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Background and Objectives: Lance-Adams syndrome (LAS), or chronic posthypoxic myoclonus, is a long-term disabling neurologic disorder occurring in survivors of anoxia. The cortical or subcortical origin of this myoclonus is unclear. We aimed to identify the neuroanatomical origin of myoclonus in LAS., Methods: We conducted a cross-sectional study and investigated patients diagnosed with LAS from the Department of Neurology of Pitié-Salpêtrière Hospital, using multimodal neurologic explorations: EEG with quantitative analyses, polygraphic EMG recording of myoclonus, coupled EEG-EMG analyses with jerk-locked back averaging, and 18 fluorodeoxyglucose PET/CT imaging., Results: All 18 patients had action multifocal or generalized myoclonus. Eleven patients also presented seizures, mainly generalized tonic-clonic seizures. For 8 patients, myoclonus decreased after seizures for a variable duration, from 1 day to 2 weeks. Epileptiform discharges were identified over the central median region (n = 14), with a maximal amplitude on the Cz (65 ± 20 µV, n = 12) and Fz (107 µV, n = 1) electrodes, and a significantly increased frequency during non-rapid eye movement sleep stages 1 (12 ± 8.5 events/minute, p = 0.004, n = 9) and 2 (11 ± 8.8 events/minute, p = 0.016, n = 7) compared with wake (5.5 ± 5.4 events/minute). The duration of the cortical and muscular events was significantly and positively correlated (ρ = 0.58, p < 0.001, n = 9). Action myoclonic jerks with a duration of <50 ms were confirmed in all patients, with a fast-descending corticospinal way organization with a mean biceps brachii-first interossei dorsalis delay of 9.8 ± 1 ms (n = 8). A central cortical transient preceding the muscular jerks was identified (n = 14), with a mean latency of -31.9 ± 2.9 ms for the tibialis anterior muscle (n = 7). A regional metabolism decrease was observed in the precentral cortex, supplementary motor area, paracentral lobule (n = 6), and postcentral cortex and precuneus (n = 5). This metabolism decrease was bilateral in the precentral cortex for 83% of the patients and in the postcentral cortex for 100%. Hypometabolism in the precentral, supplementary motor, and postcentral areas was confirmed with a voxelwise analysis ( p < 10 -3 , n = 6)., Discussion: Our findings, based on a large cohort of patients with LAS, strongly suggest a cortical myoclonus, originating within the motor cortex and related to epileptiform mechanisms. more...

This video abstract delves into the expanded definition of diabetic striatopathy, linked initially to hyperglycemia-induced choreoballism and striatal hyperintensity on magnetic resonance imaging, but now recognized to encompass a broader range of acute onset, non-choreoballistic movement disorders in diabetes mellitus, including tremors, hemifacial spasm, parkinsonism, different types of myoclonus, dystonia, restless leg syndrome, ataxia, and dyskinesias. We report the case of a 45-year-old female patient with type-2 diabetes mellitus who developed propriospinal myoclonus, characterized by painless, involuntary jerky movements of the bilateral lower limbs in a supine position after admission for suspected rhino-orbital mucormycosis. The abnormal movements resolved entirely following the control of her blood glucose levels, suggesting a direct correlation between hyperglycemia and the clinical picture. This case highlights the importance of considering a wide range of differential diagnoses for abnormal lower limb movements in diabetic patients, emphasizing the need for accurate identification of movement semiology, routine bedside capillary blood glucose checks, and prompt hyperglycemia management to resolve such movement disorders effectively., Competing Interests: The authors have no competing interests to declare., (Copyright: © 2023 The Author(s).) more...

Movement disorders have been identified as a rare early manifestation of the Moyamoya disease. Herein, we present a case of a 34-year-old man with a genetically confirmed Moyamoya disease who showed unilateral myoclonus as an initial manifestation. Neuroimaging studies showed prominent asymmetrically developed Moyamoya disease on the right hemisphere with near-complete loss of normal vessels while the left hemisphere was adjunctively fed with extension of posterior cerebral artery: uneven progression of vasculature. 99 m Tc-hexamethylpropylene amine oxime single-photon emission computed tomography demonstrated impaired vascular reserve. Electroencephalography showed occasional sharp waves on right temporal area. The phenomenon of this patient could be explained in the context of excitable cortex and hypoactive subcortical substrate that might imply putative contradictory neurobiology in Moyamoya disease., Competing Interests: Conflict of interest The authors have no conflicts of interest or financial support to report., (Copyright © 2023 Elsevier B.V. All rights reserved.) more...

Myoclonus in the context of COVID-19 is an increasingly recognized condition. The occurrence in an ICU context in hypoxic patients, with metabolic disorders, taking several types of medication, makes difficult to establish a precise cause. Also, the implication of SARS-CoV-2 by direct invasion of the CNS or by immune-mediated phenomena is not yet clear. Currently, a dozen of cases of myoclonus as a predominant clinical manifestation, immune-mediated by SARS-Cov-2 are published. In all these cases, myoclonus was preceded by respiratory or other suggestive symptoms (e.g., anosmia) for this infection making straightforward the causal link. We describe a case of an isolated generalized myoclonus without other clinical complaints nor chest CT scan abnormalities nor SARS-CoV-2 RNA detection on nasopharyngeal swabs and on the CSF, as a para-infectious phenomenon of COVID-19 infection with excellent response to steroids perfusion. This challenging diagnosis was made upon confirmation of seroconversion (serology was negative at admission, then positive for IgM at day 6, then for both IgM and IgG at day 10) underlying that repeating serology is a diagnostic key to capture a similar findings., (© 2021. Fondazione Società Italiana di Neurologia.) more...

Background: Myoclonus is an involuntary movement disorder characterized by semirhythmic jerking movements of muscle groups but is rarely seen in association with Chiari malformation type I (CM-1). CM-1 is a frequently encountered clinical entity in pediatric neurosurgery characterized by caudal displacement of the cerebellar tonsils with or without syringomyelia. We report a pediatric patient who presented with upper extremity myoclonus and was found to have CM-1 and a complex septated cervicothoracic syrinx eccentric to the left., Case Presentation: A 12-year-old female presented with 6 months of headaches and upper extremity paresthesias who subsequently developed a left upper extremity segmental myoclonus after a fall. MRI demonstrated a CM-1 and a large complex cervicothoracic syrinx with a midline and left paracentral cavities. Her myoclonus was nonepileptic and refractory to clonazepam, cyclobenzaprine, and gabapentin. She underwent an intradural Chiari decompression and duraplasty. Postoperatively, she had complete resolution of her segmental myoclonus., Discussion: This case demonstrates a durable resolution of posttraumatic upper extremity segmental myoclonus after surgical decompression of a CM-1 with syringomyelia. Thus, Chiari decompression should be considered in cases of myoclonus with CM-1 and syringomyelia., (© 2021 S. Karger AG, Basel.) more...

Aim: The aim of this paper is to describe the clinical features of COVID-19-related encephalopathy and their metabolic correlates using brain 2-desoxy-2-fluoro-D-glucose (FDG)-positron-emission tomography (PET)/computed tomography (CT) imaging., Background and Purpose: A variety of neurological manifestations have been reported in association with COVID-19. COVID-19-related encephalopathy has seldom been reported and studied., Methods: We report four cases of COVID-19-related encephalopathy. The diagnosis was made in patients with confirmed COVID-19 who presented with new-onset cognitive disturbances, central focal neurological signs, or seizures. All patients underwent cognitive screening, brain magnetic resonance imaging (MRI), lumbar puncture, and brain 2-desoxy-2-fluoro-D-glucose (FDG)-positron-emission tomography (PET)/computed tomography (CT) (FDG-PET/CT)., Results: The four patients were aged 60 years or older, and presented with various degrees of cognitive impairment, with predominant frontal lobe impairment. Two patients presented with cerebellar syndrome, one patient had myoclonus, one had psychiatric manifestations, and one had status epilepticus. The delay between first COVID-19 symptoms and onset of neurological symptoms was between 0 and 12 days. None of the patients had MRI features of encephalitis nor significant cerebrospinal fluid (CSF) abnormalities. SARS-CoV-2 RT-PCR in the CSF was negative for all patients. All patients presented with a consistent brain FDG-PET/CT pattern of abnormalities, namely frontal hypometabolism and cerebellar hypermetabolism. All patients improved after immunotherapy., Conclusions: Despite varied clinical presentations, all patients presented with a consistent FDG-PET pattern, which may reflect an immune mechanism., (© 2020 European Academy of Neurology.) more...

Tinnitus is one of the most represented otological symptom, affecting 15% of adults, worldwide. Literature describes subjective tinnitus when it's perceived by the patient only, and objective tinnitus when it's heard both, by patient and examiner. An objective tinnitus can be caused by a large variety of anomalies and diseases; one of them is Palatal Myoclonus, characterized by rhytmic movements of soft palatal muscles and, only occasionally, involving other near districts. Case presentation. We observed a rare case of essential palatal myoclonus in a 54 y.o. female, suffering from chronic objective bilateral tinnitus, since 35 years, who underwent a wide number of clinical evaluations over the years, without receiving any conclusive diagnosis. In this video, we illustrate all the districts involved in clonic movements: soft palate, larynx and nasal wings. At the same time, we report the spectrographic analysis of tinnitus, recorded in esternal ear canal, taken together with the muscle movements. Palatal Myoclonus has to be considered in the etiological diagnosis of each objective tinnitus and should always be investigated properly., (Copyright © 2020 Elsevier Inc. All rights reserved.) more...

Background and Purpose: Post-hypoxic movement disorders and chronic post-hypoxic myoclonus are rare complications after cardiac arrest in adults. Our study investigates the clinical spectrum, neuroimaging results, therapy and prognosis of these debilitating post-hypoxic sequelae., Methods: This retrospective study included 72 patients from the neurological intensive care unit at a university hospital, who were diagnosed with hypoxic-ischaemic encephalopathy after cardiac arrest between January 2007 and September 2018. Clinical records were screened for occurrence of post-hypoxic movement disorders and chronic post-hypoxic myoclonus. Affected patients were further analysed for applied neuroprognostic tests, administered therapy and treatment response, and the outcome of these movement disorders and neurological function., Results: Nineteen out of 72 screened patients exhibited post-hypoxic motor symptoms. Basal ganglia injury was the most likely neuroanatomical correlate of movement disorders as indicated by T1 hyperintensities and hypometabolism of this region in magnetic resonance imaging and positron emission tomography computed tomography. Levomepromazine and intrathecal baclofen showed first promising and mostly prompt responses to control these post-hypoxic movement disorders and even hyperkinetic storms. In contrast, chronic post-hypoxic myoclonus best responded to co-application of clonazepam, levetiracetam and primidone. Remission rates of post-hypoxic movement disorders and chronic post-hypoxic myoclonus were 58% and 50%, respectively. Affected patients seemed to present a rather good recovery of cognitive functions in contrast to the often more severe physical deficits., Conclusions: Post-hypoxic movement disorders associated with pronounced basal ganglia dysfunction might be efficiently controlled by levomepromazine or intrathecal baclofen. Their occurrence might be an indicator for a more unfavourable, but often not devastating, neurological outcome., (© 2020 The Authors. European Journal of Neurology published by John Wiley & Sons Ltd on behalf of European Academy of Neurology.) more...

Objective: To report 3 patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who developed generalized myoclonus., Methods: Patient data were obtained from medical records from the University Hospital "12 de Octubre," Madrid, Spain., Results: Three patients (2 men and 1 woman, aged 63-88 years) presented with mild hypersomnia and generalized myoclonus following the onset of the so-called inflammatory phase of coronavirus disease 2019 (COVID-19). All of them had presented previously with anosmia. Myoclonus was generalized with both positive and negative jerks, predominantly involving the facial, trapezius, sternocleidomastoid, and upper extremities muscles. These myoclonic jerks occurred spontaneously and were extremely sensitive to multisensory stimuli (auditive and tactile) or voluntary movements, with an exaggerated startle response. Other causes of myoclonus were ruled out, and none of the patients had undergone respiratory arrest or significant prolonged hypoxia. All of them improved, at least partially, with immunotherapy., Conclusions: Our 3 cases highlight the occurrence of myoclonus during the COVID-19 pandemic as a post- or para-infectious immune-mediated disorder. However, we cannot rule out that SARS-CoV-2 may spread transneuronally to first- and second-order structures connected with the olfactory bulb. Further investigation is required to clarify the full clinical spectrum of neurologic symptoms and optimal treatment., (© 2020 American Academy of Neurology.) more...

Idiopathic basal ganglia calcification (IBGC) or primary familial brain calcification is a rare genetic condition characterized by an autosomal dominant inheritance pattern and the presence of bilateral calcifications in the basal ganglia, thalami, cerebellum and cerebral subcortical white matter. The syndrome is genetically and phenotypically heterogeneous. Causal mutations have been identified in four genes: SLC20A2, PDGFRB, PDGFB and XPR1. A variety of progressive neurological and psychiatric symptoms have been described, including cognitive impairment, movement disorders, bipolar disorder, chronic headaches and migraine, and epilepsy. Here we describe a family with a novel SLC20A2 mutation mainly presenting with neurological symptoms including cortical myoclonus and epilepsy. While epilepsy, although rare, has been reported in patients with IBGC associated with SLC20A2 mutations, cortical myoclonus seems to be a new manifestation. more...

Objective: To examine the prognostic ability of the combination of EEG and MRI in identifying patients with good outcome in postanoxic myoclonus (PAM) after cardiac arrest (CA)., Methods: Adults with PAM who had an MRI within 20 days after CA were identified in 4 prospective CA registries. The primary outcome measure was coma recovery to command following by hospital discharge. Clinical examination included brainstem reflexes and motor activity. EEG was assessed for best background continuity, reactivity, presence of epileptiform activity, and burst suppression with identical bursts (BSIB). MRI was examined for presence of diffusion restriction or fluid-attenuated inversion recovery changes consistent with anoxic brain injury. A prediction model was developed using optimal combination of variables., Results: Among 78 patients, 11 (14.1%) recovered at discharge and 6 (7.7%) had good outcome (Cerebral Performance Category < 3) at 3 months. Patients who followed commands were more likely to have pupillary and corneal reflexes, flexion or better motor response, EEG continuity and reactivity, no BSIB, and no anoxic injury on MRI. The combined EEG/MRI variable of continuous background and no anoxic changes on MRI was associated with coma recovery at hospital discharge with sensitivity 91% (95% confidence interval [CI], 0.59-1.00), specificity 99% (95% CI, 0.92-1.00), positive predictive value 91% (95% CI, 0.59-1.00), and negative predictive value 99% (95% CI, 0.92-1.00)., Conclusions: EEG and MRI are complementary and identify both good and poor outcome in patients with PAM with high accuracy. An MRI should be considered in patients with myoclonus showing continuous or reactive EEGs., (© 2020 American Academy of Neurology.) more...

Background: The Lance-Adams syndrome (LAS) is a myoclonus syndrome caused by hypoxic-ischemic encephalopathy. LAS cases could be refractory to first-line medications, and the neuronal mechanism underlying LAS pathology remains unknown., Objectives: To describe a patient with LAS who underwent bilateral globus pallidus internus (GPi) stimulation and discuss the pathophysiology of LAS with intraoperative electrophysiological findings., Patients: A 79-year-old woman presented with a history of cardiopulmonary arrest due to internal carotid artery rupture following carotid endarterectomy after successful cardiopulmonary resuscitation. However, within 1 month, the patient developed sensory stimulation-induced myoclonus in her face and extremities. Because her myoclonic symptoms were refractory to pharmacotherapy, deep brain stimulation of the GPi was performed 1 year after the hypoxic attack., Results: Continuous bilateral GPi stimulation with optimal parameter settings remarkably improved the patient's myoclonic symptoms. At the 2-year follow-up, her Unified Myoclonus Rating Scale score decreased from 90 to 24. In addition, we observed burst firing and interburst pause patterns on intraoperative microelectrode recordings of the bilateral GPi and stimulated this area as the therapeutic target., Conclusion: Our results show that impairment in the basal ganglion circuitry might be involved in the pathogenesis of myoclonus in patients with LAS., (© 2020 S. Karger AG, Basel.) more...

Neuronal ceroid lipofuscinoses type 2 disease (CLN2) is a very rare, autosomal recessive neurodegerative disease caused by deficient activity of the enzyme tripeptidyl peptidase 1 (TPP1). The seizures in CLN2 are polymorphic and resistant to antiepileptic drugs. In particular, myoclonus (epileptic and non-epileptic) predominant as the disease progresses. Herein, we present a child of CLN2 disease, who had near-continuous myoclonus, and was subsequently attenuated by administration of Perampanel. This girl had initially presented with language delay and generalized tonic clonic seizure at 3 years of age. The diagnosis of CLN2 was made via genetic study, which showed compound heterozygous mutation on TPP1 gene (c.622 C > T and partial gene deletion including at least exons 1-3). Currently, at the age of 8 years, there was near-continuous myoclonus (epileptic and non-epileptic), which worsen during acute illness. Eventually, she was given Perampanel with starting dose of 1 mg/day and slowly titrated upto 6 mg/day in 4 weeks. There was significant attenuation of myoclonus (>50% seizure reduction). To our knowledge, this is the first case in the literature describing the efficacy of perampanel in treating myoclonus in CLN2 disease., (Copyright © 2019 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.) more...

Background: Subacute sclerosing panencephalitis (SSPE) is a disease of childhood and adolescence, but can affect adults. Rapidly progressive cognitive decline, seizures including myoclonic jerks, spasticity, ataxia, visual disturbances, and incontinence are typical manifestations., Case Report: A 62-year-old woman who presented with rapidly progressive dementia and myoclonus was diagnosed with SSPE. There was resolution of the movement disorder with clonazepam and valproic acid treatment and some amelioration of cognitive decline after 3 months of therapy with interferon alfa and isoprinosine., Discussion: With the recent rise in measles cases worldwide, any increased incidence of SSPE would require vigilance for early interventions., Competing Interests: Funding: None. Conflicts of interest: The authors report no conflicts of interest. Ethics Statement: The patient who appears in the video has provided written informed consent; authorization for the recording and publication of the video was provided., (© 2019 Reyes et al.) more...

Purpose: To summarize the clinical features and neuroimaging changes of epilepsy associated with TBC1D24 mutations., Methods: Genetic testing was conducted in all epilepsy patients without acquired risk factors for epilepsy. Epilepsy patients identified with TBC1D24 compound heterozygous mutations by next-generation sequencing (NGS) epilepsy panel or whole exome sequencing (WES) were enrolled. The enrolled patients were followed up to summarize the clinical features., Results: Nineteen patients were identified with TBC1D24 compound heterozygous mutations. Nine patients carried the same pathogenic variant c.241&#95;252del. The seizure onset age ranged from 1 day to 8 months of age (median age 75 days). The most prominent features were multifocal myoclonus and epilepsia partialis continua (EPC). Myoclonus could be triggered by fever or infection in 15 patients, and could be terminated by sleep or sedation drugs. Psychomotor developmental delay was presented in 11 patients. Six patients exhibited hearing loss. Brain MRIs were abnormal in eight patients. Twelve patients were diagnosed with epilepsy syndromes including one patient who was diagnosed with Dravet syndrome. Two patients died due to status epilepticus at 4 months and 19 months of age, respectively., Conclusion: TBC1D24 mutation related epilepsy was drug-resistant. Multifocal myoclonus, EPC, and fever-induced seizures were common clinical features. Most patients presented psychomotor developmental delay. The neuroimaging abnormality and hearing loss could exacerbate during follow-up., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.) more...

Background: Propriospinal myoclonus is an infrequent type of hyperkinetic movement that can be commonly idiopathic but also may occur after spinal cord lesions., Phenomenology Shown: We describe an 8-year-old female showing repetitive flexor and extensor arrhythmic brief jerks of the trunk, compatible with propriospinal myoclonus secondary to cervical myelopathy., Educational Value: Isolated propriospinal myoclonus may be the clinical sign that leads to the diagnosis of incipient myelopathy., Competing Interests: Funding: None. Conflicts of Interest: The authors report no conflict of interest. Ethics Statement: All patients that appear on video have provided written informed consent; authorization for the videotaping and for publication of the videotape was provided. more...

Myoclonus describes a movement disorder characterised by brief, abrupt and involuntary contractions of muscles or groups of muscles, usually associated with intracranial lesions, with limited evidence linking it to spinal pathologies. The pathophysiology of spinal myoclonus is extensive and multifactorial. Infection, intramedullary and extramedullary space-occupying lesions, trauma, vascular abnormalities, degenerative processes and cervical spondylosis have been implicated with the disease, the latter been associated with cervical stenosis with no reported cases linking it to an underlying cervical disc herniation. Although medical therapy with clonazepam, levetiracetam, valproate, tetrabenazine hydrochloride and spinal block injections has been equivocal, spinal myoclonus secondary to disc herniation requires surgical intervention. This report describes a case of segmental spinal myoclonus, secondary to a herniated cervical intervertebral disc. After corpectomy and a cage-augmented fusion technique, the myoclonic symptoms resolved. To our knowledge, this was the first report to describe the successful management of discogenic spinal myoclonus with spinal surgery., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2018. No commercial re-use. See rights and permissions. Published by BMJ.) more...

Objective: Lumbar transforaminal epidural steroid injection is commonly used for treating lumbar radicular pain. We report a case of segmental spinal myoclonus that developed during lumbar transforaminal epidural injection with local anesthetic and steroid., Case Report: A 58-year-old woman with failed back surgery syndrome presented with low back and right L3 and L4 radicular pain. As she had responded well previously to diagnostic selective nerve root injection with local anesthetic at the right L3 and L4 levels, lumbar transforaminal epidural steroid injection at the same levels was scheduled. During injection of ropivacaine and triamcinolone at the right L3-4 intervertebral foramen, she complained of back pain and immediately developed involuntary contraction of her right hip. The procedure was terminated. No new neurological deficit was detected when she was examined 15 minutes after the procedure. There were no abnormalities from blood tests and magnetic resonance imaging of the lower thoracic and lumbar spine. A neurologist subsequently made the clinical diagnosis of segmental spinal myoclonus. The myoclonus improved over 1 month and eventually resolved completely., Conclusions: Segmental spinal myoclonus is a rare complication after lumbar transforaminal epidural steroid and local anesthetic injection. Pain physicians should be aware of this potential complication. more...

Spinocerebellar ataxia 19/22 (SCA19/22) is a rare type of autosomal dominant SCA that was previously described in 11 families. We report the case of a 30-year-old Japanese man presenting with intellectual disability, early onset cerebellar ataxia, myoclonus, and dystonia without a family history. MRI showed cerebellar atrophy, and electroencephalograms showed paroxysmal sharp waves during hyperventilation and photic stimulation. Trio whole-exome sequencing analysis of DNA samples from the patient and his parents revealed a de novo novel missense mutation (c.1150G>A, p.G384S) in KCND3, the causative gene of SCA19/22, substituting for evolutionally conserved glycine. The mutation was predicted to be functionally deleterious by bioinformatic analysis. Although pure cerebellar ataxia is the most common clinical feature in SCA19/22 families, extracerebellar symptoms including intellectual disability and myoclonus are reported in a limited number of families, suggesting a genotype-phenotype correlation for particular mutations. Although autosomal recessive diseases are more common in patients with early onset sporadic cerebellar ataxia, the present study emphasizes that such a possibility of de novo mutation should be considered. more...

Objectives: Unverricht-Lundborg disease (ULD) is the most common form of progressive myoclonus epilepsy. Cerebellar dysfunction may appear over time, contributing along with myoclonus to motor disability. The purpose of the present work was to clarify the motor and neurophysiological characteristics of ULD patients., Methods: Nine patients with genetically proven ULD were evaluated clinically (medical history collected from patient charts, the Scale for the Assessment and Rating of Ataxia and Unified Myoclonus Rating Scale). Neurophysiological investigations included EEG, surface polymyography, long-loop C-reflexes, somatosensory evoked potentials, EEG jerk-locked back-averaging (JLBA) and oculomotor recordings. All patients underwent brain MRI. Non-parametric Mann-Whitney tests were used to compare ULD patients' oculomotor parameters with those of a matched group of healthy volunteers (HV)., Results: Myoclonus was activated by action but was virtually absent at rest and poorly induced by stimuli. Positive myoclonus was multifocal, often rhythmic and of brief duration, with top-down pyramidal temporospatial propagation. Cortical neurophysiology revealed a transient wave preceding myoclonus on EEG JLBA (n=8), enlarged somatosensory evoked potentials (n=7) and positive long-loop C-reflexes at rest (n=5). Compared with HV, ULD patients demonstrated decreased saccadic gain, increased gain dispersion and a higher frequency of hypermetric saccades associated with decreased peak velocity., Conclusion: A homogeneous motor pattern was delineated that may represent a ULD clinical and neurophysiological signature. Clinical and neurophysiological findings confirmed the pure cortical origin of the permanent myoclonus. Also, oculomotor findings shed new light on ULD pathophysiology by evidencing combined midbrain and cerebellar dysfunction., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.) more...

Supracondylar humerus fractures are associated with neurological complications. This report describes a child who suffered from persistent myoclonus-like movements of the elbow and wrist as a consequence of a previous displaced fracture. Symptoms were progressive. Seven years later, sensation was decreased in the ulnar nerve distribution. Palpation of the ulnar nerve exacerbated the myoclonic jerks. As symptoms progressed, electoneuromyography became abnormal. Cubital tunnel release and anterior transposition of the ulnar nerve were required to reach full recovery. Long-term outcome was excellent. In conclusion, myoclonus-like movements are a rare complication of supracondylar humerus fractures, resulting from ulnar nerve injury. more...

Introduction: Orthostatic myoclonus (OM) is a recognized syndrome of gait unsteadiness accompanied by lower limb myoclonus provoked by the assumption of an upright posture. OM typically affects the elderly and is often associated with neurodegenerative disease. We sought to review the clinical and electrophysiologic characteristics of OM due to brain tumor treatment, the first reported lesional cases of this rare disorder., Methods: The database of the Mayo Clinic Rochester Movement Disorders Laboratory was searched for all patients diagnosed with OM from January 2007 to December 2016. All available clinical, radiographic, and surface electromyographic data were reviewed, and patients with a history of primary or metastatic brain tumor were analyzed., Results: Two patients with OM and brain tumor were identified; both had undergone tumor resection and targeted brain radiation. Both patients complained of unsteadiness while walking and recurrent falls. Tumor pathology (atypical meningioma, gliosarcoma) was centered in the frontal lobe and extended to the supplementary motor area (SMA), pre-SMA, or prefrontal cortex. Medications did not improve gait., Conclusion: Two cases of brain tumor-related OM suggest that degeneration of frontal motor programming circuits underlies the pathophysiology of OM., (Copyright © 2017 Elsevier Ltd. All rights reserved.) more...

EPM1 (epilepsy, progressive myoclonic 1; Unverricht-Lundborg disease, OMIM #254800) is the most frequent form of progressive myoclonus epilepsy. Previous findings have suggested that its pathophysiology mainly involves the cerebellum, but the evaluation of cerebellar dysfunction is still unsatisfactory. The aim of this study was to assess the structural and functional involvement of the cerebellum in EPM1. We used voxel-based morphometry and spatially unbiased infra-tentorial template analyses of structural magnetic resonance imaging (MRI) scans, and functional MRI (fMRI) scans during block and event-related go/no-go motor tasks to study 13 EPM1 patients with mild to moderate myoclonus. We compared the results with those obtained in 12 age-matched healthy controls (HCs) and in 12 patients with hereditary spinocerebellar ataxia (SCA). Structural analyses revealed different patterns of atrophic changes in the EPM1 and SCA patients: in the former, they involved both cerebrum and cerebellum but, in the latter, only the cerebellum. During fMRI, block and event-related go/no-go tasks similarly activated the cerebellum and cerebrum in the EPM1 patients and HCs, whereas both tasks revealed much less cerebellar activation in the SCA patients than in the other two groups. Volumetric evaluation of the EPM1 patients showed that the cerebellum seemed to be marginally involved in a widespread atrophic process, and fMRI showed that it was not functionally impaired during motor tasks. more...

Objective: We describe a child with post-anoxic myoclonus of the reticular reflex type and discuss the classification of post-anoxic myoclonus., Patient Description: A nine-year-old boy with severe hypoxic-ischemic encephalopathy due to submersion developed early epileptic spasms followed by stimulus sensitive multifocal generalized myoclonus and later dystonia. Video electromyography (EMG) polygraphy performed before treatment demonstrated that the discharges associated with the myoclonus lasted less than 50 milliseconds. Cortical myoclonus was excluded by jerk-locked averaging using arm muscles, which showed no cortical correlates. The recruitment order on EMG polygraphy was consistent with a brainstem generator for the myoclonus, characteristic of reticular reflex myoclonus. Both myoclonus and dystonia responded to clonazepam. He remains in a persistent vegetative state., Conclusions: Reticular reflex myoclonus can be demonstrated by detailed neurophysiological assessment in children as in adults, and it has a similar poor prognosis in children. Post-anoxic myoclonus can have several mechanisms and should not be considered synonymous with Lance-Adams myoclonus., (Copyright © 2017 Elsevier Inc. All rights reserved.) more...

Objective: To analyze whether KCNQ2 R201C and R201H variants, which show atypical gain-of-function electrophysiologic properties in vitro, have a distinct clinical presentation and outcome., Methods: Ten children with heterozygous, de novo KCNQ2 R201C or R201H variants were identified worldwide, using an institutional review board (IRB)-approved KCNQ2 patient registry and database. We reviewed medical records and, where possible, interviewed parents and treating physicians using a structured, detailed phenotype inventory focusing on the neonatal presentation and subsequent course., Results: Nine patients had encephalopathy from birth and presented with prominent startle-like myoclonus, which could be triggered by sound or touch. In seven patients, electroencephalography (EEG) was performed in the neonatal period and showed a burst-suppression pattern. However, myoclonus did not have an EEG correlate. In many patients the paroxysmal movements were misdiagnosed as seizures. Seven patients developed epileptic spasms in infancy. In all patients, EEG showed a slow background and multifocal epileptiform discharges later in life. Other prominent features included respiratory dysfunction (perinatal respiratory failure and/or chronic hypoventilation), hypomyelination, reduced brain volume, and profound developmental delay. One patient had a later onset, and sequencing indicated that a low abundance (~20%) R201C variant had arisen by postzygotic mosaicism., Significance: Heterozygous KCNQ2 R201C and R201H gain-of-function variants present with profound neonatal encephalopathy in the absence of neonatal seizures. Neonates present with nonepileptic myoclonus that is often misdiagnosed and treated as seizures. Prognosis is poor. This clinical presentation is distinct from the phenotype associated with loss-of-function variants, supporting the value of in vitro functional screening. These findings suggest that gain-of-function and loss-of-function variants need different targeted therapeutic approaches., (Wiley Periodicals, Inc. © 2017 International League Against Epilepsy.) more...

We report a female patient with Dravet syndrome (DS) with erratic segmental myoclonus, the origin of which was first identified in the cerebral cortex by the detection of myoclonus-associated cortical discharges. The discharges were disclosed through jerk-locked back-averaging of electroencephalogram (EEG) data using the muscle activity of myoclonus as triggers. The detected spikes on the contralateral parieto-central region preceded myoclonic muscle activity in the forearms by 28-46ms. The patient was six months old at the time of examination, and was developing normally before seizure onset at two months of age. She suffered from recurrent afebrile or febrile generalized tonic-clonic seizures that often developed into status epilepticus. Interictal EEG and brain magnetic resonance imaging (MRI) showed no significant findings. The amplitudes of the somatosensory-evoked potentials were not extremely large. She has a chromosomal microdeletion involving SCN1A and adjacent genes., (Copyright © 2016 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.) more...

A woman aged 22 years presented with a 3-year history of jerks when brushing her teeth and a tremor when carrying drinks. Examination revealed a bilateral jerky tremor, stimulus-sensitive myoclonus, and difficulty with tandem gait. Thyroid and liver function test results were normal, but she had rapidly progressive renal failure. Serum copper, ceruloplasmin, and manganese levels were normal, but her urinary copper level was elevated on 2 occasions. Pathological findings on organ biopsy prompted genetic testing to confirm the diagnosis. The differential diagnosis, tissue biopsy findings, and final genetic diagnosis are discussed. more...

The physical examination findings of early posthypoxic myoclonus (PHM) are associated with poor prognosis. Recent findings indicate that patients with multifocal PHM, assumed to have a cortical origin, have a comparable outcome to resuscitated patients without PHM. Generalized PHM, assumed to have a subcortical myoclonus origin, is still associated with a bad clinical outcome. It is not known whether the electroencephalographic (EEG) findings differ between the multifocal and generalized myoclonus groups nor is the clinical significance clearly defined. Forty-three patients with PHM were retrospectively derived from an EEG database. Patients were categorized as having multifocal (i), generalized (ii), or undetermined (iii) PHM. Outcome was expressed in cerebral performance category scores. The EEG background was categorized into isoelectric (I), low voltage (II), burst suppression (III), status epilepticus (SE; IV), diffuse slowing (V), and mild encephalopathic or normal (VI). 17 patients had generalized PHM and 23 had multifocal PHM (3 undetermined). The EEG showed more SE in generalized compared to multifocal PHM (64% vs 13%, P< .001). Diffuse slowing was more often present in multifocal PHM (52% vs 17%, P < .05). Early-onset myoclonus occurred significantly more often in generalized PHM, and early generalized PHM was invariantly associated with poor outcome. In conclusion, patients with generalized PHM showed more SE. These EEG findings might be either subcortical corollaries or primarily cortical phenomena. Our retrospective results conflict with currently used clinical criteria for myoclonus classification, and we suggest that more refined difference may be needed for accurate assessment of PHM. To better understand PHM, prospective research with standardized clinical assessment and quantitative EEG analysis is needed., (© The Author(s) 2015.) more...

Levetiracetam can suppress sialidosis-related myoclonus but its effects on cerebral metabolism warrant elucidation. In this report, fluorodeoxyglucose-positron emission tomography was conducted before and after levetiracetam in a sialidosis patient. By subtracting the drug "off" from "on" signals, regions of enhanced metabolism were shown to be allocated mostly in the bilateral fronto-temporal regions whereas regions of reduced metabolism were distributed mainly in the occipital areas. Imaging changes suggest that the effects of levetiracetam may be different in different brain regions. The drug may also elicit fronto-temporal inhibitory impulses to suppress the vigorous myoclonus in sialidosis., (Copyright © 2012 Elsevier Ltd. All rights reserved.) more...