Over 80% of people with Restless Legs Syndrome also have a condition that is known as Periodic Limb Movement Disorder (PLMD).

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Periodic Limb Movement Disorders occur commonly and relate to movements or “jerking” of legs, arms and sometimes the body which can occur in an “involuntary” fashion, over which you have no control. These movements usually occur during or before sleep but can also occur while resting during daytime, sitting in a chair for instance, and can sometimes be painful. This was originally called “nocturnal myoclonus” and described by Professor Lugaresi from Italy.

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More recently we recognise PLMD as PLMS (PLMD during Sleep) and PLMA (PLMA during Awakening). While PLMD may be associated with RLS, it can occur independently, particularly in older people.

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PLMD occurs in approximately 4% of all adults and is particularly common in the elderly population and women. It can also occur in those who are shift workers and have abnormal sleep patterns, those who snore or drink excessive amounts of coffee, during severe stress or if the use of sleeping tablets is suddenly withdrawn.

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Typically, PLMD involves the foot being drawn upwards at an interval of 20-40 seconds, usually during the first part of the night. However, the movement may affect the whole leg causing jerks or flailing movements of the arms, keeping the bed partner awake. People who have troublesome PLMD can suffer from excessive sleepiness during day, and insomnia. If associated with RLS, the problem can be worse. A formal diagnosis of PLMD may need a specialised test called polysomnography which documents the movements and assesses the frequency at which these occur.

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The treatment of PLMD needs an accurate diagnosis and explanation of the problem. Medications used are similar to RLS. In some people, PLMD is very sensitive to the use of dopamine agonists such as pramipexole and ropinirole. Some anti-depressant medications can make the PLMD worse. However PLMD is treatable and it is important that a person living with PLMD visits their GP to get a referral to a sleep physician who may be able to analyse and advise on treatment.