Sleep apnea in patients with postpolio syndrome

We studied sleep architecture and sleep apnea pattern in patients with postpolio syndrome (PPS). Ten patients with clinical signs of PPS underwent polysomnographic recording for two consecutive nights. Although sleep efficiency and proportions of sleep stages were within the normal range, sleep architecture was disrupted owing to sleep apnea. Patients with bulbar involvement had more frequent sleep apnea (mean sleep apnea index, 11.09) than patients without (apnea index, 5.88). The former also had significantly more central apnea, which occurred more commonly during non-rapid-eye-movement (NREM) than rapid-eye-movement (REM) sleep, than those without bulbar signs. This finding suggests reduction in forebrain control of compromised bulbar respiratory centers during NREM sleep in PPS.