Which statement accurately differentiates delirium from dementia with respect to attention and consciousness?

• A. Delirium shows stable attention; dementia shows fluctuations.
• B. Delirium features fluctuating attention and consciousness; dementia shows relatively preserved attention early with gradual decline.
• C. Delirium has improved consciousness; dementia has reduced consciousness.
• D. Delirium only affects memory; dementia only affects language.

Answer: (B)

Delirium is an acute, fluctuating disturbance of attention and awareness. In delirium, attention can wax and wane over hours to days, and the level of consciousness may be altered (ranging from agitation to lethargy). This fluctuating pattern is a hallmark of delirium and signals an underlying medical or metabolic issue that often is reversible with treatment.

Dementia, on the other hand, is a chronic, progressive decline in cognitive function. In the early stages, attention and arousal are relatively preserved, with memory loss and other cognitive deficits gradually worsening over months to years. Consciousness is not acutely impaired in the same fluctuating way as in delirium.

Thus, the statement that best differentiates the two is that delirium features fluctuating attention and consciousness, whereas dementia shows relatively preserved attention early with gradual decline.