The symptoms of periodic limb movement disorder include repetitive leg movements during sleep, which can lead to frequent sleep disruption, explains Cleveland Clinic. These can be jerking motions or upward flexing of the feet. These movements tend to occur in clusters of a few minutes to a few hours in length, and these clusters occur between 20 and 40 seconds apart. Because the movements occur during sleep, the person experiencing them may not be aware of the condition.
Periodic limb movement disorder usually only causes brief and subtle awakening during sleep, which can be difficult for an onlooker to spot, says Cleveland Clinic. An electroencephalogram can detect the change in brain states, however. Despite the fact that waking may not be complete, the disruption to sleep can leave a person with periodic limb movement disorder sleepy, hyperactive or irritable during the day. Diagnosis of this condition requires a sleep study and uses a tool known as a polysomnogram.
Periodic limb movement disorder appears to be connected to restless leg syndrome, a condition where a person has a strong urge to move a leg repetitively during waking hours, explains Cleveland Clinic. Caffeine consumption, anemia, diabetes and kidney problems may also be connected. Medications such as antidepressants may also contribute to it.