I'm a twitcher as I fall asleep. I twitch for the first 15 or 20 minutes I'm asleep (but don't usually wake myself up) and then stop all together. It doesn't bother me, but it often bothers my bedfellow, who doesn't think it's particularly normal. I figure it's just my muscles relaxing after a long day at work. What causes this and do I need to do something about it?
Many of the questions I receive seem to come from readers under-appreciated by their spouses or partners. Their mates often overlook obvious gifts in order to point out peculiarities and destroy self-esteem. Doesn't your partner know that every night, hundreds of people in cheap, poorly-decorated, rural motel rooms across this country plunk down a hard-earned quarter for the same amount of time on a Magic Fingers vibrating bed? My response to your bedfellow happens to be the same as the scientific name of your condition: myoclonic jerk.
There is a range of severity of the twitching you describe from the inconsequential to the debilitating. Probably 75 percent or more of us have had the experience of drifting peacefully off to sleep and suddenly lurching awake to find a scowling lady in the window seat soaking up her complementary beverage with the SkyMall catalog. Alone, these are known as sleep starts or hypnic jerks and, except for the dirty looks and possible revenge elbowing, are completely harmless. Myoclonic jerks, the repeated periodic shudder or shake for which you are criticized, occur during the lightest levels of sleep, don't recur and are equally innocuous. Innocuous, that is, unless you kick some unprotected area of your sleep mate.
Speculation is plentiful on the cause of these sleepquakes, which are often accompanied by dreams of falling. One theory is that the same system that supposedly tries to twitch-start a dying body accidentally kicks in after misinterpreting the muscle relaxation preceding sleep. Another, more plausible theory says the relaxation is mistaken as loss of balance and your not-yet-shutdown reflexes take action to steady you. Regardless, this system provides hours of fun for watching not only fellow air travelers, but also those on jury duty, at the symphony and in the college library during finals week.
As we move up the scale of intensity, the next stop is Periodic Limb Movement Disorder (PLMD). Repetitive, involuntary movements ranging from shallow twitching to wildly flailing legs or arms characterize this condition. This lively commotion takes place during sleep, but unlike those described above, movements repeat every about 30 seconds for an hour or more, with several encore performances through the night. The main concern in PLMD is not the movements, but the frequent awakenings, resulting in poor sleep and excessive daytime sleepinessnot to mention a husband's insomnia from the required mouth guard, pads and cup. PLMD occurs mainly all alone, but it is a common symptom in about 80 percent of people with Restless Leg Syndrome (RLS).
RLS is, by far, the most severe of these disorders. People with this condition describe creeping, crawling or burning sensations in their legs almost anytime they are at rest. While the other conditions occur only during sleep, RLS allows very little shut-eye from a constant need to move to get even temporary relief. The cause is unknown, but it is associated with neurological disorders, diabetes, stress and pregnancy. The serious sleep loss can not only lead to drowsiness, but to depression and accidental injuries as well. In recent years, researchers have discovered that iron, folate or vitamin E levels are often low in RLS sufferers and supplementation can frequently help.
Your myoclonic jerks do not make you more likely to develop Restless Leg Syndrome, nor are they anything more serious than an endearing quirk that keeps the dog off the bed. If, however, your heedless partner cannot see the charm, you might try eliminating caffeine. The mild central nervous system stimulant, as well as stress, may amplify the intensity or frequency of your twitching. In addition, excessive physical activity near bedtime also seems to increase the vibratory tendencies. This last detail may be the key to changing the attitude of your bed partner, but since relationship negotiation is outside my area of expertise, I'll let you figure out how to strike a bargain.