Influence of education on the pattern of cognitive deterioration in AD patients: the cognitive reserve hypothesis.

The cognitive reserve hypothesis proposes that a high educational level could delay the clinical expression of Alzheimer's disease (AD) although neuropathologic changes develop in the brain. Therefore, some studies have reported that when the clinical signs of the disease emerge, high-educated patients may decline more rapidly than low-educated patients because the neuropathology is more advanced. However, these studies have only investigated the decline of global cognition or an isolated cognitive process. To study the differential deterioration pattern of several cognitive processes according to education, the performance of 20 AD patients with a high educational level and a low educational level were compared with the performance of 20 control subjects on a neuropsychological battery. The results showed that cognitive deterioration of AD patients is different according to education, although the global performance was similar in AD patients. The high-educated patients exhibited greater impairment of abstract thinking whereas the low-educated patients showed greater impairment of memory and attentional function. This confirms that some cognitive processes, such as abstract thinking, decline more rapidly in high-educated patients whereas others seem to evolve more slowly if compared to low-educated patients. In this latter case, high-educated patients may still benefit from cognitive reserve after the diagnosis of the dementia.