Sound waves travel through the air as pressure vibrations of varying intensity.
Your ear senses those fluctuations and translates them into electrical impulses that your brain can interpret.
Any abnormality in the transmission of sound between the outer ear and the inner ear or a problem of interpretation by the brain causes partial or total deafness.
Hearing loss is detected during an audiometric test carried out by a specialist. The result takes the form of a graph called an audiogram.