Complex periodic limb movements during sleep or partial epileptic seizures?

Abstract

A 69-year-old woman had insomnia, restless legs syndrome, and violent movements during sleep; she had had a generalized seizure several years previously. She underwent 4 days of video-EEG investigation for these movements (table, and figure e-1 on the Neurology ® Web site at Neurology.org). There was no epileptic activity, but repetitive, stereotyped movements (88 movements/hour; movement duration: 2.5 seconds) occurred only during sleep, which were typical of periodic leg movements but associated with atypical, polyphasic hand cycling/rubbing movements (see video). This complex motor pattern might be confused with a focal epileptic seizure.Treatment with pramipexole (0.18 mg/night) alleviated the insomnia and movements, arguing further for complex periodic leg (and arm) movements of sleep.

Seizures and movement disorders: phenomenology, diagnostic challenges and therapeutic approaches

“…33 PLMS may mimic focal seizures, and in some cases further investigation (eg, EEG) is required. 34 Status dystonicus (SD) is currently defined as 'a movement disorder emergency characterized by severe episodes of generalized or focal hyperkinetic movements that have necessitated urgent hospital admission because of the direct life-threatening complications of these movements'. 35 SD can be triggered by precipitating factors such as infections, medication adjustments, surgical procedures, metabolic disorders and failure of deep brain stimulation.…”

“…The main differential diagnosis is non-epileptic paroxysmal MDs occurring during sleep, which are often difficult to differentiate on the clinical ground alone unless EEG polysomnography is performed. 34 Adding to the diagnostic difficulty, EEG is typically normal or may be masked by excessive movement artefact during the events. The high incidence of uninformative EEG emphasises the importance of other characteristics in the differential diagnosis (eg, the highly stereotyped nature of the episodes).…”