In pure tone audiometry using supra-aural headphones, interaural attenuation is approximately 40 dB. A patient has a right ear air conduction threshold of 75 dB HL and a left ear bone conduction threshold of 0 dB HL. What phenomenon must be prevented during testing of the right ear?

• A Cross hearing via bone conduction, requiring masking of the left ear ✓
• B Tone decay in the right ear
• C Stenger effect producing a false normal threshold
• D Recruitment in the left ear

Explanation

When the air conduction threshold of the test ear exceeds the bone conduction threshold of the non-test ear by more than the interaural attenuation (about 40 dB for supra-aural headphones), sound crosses the skull and is heard by the better cochlea. This is cross hearing, and it produces a shadow curve unless the non-test ear is masked with narrow band noise through bone conduction. The Stenger applies to functional hearing loss with unilateral malingered loss, not to genuine crossover.

Reference: Katz's Handbook of Clinical Audiology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.