As well as affecting movement, some people with CP may have hearing, vision or perception difficulties or an impaired intellectual capacity.

BBC: Disabled person

Researchers found that genes relating to sensory perception, hearing and brain development showed "accelerated evolution" in all three, but particularly in humans and gorillas.

CNN: First gorilla genome map offers clues to human evolution

Recent research suggests that if left untreated, hearing loss might contribute to an acceleration in cognitive decline - relating to our understanding, reasoning and perception skills - as we age.

BBC: Viewpoint: Does deafness contribute to dementia?