Impact on Sleep Quality

Restless Legs Syndrome (RLS)   is one of the most common causes of sleep disturbance. Patients with moderate to severe RLS are known to have less sleep than patients with almost any other type of persistent sleep disorder.¹

Because of the increasing severity of RLS symptoms when at rest, especially at night, RLS can cause great difficulty initiating sleep.¹

• A study in primary care found that almost 70% of RLS sufferers take more than half an hour to get to sleep and about 15% take two or more hours to fall asleep²

Having fallen asleep, RLS patients are often woken up by RLS symptoms. Patients with moderate to severe RLS may sleep less than five hours per night.³

• About 60% wake up three or more times per night²
• About 80% experience periodic limb movements of sleep (PLMS) which can disrupt sleep³

Periodic limb movements in sleep (PLMS) are involuntary movements of the legs while asleep. They are characterised by repeated stereotypic movements of the legs which typically consist of an upward extension of the great toe and foot as well as flexion of the ankle, knee, or hip.⁴ They occur every 15 to 40 seconds and last for one half of a second up to six seconds.⁴ These movements happen during the night, at regular intervals usually during periods of lighter sleep such as non-REM (NREM) sleep.⁴ The number of PLMS seems to increase along with the severity of RLS symptoms.⁴

Where differential diagnosis is required or in more severe cases of RLS, a specialised sleep study at a sleep laboratory can help to exclude other sleep disorders and confirm the frequency of PLMS. In the sleep laboratory, the patient's sleep is monitored at periods of rest and during sleep. The monitoring diagram will not only capture the specific involuntary movements associated with RLS but also the sleep disruption experienced by the patient.

Visit to a sleep laboratory

Polysomnographic record

Example of a polysomnographic record for an RLS patient with PMLS:

Figure 1*:
Patient with RLS and many PLMS during the night. Periodic limb movements are little muscle jerks or even cramps, that occur periodically every five to twenty seconds mostly during light sleep or during the waking periods at night. This patient is lying awake in bed and suffers from painful muscle contractions in his legs.

Figure 2*:
In figure 2, there is a part during deep sleep with only single mild PLM that do not disturb the patient’s sleep. After some uncomfortable hours of trying to fall asleep, the patient received some medication and his PLM were reduced, and he could sleep for some hours (see above). The red vertical line marks the time in the sleep profile that is shown here.

*Polysomnographic records courtesy of Prof. Claudia Trenkwalder

RLS and the impact on sleep – The patient experience

RLS patients often find it very difficult to cope with their reduced quality of sleep and long-term sleep deprivation. Here is how they describe their experiences:

 

References

1. Allen RP et al. Restless Legs Syndrome: a review of clinical and pathophysiologic features. J Clin Neurophysiol 2001; 18(2): 128–147.
2. Hening W et al. Impact, diagnosis and treatment of Restless Legs Syndrome in a primary care population: REST (RLS epidemiology, symptoms and treatment) primary care study. Sleep Med 2004; 5(3): 237–246.
3. Allen RP et al. Restless Legs Syndrome: diagnostic criteria, special considerations, and epidemiology – A report from the Restless Legs Syndrome diagnosis and epidemiology workshop at the National Institutes of Health. Sleep Med 2003; 4(2): 101–119.
4. WeMove^TM. Additional findings associated with Restless Legs Syndrome. http://www.wemove.org/rls/rls_afa.html. Accessed in December 2008.