Vestibular myogenic potentials evoked by air-conducted stimuli at safe acoustic intensity levels retain optimal diagnostic properties for superior canal dehiscence syndrome.

BACKGROUND

Vestibular-evoked myogenic potential (VEMP) is commonly conducted with air-conducted (AC) stimuli whose intensity may exceed the prudential levels of acoustic exposure in susceptible subjects.

OBJECTIVES

To determine the diagnostic accuracy of AC VEMP for superior canal dehiscence syndrome (SCDS) at lowered acoustic stimulation levels.

MATERIAL AND METHODS

VEMP was tested in 10 SCDS patients and in 10 age/sex matched control subjects. VEMP were recorded on cervical muscles (cVEMP) and extraocular muscles (oVEMP) in response to short AC tone bursts at 500, 1000 and 2000 Hz delivered at 80 dB nHL (103 dB peSPL). Parameters of interest were the response amplitude and the frequency tuning.

RESULTS

VEMP evoked by AC stimuli at safe acoustic stimulation levels did effectively separate SCDS patients from healthy controls. The separation was optimal at all the frequencies tested, however 500 Hz resulted the best VEMP tuning frequency, especially at oVEMP.

CONCLUSIONS

Lowering the AC stimulation to the levels compatible with testing of patients susceptible to acoustic exposure didn't affect the VEMP diagnostic properties for SCDS.

SIGNIFICANCE

SCDS may be screened by VEMP even among subjects susceptible for acoustic exposure.