Periodic Limb Movements in Sleep

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If the legs are moving whilst the person is asleep it is likely to be a movement disorder called ‘Periodic Limb Movements in Sleep’ (PLMS). Studies show these leg movements occur in about 80% of people with RLS, however, PLMS is also common in conjunction with other disorders and among the elderly.

This neurological movement disorder is also known as 'Nocturnal Myoclonus', meaning a sudden shock-like involuntary movement. It is characterised by repetitive movements, usually described as twitching or jerking, which have a rhythm, recurring about every 20 to 30 seconds. Some are small flexing movements but they can vary in intensity to large jerks or kicks. The legs are mostly involved but for some, the arms move too.

The state of disarray of the bed may be a good indicator for this condition, but reliable reports usually come from the patient's unfortunate bed partner. This person may become a victim of insomnia, or can be forced to leave the bed, due to their partner's incessant movements and continual rustling of the sheets.

These frequent arousals cause a disturbance of the sleep pattern, robbing sufferers of sound, restful sleep, including valuable REM sleep (Rapid Eye Movement). This REM stage of sleep is vitally important for refreshing both mind and the body. Advisory Board member for the United States RLS Foundation, Dr Ralph Pascualy, MD, comments that many of his patients complain about being tired in the daytime, despite the fact that they may have slept for six or seven hours. He explains that the twitching movements ".... disturb the brain just a little bit, but not enough to wake up and know there is a problem."

Other associated conditions:

Other associated conditions in which patients may experience symptoms include: iron deficiency anaemia, diabetes, alcoholism, rheumatoid arthritis, kidney failure and Parkinson's Disease. It should be noted that autopsies on the brains of people suffering from long term RLS showed no Neuro degeneration, (i.e. no loss or damage of brain cells) as seen in Parkinson’s and Alzheimer’s Disease.

The other condition which causes some women to develop RLS symptoms is pregnancy. It is thought the high demands on iron stores causes a deficiency. For many it is a temporary, although exasperating problem but it may be a sign for some that they could be vulnerable to developing symptoms when older.