Once called Pick's disease and now FTD, frontotemporal dementia hides its symptoms well. Like Alzheimer's, it is the result of the degeneration of neurons caused by an abnormal accumulation of proteins in the brain.

In early stages, Alzheimer's affects predominantly the hippocampus in the inner part of the brain, where memories are formed, and FTD affects the frontal and temporal lobes, above and behind the eyes, where social emotions are formed. Alzheimer's patients sense a fuzziness in their thinking — a word misplaced, a confusion between the past and present — and realize their errors. Most patients with FTD have no such insight into their disease.