For their paper, researchers from the University of Wisconsin – Madison (UWM) School of Medicine and Public Health looked at data they collected from the Wisconsin Registry for Alzheimer’s Prevention, or WRAP. WRAP involves a cohort of middle-aged people averaging 54 years in age who were given a battery of psychological and cognitive tests over a period of time in order to pinpoint their disease progression.
The UWM team looked specifically at 312 people who had previously undergone one or more surgeries that involved the use of general anesthesia. They then compared what they observed in this group to 652 other patients who had not previously had surgeries with anesthesia, excluding all patients who had had neurological or heart surgeries, as these procedures in and of themselves can directly affect cognitive performance.
All of those evaluated, regardless of surgery and anesthesia status, had reportedly registered as being cognitively normal at the beginning of the study. So any and all deviations the team observed among these individuals at the end of the study could be traced back to the variations in how they were treated prior to surgery.
What was found is that, on average, patients who go under general anesthesia prior to surgery experience minor declines in their immediate memory over the following four years. Meanwhile, those who don’t undergo anesthesia tend to have the same memory capacity post-surgery that they had prior to surgery.