Myoclonus: an update.

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.

Deep Brain Stimulation for an Unusual Presentation of Myoclonus Dystonia Associated with Russell-Silver Syndrome.

Background: Myoclonus dystonia syndrome typically results from autosomal dominant mutations in the epsilon-sarcoglycan gene (SGCE) via the paternally expressed allele on chromosome 7q21. There is evidence that deep brain stimulation (DBS) is beneficial for this genotype, however, there are few prior case reports on DBS for myoclonus dystonia syndrome secondary to other confirmed genetic etiologies. Case Report: A 20-year-old female with concomitant Russell-Silver syndrome and myoclonus dystonia syndrome secondary to maternal uniparental disomy of chromosome 7 (mUPD7) presented for medically refractory symptoms. She underwent DBS surgery targeting the bilateral globus pallidus interna with positive effects that persisted 16 months post-procedure. Discussion: We present a patient with the mUPD7 genotype for myoclonus dystonia syndrome who exhibited a similar, if not superior, response to DBS when compared to patients with other genotypes. Highlights: This report outlines the first described case of successful deep brain stimulation treatment for a rare genetic variant of myoclonus dystonia syndrome caused by uniparental disomy at chromosome 7. These findings may expand treatment options for patients with similar conditions.

[Diagnosis and treatment strategies of 56 cases of middle ear myoclonus].

Objective: To analyze the clinical characteristics and treatment of middle ear myoclonus. Methods: Fifty-six cases of middle ear myoclonus were enrolled in Shandong Provincial ENT Hospital, Shandong University from September 2019 to August 2021, including 23 males and 33 females. The age ranged from 6 to 75 years, with a median age of 35 years; Forty-seven cases were unilateral tinnitus, nine cases were bilateral tinnitus. The time of tinnitus ranged from 20 days to 8 years. The voice characteristics, inducing factors, nature (frequency) of tinnitus, tympanic membrane conditions during tinnitus, audiological related tests, including long-term acoustic tympanogram, stapedius acoustic reflex, pure tone auditory threshold, short increment sensitivity test, alternate binaural loudness balance test, loudness discomfort threshold, vestibular function examination, facial electromyography, and imaging examination were recorded. Oral carbamazepine and/or surgical treatment were used. The patients were followed up for 6-24 months and the tinnitus changes were observed. Results: Tinnitus was diverse, including stepping on snow liking sound, rhythmic drumming, white noise, and so on. The inducing factors included external sound, body position change, touching the skin around the face and ears, speaking, chewing and blinking, etc. Forty-four cases were induced by single factor and 9 cases were induced by two or more factors. There was no definite inducing factor in 1 case. One patient had tinnitus with epilepsy. One case of traumatic facial paralysis after facial nerve decompression could induce tinnitus on the affected side when the auricle moved. Tympanic membrane flutter with the same frequency as tinnitus was found in 12 cases by otoscopy, and the waveform with the same frequency as tinnitus was found by long-term tympanogram examination. There were 7 patients with no tympanic membrane activity by otoscopy, the 7 cases also with the same frequency of tinnitus by long-term tympanogram examination, but the change rate of the waveform was faster than that of the patients with tympanic membrane flutter. All patients with tinnitus had no change in hearing. One case of tinnitus complicated with epilepsy (a 6-year-old child) was treated with antiepileptic drug (topiramate) and tinnitus subsided. One case suffered from tinnitus after facial nerve decompression for traumatic facial paralysis was not given special treatment. Fifty-four cases were treated with oral drug (carbamazepine), of which 10 cases were completely controlled and 23 cases were relieved; 21 cases were invalid. Among the 21 patients with no effect of carbamazepine treatment, 8 patients were treated by surgery, 7 patients had no tinnitus after surgery, 1 patient received three times of operation, and the third operation was followed up for 6 months, no tinnitus occurred again. The other 13 cases refused the surgical treatment due to personal reasons. Conclusions: Middle ear myoclonus tinnitus and the inducing factors manifestate diversity. Oral carbamazepine and other sedative drugs are effective for some patients, and surgical treatment is feasible for those who are ineffective for medication.

Neuropsychiatric syndrome with myoclonus after SARS-CoV-2 infection in a paediatric patient.

We report the case of a 12-years-old patient who subacutely developed a positive and negative myoclonus of limbs and face, drowsiness and memory deficits after getting infected by SARS-CoV-2. On admission, nasopharyngeal swab for SARS-CoV-2, brain and spinal MRI with and without contrast, EEG, chest X-ray and abdominal ultrasound were negative. CSF physical-chemical examination, culture, PCR testing for SARS-CoV-2 and other pathogens, and oligoclonal IgG bands were negative as well. A full panel blood test, including clotting, autoimmunity and paraneoplastic blood studies, did not show any alteration. The neuropsychological examination showed an impairment in memory, visual-motor coordination, inductive reasoning skills, attention, and concentration. The patient was first treated with clonazepam and then with intravenous methylprednisolone for five days, with poor response. For this reason, he then received a cycle of IVIG, thus reaching a gradual and complete recovery. To date, this is the first case of a COVID-19 associated myoclonus affecting a paediatric patient.

Mioclonía palatina esencial. Reporte de un caso pediátrico / Essential palatal myoclonus. A pediatric case report

La mioclonía palatina esencial es una entidad otoneurológi-ca rara. Se caracteriza por movimientos involuntarios de los músculos del paladar blando que causan un tinnitus objetivo.La mioclonía del paladar se clasifica en dos tipos: secundaria y primaria (mioclonía palatina esencial); esta última es más frecuente en pediatría. La tomografía computada y la reso-nancia magnética de cerebro normal orientan al diagnóstico. La mioclonía palatina esencial, generalmente, se resuelve en forma espontánea.Se presenta a una paciente de 8 años de edad con un "clic" rápido en forma rítmica en su boca que cedía en forma espontánea

Essential palatal myoclonus is a rare neurological disorder characterized by involuntary movements of the soft palate musculature causing objective-clicking tinnitus. The palatal myoclonus is classified in two forms, secondary and essential palatal myoclonus. Primary (essential) palatal myoclonus is the most common type in childhood. Normal computed tomography and magnetic resonance guide the diagnosis. Spontaneous resolution usually occurs in the essential type of palatal myoclonus.In this report, we present an 8-year-old child making rhythmic, rapid clicking noises from her throat with spontaneous resolution.

A Case of Paraneoplastic Myoclonus Attributed to Non-Small Cell Lung Cancer.

Background: It is well known that myoclonus can be a paraneoplastic manifestation of underlying malignancy. Case Report: A 78-year-old male diagnosed with papillary variant non-small cell lung cancer (NSCLC) presented with tremulousness that rapidly evolved into severe, diffuse myoclonus with prominent palatal involvement requiring intubation. The generalized myoclonus resolved with on levetiracetam, chemotherapy and immune modulation. While low titer positive P/Q type calcium channel autoantibodies were detected, it's etiologic relevance is unclear. Discussion: This case highlights a rare neurologic paraneoplastic presentation of papillary NSCLC. It also illustrates the importance of monitoring airway safety when myoclonus is generalized. Highlights: A new, rare paraneoplastic presentation of papillary variant non-small cell lung adenocarcinoma is described. The patient presented with severe diffuse myoclonus with prominent palatal involvement without encephalitis that responded to a combination of chemotherapy, immune modulation, and levetiracetam. No clear causal antibody was found.

Recognizing Movement Disorder Emergencies - A Practical Review For Non-Neurologist.

Neurology still remains one of the most underserved specialties of medicine in Pakistan with roughly one neurologist per million people. Movement disorders (MD) are neurological problems that interfere with patient's motor abilities and diagnosis is typically clinical. In this review, we describe a practical approach to common MD emergencies that may be encountered by a non-neurologist physician, emphasizing on formulating a working diagnosis and their immediate management. Movement disorder emergencies can be classified based on MD phenomenology and we will provide a brief overview of dystonia including acute dystonic reaction, PAID syndrome and dystonic storm; chorea, myoclonus including serotonin syndrome and startle disease; and rigidity including neuroleptic malignant syndrome and malignant hyperthermia.

Redefining progressive encephalomyelitis with rigidity and myoclonus after the discovery of antibodies to glycine receptors.

PURPOSE OF REVIEW: This review highlights the recent discovery of antibodies to glycine receptor (GlyR-Ab) and discusses the relationship between these antibodies and neurological disorders. RECENT FINDINGS: Since the initial description in 2008 of antibodies to glycine receptors (GlyR-Abs) in a patient with progressive encephalomyelitis with rigidity and myoclonus (PERM), these antibodies have been found in PERM and in some patients with a variety of stiff person spectrum (SPS) or related disorders. Patients with GlyR-Abs often improve with aggressive immunotherapy, and antibody titres correlate with disease severity. Around 25% of patients have another autoimmune condition and 10-20% have an underlying malignancy. GlyR-Abs bind to extracellular determinants, are mainly Immunoglobulin G1 subclass and induce GlyR internalization in Human embryonic kidney 293 cells, suggesting pathogenicity. The spectrum of neurological disease associated with GlyR-Abs has not been fully characterized, and lower titres may not be syndrome specific, but GlyR-Abs, like antibodies to other neuronal cell-surface antigens, define immunotherapy-responsive disease and are likely to be pathogenic. This distinguishes them from the glutamic acid decarboxylase antibodies that can also be found at high titres in patients with classical stiff person syndrome which is more often chronic and relatively resistant to immunological treatments. SUMMARY: Irrespective of the clinical features, GlyR-Abs are helpful in the diagnosis of patients who very often have a subacute, progressive and life-threatening disorder which shows a favourable response to immunotherapy.

"Jumping stump" phenomenon.

Myoclonic spasm of an amputated extremity can be problematic for amputees and requires recognition and understanding by surgeons encountering the phenomenon. In the present brief report, we describe the condition in a female amputee after below-the-knee amputation. Our aim is to increase awareness of this condition among foot and ankle surgeons.

Medically assisted hydration for adult palliative care patients.

BACKGROUND: Many palliative care patients have reduced oral intake during their illness. The management of this can include the provision of medically assisted hydration with the aim of prolonging the life of a patient, improving their quality of life, or both. This is an updated version of the original Cochrane review published in Issue 2, 2008, and updated in February 2011. OBJECTIVES: To determine the effect of medically assisted hydration in palliative care patients on their quality and length of life. SEARCH METHODS: We identified studies by searching the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL, CANCERLIT, Caresearch, Dissertation abstracts, SCIENCE CITATION INDEX and the reference lists of all eligible studies, key textbooks and previous systematic reviews. The date of the latest search conducted on CENTRAL, MEDLINE and EMBASE was March 2014. SELECTION CRITERIA: All relevant randomised controlled trials (RCTs) or prospective controlled studies of medically assisted hydration in palliative care patients. DATA COLLECTION AND ANALYSIS: We identified six relevant studies for this update. These included three RCTs (222 participants), and three prospective controlled trials (360 participants). Two review authors independently assessed the studies for quality and validity. The small number of studies and the heterogeneity of the data meant that a quantitative analysis was not possible, so we included a description of the main findings. MAIN RESULTS: One study found that sedation and myoclonus (involuntary contractions of muscles) scores were improved more in the intervention group. Another study found that dehydration was significantly higher in the non-hydration group, but that some fluid retention symptoms (pleural effusion, peripheral oedema and ascites) were significantly higher in the hydration group. The other four studies (including the three RCTs) did not show significant differences in outcomes between the two groups. The only study that had survival as an outcome found no difference in survival between the hydration and control arms. AUTHORS' CONCLUSIONS: Since the last version of this review, we found one new study. The studies published do not show a significant benefit in the use of medically assisted hydration in palliative care patients; however, there are insufficient good-quality studies to inform definitive recommendations for practice with regard to the use of medically assisted hydration in palliative care patients.

Progressive encephalomyelitis with rigidity and myoclonus: a syndrome with diverse clinical features and antibody responses.

BACKGROUND/AIMS: To better characterize progressive encephalomyelitis with rigidity and myoclonus (PERM) syndrome and identify novel PERM phenotypes. METHODS: The clinical features and antibody status of PERM patients were investigated using immunoblots, cell-based assays, RIA, protein macroarray and ELISA. RESULTS: Two patients with supratentorial involvement showed abnormal PET or EEG findings. One patient was discovered to have renal cell carcinoma, and protein macroarray revealed Ma3-antibodies. Another patient with leucine-rich, glioma-inactivated 1 (LGI1) and glutamic acid decarboxylase (GAD) antibodies showed a good response to immunotherapy. CONCLUSION: The heterogeneity of the immunological features suggests that PERM is caused by diverse pathogenic mechanisms. Seropositivity to well-characterized neuronal cell surface antigens might indicate a good treatment response.

Deep brain stimulation for dystonia.

The few controlled studies that have been carried out have shown that bilateral internal globus pallidum stimulation is a safe and long-term effective treatment for hyperkinetic disorders. However, most recent published data on deep brain stimulation (DBS) for dystonia, applied to different targets and patients, are still mainly from uncontrolled case reports (especially for secondary dystonia). This precludes clear determination of the efficacy of this procedure and the choice of the 'good' target for the 'good' patient. We performed a literature analysis on DBS for dystonia according to the expected outcome. We separated those with good evidence of favourable outcome from those with less predictable outcome. In the former group, we review the main results for primary dystonia (generalised/focal) and highlight recent data on myoclonus-dystonia and tardive dystonia (as they share, with primary dystonia, a marked beneficial effect from pallidal stimulation with good risk/benefit ratio). In the latter group, poor or variable results have been obtained for secondary dystonia (with a focus on heredodegenerative and metabolic disorders). From this overview, the main results and limits for each subgroup of patients that may help in the selection of dystonic patients who will benefit from DBS are discussed.

Systematic review of management strategies for middle ear myoclonus.

OBJECTIVE: Middle ear myoclonus is a rare condition with distinct characteristics at presentation. Diagnosis is based primarily on history, clinical examination, and long-time-based tympanometry. No consensus exists regarding treatment at present. This review was designed to identify relevant studies on current investigation and management. DATA SOURCE: A systematic electronic literature search of MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Cochrane Trials register, and Web of Science was conducted for articles describing middle ear myoclonus through to May 2011. English- and non-English-language articles that focused on investigation and treatment were considered for review. REVIEW METHOD: Two authors independently reviewed the articles for study design, treatment, intervention, and outcome. Data from human and experimental studies were considered. RESULTS: A total of 21 articles were identified for this review. Most studies were found to be case reports or small case series. In general, there was no evidence of a conclusive diagnostic test or treatment for middle ear myoclonus. CONCLUSION: There is a need for high-quality prospective controlled trials to determine the most effective management of middle ear myoclonus. The authors describe a treatment algorithm based on the data available and clinical knowledge.

CENTRAL NERVOUS SYSTEM LIGNOCAINE TOXICITY IN AN INFANT FOLLOWING VENTRICULO-PERITONEAL SHUNT AND SPINA BIFIDA REPAIR: A CASE REPORT.

A 3.7 kg one-month-old male infant with Spina Bifida Cystica with Hydrocephalus had Ventriculo-Peritoneal (VP) Shunting and repair of the Spina Bifida Cystica done. Lignocaine with Adrenaline 1:100,000 was infiltrated intra-operatively to reduce blood loss. Overenthusiastic infiltration, an oversight, led to Lignocaine toxicity. In Pediatrics, prior calculation of maximum dosage, based on child's weight, and use of dilute solutions for multiple sites could have prevented this.

Myoclonus.

Myoclonus can be classified as physiologic, essential, epileptic, and symptomatic. Animal models of myoclonus include DDT and posthypoxic myoclonus in the rat. 5-Hydrotryptophan, clonazepam, and valproic acid suppress myoclonus induced by posthypoxia. The diagnostic evaluation of myoclonus is complex and involves an extensive work-up including basic electrolytes, glucose, renal and hepatic function tests, paraneoplastic antibodies, drug and toxicology screens, thyroid antibody and function studies, neurophysiology testing, imaging, and tests for malabsorption disorders, assays for enzyme deficiencies, tissue biopsy, copper studies, alpha-fetoprotein, cytogenetic analysis, radiosensitivity DNA synthesis, genetic testing for inherited disorders, and mitochondrial function studies. Treatment of myoclonus is targeted to the underlying disorder. If myoclonus physiology cannot be demonstrated, treatment should be aimed at the common pattern of symptoms. If the diagnosis is not known, treatment could be directed empirically at cortical myoclonus as the most common physiology. In cortical myoclonus, the most effective drugs are sodium valproic acid, clonazepam, levetiracetam, and piracetam. For cortical-subcortical myoclonus, valproic acid is the drug of choice. Here, lamotrigine can be used either alone or in combination with valproic acid. Ethosuximide, levetiracetam, or zonisamide can also be used as adjunct therapy with valproic acid. A ketogenic diet can be considered if everything else fails. Subcortical-nonsegmental myoclonus may respond to clonazepam and deep-brain stimulation. Rituximab, adrenocorticotropic hormone, high-dose dexamethasone pulse, or plasmapheresis have been reported to improve opsoclonus myoclonus syndrome. Reticular reflex myoclonus can be treated with clonazepam, diazepam and 5-hydrotryptophan. For palatal myoclonus, a variety of drugs have been used.

Clinical and neurophysiological improvement of SGCE myoclonus-dystonia with GPi deep brain stimulation.

Myoclonus-dystonia (M-D) is characterized by early onset myoclonus and dystonia. It is thought to be subcortical in origin. Response to oral medications may be incomplete, such that deep brain stimulation (DBS) surgery to the globus pallidum interna (GPi) or ventral intermediate thalamic nucleus (VIM) may be considered. The optimal site is not known. The physiology and surgical response for a 63-year-old woman who underwent GPi DBS for M-D with onset at age 2 and related to a mutation in the epsilon-sarcoglycan gene (SGCE) is described. She showed excellent clinical and neurophysiological improvement of both myoclonus and dystonia, suggesting that modulation by DBS is effective even after long disease duration and only partial response to oral medications.

Both thalamic and pallidal deep brain stimulation for myoclonic dystonia.

Myoclonic dystonia is poorly managed with medication and may be severe enough to warrant surgical intervention. Surgery has targeted either the globus pallidus pars interna (GPi) or the thalamus, but there is no accepted target for this condition. The authors present the case of a 23-year-old man treated with unilateral deep brain stimulation in both the thalamus and GPi. His movement disorder improved dramatically with stimulation. Two years postoperatively, the authors performed a double-blind assessment of the effects of each stimulator together, separately, and off stimulation. Videotape assessment, using tremor, dystonia, and myoclonus rating scales, showed that most of the benefit could be attributed to pallidal stimulation, although there was some advantage to stimulation at both sites. These results suggest that while GPi stimulation may be the better target for this condition, thalamic stimulation may be added in cases in which the benefit is insufficient.

[Sleep disorders in the newborn]. / Enfermedades del sueño en el recién nacido.

Sleep disorders are classified in dyssomnias, parasomnias, sleep disorder associated with medical and psychiatric disorders and proposed sleep disorders. Only the parasomnias have been studied as such in the newborn period. The parasomnias that occur in this age group are infant sleep apnea, congenital central hypoventilation syndrome, sudden infant death syndrome, and benign neonatal sleep myoclonus. Infant sleep apnea includes three entities: (1) apnea of prematurity, (2), apparent life threatening episodes with apnea and (3) obstructive sleep apnea. Congenital central hypoventilation syndrome can be associated with other autonomic system illness, such as Hirschsprung disease (Haddad syndrome) and neuroblastoma. The implementation of the supine sleep position and smoking free homes has diminished the frequency of sudden infant death syndrome. Benign neonatal sleep myoclonus should be considered in all newborns with a normal exam between the episodes when they always occur during sleep. This entity may be mistaken for status epilepticus, because it is associated with increases in heart rate. Benzodiazepines prolongs the duration of the episodes.

Palliative sedation in dying patients: "we turn to it when everything else hasn't worked".

Despite skilled palliative care, some dying patients experience distressing symptoms that cannot be adequately relieved. A patient with metastatic breast cancer, receiving high doses of opioids administered to relieve pain, developed myoclonus. After other approaches proved ineffective, palliative sedation was an option of last resort. The doctrine of double effect, the traditional justification for palliative sedation, permits physicians to provide high doses of opioids and sedatives to relieve suffering, provided that the intention is not to cause the patient's death and that certain other conditions are met. Such high doses are permissible even if the risk of hastening death is foreseen. Because intention plays a key role in this doctrine, clinicians must understand and document which actions are consistent with an intention to relieve symptoms rather than to hasten death. The patient or family should agree with plans for palliative sedation. The attending physician needs to explain to them, as well as to the medical and nursing staff, the details of care and the justification for palliative sedation. Because cases involving palliative sedation are emotionally stressful, the patient, family, and health care workers can all benefit from talking about the complex medical, ethical, and emotional issues they raise.