Which of the following describes mixed hearing loss on an audiogram?

• A. AC abnormal; BC abnormal; Air-bone gap ≥ 15 dB
• B. AC abnormal; BC normal; Air-bone gap ≥ 15 dB
• C. AC normal; BC abnormal; No air-bone gap
• D. AC abnormal; BC abnormal; Air-bone gap ≥ 15 dB

Answer: (D)

Understanding mixed hearing loss on an audiogram means recognizing a combination of conductive and sensorineural problems. In this pattern, both air-conduction (AC) and bone-conduction (BC) thresholds are abnormal, and there is an air-bone gap (the difference between AC and BC) of at least about 15 dB. That gap shows that part of the hearing loss comes from the conductive pathway (outer/middle ear) while the abnormal BC reveals a sensorineural component (inner ear or nerve). So the description AC abnormal, BC abnormal, and a significant air-bone gap is the hallmark of mixed hearing loss. If you see AC abnormal with BC normal, that points to conductive loss; if BC abnormal with no gap, that's sensorineural loss; if both are abnormal but without a gap, that’s typically sensorineural as well.