250: 12.4/Minishaker: 13.3 ms), and with the Tendon hammer response in between. This finding was supported by a reinvestigation of a previous study (n=15). LDV velocity shows several positive peaks for B250 and one positive peak for the Minishaker. The acceleration response has two peaks 4 ms apart for both transducers, which seem to relate to the early and late oVEMP latencies. Conclusion: B250 may serve as a potential alternative, pending validation in larger samples, to the Minishaker at the forehead, but with care to polarity choice and latency interpretation.

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