What symbol indicates unmasked bone conduction for the left ear?

The symbol indicating unmasked bone conduction for the left ear is indeed represented by the symbol "<." In audiometric notation, different symbols are utilized to denote various types of hearing tests and specific conditions for each ear.

The "<" symbol specifically represents unmasked bone conduction for the left ear, which conveys information about the conductive and sensorineural mechanisms of hearing without affecting the other ear. Bone conduction testing is critical for determining how sound is transmitted through the bones of the skull directly to the inner ear, providing insight into hearing ability when no external noise interference occurs.

In contrast, other symbols serve different purposes: "O" typically represents air conduction for the right ear, "X" is for air conduction of the left ear, and ">" indicates unmasked bone conduction for the right ear. Understanding these symbols is crucial for accurate interpretation of audiograms, which guide hearing aid fitting and management of hearing loss.