One becomes seasick (or any type of motion sickness) when the eyes and the inner-ear’s sense of balance are in conflict. Part of the function of the inner-ear, or vestibular system (which includes the cochlea), is to understand ones balance. So what happens if the vestibular system isn’t working? Can one then become seasick?
The US Navy ran an experiment in the 1960’s where they put a few Deaf men with damaged vestibular systems in a window-less galley of a ship in the middle of a horrendous storm off of Newfoundland. As the ship tossed, the Deaf men sat at a table and played cards. Meanwhile, every Naval scientist became seasick. The Deaf men never fell ill.
So can the Deaf become seasick?
Well, yes and no. The truth is not all Deaf people have a damaged vestibular system. However, of the Deaf that do not have that sense of balance that the inner-ear provides, it seems indeed they can not become seasick!