Doctors at the Mayo Clinic have found that young people who develop dementia often don't actually have Alzheimer's.
Neurologist Brendan Kelley wanted to understand why some patients in their 20s and 30s developed severe dementia.
By studying MRIs and other medical data, Kelley found that about a third of the patients suffered from neuro-degenerative diseases and not early-onset Alzheimers.
"We also identified a number of patients, about 20 percent, experienced what we would term auto-immune or inflamatory disorders. Among that 20 percent, about half of those the neurological decline was caused by multiple sclerosis," Kelley said.
Kelley says many of these diseases are treatable, which means doctors can help young patients make some recovery.