It affects the frontal lobes (front) and temporal lobes (sides) of the brain.
Onset is usually earlier than alzheimer's. Initial sx may involve changes in personality, judgement and social functioning. Pick's disease is one of the forms of the frontotemporal dementia. Here's a link to fuller description of the disease http://www.Alz.Org/alzheimers_disease_frontotemporal_dementia.Asp.