What Is Restless Legs Syndrome?

Restless Legs Syndrome (RLS) is a chronic neurological condition where sufferers experience unusual and uncomfortable sensations, and on occasion movement, in their limbs. This is usually in their legs (hence the name) but it may affect the arms and sometimes the trunk.

The subject experiences a sudden need to reposition the limbs to attain relief from these sensations. Those who have experienced RLS describe the sensations in their legs as;

• Aching
• Antsy
• Burning
• Cramps
• Creepy
• Crawly
• Discomfort
• Electric
• Heavy
• Itchy
• Jerking
• Numb
• Painful
• Pins & Needles
• Pulling
• Tingling

The symptoms are more pronounced in the evenings and at night, when sitting or lying down, and are relieved by movement, in particular by walking around. When the sensations are experienced during the night, sleep is disturbed, (though the patient might not actually be wakened) with the cumulative result of daytime fatigue. The symptoms come about more frequently with age and more women are affected than men. RLS appears to have a genetic connection.

Diagnosis

In order that the condition can be diagnosed as Restless Legs Syndrome, there are four criteria to be met; these were set by the National Institutes of Health in 2003.

• An urge to reposition the affected limbs (with/ without sensations).
• Feelings lessen with movement. Many realize respite when moving but not all find total respite; symptoms can return on termination of movement.
• Symptoms worse at rest. Subjects are affected as a rule when sedentary for long periods, e.g. the forced inactivity of travelling by car or airplane, attending a meeting, or watching a performance.
• Symptoms worse in the evening and at night. Those with mild to moderate RLS show a clear increase in sensory symptoms and restlessness in the evening and during the night.

Causes of RLS

The real cause of RLS is unknown. Separate hypotheses introduce assorted possible factors, including excessive caffeine consumption; iron deficiency; and magnesium deficiency.

Some pre-existing medical conditions are also related to RLS, including Parkinson's disease, fibromyalgia, diabetes, thyroid disease and peripheral neuropathy. It is also notable that many pregnant women experience RLS.

RLS is also known to be caused, or the symptoms made worse, by several drugs. These include some, but not all, of the preparations in the following groups of drugs: antiemetics, antihistamines, antidepressants, antipsychotics and anticonvulsants.

The relationship between RLS and depression (and other mental illnesses) is not clear; is depression a result of the sleep deprivation brought about by RLS or is the medication used to treat depression the cause of RLS?

Alternative Names for RLS

RLS is also known as Periodic Limb Movement Disorder (PLMD) but there are numerous colloquial names for it. These include; shaky leg syndrome, nervous leg syndrome, sleepless leg syndrome, lazy leg syndrome, jumpy leg syndrome and tired leg syndrome. The author, herself a sufferer, for many years knew it simply as ‘tired legs', never knowing it was ‘syndrome' at all.

Announcement

At the Annual Meeting of the American Academy of Neurology (AAN), in April 2009, it was announced by Diego Garcia-Borreguero PhD that, after a twelve week study of people suffering from Restless Legs Syndrome, a new therapy was being proposed. The drug Pregabalin, at that time already widely used for the management of seizures in epilepsy; post-herpetic neuralgia; diabetic peripheral neuropathy; fibromyalgia and general anxiety disorder, had been trialled and its treatment effects shown to be superior to prior drugs of choice for RLS.

Prior to the study, no research had been published into discovering another drug of preference to the Dopamine Agonists currently in use for the treatment of RLS. Though somewhat effective, dopamine agonists were not ideal; in some sufferers there was a failure to respond and there was inadequate enhancement in sleep or the quality of sleep. Though dopamine agonists could be highly effective in the short term, long term use was known to augment (make worse) the symptoms of RLS.

The Study

The study was conducted over a period of twelve weeks and consisted of 58 patients who were suffering the symptoms of Restless Legs Syndrome. It was a double blind study and had been designed to the best of the researchers' abilities. Sleep studies were performed at the beginning and the end of the research

The study began with a two-week placebo run-out, in order to eliminate ‘placebo responders'. Of the 58 participants, 30 subjects were administered the drug Pregabalin, with the remainder being given a placebo.

The starting dose of Pregabalin was 150mg. This was raised in stages to a maximum of 600mg. The drug was given once daily in the evening (9pm), but when doses were over 450mg; they were split and given twice a day (2pm and 9pm). The flexible doses were reviewed every 2 weeks, aiming to achieve the optimum therapeutic level.

Findings of the Study

The research team found that almost two-thirds of those taking the Pregabalin were RLS symptom-free whilst taking the drug and that, of those still experiencing symptoms, those symptoms showed an improvement of 66% while taking the drug. Evidence regarding the group on the placebo was that, overall, their symptoms had worsened by 29%.

The symptoms of RLS were monitored using the International Restless Legs Severity Scale. The average starting baseline measurement was 20 points. After the 12 week study this was noted to be reduced to 6.8 points which is classed as virtual remission; 63% of patients on Pregabalin achieved this virtual remission.

When analysing the outcome of the sleep study, it was apparent that those who had been taking the Pregabalin experienced added time in ‘slow wave' sleep (otherwise known as Stage 3 or deep sleep), and reduced time in the lesser Stage 1 and Stage 2 (lighter) sleep, when compared with the group taking the placebo. It is Stage 3 sleep which ensures we wake refreshed in the morning.

The optimum therapeutic dose of Pregabalin was established at 337mg per day. Dr Garcia-Borreguero stated that he thought this dose would be reduced by future studies, now that this study had recognized the beneficial effects of Pregabalin. The drug was well tolerated, with the only notable side-effect being ‘unsteadiness'.

Dr Garcia-Borreguero was quite satisfied with the effects of Pregabalin on the sensory symptoms of RLS. However he appeared to be animated and quite excited at the outcome of the sleep study, showing the complete normalization of sleep. He stated that he expected Pregabalin to be more beneficial in long-term use.

Researched from:

AAN Press Release April 2009

http://en.wikipedia.org/wiki/Pregabalin

http://en.wikipedia.org/wiki/Restless_legs_syndrome

http://youtu.be/KkSvmoOmfMI

http://youtu.be/AZg8kpU1D8M