Frontotemporal lobar degeneration is the name for a group of clinically, pathologically and genetically heterogeneous disorders associated with atrophy in the frontal lobe and temporal lobe of the brain, and includes Picks disease.

In the over 65 age group, Frontotemporal lobar degeneration is probably the fourth most common cause of dementia after Alzheimer's disease, Dementia with Lewy bodies and Vascular dementia. In the below 65 age group, it is the second most common cause after Alzheimer's disease.

A person with Frontotemporal lobar degeneration may behave in an unacceptable manner, have little concentration and follow repetitive, compulsive routines.