Sudden Hearing loss explained ENT Surgeon of Gwalior Dr Rahul Agrawal from Agrawal Hospital & Research Institute, Gwalior. Sudden sensorineural hearing loss (SSHL) is also known as sudden deafness. It happen when you lose your hearing very quickly, typically only in one ear. It can happen instantly or over a span of several days. During this time, sound gradually becomes muffled or low.