Which statement best describes delirium in older adults?

• A. Acute onset and fluctuating attention and cognition
• B. Progressive cognitive decline without fluctuations
• C. Mood-only changes without cognitive impairment
• D. Delirium cannot be distinguished from dementia

Answer: (A)

Delirium is an acute, fluctuating disturbance of attention and cognition seen in older adults. The hallmark is a sudden onset over hours to days with inattention and disorganized thinking, and the level of alertness can swing up and down during the day. This contrasts with dementia, which is a chronic, progressive decline in cognition without these rapid fluctuations in attention. Mood-only changes without clear cognitive impairment don’t describe delirium. Delirium also isn’t indistinguishable from dementia; its distinguishing feature is the abrupt, fluctuating cognitive disturbance caused by an underlying medical issue, medication, or other insults, which is usually reversible with appropriate treatment.