Sleep Disorders and Memory
Sleep disorders can cause many difficulties in waking life, but did you know that they can seriously affect your memory? New research is uncovering the mechanisms by which this happens. Even if insomnia itself remains a problem, it may become possible to treat this symptom and enable sufferers to live much more normal lives.
Short Term and Long Term MemoryThere are two basic types of memory stored by the brain - short term and long term memory. When you are healthy, all the things you sense and do that the brain perceives as important are immediately recorded in short term memory. This is what you use when, for instance, you put something down temporarily and have to remember where you left it. The brain then transfers memories it thinks are especially important to long term memory for later use.
Because short term memory often seems compromised when we're overtired, scientists used to think that sleeplessness caused a problem with short term memory processing. This is now thought to be incorrect. Prolonged insomnia can, however, affect the transfer of short term memories into long term memory, making it difficult to recall important events even just a few days after they happen.
Memory Transfer During SleepOne of the activities the brain undertakes whilst we sleep is the processing of the day's short term memories, setting aside those that seem insignificant and storing the important ones (we are not born knowing which is which but learn this during our early years, which is why some people with learning disorders are better at remembering unusual things). If we don't sleep at all for a long time, this process can break down and important memories can simply be lost.
If you are struggling to get enough sleep because you are studying for exams, it's better to set aside the textbooks and do your best to get a nap. Studies consistently show that people do better in memory tests when they have the chance to sleep between learning things and using or repeating them. Brain scans show matching neural energy patterns in people who are studying and in the same individuals when they are sleeping shortly afterwards.
Visualisation and MemorySo if short term memory processing isn't a problem, what's really going on when we find ourselves forgetting where we put things because we are tired? This is now thought to be caused not by the processing but by the very formation of new memories, especially where vision is involved.
Recent research has shown that the visual cortex - the part of the brain that processes what we see - doesn't function properly when we are overtired. This means that when we try to remember what we saw, we can't access the memory because it was never properly created in the first place. The good news is that we may be able to remember associated sounds and smells more effectively. By focusing on these other senses we can remember things more effectively even when exhausted.
TreatmentAt present there is no treatment for memory problems caused by insomnia other than attempts to cure the insomnia itself. There are, however, some promising avenues of research. Scientists have now linked the problems with memory transfer in insomniacs to changes in a particular protein in brain cells. Drugs are now being developed to try and prevent these changes so that memory can be stored as usual even in the absence of sleep.
In the meantime, a good approach to coping with insomnia elated memory problems is to take micro-naps. In fact, if you have ever experienced short blackouts during a long period without sleep, your brain will have been ding this by itself. It's often easier that getting a proper sleep and it can enable to brain to deal with really urgent memory processing tasks so that you can function more normally even when you're really tired.