Memory loss alone doesn’t mean a person has dementia because memory loss is an integral part of ageing. Most aged people suffer from memory loss, but that doesn’t mean they have dementia. There are many causes dementia one of which is Alzheimer's disease.
Frontal lobe dementia, also known as frontotemporal dementia, is a form of dementia that occurs when the frontal lobes of the brain begin to shrink (or “atrophy”). Experts estimate that it is responsible for of dementia cases.
What Is Dementia? - Alzheimer's Society Dementia Brain Video This video provides a detail description of dementua. It is caused by loss of cells. It is progressive and their is no cure for it. Symptoms vary on the area of the brain it affects.