An adult patient's audiogram reveals air conduction thresholds at 45 dB HL and bone conduction thresholds at 40 dB HL across tested frequencies. What type of hearing loss is indicated?

• A. Mixed hearing loss
• B. Sensorineural hearing loss
• C. Central auditory processing deficit
• D. Conductive hearing loss

Answer: (B)

The main idea here is differentiating hearing loss types by comparing air conduction with bone conduction thresholds and looking at the air-bone gap. Air conduction is 45 dB HL and bone conduction is 40 dB HL, giving an air-bone gap of only 5 dB. That small difference means there isn’t a conductive component, since a conductive loss would show a larger gap with normal bone conduction. The bone conduction threshold of 40 dB HL shows a sensorineural loss affecting the inner ear or auditory nerve, and the air conduction is in a similar range, which is typical for sensorineural loss.

Central auditory processing deficits wouldn’t produce elevated pure-tone thresholds, so that option isn’t supported by this data. A mixed loss would require a larger air-bone gap and typically elevated bone thresholds beyond the SNHL level, which isn’t the case here. Conductive loss would show a normal bone conduction threshold with a much worse air conduction due to middle ear involvement, also not matching this pattern.

So the pattern indicates sensorineural hearing loss.