Which clinical finding is commonly seen in delirium but not in dementia?

Impaired alertness is a hallmark of delirium, distinguishing it from dementia. In delirium, patients often exhibit fluctuations in consciousness and attention, which can lead to increased confusion and disorientation. This acute change in mental status can develop rapidly, often in hours to days, and is typically linked to an underlying medical condition such as infection, metabolic derangement, or medication effects.

In contrast, dementia is characterized by a more gradual decline in cognitive function, including memory loss, reasoning impairments, and changes in behavior, but does not typically manifest with significant impairments in alertness. Patients with dementia often remain alert and attentive, even if they are confused or memory-impaired.

Other findings such as impaired memory can occur in both conditions, but the acute and fluctuating impairment of alertness is specific to delirium. Confabulation, which involves the creation of false memories without the intention to deceive, is more associated with certain types of brain dysfunction seen in dementia. Psychotic features can be present in both delirium and some forms of dementia, such as Alzheimer's disease, making alertness the most distinguishing feature of delirium.