John Peever, Assistant Professor at the University of Toronto, discovered that an inhibitory brain chemical called glycine is responsible for actively suppressing muscle twitches in REM sleep.

• 常伴有精神压抑、过度饮酒、脑血管疾病和变性性神经系统疾病等。可见于任何年龄，但多见于60-70岁具有暴力性梦境的老年男性。