The rate of mental decline seen with in patients with Alzheimer’s disease is directly related to the educational level of the affected individual, according to a report in the Journal of Neurology, Neurosurgery, and Psychiatry.

The new findings are based on a study of 312 patients living in New York who were diagnosed with Alzheimer’s disease and followed for an average of 5.6 years. Up to nine neuropsychological tests were performed on each subject during the course of the study.

Overall, mental agility fell by 9 percent of a standard deviation each year, lead author Dr. Nikolaos Scarmeas and colleagues, from Columbia University Medical Center in New York, note. For each year of additional education, the decline increased by 0.3 percent.

Memory and executive speed, which includes the ability to adapt to change and organize thoughts, were the primary areas affected by education level, the report indicates.

Further analysis showed that the link between education and mental decline was not influenced by age, mental function at the time of diagnosis, or other factors known to influence brain function, such as depression and vascular disease.

Previous studies have provided evidence that high levels of education can delay Alzheimer’s disease. The “cognitive reserve” hypothesis has been put forth to explain the effects of education on Alzheimer’s disease, Scarmeas and colleagues note.

This theory, they explain, holds that highly educated individuals have more intellectual reserve so the onset of overt Alzheimer’s disease symptoms is delayed. However, once symptoms become apparent, more damage has accumulated than in less educated brains, so the subsequent decline in mental function is more rapid.

SOURCE: Journal of Neurology, Neurosurgery, and Psychiatry, March 2006.