What does the key "R-circle, L-X" refer to in an audiogram?

The notation "R-circle" and "L-X" on an audiogram specifically indicates air conduction unmasked thresholds for the right and left ears, respectively. In audiological terms, "air conduction" refers to the way sound is transmitted through the air and detected by the ear, using headphones or loudspeakers.

The "R-circle" represents the right ear's air conduction threshold, marked by a circle, while "L-X" indicates the left ear's threshold for the same type of conduction, marked by an 'X.' This setup is standard in audiograms to easily distinguish between the hearing levels of each ear using air conduction without any masking noise applied, which would be used in cases where there is a risk of cross-hearing.

Understanding this notation is important for interpreting audiograms correctly, as it provides vital information about an individual's hearing ability through the conventional air conduction method.