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Continuum (Minneapolis, Minn.) Aug 2019This article offers clinicians a strategic approach for making sense of a symptom complex that contains myoclonus. The article presents an evaluation strategy that... (Review)
Review
PURPOSE OF REVIEW
This article offers clinicians a strategic approach for making sense of a symptom complex that contains myoclonus. The article presents an evaluation strategy that highly leverages the two major classification schemes of myoclonus. The goal of this article is to link evaluation strategy with diagnosis and treatment of myoclonus.
RECENT FINDINGS
The growth of medical literature has helped better define myoclonus etiologies. Physiologic study of myoclonus types and etiologies with electrophysiologic testing has provided greater clarity to the pathophysiology of the myoclonus in various diseases. Although studies have been limited, the role of newer treatment agents and methods has made progress.
SUMMARY
Myoclonus has hundreds of different etiologies. Classification is necessary to evaluate myoclonus efficiently and pragmatically. The classification of myoclonus etiology, which is grouped by different clinical presentations, helps determine the etiology and treatment of the myoclonus. The classification of myoclonus physiology using electrophysiologic test results helps determine the pathophysiology of the myoclonus and can be used to strategize symptomatic treatment approaches. Both basic ancillary testing (including EEG and imaging) and more comprehensive testing may be necessary. Treatment of the underlying etiology is the ideal approach. However, if such treatment is not possible or is delayed, symptomatic treatment guided by the myoclonus physiology should be considered. More controlled study of myoclonus treatment is needed. Further research on myoclonus generation mechanisms should shed light on future treatment possibilities.
Topics: Adult; Aged; Anticonvulsants; Carbamazepine; Electroencephalography; Female; Humans; Male; Middle Aged; Myoclonus; Young Adult
PubMed: 31356293
DOI: 10.1212/CON.0000000000000750 -
Neurology(R) Neuroimmunology &... May 2022Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare disorder of the nervous system that classically presents with a combination of characteristic eye movement disorder... (Review)
Review
BACKGROUND AND OBJECTIVES
Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare disorder of the nervous system that classically presents with a combination of characteristic eye movement disorder and myoclonus, in addition to ataxia, irritability, and sleep disturbance. There is good evidence that OMAS is an immune-mediated condition that may be paraneoplastic in the context of neuroblastoma. This syndrome may be associated with long-term cognitive impairment, yet it remains unclear how this is influenced by disease course and treatment. Treatment is largely predicated on immune suppression, but there is limited evidence to indicate an optimal regimen.
METHODS
Following an international multiprofessional workshop in 2004, a body of clinicians and scientists comprising the International OMS Study group continued to meet biennially in a joint professionals and family workshop focusing on pediatric OMAS. Seventeen years after publication of the first report, a writing group was convened to provide a clinical update on the definitions and clinical presentation of OMAS, biomarkers and the role of investigations in a child presenting with OMAS, treatment and management strategies including identification and support of long-term sequelae.
RESULTS
The clinical criteria for diagnosis were reviewed, with a proposed approach to laboratory and radiologic investigation of a child presenting with possible OMAS. The evidence for an upfront vs escalating treatment regimen was reviewed, and a treatment algorithm proposed to recognize both these approaches. Importantly, recommendations on monitoring of immunotherapy response and longer-term follow-up based on an expert consensus are provided.
DISCUSSION
OMAS is a rare neurologic condition that can be associated with poor cognitive outcomes. This report proposes an approach to investigation and treatment of children presenting with OMAS, based on expert international opinion recognizing the limited data available.
Topics: Ataxia; Child; Disease Progression; Humans; Internationality; Neuroblastoma; Ocular Motility Disorders; Opsoclonus-Myoclonus Syndrome
PubMed: 35260471
DOI: 10.1212/NXI.0000000000001153 -
Journal of Neurology Feb 2022Opsoclonus-myoclonus-ataxia syndrome is a rare neuroimmunologic disorder typically presenting in previously healthy infants and toddlers. It is characterized by a... (Review)
Review
Opsoclonus-myoclonus-ataxia syndrome is a rare neuroimmunologic disorder typically presenting in previously healthy infants and toddlers. It is characterized by a clinical triad of (1) erratic saccadic intrusions; (2) myoclonus and/or ataxia; (3) behavioral features, typified by developmental plateauing, irritability and insomnia. About half of cases are associated with an underlying neuroblastoma and diagnostic imaging is essential once OMAS is suspected. A thorough workup, including serum, urine, and cerebrospinal fluid studies is critical to identify underlying biomarkers of OMAS itself or neuroblastoma. Historically, many children had relatively poor long-term outcomes, with residual neurologic and/or neuropsychiatry sequelae typical. More recent concepts have emphasized combined immunotherapy regimens that offer hope for better outcomes in children with this remarkable, challenging disease.
Topics: Ataxia; Disease Progression; Humans; Infant; Neuroblastoma; Ocular Motility Disorders; Opsoclonus-Myoclonus Syndrome
PubMed: 33779841
DOI: 10.1007/s00415-021-10536-3 -
Pediatric Neurology Aug 2021The purpose of this review is to provide a comprehensive update and highlight the distinct electroclinical features and discuss recent advances in the etiology,... (Review)
Review
The purpose of this review is to provide a comprehensive update and highlight the distinct electroclinical features and discuss recent advances in the etiology, pathophysiology, and management strategies of epilepsy with eyelid myoclonia. Recent studies indicate that variations of certain genes including CHD2 (chromodomain helicase DNA-binding protein 2), KCNB1, KIAA2022, and NAA10 may occur in these patients. It has been postulated that the occipital cortex may play a role in the pathophysiology. Recent studies of functional imaging and connectivity of neuronal electrical activity have provided additional evidence to support this hypothesis. The frontal cortex has additionally been implicated, and it has been suggested that the epileptic cortex may extend beyond the occipital cortex to involve the posterior temporal cortex. We update the management strategies and describe tools that may predict seizure persistence. Epilepsy with eyelid myoclonias, or Jeavons syndrome, is an idiopathic generalized epilepsy characterized by the triad of eyelid myoclonia with or without absence seizures, eyelid closure-elicited electroencephalographic (EEG) paroxysms (epileptiform discharges and/or seizures), and photosensitivity. This condition may account for up to 13% of generalized epilepsies. However, it is frequently under-reported and under-recognized. Many of the patients develop medically refractory epilepsy, and seizures tend to persist throughout life.
Topics: Child; Epilepsy, Generalized; Eyelid Diseases; Humans; Myoclonus
PubMed: 34167046
DOI: 10.1016/j.pediatrneurol.2020.11.018 -
Tremor and Other Hyperkinetic Movements... 2023Peripherally-induced movement disorders (PIMD) should be considered when involuntary or abnormal movements emerge shortly after an injury to a body part. A close... (Review)
Review
BACKGROUND
Peripherally-induced movement disorders (PIMD) should be considered when involuntary or abnormal movements emerge shortly after an injury to a body part. A close topographic and temporal association between peripheral injury and onset of the movement disorders is crucial to diagnosing PIMD. PIMD is under-recognized and often misdiagnosed as functional movement disorder, although both may co-exist. Given the considerable diagnostic, therapeutic, and psychosocial-legal challenges associated with PIMD, it is crucial to update the clinical and scientific information about this important movement disorder.
METHODS
A comprehensive PubMed search through a broad range of keywords and combinations was performed in February 2023 to identify relevant articles for this narrative review.
RESULTS
The spectrum of the phenomenology of PIMD is broad and it encompasses both hyperkinetic and hypokinetic movements. Hemifacial spasm is probably the most common PIMD. Others include dystonia, tremor, parkinsonism, myoclonus, painful leg moving toe syndrome, tics, polyminimyoclonus, and amputation stump dyskinesia. We also highlight conditions such as neuropathic tremor, pseudoathetosis, and -associated myogenic tremor as examples of PIMD.
DISCUSSION
There is considerable heterogeneity among PIMD in terms of severity and nature of injury, natural course, association with pain, and response to treatment. As some patients may have co-existing functional movement disorder, neurologists should be able to differentiate the two disorders. While the exact pathophysiology remains elusive, aberrant central sensitization after peripheral stimuli and maladaptive plasticity in the sensorimotor cortex, on a background of genetic (two-hit hypothesis) or other predisposition, seem to play a role in the pathogenesis of PIMD.
Topics: Humans; Tremor; Movement Disorders; Dystonic Disorders; Tic Disorders; Dyskinesias; Myoclonus
PubMed: 37008994
DOI: 10.5334/tohm.758 -
Sleep Medicine Clinics Jun 2021Propriospinal myoclonus (PSM) consists of paroxysmal and sudden jerks involving axial flexion trunk and hip muscles, conditioning sudden myoclonias of the trunk and... (Review)
Review
Propriospinal myoclonus (PSM) consists of paroxysmal and sudden jerks involving axial flexion trunk and hip muscles, conditioning sudden myoclonias of the trunk and arms/limbs, both spontaneous and triggered by sensory stimulations, emerging in relaxed wakefulness typically during the transition between wake and sleep. Generally, PSM originates from a thoracic myelomere and spreads caudally and rostrally, provoking flexion and/or extension movements, leading to jumps or trunk jerks. They appear triggered by the lying-down position and disappear when the subject stands up. The main consequences are the difficulties in sleep start and the reappearance during the period of wakefulness after sleep onset.
Topics: Humans; Myoclonus
PubMed: 33985660
DOI: 10.1016/j.jsmc.2021.02.009 -
Current Opinion in Neurology Aug 2024Myoclonus, a common hyperkinetic movement disorder, can be disabling for patients. It is important to identify and classify myoclonus correctly to ensure appropriate... (Review)
Review
PURPOSE OF REVIEW
Myoclonus, a common hyperkinetic movement disorder, can be disabling for patients. It is important to identify and classify myoclonus correctly to ensure appropriate workup and treatment. While the clinical history, examination, and process of classifying myoclonus remain largely unchanged, new causes and triggers for myoclonus are being elucidated, and new genetic causes have been found. Treatment can be challenging, though preliminary data about new options has been promising.
RECENT FINDINGS
In this article, we will briefly outline the process of classifying and treating myoclonus. We will then discuss three specific scenarios where myoclonus has been identified: myoclonus associated with SARS-CoV-2 infections, spinal myoclonus following surgery or anesthesia of the spine, and auricular myoclonus. We will also discuss new genetic findings associated with myoclonus-dystonia, and promising results regarding the use of perampanel in treating myoclonus.
SUMMARY
The process of describing unique scenarios associated with myoclonus has helped us build our understanding of the causes, genetic background, expected prognosis, and effective treatment of specific types of myoclonus. We hope that further studies on this topic will help tailor treatment.
Topics: Humans; Myoclonus; COVID-19
PubMed: 38785158
DOI: 10.1097/WCO.0000000000001276 -
Parkinsonism & Related Disorders May 2022Speech-induced action myoclonus may occur as a component of a generalized myoclonus syndrome. However, it may also present in isolation, or with a paucity of other... (Review)
Review
BACKGROUND
Speech-induced action myoclonus may occur as a component of a generalized myoclonus syndrome. However, it may also present in isolation, or with a paucity of other findings, and be diagnostically challenging.
OBJECTIVES
To report a retrospective case series of restricted speech-induced action myoclonus.
METHODS
We reviewed cases of speech-induced action myoclonus evaluated at Mayo Clinic Rochester from 1989 to 2020. We eliminated cases where a more generalized myoclonic disorder was also present. Clinical, imaging, and electrophysiologic data were extracted.
RESULTS
Four cases were identified in which speech-induced action myoclonus of craniofacial muscles was the predominant clinical presentation. All described cranial muscle twitching induced by speaking, and two cases also reported speech interruptions. Diagnosis was confirmed by expert speech pathologists in all cases. Diagnostic aids included modulation with different speech tasks and speaking rates, and surface electrophysiology which confirmed craniofacial myoclonus induced by speaking tasks (three cases). Previous misdiagnosis included functional, dystonic, neuromuscular junction pathology, or hemifacial spasm. Two cases had isolated speech-induced myoclonus, and the other two had coexistent upper limb tremor. Potential etiologic factors were identified in three cases - medication (2), epilepsy (1) - while in one patient no cause was identified. One patient partially improved with anti-myoclonic medication and speech therapy.
CONCLUSIONS
Speech-induced action myoclonus may occur in isolation and is frequently misdiagnosed. Diagnostic aids include modulation with different speech tasks and speaking rates, and surface electrophysiology.
Topics: Humans; Myoclonus; Retrospective Studies; Speech
PubMed: 35468498
DOI: 10.1016/j.parkreldis.2022.04.002 -
Neurotherapeutics : the Journal of the... Oct 2020Myoclonus can cause significant disability for patients. Myoclonus has a strikingly diverse array of underlying etiologies, clinical presentations, and... (Review)
Review
Myoclonus can cause significant disability for patients. Myoclonus has a strikingly diverse array of underlying etiologies, clinical presentations, and pathophysiological mechanisms. Treatment of myoclonus is vital to improving the quality of life of patients with these disorders. The optimal treatment strategy for myoclonus is best determined based upon careful evaluation and consideration of the underlying etiology and neurophysiological classification. Electrophysiological testing including EEG (electroencephalogram) and EMG (electromyogram) data is helpful in determining the neurophysiological classification of myoclonus. The neurophysiological subtypes of myoclonus include cortical, cortical-subcortical, subcortical-nonsegmental, segmental, and peripheral. Levetiracetam, valproic acid, and clonazepam are often used to treat cortical myoclonus. In cortical-subcortical myoclonus, treatment of myoclonic seizures is prioritized, valproic acid being the mainstay of therapy. Subcortical-nonsegmental myoclonus may be treated with clonazepam, though numerous agents have been used depending on the etiology. Segmental and peripheral myoclonus are often resistant to treatment, but anticonvulsants and botulinum toxin injections may be of utility depending upon the case. Pharmacological treatments are often hampered by scarce evidence-based knowledge, adverse effects, and variable efficacy of medications.
Topics: Anticonvulsants; Deep Brain Stimulation; Electroencephalography; Electromyography; Electrophysiological Phenomena; Humans; Myoclonus; Transcranial Magnetic Stimulation; Treatment Outcome
PubMed: 32910414
DOI: 10.1007/s13311-020-00922-6 -
Ugeskrift For Laeger Feb 2023Creutzfeldt-Jakob disease is the most common prion disease in humans. Neuropsychiatric symptoms are common, and objective findings are myoclonus, pyramidal and...
Creutzfeldt-Jakob disease is the most common prion disease in humans. Neuropsychiatric symptoms are common, and objective findings are myoclonus, pyramidal and extrapyramidal including cerebellar dysfunction. This is a case report of a 77-year-old woman with gradual onset of repeated falls due to cerebellar dysfunction. She had severe visuospatial difficulties, and she was unaware of her problems. Her MRI showed increased diffusion restriction in the caudate and lentiform nuclei. Her cerebrospinal fluid real-time quaking-induced conversion test was positive, fulfilling criteria for probable sporadic Creutzfeldt-Jakob disease.
Topics: Humans; Female; Aged; Creutzfeldt-Jakob Syndrome; Accidental Falls; Magnetic Resonance Imaging; Myoclonus
PubMed: 36892320
DOI: No ID Found