Restless Leg Syndrome

Years ago, when she was a young adult, Agnes began to notice a peculiar, unpleasant feeling or sensation in her legs that was present only when she happened to be sitting or lying quietly with little or no movement. The feeling wasn't exactly painful, but was irritating and persistent, and it vanished as soon as she began to use her leg muscles, either by getting up and walking about or by bouncing or jiggling her legs. However, it returned as soon as she rested again.

Her husband was right: she just couldn't sit still. The need to counteract the queer feeling in her legs was too compelling. 

This phenomenon of an abnormal leg sensation relieved by movement is known as "restless leg syndrome." In this syndrome, the abnormal feeling in the legs is present whenever the muscles are immobile, at any time of the day or night. Of course, one of the quietest times of the day in terms of reduced muscle activity is just before going to sleep - while lying in bed, waiting for sleep to wash over you. 

Restless leg syndrome is common, occurring in 5 to 15 percent of the population. It often begins in early adult life and becomes much more troublesome as one ages. It is very common among pregnant women, affecting up to 30 percent of them, but usually disappears soon after delivery. There seems to be a genetic predisposition to the problem, as fully one-third of reported cases share the symptoms with a family member. 

Though they all agree it is an irritating feeling, patients find it hard to describe the sensation of being "restless." Descriptions vary widely, as do the perceptions of the problem. Some report that the irritating feeling is simply a "tingling" or "pins and needles." Others experience a crawling or drawing on the skin. However, most insist that the feeling is below the surface, a deep unpleasant ache in the bones. Occasionally, the feeling seems to be one of heaviness or tiredness, sometimes even outright pain. These annoying sensations are usually most pronounced in the calves of the leg, and they are accompanied by an irresistible urge to move. Sometimes patients focus on the movements that relieve the feeling, rather than on the feeling itself, and they describe their legs as being "convulsive" or "jumpy" or, "thumping." The poor sufferer is unable to keep the leg still, but the feeling of "restlessness" is immediately relieved with the slightest movement. The sensation becomes progressively worse as the day wears on, so the evening is often spent in some sort of muscle activity - walking, exercise, leg rubbing, or simple fidgeting.

Though restless leg syndrome may be caused by nerve damage from a variety of diseases (such as diabetes, vitamin deficiency, anemia, or renal failure), most affected people are otherwise perfectly well. It can be caused by lack of exercise, by some drugs, especially amphetamines, stimulants of the central nervous system such as methylphenidate, and verapamil, a drug used for heart disease and high blood pressure. It can also be caused, or aggravated, by caffeine or alcohol.

Though restless leg syndrome is primarily a daytime problem, the distressing sensations prevent or significantly delay the onset of sleep. Once sleep finally comes, the sensations may awaken the sleeper from a light sleep, but this is not common. However, if he or she is awakened for some other reason, returning to the comfort of sleep may be very difficult. To make matters worse, restless leg syndrome is lifelong. It is totally understandable that severe emotional distress, including both anxiety and depression, is commonly seen as part of the syndrome. One third of cases have a similar history in a family member.

Have you ever been comfortably resting in bed, just entering twilight-zone sleep, with the feeling of a long, slow, peaceful falling into slumber as you drift off, the world around you fading away gloriously, when suddenly your arms and legs jerk you awake with one horrendous contraction? These body jerks occur only during the early stages of sleep and are quite normal, even though they often force you to sit up in bed and are sometimes accompanied by an exclamation or cry of surprise. Between 60 and 70 percent of normal subjects describe such episodes of uncontrollable, instantaneous flexing of muscles during the first few minutes of rest. They are often preceded by a feeling of falling, or sometimes a short vivid image or dream. Some people describe a bright flash of light, or a sudden "hot" feeling or "flowing" just before the jerk occurs. These sudden muscular spasms occur more frequently after heavy physical work, increased emotional stress, and excessive intake of caffeine. The current theory to explain this phenomenon, universally considered to be of no significance whatsoever, goes like this: during the early stages of sleep, you progressively lose awareness of the environment, and your muscles slowly relax. However, occasionally this process does not go smoothly, and there is a glitch. In fact, you have an exaggerated response to some external stimulus. It's like popping the clutch on a standard car - your muscles are out of rhythm, out of gear, and instead of being relaxed and immobile, they are suddenly overstimulated, and a pronounced spasmodic contraction occurs. Though it does disturb your sleep, there is no disease involved; it's simply a variant of normal.

Periodic Limb Movement Disorder

Most people with restless leg syndrome have another sleep disorder, consisting of repetitive kick-like movements, called "periodic limb movement disorder."

With restless leg syndrome, the basic problem is an unpleasant sensation originating deep in the legs, and movement of the legs simply controls this irritating feeling. Thus, the movement itself is secondary, not the main problem. However, there is a more common leg movement that disturbs sleep - and most people who have it are completely unaware. This type of movement is called by the pedestrian but descriptive term "periodic limb movements." The limbs that the title refers to are usually the legs (though occasionally the arms are involved), and it's called "periodic" because the movements occur in intermittent episodes, or groups of movements, throughout the night. Unlike restless leg syndrome, periodic limb movement is a nocturnal phenomenon; the muscles of the legs are perfectly normal and behave respectably during the day.

Soon after sleep onset, however, the legs begin to move, or twitch really, in a predictable and typical manner. The movement is like a sudden lifting of the big toe and a simultaneous flexing of the knee and ankle - rather like a clumsy type of kick. The movements are caused by sudden contraction of the various muscles of the leg and are beyond the sleeper's control - in fact, the sleeper doesn't even know that they are happening. The twitches or jerks are brief, lasting only about half a second, and occur on a regular, rhythmic basis once every twenty to forty seconds, creating long "trains" or groups of movements that continue throughout the night, separated by intervals of no movement. The kicking is usually not present in REM sleep, and the frequency and severity of the kicks vary from night to night, with physical and emotional stress worsening the problem.

Although the sleeper is unaware of the regular jerking motion, the movements often disturb sleep, perhaps not awakening the sleeper completely, but increasing the level of awareness enough to prevent entrance into the deep restorative sleep that is so beneficial. Frequently, the sleeper is awakened by the contractions but, because they are so short-lived, has no idea what is causing the repetitive awakenings throughout the night. The sleeper's bed partner, of course, can identify the pattern, as he or she is often repeatedly kicked or hit. Apart from the resulting bruises, there is another tell-tale sign in the morning - the bedclothes look like they have been through the wringer washer, and sometimes are even shredded.

Periodic limb movement is much more common in middle-aged and older people. It is unusual in those under age thirty, and is found in about 30 percent of those over age fifty and nearly 44 percent of those over age sixty-five. Because patients are unaware of what woke them up, the main complaint reported is often simply difficulty staying awake during the day - the drowsiness that results from disturbed sleep - rather than any reference to the movements themselves.