When fluid builds up around or inside your brain and inhibits typical functioning, it results in normal pressure hydrocephalus, or NPH, according to the Cleveland Clinic. This may lead to difficulties thinking and concentrating, as well as impair movement and memory. The condition may be reversible, and its symptoms could look a lot like dementia.

Billy Joel is canceling all of his upcoming concert dates after being diagnosed with normal pressure hydrocephalus or NPH.