According to the National Institute of Neurological Disorders and Stroke (NINDS), myoclonus refers to involuntary spasms that involve a muscle or group of muscles. For example, a hiccup is a type of myoclonus affecting the diaphragm’s muscles.
The symptoms of sleep myoclonus occur when a person falls asleep or during sleep. It causes unpredictable and involuntary muscle jerks or spasms that may affect a single muscle or multiple muscle groups.
These movements may include:
sudden jerking of the arms, legs, or torsoshock-like muscle twitches that last for a brief periodlocalized or widespread muscle spasmsmuscle spasms that occur in response to external stimuliThere are two types of myoclonus:
Physiologic myoclonus: These involve quick muscle twitches followed by relaxation. One example is when a person experiences “sleep starts” as they drift to sleep.Pathologic myoclonus: This involves contractions that begin in one part of the body and spread to other muscles in other areas.People with sleep myoclonus may he difficulty falling asleep or experience poor sleep quality.
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