A good nights sleep improves the memory

Apr 26 2007

According to a new study people who have a good nights sleep have better memories than people who sleep poorly.

A good nights sleep say scientists not only protects memories from outside interferences, but also helps strengthen them.

The researchers at the Brigham and Women's Hospital, Boston, found that the benefit of sleep for memory consolidation, was greater than anticipated and the sleeping brain interacts with memories and appears to strengthen them.

Neurologist Dr. Jeffrey Ellenbogen, says the study looked at the impact of sleep on a certain type of memory called "declarative" memories, which refer to those dealing with certain facts, episodes and events.

Forty-eight people between the ages of 18 and 30 with normal, healthy sleep routines took part in the study; none were taking any sleep medications.

They were divided evenly into four groups - a wake group without interference, a wake group with interference, a sleep group without interference and a sleep group with interference.

All the groups were taught the same 20 pairs of words in the initial training session.

The wake groups were taught the word pairings at 9 a.m. and then tested on them at 9 p.m. after 12 hours awake.

The sleep groups were taught the word pairs at 9 p.m. and tested on them at 9 a.m. after a night of sleep.

Just prior to testing, the interference groups were given a second list of word pairs to remember; the first word in each pair was the same on both lists, but the second word was different, testing the brain's ability to handle competing information, known as interference.

The interference groups were then tested on both lists.

The researchers found that people who slept after learning the information performed best, successfully recalling more words.

Those in the sleep group without interference were able to recall 12 percent more word pairings from the first list than the wake group without interference.

With interference, the recall rate was 44 percent higher for the sleep group.

An analysis of the data showed that the memory of those people who had quality sleep was better overall than the memory of those participants who slept poorly.

The researchers will present the study at the American Academy of Neurology annual meeting in Boston in May.