Diagnosis of Periodic Limb Movement Disorder and Willis-Ekbom disease (WED), or Restless Legs Syndrome (RLS)
A sleep partner may observe the occurrence of periodic limb movements, which often affect the partner before the patient knows of his or her behavior. In other cases, however, the diagnosis is made by a sleep technician during an overnight polysomnogram, which records sleep and the bioelectrical processes that govern it. This test is often used to assess the cause of excessive daytime sleepiness, such as PLMD and obstructive sleep apnea.
Willis-Ekbom Disease (WED) Diagnosis
The diagnosis of Willis-Ekbom disease (WED), formerly called restless legs syndrome (RLS) is based on the patient's description and personal history of his or her affliction. Because it presents no external secondary symptoms, RLS can be difficult to identify.
According to the Willis-Ekbom Disease Foundation, formerly the RLS Foundation, the following criteria are necessary for a diagnosis of for WED/RLS:
- a strong urge to move your legs (sometimes arms and trunk), usually accompanied or caused by uncomfortable and unpleasant sensations in the legs
- symptoms begin or become worse with rest or inactivity, such as when lying down or sitting
- symptoms get better with movement, such as walking or stretching, at least as long as the activity is continued
- symptoms are worse in the evening or night than during the day, or only occur in the evening or nighttime hours
- symptoms are not solely accounted for by another condition (e.g., leg cramps or swelling, positional discomfort, arthritis)
There are studies designed to quantify the effects of RLS, though these are used mostly for research purposes. For example, a Suggested Immobilization Test, or Forced Immobilization Test, is performed while the patient either voluntarily keeps his or her legs motionless or while the legs are immobilized with a stretcher. The limb movements are then monitored with an EMG.
In both PLMD and WED, a complete examination to exclude secondary causes is warranted. It is necessary to distinguish Willis-Ekbom disease and PLMD from other more serious types of nocturnal movement, such as seizure. Nocturnal seizures present problems for patients because they can cause injury and are indicative of disorders that require specialized treatment. Also, iron and calcium deficiencies often produce symptoms that mirror WED, such as leg cramping and tenderness.