What it is: Frontotemporal dementia is associated with rare diseases or disorders that affect the frontal lobe or front of the temporal lobes of the brain. Pick's disease is one example. Pick's involves abnormal deposits of the tau protein in the brain (called Pick bodies). Damage to the frontal and temporal lobes affects personality, memory, and behavior.

How the symptoms compare to Alzheimer's: Frontotemporal dementia is associated with impaired judgment, changes in personality, mood swings, problems with language, and a decreased interest in activities that were once enjoyed. Symptoms can occur suddenly.

Though frontotemporal dementia is a progressive disease, personality and behavioral symptoms tend to occur early on, whereas disorientation (getting lost) tends to occur late. (It's typically reversed in Alzheimer's.) Semantic memory (memory of the meaning of words and objects) is more affected than episodic (time related) memory.

Uninhibited or inappropriate behavior is common in people with frontotemporal dementia. They may demonstrate a marked lack of empathy, acting without regard to what other people think or feel.

How it's diagnosed and treated: In addition to the findings of a full medical exam, a brain scan may show evidence of atrophy (deterioration) of the frontal or temporal lobes. There are no medical treatments available, so the emphasis is on managing symptoms for better quality of life.