Fox News senior medical analyst Dr. Marc Siegel breaks down the symptoms of Normal Pressure Hydrocephalus amid music legend Billy Joel's brain diagnosis and why it's under-diagnosed on 'Fox Report.' ...

Dr. Matthew Potts, a neurosurgeon at Northwestern Medicine, joins ABC News Live to answer questions about normal pressure hydrocephalus (NPH), the rare brain disorder impacting Billy Joel.

Singer Billy Joel has been diagnosed with normal pressure hydrocephalus, leading to concert cancellations. Discover how this ...