Cognitive reserve and its implications for rehabilitation and Alzheimer's disease.

According to the Cognitive reserve hypothesis, several factors related to mental engagement, such as level of education, type of occupation, leisure activities and social network, appear to affect the risk of developing clinical dementia. The present article provides an overview of the studies that have investigated the effects of mental engagement and cognitive stimulation specifically on dementia of the Alzheimer's type (AD). Mental training and cognitive stimulation interventions in AD have been shown to be useful in increasing patients' ability in performing activities of daily living (ADL), allowing them to maintain relative independence. Since cognitive engagement and stimulation are known to modify the brain processes to perform tasks, by recruiting alternative and more efficient networks, this review is especially focused on cognitive rehabilitation in AD patients, which has been shown to improve their global functioning and cognition. This perspective stresses the idea that cognitive reserve is not a fixed factor, but can be continuously modified by life experiences, even when the brain is already affected by neuropathology.