Sudden Hearing Loss Causes More Condition_symptoms What Are Some Possible Things To Cause Sudden Hearing Loss?***Serious Answers ONLY***?

What are some possible things to cause sudden hearing loss?***Serious answers ONLY***? - sudden hearing loss causes more condition_symptoms

The infection can lead to hearing loss? if so, how? Can stress? How Doctors check for loss of hearing?
such as people with hearing problems, I need hearing aids?