myoklonie

Myoclonus, or myoklonie, refers to sudden, brief, involuntary jerks of muscles or muscle groups. These movements can be positive (muscle contraction) or negative (temporary lapse in muscle activity, as in asterixis). They may be focal, multifocal, or generalized and can occur at rest, with movement, or during sleep.

Classification is based on origin, clinical presentation, and etiology. Origin can be cortical, subcortical, brainstem, spinal, segmental, or psychogenic. Clinically, myoclonus may be action-induced, stimulus-sensitive, reflex, sleep-related, or palatal. Etiologies include physiological (benign sleep-related jerks, hypnic jerks), epileptic or non-epileptic cortical myoclonus, progressive myoclonus epilepsies, and a range of symptomatic disorders due to metabolic or structural brain disease. Medications (for example, opioids, certain antidepressants, or withdrawal states) and genetic disorders are additional causes.

Evaluation involves a detailed history and neurologic examination, with electrophysiological testing (EMG and EEG) to characterize the jerk and its timing. Cortical myoclonus often shows a time-locked cortical discharge preceding the jerk. Imaging and laboratory studies are used to identify structural or metabolic causes.

Treatment targets the underlying disorder when possible. Symptomatic therapy commonly includes antiepileptic drugs such as valproate, levetiracetam, or clonazepam; other agents like piracetam or zonisamide may be used in some cases. Sleep-related or physiologic myoclonus may respond to specific sedatives or supportive measures. Prognosis varies widely, from benign, self-limited forms to progressive conditions that worsen over time. Research continues to refine classification and management.