Supra-aural and insert earphone occlusion effects

Monaural and binaural occlusion effects were determined for 30 subjects using mastoid placement of a B-71 bone vibrator using supra-aural earphones (TDH-49/P/N 51) and insert earphones (Eartone-3A/Earlink-3A), which had a shallow or full insertion depth. Statistically significant differences were found for earphone type, frequency, and insert earphone insertion depth. Overall, the mean occlusion effect for all conditions decreased as frequency increased from 250–2000 Hz and was greater for the binaural than the monaural occlusion and for the supra-aural than the insert earphone occlusion. Also, the mean occlusion effect was greater for the shallow compared with the full insertion depth for the insert earphone indicating the occlusion effect increased as the volume of air between the occluder and the ear drum increased. The standard deviations were not consistently higher or lower across frequency for any one occlusion condition. Clinical implications regarding the magnitude of the occlusion effect with supra-aural and insert earphone systems will be discussed.