Because long-term cognitive decline can occur in some older adults after undergoing surgery, there has been some concern that exposure to anesthesia may be associated with increased dementia risk. It is therefore pleasing to report that data from the very large, long-running Mayo Clinic Study, the Rochester Epidemiology Project, has found that receiving general anesthesia for procedures after age 45 is not a risk factor for developing dementia.

[3409] Sprung J, Jankowski CJ, Roberts RO, Weingarten TN, Aguilar AL, Runkle KJ, Tucker AK, McLaren KC, Schroeder DR, Hanson AC, et al. Anesthesia and Incident Dementia: A Population-Based, Nested, Case-Control Study. Mayo Clinic Proceedings [Internet]. Submitted . Available from:

Supporting the idea that repeated anaesthesia in children can lead to memory impairment, a rodent study has revealed that repeated anaesthesia wiped out a large portion of the stem cells in the hippocampus. This was associated with impaired memory in young animals, which worsened as they got older. The effect did not occur in adult animals. A similar effect has also been found with radiotherapy, and animal studies have found physical activity after radiotherapy results in a greater number of new stem cells that partly replace those that have been lost.

Older news items (pre-2010) brought over from the old website

Anesthesia exposure before age 3 found not to impact cognitive performance

A twin study challenges findings that receiving anesthesia at a very young age (below four) is associated with subsequent learning problems. The Dutch study involved 1,143 pairs of identical twins, and compared groups where both twins had been exposed to anesthesia before age 3, where neither had been exposed to anesthesia, or where only one member of the pair had been exposed to anesthesia. Cognitive performance at age 12 was assessed from a standardized national exam administered to all children in the Netherlands at that age. It was found that there was no difference in cognitive performance between twins where one had been exposed to anesthesia and the other had not. It therefore seems likely that the association is due to children likely to undergo surgery early in life having significant medical problems that are associated with a vulnerability to learning disabilities.

[1217] Bartels M, Althoff RR, Boomsma DI. Anesthesia and cognitive performance in children: no evidence for a causal relationship. Twin Research and Human Genetics: The Official Journal of the International Society for Twin Studies [Internet]. 2009 ;12(3):246 - 253. Available from:

Common pediatric anesthesia drugs cause brain damage and learning and memory problems in infant rats

A new study has found that drugs commonly used to anesthetize children can cause brain damage and long-term learning and memory disturbances in infant rats. The rats appeared to behave normally in most other ways, and there were no outward signs of brain damage.

[207] Jevtovic-Todorovic V, Hartman RE, Izumi Y, Benshoff ND, Dikranian K, Zorumski CF, Olney JW, Wozniak DF. Early Exposure to Common Anesthetic Agents Causes Widespread Neurodegeneration in the Developing Rat Brain and Persistent Learning Deficits. J. Neurosci. [Internet]. 2003 ;23(3):876 - 882. Available from: