Many people with Usher syndrome are born profoundly deaf. People with profound hearing loss often get little benefit from hearing aids. Those that choose cochlear implants have very little degradation in hearing as they age since cochlear implant bypass the hair cells in the cochlear.
The most common genetic cause of Usher syndrome, Usher Type 2a, often causes moderate to severe hearing loss at birth. Like all people, those with Usher syndrome often experience a degradation in hearing as they age. Those that may have benefited from hearing aids may find the benefit wanes as they age. Some chose to have cochlear implants to compensate for the loss. Studies show that the majority of people with Usher syndrome experience a similar rate of hearing loss with age as the general population. However, a small percentage of people with Usher Type 2 may experience a faster rate of age-related hearing loss.
People with Usher Type 3 often have normal hearing or a mild loss that deteriorates throughout life. By the third decade of life, most people with Usher Type 3 have hearing loss that is similar to all other types of Usher syndrome.
People with Usher syndrome often greatly benefit from hearing interventions such as hearing aids and cochlear implants.
Boys Town National Research Hospital maintains an excellent site that describes hearing loss in children. It is also applicable to adults.