Deaf people are typically defined as those who have profound hearing impairment in both ears as a result of either acquired or congenital hearing loss. Such people may be associated with deaf culture. Deafness (little to no hearing) is distinguished from partial hearing loss or damage (such as tinnitus), which is less severe impairment in one or both sides. The definition of deafness varies across countries, cultures, and time, though the World Health Organization classes profound hearing loss as the failure to hear a sound of 90 decibels or louder in a hearing test.