By: 29 May 2012

A study published in Anesthesiology found that elderly patients with mild cognitive impairment (MCI), as well as normal elderly undergoing surgery, experienced increased levels of brain atrophy beyond what is expected from normal ageing.

The brain atrophy detected in the study’s patients occurred during the initial three months after surgery, but atrophy and cognitive effects were not detected beyond this first observational stage.

According to lead study author Richard Kline, Ph.D. and the research team from NYU Langone Medical Center, many previous studies have reported that surgery can lead to postoperative cognitive dysfunction (POCD), but the nature of this phenomenon is controversial because of a lack of consensus on how to diagnose the condition.

“Our findings suggest that brain volume degeneration be used as an objective measure for researching treatment programmes and that the identification of patients at risk for development of POCD is warranted,” said Dr Kline.

POCD occurs in approximately ten percent of elderly patients undergoing noncardiac surgery, and its presence is determined by tests that assess memory and the ability to connect past experience with present action.

However, researchers have had difficulty objectively measuring POCD because the elderly are often subjected to other sometimes unrelated risks, such as dementia, vascular injury and various nonspecific impacts of normal ageing.

Dr. Kline and his collaborators focused specifically on the pre-surgical diagnosis of MCI, which indicates impairment in one or more mental processes greater than what would be expected for a person’s age, but who functions well and is capable of independent living.

Through data obtained from the Alzheimer’s Disease Neuro-Imaging Initiative (ADNI) database, the NYU research group found that quantitative MRI scans could offer a way to find consistent and reproducible anatomical markers associated with POCD and surgery.

“We found that surgery was associated with atrophy of some brain regions. Patients already exhibiting signs of cognitive decline were at greater risk for further cognitive deterioration accompanying the atrophy,” said Dr. Kline.

Dr. Kline said that the brain volume changes observed were plastic in nature [showing the ability for the brain to change through learning], with some groups showing a greater likelihood of return toward normal volume and function.

“Our study more readily supports the notion of temporary POCD associated with surgical patients than it contributes to the analysis of risk factors leading to dementia progression. These questions suggest the need for a more comprehensive examination of surgery, cognition and atrophy,” he said.