Final answer:
Cochlear implants are designed to restore hearing in individuals with sensorineural hearing loss by directly stimulating the auditory nerve, but they are not effective for conductive hearing loss or issues involving an abnormal auditory nerve.
Step-by-step explanation:
Hearing problems can be caused by various issues affecting the middle or inner ear and can be broadly categorized as conductive or sensorineural hearing loss. Cochlear implants are a sophisticated medical device that can restore the hearing ability in individuals with nonfunctional cochleae. These implants work by bypassing damaged hair cells in the cochlea and directly stimulating the auditory nerve with electrical impulses, which are interpreted by the brain as sound. However, they would not restore hearing in cases where an abnormal auditory nerve is present, as the crucial link between the cochlea and the brain would be compromised. Conductive hearing loss, resulting from damage to the middle ear bones or other obstructions, cannot be treated by cochlear implants, which are designed for sensorineural defects.