The term "dementia" describes all of the following clinical states, EXCEPT:
Dementia is a loss of intellectual functioning. Other operations are affected in dementia, such as language, skilled movements, and perception. However, isolated neurological defects like aphasia are not themselves classified as dementias. Likewise, sensory defects or hemiplegia of body pas would not be included. Nonetheless many of these neurological abnormalities may precede or follow the onset of intellectual dysfunction, thereby taxing the diagnostic acumen of the clinician. Dementia does not necessarily mean a gradual loss of these functions, for it may be of sudden onset (eg, following a stroke). It is a syndrome resulting from a variety of diseases affecting the brain and, in many cases, is remediable with proper diagnosis and treatment. Irrespective of the cause of the disorder, the symptoms are a function of the locus and not the type of disease. Therefore, atrophy affecting the frontal lobes or a tumor involving the same areas may present in a similar fashion. Additionally, there are typical and often prominent behavioral changes that may become evident much earlier in the evolution of the disorder than do problems with orientation, cognition, or memory. Ref: Stoudemire, Clinical Psychiatry, pp 114-118
Gradual decline in ceain mental operations such as orientation, cognition, and memory
Presence of a specific language disorder such as aphasia, alexia, or agraphia
Onset of behavioral changes including apathy, eccentricity, and distractibility
Sudden loss of intellectual functioning, such as following an anoxic episode or a cerebrovascular accident