Effect of static force on bone conduction hearing thresholds and comfort

Objective : To assess the effect of the static force of a bone vibrator on the results of bone conduction (BC) threshold measurements and comfort. Design : BC thresholds were determined for 40 participants using the standardized P-3333 headband and a leather adjustable headstrap with variable static forces (2.4, 3.4, 4.4, 5.4 N). Comfort ratings were examined using a five-point Likert scale. Results : Mean BC thresholds were within +/- 2 dB across all conditions; differences may be considered small enough to be clinically insignificant. Participants experienced significantly greater discomfort with the P-3333 versus the adjustable headstrap. The mean static force of the P-3333 varied considerably and was higher in situ than the calibration standard of 5.4 N. Conclusions: The results suggest that future revisions of relevant international and national standards should address the use of an adjustable headstrap and a static force less than 5.4 N.