PLMD - Periodic Limb Movements in Sleep

Periodic Limb Movements in Sleep is a symptom that is commonly associated with another type of sleep disorder known as Restless Leg Syndrome or RLS. However, PLMS is a separate condition and RLS need not be present. PLMS is also known as Periodic Limb Movement Disorder or PLMD and refers to the same condition.

Although the problem itself does not seem to cause or aggravate any other medical conditions, the frequent limb movements or twitching of the lower limbs can cause a disruption in a person's sleep. In fact, it can lead to significant insomnia, which can have adverse affects. It is for this reason that PLMS is considered a sleep disorder.

Symptoms are few but they are obvious. As the name implies, the lower limbs of individuals with this disorder move, often repetitively, for varying periods. These movements, which are characterized as either sudden jerks, or twitches, or a flexing of the foot upwards, occur while the affected person is asleep. These types of limb movements occur in episodes that can last just a minute or they can last for many hours. Once an episode stops, however, it typically takes less than a minute for the episode to repeat.

The same person may also have symptoms of Restless Leg Syndrome or RLS, which also consists of awkward feelings in the limbs. Those with RLS describe these feelings as a crawling, or prickly, or tingling sensation in the upper and lower legs and the arms. Absent RLS, there generally are not any other symptoms. In addition, since the leg movements happen during sleep, it is not unusual for the person to not even be aware of this condition. Interestingly, more often the bed partner first becomes aware of the condition because he or she will notice the annoying movement of the bed.

To date, no one has been able to identify the primary cause of PLMD. It is believed that the movements have something to do with the way the individual's central nervous system functions. It can be secondary meaning that it is caused by some other condition such as diabetes, sleep apnea, narcolepsy or anemia.

If a person experiences these types of movements during sleep, and if the person also has symptoms of Restless Leg Syndrome, a diagnosis of PLMD is generally suspected. If an individual is complaining of constant fatigue for which no other cause has been identified, a doctor might suspect PLMD. To confirm a diagnosis, a doctor will prescribe spending a night in a sleep center so that the patient's sleeping patterns can be closely monitored.

It is difficult to prescribe a treatment for PLMD because its causes are not understood. For some patients, treatment consists of medications such as Benzodiazepine that can help them get a better night's sleep. There are also medications that can be taken to help control the movements including anti convulsive agents, dopaminergic and GABA agonists.