<unk>  is a<unk>  which develops after the acquisition of speech and language, usually after the age of six.<unk><unk>  hearing impairments are far more common than prelingual<unk> . Typically, hearing loss is gradual, and often detected by family and friends of the people so affected long before the patients themselves will acknowledge the disability.
Post-lingual deafness
Nonsyndromic deafness
Cortical deafness
Hearing loss with craniofacial syndromes
Optic nerve hypoplasia
Septo-optic dysplasia
Prelingual deafness
Vibroacoustic disease