SHS 401 Principles of Audiology PART 2: Bone Conduction 1. Is masking necessary to obtain left ear bone conduction thresholds? The LEFT ear is the TEST ear. Formulas: Is masking necessary: TE AC - TE BC > 10 dB Minimum masking level: NTE AC + 10 dB - Maximum masking level: TE BC + 40 dB enter "No" for minimum/maximum level if masking is not needed** Example Q14: 250 Hz Q15: 500 Hz Q16: 1000 Hz Q17: 2000 Hz Q18: 4000 Hz Q19: 8000 Hz Masking? Minimum level Maximum level Audiogram -10 AC Unmasked (L] X ac Unmasked (L) > AO AC Masked (L) BC Masked (L) ] No Response (L) ) AC Unmasked (R) O BC Unmasked (R) V 09 2 8 9 2 8 2 8 8 8 AC Masked IR) Hearing Level in dB BC Maked (R) No Response (R) V BC Unspecited No Response MCL M Soundfield Unaided Soundfield Aided A 250 500 750 1000 1500 2000 3000 4000 6000 8000 Frequency in Hz