These types of myoclonus are rarely harmful. However, some forms of myoclonus can cause recurring, shock-like spasms that can interfere with a person’s ability to eat, talk, and walk.

Stimulus-sensitive myoclonus is triggered by various external events, including noise, movement, and light. Being surprised may increase the sensitivity of the individual. Sleep myoclonus (or hypnic myoclonus) occurs during sleep and sleep transitions, often as one is dropping off to sleep.

Drug-induced myoclonus usually resolves after withdrawal of the offending drug, but in some cases specific treatments are needed.

Opiates such as morphine, heroin and methadone have been reported to cause these jerks with regular frequency along with sudden jerking and waking during the night’s sleep.

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.

Treatment of myoclonus focuses on medications that may help reduce symptoms. The drug of first choice is clonazepam, a type of tranquilizer. Many of the drugs used for myoclonus, such as barbiturates, phenytoin, and primidone, are also used to treat epilepsy.

Some forms of myoclonus are common and some forms are rare. In general, the incidence of myoclonus is 1.3 cases per 100,000 person-years, and the prevalence is 8.6 cases per 100,000 populations.

Sleep myoclonus usually disappears after a period of weeks and has resolved in most cases by 3 months of age.

A myoclonic seizure happens when your muscles suddenly contract, causing quick twitching movements. It usually affects one side of the body and involves the neck, shoulders, and upper arms. It can also affect the whole body.

Agitation during sleep can be seen with sleep disorders such as night terrors. It is also possible for these symptoms to occur as part of another emotional or psychological conditions, or even as a reaction to medications.

Tremor. Involuntary trembling, shaking, or shivering can be due to a medical condition called essential tremor. Essential tremor is a neurological condition, meaning that it relates to the brain.

Internal vibrations are thought to stem from the same causes as tremors. The shaking may simply be too subtle to see. Nervous system conditions such as Parkinson’s disease, multiple sclerosis (MS), and essential tremor can all cause these tremors.

Rest tremors — Rest tremors happen while you are sitting or lying down and relaxed. People who have a rest tremor can usually stop the tremor by deliberately moving the affected body part. Action tremors — Action tremors occur with voluntary muscle contraction.

It’s not common to see Parkinson’s disease in people younger than 50, but for a small subset of sufferers, the disease strikes early. While people are diagnosed with Parkinson’s at an average age of 60, anything younger than 50 is considered young-onset Parkinson’s, or YOPD.

The type a person experiences can sometimes indicate the cause. Sometimes, body tremors are due to an underlying neurological condition, such as stroke, Parkinson’s Disease, or multiple sclerosis. However, they may also be a side effect of medications, anxiety, fatigue, or stimulant use.

When we orgasm, tension builds around our muscles, and so when sex is over and the tension is released, it can trigger cramping, shaking or contractions can occur.

If you suddenly feel weak, shaky, or lightheaded—or if you even faint—you could be experiencing hypoglycemia. A headache that comes on quickly, weakness or tremor in your arms or legs, and a slight trembling of your body are also signs that your blood sugar is too low.