Wendy Berings is sitting in her sixth grade class. When the bell rings to let her class out, all her classmates jump up and leave. She doesn't understand this because she heard nothing. She realizes that she might be losing her hearing. She goes to a doctor and has some tests. Here are the results:
When a vibrating tuning fork is held just outside her ear, she cannot hear it
When a vibrating tuning fork is held against (touching) her skull bones, she can hear it
Wendy's mother is confused. She asks the doctor how this is possible. The doctor tells her that the cochlea is surrounded by bones of the skull. He tells her that sound waves can travel through bone and enter the cochlea from the bone that is all around the cochlea. This stimulates the basilar membrane in the cochlea.
All of the following are causes of hearing loss. However, given the story just above, what it the most likely cause of Wendy's hearing loss?
• Loss of K* in the fluid of the cochlear duct (also called endolymph)
• Ruptured tympanic membrane
• Damage to cranial nerve VIII