This frustrating sleep starts have another cool medical name, hypnagogic myoclonus.

性肌阵挛。

There are positive sides to this hypnagogic period too.

这个期也有积极的一面。

It's in this first stage of sleep you might experience hypnagogic sensations -- those brief moments when you feel like you're falling, and your body jerks, startling you.

在这个睡的第一阶，能会经历入睡前幻觉，例如感觉在坠落，身体抽搐。