In audiogram shorthand, AC stands for which of the following?

• A. Air conduction
• B. Acoustic conduction
• C. Auditory conduction
• D. Air vibration conduction

Answer: (A)

Air conduction is the pathway used when reporting on an audiogram with AC. It means sounds are delivered through the air via headphones or earphones, so the thresholds reflect the entire hearing system from the outer ear through the middle ear to the inner ear. This is why AC is used on audiograms—to show how well the auditory system works with normal air-based sound transmission. In contrast, bone conduction uses a bone vibrator and bypasses the outer and middle ears to test the inner ear and beyond, which is not what AC measures. The other phrases listed aren’t standard shorthand in audiology.