Sam:  I have a great idea for a Christmas gift for Grandpa.

Me:  What is it?

Sam:  A hearing aid.  I think that would really help Grandpa to hear us better.

Me:  You cannot just buy someone a hearing aid, they have to go to a doctor, and they are expensive.

Sam:  We need to start saving now for December gifts.  Did you know that hearing aids send electric signals to the brain so that you can hear what people are saying?

Me:  I think you might be talking about cochlear implants, hearing aids just magnify the sound and just make it louder so you can hear.

Sam:  What are cochlear implants?

Me:  They are devices that are implanted near your ear and they send electric signals to the brain or nerves and then that is somehow translated into sounds.  They are for people who are deaf or almost deaf.

Sam:  Well, Grandpa is not deaf, but that is a good thing to keep in mind for later when he is.