Restless legs syndrome (RLS) is a neurological disorder characterized by uncomfortable, tingling or creeping sensations in the legs, which create an uncontrollable urge to keep them moving. A similar disorder, periodic limb movement in sleep (PLMS) causes rhythmic jerking of the feet or legs, which interrupts sleep.

According to the National Center on Sleep Disorders Research, the common characteristics of RLS and PLMS are:

• Pain or nagging sensations in the legs, sometimes characterized as creeping, crawling, tingling or pulling. Discomfort often feels like it is deep inside the leg and can also affect the feet, upper leg, arms and hands.

• People often feel an uncontrollable urge to get up and move around. Sometimes the discomfort is relieved by pacing, walking, stretching, knee bends, massage, or hot or cold baths.

• Leg discomfort occurs when lying down or sitting for prolonged periods of time, like during the movies, car rides or plane flights.

• Increased symptoms in the afternoon, evening and night.

• Sudden, involuntary leg (and occasionally arm) movements while asleep.

• Difficulty staying asleep or achieving restful sleep because of repeated awakenings due to pain, discomfort or sudden movement.

• Extreme daytime sleepiness.

• Cause of the leg discomfort not detected by medical tests.

• Family members sometimes have similar characteristics.

People experience the symptoms at different intensity levels. Some describe the sensations as merely bothersome, while others describe them as quite painful.

Medication can be very effective for 90% of those with RLS and PLMS.