Cheyne J A
Department of Psychology, University of Waterloo, Waterloo, Ontario, Canada.
J Sleep Res. 2002 Jun;11(2):169-77. doi: 10.1046/j.1365-2869.2002.00297.x.
Sleep paralysis (SP) entails a period of paralysis upon waking or falling asleep and is often accompanied by terrifying hallucinations. Two situational conditions for sleep paralysis, body position (supine, prone, and left or right lateral decubitus) and timing (beginning, middle, or end of sleep), were investigated in two studies involving 6730 subjects, including 4699 SP experients. A greater number of individuals reported SP in the supine position than all other positions combined. The supine position was also 3-4 times more common during SP than when normally falling asleep. The supine position during SP was reported to be more prevalent at the middle and end of sleep than at the beginning suggesting that the SP episodes at the later times might arise from brief microarousals during REM, possibly induced by apnea. Reported frequency of SP was also greater among those consistently reporting episodes at the beginning and middle of sleep than among those reporting episodes when waking up at the end of sleep. The effects of position and timing of SP on the nature of hallucinations that accompany SP were also examined. Modest effects were found for SP timing, but not body position, and the reported intensity of hallucinations and fear during SP. Thus, body position and timing of SP episodes appear to affect both the incidence and, to a lesser extent, the quality of the SP experience.
睡眠瘫痪症（SP）指在醒来或入睡时出现的一段瘫痪期，常伴有可怕的幻觉。在两项涉及6730名受试者（其中包括4699名有睡眠瘫痪症经历者）的研究中，对睡眠瘫痪症的两种情境条件，即身体姿势（仰卧、俯卧以及左侧或右侧卧位）和时间（睡眠开始、中间或结束阶段）进行了调查。报告称处于仰卧姿势时出现睡眠瘫痪症的人数比处于其他所有姿势的人数总和还多。在睡眠瘫痪症发作期间，仰卧姿势出现的频率也比正常入睡时高3至4倍。据报告，睡眠瘫痪症发作期间的仰卧姿势在睡眠中期和末期比在开始时更为普遍，这表明后期的睡眠瘫痪症发作可能源于快速眼动睡眠期的短暂微觉醒，可能是由呼吸暂停诱发的。在睡眠开始和中间阶段持续报告有发作经历的人群中，睡眠瘫痪症的报告频率也高于在睡眠结束醒来时报告有发作经历的人群。还研究了睡眠瘫痪症的姿势和时间对其伴随幻觉性质的影响。发现睡眠瘫痪症的时间对幻觉有一定影响，但身体姿势以及报告的睡眠瘫痪症发作期间幻觉强度和恐惧程度没有影响。因此，睡眠瘫痪症发作的身体姿势和时间似乎既会影响其发生率，也会在较小程度上影响睡眠瘫痪症体验的质量。
