Restless Leg Syndrome and Periodic Limb Movement

Restless leg syndrome (RSL) affects around 10% of the population and is characterised by an irresistible urge to move their legs. This feels like an abnormal sensation in the leg muscles. During sleep RSL is commonly associated with the sleep disorder periodic limb movement disturbance (PLMD). Around 80-90% of people with RSL have PLMD.

Periodic limb movement disorder (PLMD) is a rare sleep disorder. This affects between 4-11% of the population. A patient suffering from PLMD in their sleep might experience legs and in some cases the arms repetitively twitch or jerk every 50-90 seconds for up to an hour.

PLMD may either be primary (appears on its own) or secondary (due to a contributing medical condition) disorder. Research still doesn’t know the cause of primary PLMD. For secondary PLMD common medical issues associated with the condition include diabetes, iron deficiency, caffeine use, ADHD, withdrawals, medication side effects, and other sleep disorders, such restless leg syndrome (RLS), narcolepsy, REM sleep behaviour disorder, or sleep apnoea.

While in most cases PLMD is not considered medically serious, the movements have been associated as an indicator for more serious medical conditions.