All of the following are features of dementia, EXCEPT:
Dementia is a persistent progressive impairment in intellectual function. It is associated with loss of memory and at least one of the following cognitive domains such as aphasia, apraxia, agnosia and impaired executive function. Clouding of consciousness is not seen in dementia, it is seen in delirium. Ref: Current Medical Diagnosis and Treatment 2012, chapter 4.
Insidious in onset
Usually irreversible
Clouding of consciousness present
Hallucinations are rare