Restless Legs Syndrome and Related Disorders - Introduction

(Page 2)

Late-onset and Early-onset Forms. There appear to be two forms of RLS, early-onset and late-onset. Each form may have different characteristics:

• People with early-onset RLS (occurring in the teenage years or earlier) tend to have a family history of the disorder. They also usually have RLS without accompanying pain.
• People with late-onset RLS usually do not have a family history of RLS. Their condition is more likely the result of a problem with the nervous system, and symptoms may include pain in the lower legs.

Periodic Limb Movement Disorder

Another medical term for periodic limb movement disorder (PLMD) is nocturnal myoclonus. PLMD symptoms include:

---

---

• Episodes that usually occur during the night, peaking near midnight, as they do in restless legs syndrome.
• Leg muscles contract and jerk every 20 - 40 seconds during sleep. Such movements may last less than 1 second, or as long as 10 seconds.
• Unlike RLS, contractions in PLMD usually do not wake patients. PLMD is distinct from the brief and sudden movements that occur just as people are falling asleep, jolting them awake.

Although 80% of RLS sufferers have PLMD, only about 30% of people with PLMD also have RLS. While treatments for the two conditions are similar, PLMD is a separate syndrome. PLMD is also very common in narcolepsy, a sleep disorder that causes people to fall asleep suddenly and uncontrollably.

Review Date: 10/15/2010
Reviewed By: Reviewed by: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org).