Feature | Delirium | Dementia |
---|---|---|
Development | Sudden, sometimes with a definite beginning point | Slow, with an uncertain beginning point |
Cause | Almost always another condition, such as an infection, dehydration, or use or stopping of certain medications | Usually a brain disorder, such as Alzheimer disease Alzheimer Disease Alzheimer disease is a progressive loss of mental function, characterized by degeneration of brain tissue, including loss of nerve cells, the accumulation of an abnormal protein called beta-amyloid... read more , vascular dementia Vascular Dementia Vascular dementia is loss of mental function due to destruction of brain tissue because its blood supply is reduced or blocked. The cause is usually strokes, either a few large ones or many... read more , or dementia with Lewy bodies Dementia With Lewy Bodies and Parkinson Disease Dementia Dementia with Lewy bodies is progressive loss of mental function characterized by the development of Lewy bodies in nerve cells. Parkinson disease dementia is loss of mental function characterized... read more |
Main early symptom | Inability to pay attention | Loss of memory, especially for recent events |
Effect at night | Almost always worse | Often worse |
Level of alertness (consciousness) | Impaired to varying degrees, can vary from being hyperalert to sluggish | Normal until late stages |
Orientation to surroundings | Varies | Impaired |
Effect on language | Slowed speech, often with incoherent and inappropriate language | Sometimes difficulty finding the right word |
Memory | Varies | Lost, especially for recent events |
Progression | Causes variations in mental function—people are alert one moment and sluggish and drowsy the next | Slowly progresses, gradually but eventually greatly impairing all mental functions |
Duration | Days to weeks, sometimes longer | Almost always permanent |
Need for treatment | Immediate | Needed but less urgently |
Effect of treatment | Usually resolution of the symptoms | May slow progression but cannot reverse or cure the disorder |