For the millions who suffer from Restless Legs Syndrome,
sleep can be exceedingly difficult and disrupted. RLS is a neurological
disorder and a sleep disorder, a condition that causes tingling, twitching,
“creepy-crawly” feelings in the legs. These uncomfortable sensations bring
about an often-urgent need to move the legs. The symptoms of RLS are most often
felt when a person is lying still for a period of time, and are frequently
experienced at bedtime. People with RLS commonly experience symptoms of
insomnia—difficulty falling asleep and staying asleep. Medications for RLS can
be successful in alleviating the twitching and tingling sensations in the lower
body, but very often the insomnia symptoms remain, leaving people with RLS
coping with chronic sleep problems even after the other RLS symptoms have
This is just one of the puzzling aspects of RLS, a condition
that has proved mysterious and difficult to understand, diagnose, and treat.
But new research may have
delivered an important breakthrough in our understanding of how RLS works in
the body, and why sleep problems can stubbornly persist even after successful
treatment for tingling, twitching legs.
Researchers at Johns Hopkins University School of Medicine investigated the
relationship between brain chemistry and sleep among patients with RLS. They
discovered abnormally high levels of a brain chemical involved in stimulating
arousal. The brain chemical glutamate is an
important neurotransmitter that arouses both the brain and the central nervous
system. Researchers found elevated levels of glutamate present in the brains of
patients with RLS. Abnormal levels of glutamate may help explain why RLS
patients continue to have trouble sleeping, even after other medications have
quieted the disruptive sensations in their legs.
Researchers evaluated 48 adults, including 28 patients with
RLS and 20 subjects without the condition. Those with RLS had experienced
symptoms of the condition for at least 6 months, on 6 or 7 nights per week.
Researchers first measured glutamate levels in the brain using MRI. They then
spent two days measuring participants’ sleep. They found significantly higher
levels of glutamate among RLS patients than in those without the condition.
Among the RLS patients in the study, those with higher levels of glutamate
experienced more severely disrupted sleep.
This was a small study, and we’ll need to see follow-up
research on a larger scale to confirm and further establish the role of
glutamate in RLS. But these findings could represent an important step forward
in our understanding of RLS. What’s more, this new information could bring
about significant changes in treatment of the condition.
Previous research and treatment for RLS has focused on
another of the brain’s neurotransmitters: dopamine. Dopamine
plays an important role in muscle activity and body movement, and dopamine
deficiency can result in involuntary muscle movement. Several drug treatments
for RLS involve
raising levels of dopamine, in order to soothe the involuntary twinges and
intense urges to move the legs. But these drugs have not been successful in
improving RLS patients’ sleep.
This new research may deliver an important piece of
information to the RLS-sleep puzzle. High levels of glutamate in patients with
RLS may be preventing these patients from sleeping well, a problem that is not
currently being addressed by the array of dopamine-related medications being
used to treat other symptoms of the condition.
As many as 10% of adults in the U.S. suffer
from RLS, according to the National Sleep Foundation. RLS is a condition that
very often goes undiagnosed or misdiagnosed. RLS can often be misdiagnosed as
another sleep disorder or another neurological disorder, a muscular disorder.
Depression is another common misdiagnosis for RLS. Research shows a strong association between
depression and RLS. People with RLS appear to be at a significantly elevated
risk for depression. The poor sleep experienced by so many RLS patients may
play a role in their increased risk for depression. In addition to chronic
sleep problems and depression, patients with RLS also appear to be at elevated risk
for other serious health conditions, including hypertension and coronary heart
disease. The cause of RLS is not known, but the condition does run in families,
and recent research
has shown evidence of a genetic link.
This latest research is an exciting breakthrough, with
the potential to transform our understanding of RLS. There are many steps still
to take, and questions to be explored and answered, before we know what changes
are best made to the way we treat RLS. But for a condition that has often
confounded experts, and caused such discomfort, disruption, and sleeplessness
to so many patients, this study brings both welcome and encouraging news.
Michael J. Breus, PhD
The Sleep Doctor®
Everything you do, you do better with a good night’s sleep™
twitter: @thesleepdoctor @sleepdrteam