A brief, involuntary twitching of a muscle or a group of muscles. Myoclonus is one of several signs in a wide variety of nervous system disorders such as multiple sclerosis, parkinson’s disease, alzheimer’s disease, creutzfeldt-jakob disease, and some forms of epilepsy. In almost all instances in which myoclonus is caused by central nervous system (CNS) disease, it is preceded by other symptoms; for instance, in creutzfeldt-jakob disease myoclonus is generally a late-stage clinical feature that appears after the patient has already started to exhibit gross neurological deficits. Anatomically, myoclonus may originate from lesions of the cerebral cortex, subcortex, or spinal cord.
A twitching or spasm in a maximally stretched muscle group.
A condition wherein the muscles jerk involuntarily.
Alternating contraction and relaxation of muscle.
A muscle spasm which makes a limb give an involuntary jerk.
Myoclonus is a symptom and not a diagnosable disease (National Institute of Neurological Disorders and Stroke [NINDS], 2000). It is defined as a sudden, brief, jerky, shock-like, and usually irregular, involuntary movement emanating from the central nervous system. Five distinguishing traits characterize myoclonus: positivity or negativity, distribution, regularity, its relation to motor activity, and synchronization.
Sudden spasm of muscles, occurring in some forms of epilepsy and in certain progressive neurological disorders.
Rapid, intense contractions of a muscle group that is usually indicative of a central nervous system lesion.
A spasm of a muscle or group of muscles. In epilepsy (a brain disorder in which clusters of nerve cells in the brain sometimes signal abnormally), myoclonic seizures cause twitches or jerks of the arms, legs, or upper body. In most people, seizures are controlled with antiepileptic drugs such as carbamazepine, valproate, and phenytoin.
A sudden spasm of the muscles typically lifting and flexing the arms. Occasional myoclonic jerks occur between fits in patients with idiopathic epilepsy, and myoclonus is a major feature of some progressive neurological illnesses with extensive degeneration of brain cells.
A brief, twitching muscular contraction which may involve only a single muscle or many muscles. It may be too slight to cause movement of the affected limb, or so violent as to throw the victim to the floor. The cause is not known, but in some cases may be a form of epilepsy. A single myoclonic jerk in the upper limbs occasionally occurs in minor motor epilepsy (petit mal). Myoclonic jerks, which many people experience on falling asleep, are a normal phenomenon.
Sudden and uncontrolled motions of the arms and legs, known as jerking, can occur naturally while sleeping.
Sudden and involuntary twitching or spasms of one or multiple muscles, either while at rest or during movement, characterize myoclonus. This phenomenon could be linked to muscular or nervous system disorders, yet it can also manifest in individuals without health issues. For instance, limbs might experience twitches before falling asleep.
A rapid tightening of the muscles.