CHAT and delirium: A recent study on postoperative delirium found that the changes in the preoperative activity of Acetylcholinesterase (AChE), Butyrylcholinesterase (BuChE) and Choline acetyltransferase (ChAT) in CSF were associated with the development of postoperative delirium in elderly patients, which may be related to central cholinergic degradation (108).