Alzheimer's - slow memory loss, difficulty forming new memories, lose ability to perform daily tasks
Lewy Body - periods of confusion, hallucinations, sleeping difficulties
Vascular Dementia - generally caused by strokes, difficulty walking, disorientation
Fronto Temporal Lobe - early onset (45-65) - poor personal hygiene, tactless
Other Types of Dementia are outlined on the Alzheimer's Association's Website.