Rate of memory decline in AD is related to education and occupation - Cognitive reserve?

Objective: To determine whether the rate of decline in performance on a mem ory test is more rapid in AD patients with higher versus lower educational and occupational attainment. Background: Epidemiologic and imaging studies have suggested that, given comparable clinical severity of dementia, AD pat hology is more advanced in patients with higher educational and occupationa l attainment. Because educational and occupational attainment should not in fluence the progression of AD pathology, and because severe AD pathology wi ll eventually produce a mortality-causing condition, people with higher att ainment might experience clinical AD for a shorter time and have a more rap id clinical progression Methods: A total of 177 AD patients were tested yea rly for up to four study visits with the Selective Reminding Test (a memory test). Analysis of prospective change in the total recall score was perfor med by applying generalized estimating equations to regression analyses wit h repeated measures. Results: At the initial visit, scores were comparable in the high- and low-education and the high- and low-occupation groups. Ove rall, memory scores declined by approximately 1 point yearly (p < 0.01). Th ere was a more rapid decline in memory scores in patients with higher educa tional (p < 0.057) and higher occupational attainment (p < 0.02). The autho rs then stratified patients based on their initial memory scores. The more rapid decline in memory scores associated with higher educational and occup ational attainment was noted only in the group with low initial scores (p < 0.05 for bath). The full group and stratified group analyses were also rep eated controlling for other potentially relevant variables including age, g ender, race, ethnicity, and the presence of extrapyramidal signs, stroke, o r at least one apolipoprotein E-epsilon 4 allele. The results remained unch anged. Conclusions: Memory declined more rapidly in AD patients with higher educational and occupational attainment. This adds support to the idea tha t the discontinuity between the degree of AD pathology and the observed cli nical severity of AD is mediated through some form of reserve.