Sleep and Memory

Memory is the cognitive process whereby experiences, learning and recognition are recalled. Memory processes have been shown to be stabilised and enhanced by nocturnal sleep and even daytime naps. Certain sleep stages are noted to improve an individual’s memory, although this is task specific. Generally, declarative memories are enhanced by slow-wave sleep, while non declarative memories are enhanced by rapid eye movement (REM) sleep, although there are some inconsistencies among experimental results

There are essentially three phases of memory consolidation and all are thought to be facilitated by sleep. The positive correlation between sleep and memory breaks down with aging. In general, older adults suffer from decreased sleep efficiency. The amount of time and density of REM sleep and SWS decreases with age. Consequently, it is common that the elderly receive no increase in memory after a period of rest.