Surgery in the Elderly Not Necessarily a ‘Memory Buster’

It’s widely assumed that older people having surgery experience postoperative cognitive decline i.e. impaired mental functioning, including memory loss.  There’s even a name and an acronym for it: Postoperative Cognitive Dysfunction or Decline (POCD), and there have been several publications documenting it.  However, a new study from Washington School of Medicine in St Louis, and published in the journal Anesthesiology, disputes the idea that there will be any long-term cognitive disability.

Patients were enrolled from an Alzheimer's Disease Research Center.  They were classified into three groups based on whether they underwent surgery, were admitted to hospital for a major illness not requiring surgery, or didn’t undergo surgery and had no major illness (i.e. a control group). Subjects were assessed annually, in some cases for as many as 21 years. A comprehensive battery of neuropsychological tests was administered on each occasion.

There were 575 participants; 361 had very mild dementia or mild dementia at enrollment, while 214 were non-demented.  The analyses showed that neither non-demented nor mildly demented patients had accelerated long-term decline in cognitive function attributable to surgery or major illness, compared with the controls.

Previous research in this area has yielded conflicting results.  The present study suggests that the conclusions in previous studies may be due to methodological issues that may have affected results.  Having patients enrolled before they have their surgery, or hospitalization, eliminates most to these methodological problems.  As the principal investigator, Dr Michael Avidan, states: “Our findings suggest that if older people physically recover from surgery, they should expect that, within 6 months or a year, they will return to their previous level of cognitive ability.”