Potential causes of sudden muscle contractions while sleeping include sleep myoclonus, a condition that produces brief twitching of the muscles, and restless leg syndrome, according to the American Sleep Association. Muscle contractions may also be caused by nervous system disorders such as multiple sclerosis, epilepsy, Parkinson's disease and Alzheimer's disease.
Involuntary movements, muscle contractions and twitches in adults could be caused by seizure disorders, thyroid disease, a brain injury or a stroke, according to Healthline. Drug use, neuroleptic medications, tumors and untreated syphilis can also produce involuntary movements.
Muscle contractions during sleep in the form of sleep myoclonus primarily affect the eyes, lips, toes and fingers, explains the American Sleep Association. The condition is often triggered by environmental factors such as movement, sound or light. Sleep myoclonus could be an indicator that sleeping disorders such as narcolepsy and sleep apnea exist within patients.
Muscle contractions during sleep that have been diagnosed as sleep myoclonus do not typically require treatment unless the condition is causing insomnia, according to the American Sleep Association. Physicians often perform a sleep study to rule out other sleeping disorders causing muscle contractions and to determine if additional treatment for a disease or nervous system malfunction is necessary.