Clinical Definitions and Terms

Delirium is a clinical diagnosis given to patients with an acute attentional deficit which waxes and wanes. Postoperative cognitive dysfunction (“POCD”) is a research construction, (not a diagnosis,) and involves defining a negative change from the patient’s preoperative cognitive performance on a neuropsychologic battery of tests.


Delirium is an acute attentional deficit which waxes and wanes.  It has been established as a clinical diagnosis and there are multiple validated tools to identify delirium. While research has identified many different risk factors, some of the strongest predictors are age and presence of cognitive impairment prior to surgery.

Postoperative Neurocognitive Disorders

Cognitive dysfunction after anesthesia and surgery can take many forms and may last for highly variable periods of time. Up until now, they have all been termed "postoperative cognitive decline or POCD", which was largely a research diagnosis, since it did not require, nor include a subjective component. A multidisciplinary, international team has been working on a more reflective and specific nomenclature, and one that is aligned with the diagnostic terminology used for cognitive dysfunction in the medical community at large. This work was published on October 16, 2018, and is available on the Anesthesiology journal website. Read the press release for additional information.