Education may delay the onset of dementia in individuals with higher education, but once dementia does appear the symptoms of dementia develop rapidly.
The study consisted of 488 people, born between 1894 and 1908. Participants were followed for 6 years and given an annual cognitive test. From this group 117 developed dementia.
For each additional year of formal education dementia was delayed by about 2½ months. One reason for the delay of dementia onset is contributed to a greater cognitive reserve, which means that the brain has a greater ability to maintain cognitive function in spite of brain damage. Once the symptoms do appear in individuals with higher education the rapid memory loss is likely due to the result of the brain not being able to compensate for the brain damage that has occurred.
Researchers give, as an example, that someone with 4 years of education who develops dementia at age 79-years, will have a less rapid rate of cognitive decline. Someone with 16 years of education would be diagnosed at age 85-years and will experience a rapid decline in cognitive function.