High-frequency audiometry. Masking in electric bone-conduction audiometry.
Recently, the 'electric bone-conduction' (EBC) audiometer (Audimax 500) has been used to measure high-frequency (HF) hearing. With this audiometer stimulation is binaural. No commercial masking method was available. In this study, white noise from a Madsen OB822 audiometer and presented via Sony MDR-V4 dynamic earphones, was used for masking. The masking and cross-hearing effect was measured in 8 unilaterally deaf subjects and the masking procedure was tested with 104 young normal-hearing subjects. The results showed that the EBC signals can be masked with air-conduction signals, and thus, the EBC measurements reflect monaural thresholds. The minimum masking level was 50-60 dB SPL in the HF range. There were no cross-hearing problems in the HF range with the earphones used. At the frequencies 0.5-14 kHz, the better ear's masked EBC thresholds were on the average 2.6 dB (range 0-4.5 dB) poorer, compared with the binaural EBC thresholds, indicating a binaural summation effect.
Löppönen
H
H
Department of Otolaryngology, University of Oulu, Finland.
D000161:Acoustic Stimulation; D000293:Adolescent; D000328:Adult; D000669:Amplifiers, Electronic; D001299:Audiometry; D001309:Auditory Threshold; D001844:Bone Conduction / Q000502:physiology; D002648:Child; D004867:Equipment Design; D005260:Female; D006309:Hearing / Q000502:physiology; D006801:Humans; D008297:Male; D009622:Noise; D010470:Perceptual Masking