The small device that helped a deaf woman hear for the first time in 40 years

A cochlear implant transmits signals to the brain, enabling deaf people to hear sounds. Credit: AAP AUSTRALIAN ASSOCIATED PRESS/AAP/Press Association Images

A video of 40-year-old Joanne Milne hearing for the very first time has gone viral, and it is all thanks to a small device fitted on to her ear.

Although Joanne had worn hearing aids before, it was only with a cochlear implant that she was able to hear properly for the first time.

Here is how the technology works:

She said she was overcome with emotion when the implants were first switched on:

Read: These songs are the first tracks a deaf woman ever heard