Myoclonus can begin in childhood or adulthood, with symptoms ranging from mild to severe. Myoclonic twitches or jerks are caused by: sudden muscle contractions (tightening), called positive myoclonus, or. muscle relaxation, called negative myoclonus.

Is it normal to have jerky movements?

Jerky movements usually have a regular rhythm and may be limited to one muscle or muscle group (focal) or several different muscle groups (multifocal). They may occur without an obvious cause or be a result of many diseases.

Why does my body jerk out of nowhere?

It's normal for the muscles to relax, of course, but the brain gets confused. For a minute, it thinks you're falling. In response, the brain causes your muscles to tense as a way to "catch yourself" before falling down — and that makes your body jerk.