- Obs. insanity; madness
- Psychiatry a disorder of the mind affecting perception, memory, and judgment, characterized by reduced ability to remember, control muscular movements, recognize familiar objects and sounds, etc.
Origin of dementiaL, insanity from demens: see dement
Loss of cognitive abilities, including memory, concentration, communication, planning, and abstract thinking, resulting from brain injury or from a disease such as Alzheimer's disease or Parkinson's disease. It is sometimes accompanied by emotional disturbance and personality changes.
Origin of dementiaLatin dēmentia madness from dēmēns dēment- senseless ; see dement .
(usually uncountable, plural dementias)