Pure tone bone conduction (BC) threshold measurement stimulates which part of the auditory system?

The measurement of pure tone bone conduction (BC) thresholds is specifically designed to evaluate the function of the cochlea. When a bone conduction stimulus is applied, it bypasses the outer ear and middle ear structures, directly causing vibrations in the skull. These vibrations are transmitted to the cochlea located in the inner ear, where the sensory cells (hair cells) convert these mechanical vibrations into neural signals.

This differentiation is essential in audiometry because it allows practitioners to determine whether a patient’s hearing loss is conductive or sensorineural. If bone conduction thresholds are within normal limits while air conduction thresholds show a loss, it indicates that the issue lies primarily in the outer or middle ear rather than the cochlea itself.

Understanding that bone conduction directly stimulates the cochlea helps hearing specialists diagnose and determine appropriate interventions for various types of hearing disorders.