Table of Contents
What is Propriospinal myoclonus?
Propriospinal myoclonus (PSM) is a rare movement disorder first described in 1991. It is characterized by painless, repetitive jerking of the trunk, neck, hips, and knees. The jerking may be spontaneous but may also occur in response to a stimulus.
What is Propriospinal myoclonus at sleep onset?
Propriospinal myoclonus (PSM) is characterized by jerks arising in axial muscles that spread to more caudal and rostral segments along propriospinal pathways. PSM at sleep onset is a subtype of PSM that occurs during the sleep-awake transition and causes severe sleep-onset insomnia.
How do you assess myoclonus?
Electromyography (EMG), which measures electrical activity of muscle, is the commonly used method to diagnose myoclonus as well as nerve and muscle dysfunction. Electroencephalography (EEG) uses electrodes attached to the scalp to record the electrical activity of the brain that may trigger the myoclonic jerk.
Can hyponatremia cause myoclonus?
Causes The etiologies of myoclonus are numerous. Near the end of life, metabolic abnormalities and medication-induced myoclonus predominate. Metabolic causes include liver failure, renal failure, hyponatremia, and hypoglycemia.
What are Propriospinal fibers?
Propriospinal tracts are collections of nerve fibers ascending, descending, crossed and uncrossed, that interconnect various levels of the spinal cord. They are located in the white columns of the spinal cord where the columns meet the spinal central gray.
What is myoclonus disease?
Overview. Myoclonus refers to a quick, involuntary muscle jerk. Hiccups are a form of myoclonus, as are the sudden jerks, or “sleep starts,” you may feel just before falling asleep. These forms of myoclonus occur in healthy people and rarely present a problem.
What do Propriospinal interneurons do?
Propriospinal interneurons (INs) communicate information over short and long distances within the spinal cord. They act to coordinate different parts of the body by linking motor circuits that control muscles across the forelimbs, trunk, and hindlimbs.
What drugs can cause myoclonus?
The most frequently reported classes of drugs causing myoclonus include opiates, antidepressants, antipsychotics, and antibiotics.
How do you treat psychogenic movement disorder?
Movements are persistently relieved by psychotherapy or psychological suggestion or with the administration of placebos. If the patient is observed to be symptom free when left alone, this may also be documented as psychogenic; however, this feature is usually indicative of malingering or factitious disorder.
What is propriospinal myoclonus (PSM)?
Objective: Propriospinal myoclonus (PSM) is a rare disorder with repetitive, usually flexor arrhythmic brief jerks of the trunk, hips, and knees in a fixed pattern. It has a presumed generation in the spinal cord and diagnosis depends on characteristic features at polymyography.
How should we assess recruitment variability in patients with propriospinal myoclonus (PSM)?
Based on our clinical experience and the reviewed literature, we recommend polymyography to assess recruitment variability combined with a Bereitschaftspotential recording in all cases. Propriospinal myoclonus (PSM) is a rare hyperkinetic movement disorder involving the axial muscles. 1 Brown et al.
What is spinal segmental myoclonus?
Spinal segmental myoclonus (SSM) consists in relatively long (up to 1000 ms) synchronous rhythmic jerks with a fairly constant frequency ranging from 20 to 180 per min, and confined to a group of muscles supplied by either one segment or several contiguous segments of the spinal cord [5].
Is there a thoracic propriospinal system in humans?
The propriospinal system has been described at C3–C4 spine level in the cat [53] and same data have been provided for the existence of a similar thoracic system in humans [54], [55], even if evidence is still lacking.