Onset | Abrupt/sub-acute | Insidious |
Course | Fluctuating | Slow progression |
Duration | Hours–weeks | Months–years |
Alertness | Abnormally high or low | Typically normal |
Sleep-wake | Disrupted | Typically normal |
Attention | Impaired | Relatively normal |
Orientation | Impaired | Intact in early dementia |
Working memory | Impaired | Intact in early dementia |
Episodic memory | Impaired | Impaired |
Thought | Disorganised, delusions | Impoverished |
Speech | Slow/rapid, incoherent | Word finding difficulty |
Perception | Illusions/hallucinations common | Usually intact in early dementia |
Behaviour | Withdrawn/agitated | Varies: often intact early |