Periodic leg movement, sleep fragmentation and central sleep apnoea in two cases: reduction with Clonazepam

Two subjects presented with periodic leg movement (PLM) syndrome during sleep that was characterized by marked sleep fragmentation and repetitive short central apnoeas. Treatment of PLM using Clonazepam, a benzodiazepine with hypnotic properties, markedly reduced the sleep fragmentation due to PLM and, despite its depressant properties on the central nervous system, controlled the repetitive central apnoeas. These two observations, although rare, give insight into the role of non-ventilatory variables in the development of sleep apnoea. Significant sleep fragmentation should be considered when assessing factors leading to respiratory instability during sleep and/or the pathophysiology of sleep apnoea syndromes.