Periodic leg movements in Cheyne-Stokes respiration.

Periodic leg movements during sleep (PLMS) are repetitive jerks of the lower limbs. Their occurrence can be isolated or part of various sleep disorders, such as restless legs syndrome (RLS), narcolepsy and obstructive sleep apnoea. Dopamine agonists are very effective in suppressing PLMS in RLS from the first night of administration. PLMS are often associated with cortical and autonomic arousals and may contribute to sleep disruption. Herein, a case of association between PLMS, Cheyne-Stokes respiration (CSR) and severe insomnia is described. Repeated polysomnographic studies demonstrated a clear synchronisation between PLMS and hyperventilation episodes, and the complete recovery of CSR, sleep quality and PLMS during nocturnal ventilation. In the same patient, pharmacological treatment with a dopamine agonist was ineffective on both PLMS and CSR. These results suggest that periodic leg movements during sleep coupled with central breathing events, similar to those observed in conjunction with obstructive events, may have a different origin in terms of neurotransmitter and pathway implicated, compared with periodic leg movements during sleep in restless legs syndrome, and are resolved by treatment of the respiratory abnormalities.