#slp4Dementia. Dementia involves damage of nerve cells in the brain, which may occur in several areas of the brain. Dementia may affect people differently, depending on the area of the brain affected.
Dementias can be classified in a variety of ways and are often grouped by what they have in common, such as what part of the brain is affected, or whether they worsen over time (progressive dementias).
Some dementias, such as those caused by a reaction to medications or an infection, are reversible with treatment.
From Mayo Clinic