Implants Vs Hearing Aids

Hearing is a complex process that originates in the cochlea; the organ of hearing that is located inside the temporal bone of the skull. The cochlea is a tiny snail shell shaped organ that is comprised of thousands of microscopic sensory cells. These sensory cells work like keys on a piano. Each sensory cell is organized and tuned to match a certain pitch, much like piano keys are. In a normal hearing person, these sensory cells respond to acoustic information in the environment and translate it into a neurological code that the brain can interpret. If any of the sensory cells do not work properly, the information that arrives in the brain will be distorted and incomplete. The listener may have difficulty understanding what is said.

Speech is a complex acoustic signal. When a speech signal arrives at the cochlea, many sensory cells respond. This would be analogous to a sonata playing on a piano. Many keys are being played at once to make rich, full music or, in this case, speech. When sensory cells are damaged and/or missing, incomplete and distorted sound arrives at the brain. The listener has to work even harder to understand what he or she is listening to.

Hearing aids only make sound louder. Increases in loudness may not overcome the damage of the sensory cells. The damage is permanent.

A cochlear implant is not a hearing aid. Rather, it is a neural prosthesis that bypasses the damaged sensory cells of the cochlea for individuals that cannot make use of the sound amplified by the hearing aid. The patient's traditional means of hearing, "acoustic hearing," is then replaced with "electric hearing" through the cochlear implant. With time and experience, the brain learns to decode and understand this new signal.