The auditory nerve consists of the cochlear nerve and the vestibular nerve, both of which travel together through the inner ear canal to the inner ear, so they can often be damaged at the same time, showing symptoms of both hearing and balance. Although they are two different components of the same nerve, they do not respond well to the cause of the disease. Hearing aids, which amplify sound, are used to help patients with conductive or sensorineural hearing loss, especially in those with normal speech frequency hearing loss. Hearing aids can also help patients with predominantly high-frequency hearing loss or those with monaural hearing loss. Hearing aids consist of a microphone to collect sound, an amplifier to increase the volume, and a speaker to transmit the amplified sound. Patients with severe hearing loss who are still unable to hear with hearing aids may have a cochlear implant. The implant consists of an electrode inserted into the cochlea and an internal driver placed in the skull, which is connected to an external driver, a speech processor, and a microphone. The microphone collects sound waves, which the processor converts into electrical impulses that are transmitted through the external driver to the internal driver and then to the electrodes, which stimulate the auditory nerve. The cochlear implant does not convert sound like a normal cochlea, and produces varying degrees of effect for different patients, helping some patients with lip reading, some with distinguishing certain words, and some with listening to phone calls. Cochlear implants can also help deaf people listen to and distinguish between environmental sounds and alarm signals such as doorbells, telephone and alarm clock sounds. Cochlear implants are more effective for people with recent hearing loss or who have successfully used hearing aids.