Complex sentence: Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset (meaning it has been present from hours to days, but not months or years) and fluctuating course, attentional deficits and generalized severe disorganization of behavior.
Split into simpler sentences: Delirium or acute confusional state is a common and severe neuropsychiatric syndrome with core features of acute onset, meaning it has been present from hours to days, but not months or years. It is typified by fluctuating course, attentional deficits and generalized severe disorganization of behavior.