Basilar Membrane
Membrane extending the length of the cochlea in the inner ear that contains hair cells or nerve cells. Different sections of the basilar membrane respond to different sound frequencies.

Behavioral Observation Audiometry (BOA)
During a hearing test, an audiologist presents sounds to an individual and watches for the individual's responses to the sounds.

Bilateral Hearing Loss
Hearing loss in both ears.

Bone Conduction
Passing of sound to the inner ear through vibration applied to the bones in the skull, instead of through the outer and middle ear.