Nine-week-old Elijah Cook just heard the best sound in the world for the first time: his mom’s voice.

Only able to hear 75 decibels in his right ear and profoundly deaf in his left ear, the baby boy was born with severe deafness, according to a description accompanying the video uploaded by Elijah’s mother Ahavah Cook.

But all that changed after he was fitted with hearing aids.

“The first time I saw him blink, I had a lot of emotions. I was trying really hard not to cry. I didn’t want him to see me cry. I was trying hard to keep it together and just talk to him,” Cook said in a post on the Children’s Hospitals and Clinics of Minnesota blog.

Elijah will get another hearing test while wearing the aids when he is 7-months-old, so doctors can determine exactly how much he can hear, the hospital said.