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Pollini L, van der Veen S, Elting JWJ, Tijssen MAJ. Negative Myoclonus: Neurophysiological Study and Clinical Impact in Progressive Myoclonus Ataxia. Mov Disord 2024; 39:674-683. [PMID: 38385661 DOI: 10.1002/mds.29741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 01/13/2024] [Accepted: 01/25/2024] [Indexed: 02/23/2024] Open
Abstract
INTRODUCTION Negative myoclonus (NM) is an involuntary movement caused by a sudden interruption of muscular activity, resulting in gait problems and falls. OBJECTIVE To establish frequency, clinical impact, and neurophysiology of NM in progressive myoclonus ataxia (PMA) patients. METHODS Clinical, neurophysiological, and genetic data of 14 PMA individuals from University Medical Centre Groningen (UMCG) Expertise Center Movement Disorder Groningen were retrospectively collected. Neurophysiological examination included video-electromyography-accelerometry assessment in all patients and electroencephalography (EEG) examination in 13 individuals. Jerk-locked (or silent period-locked) back-averaging and cortico-muscular coherence (CMC) analysis aided the classification of myoclonus. RESULTS NM was present in 6 (NM+) and absent in 8 (NM-) PMA patients. NM+ individuals have more frequent falls (100% vs. 37.5%) and higher scores on the Gross Motor Function Classification System (GMFCS) (4.3 ±0.74 vs. 2.5 ±1.2) than NM- individuals. Genetic background of NM+ included GOSR2 and SEMA6B, while that of NM- included ATM, KCNC3, NUS1, STPBN2, and GOSR2. NM was frequently preceded by positive myoclonus (PM) and silent-period length was between 88 and 194 ms. EEG epileptiform discharges were associated with NM in 2 cases. PM was classified as cortical in 5 NM+ and 2 NM- through EEG inspection, jerk-locked back-averaging, or CMC analysis. DISCUSSION Neurophysiological examination is crucial for detecting NM that could be missed on clinical examination due to a preceding PM. Evidence points to a cortical origin of NM, an association with more severe motor phenotype, and suggests the presence of genetic disorders causing either a PMA or progressive myoclonus epilepsy, rather than pure PMA phenotype. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Luca Pollini
- Department of Human Neuroscience, Sapienza University of Rome, Rome, Italy
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - Sterre van der Veen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - Jan Willem J Elting
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Department of Clinical Neurophysiology, University of Groningen, University Medical Center Groningen (UMCG), Groningen, The Netherlands
| | - Marina A J Tijssen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
- Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
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van der Veen S, Caviness JN, Dreissen YE, Ganos C, Ibrahim A, Koelman JH, Stefani A, Tijssen MA. Myoclonus and other jerky movement disorders. Clin Neurophysiol Pract 2022; 7:285-316. [PMID: 36324989 PMCID: PMC9619152 DOI: 10.1016/j.cnp.2022.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 08/29/2022] [Accepted: 09/11/2022] [Indexed: 11/27/2022] Open
Abstract
Myoclonus and other jerky movements form a large heterogeneous group of disorders. Clinical neurophysiology studies can have an important contribution to support diagnosis but also to gain insight in the pathophysiology of different kind of jerks. This review focuses on myoclonus, tics, startle disorders, restless legs syndrome, and periodic leg movements during sleep. Myoclonus is defined as brief, shock-like movements, and subtypes can be classified based the anatomical origin. Both the clinical phenotype and the neurophysiological tests support this classification: cortical, cortical-subcortical, subcortical/non-segmental, segmental, peripheral, and functional jerks. The most important techniques used are polymyography and the combination of electromyography-electroencephalography focused on jerk-locked back-averaging, cortico-muscular coherence, and the Bereitschaftspotential. Clinically, the differential diagnosis of myoclonus includes tics, and this diagnosis is mainly based on the history with premonitory urges and the ability to suppress the tic. Electrophysiological tests are mainly applied in a research setting and include the Bereitschaftspotential, local field potentials, transcranial magnetic stimulation, and pre-pulse inhibition. Jerks due to a startling stimulus form the group of startle syndromes. This group includes disorders with an exaggerated startle reflex, such as hyperekplexia and stiff person syndrome, but also neuropsychiatric and stimulus-induced disorders. For these disorders polymyography combined with a startling stimulus can be useful to determine the pattern of muscle activation and thus the diagnosis. Assessment of symptoms in restless legs syndrome and periodic leg movements during sleep can be performed with different validated scoring criteria with the help of electromyography.
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Affiliation(s)
- Sterre van der Veen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands,Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands
| | - John N. Caviness
- Department of Neurology, Mayo Clinic Arizona, Movement Neurophysiology Laboratory, Scottsdale, AZ, USA
| | - Yasmine E.M. Dreissen
- Department of Neurosurgery, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Christos Ganos
- Movement Disorders and Neuromodulation Unit, Department of Neurology, Charité University Medicine Berlin, Berlin, Germany
| | - Abubaker Ibrahim
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes H.T.M. Koelman
- Department of Neurology and Clinical Neurophysiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Ambra Stefani
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Marina A.J. Tijssen
- Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands,Expertise Centre Movement Disorders Groningen, University Medical Centre Groningen (UMCG), Groningen, The Netherlands,Corresponding author at: Department of Neurology, University of Groningen, University Medical Centre Groningen (UMCG), PO Box 30.001, 9700 RB Groningen, The Netherlands.
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Chen KHS, Chen R. Principles of Electrophysiological Assessments for Movement Disorders. J Mov Disord 2020; 13:27-38. [PMID: 31986867 PMCID: PMC6987526 DOI: 10.14802/jmd.19064] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/21/2019] [Indexed: 12/22/2022] Open
Abstract
Electrophysiological studies can provide objective and quantifiable assessments of movement disorders. They are useful in the diagnosis of hyperkinetic movement disorders, particularly tremors and myoclonus. The most commonly used measures are surface electromyography (sEMG), electroencephalography (EEG) and accelerometry. Frequency and coherence analyses of sEMG signals may reveal the nature of tremors and the source of the tremors. The effects of voluntary tapping, ballistic movements and weighting of the limbs can help to distinguish between organic and functional tremors. The presence of Bereitschafts-potentials and beta-band desynchronization recorded by EEG before movement onset provide strong evidence for functional movement disorders. EMG burst durations, distributions and muscle recruitment orders may identify and classify myoclonus to cortical, subcortical or spinal origins and help in the diagnosis of functional myoclonus. Organic and functional cervical dystonia can potentially be distinguished by EMG power spectral analysis. Several reflex circuits, such as the long latency reflex, blink reflex and startle reflex, can be elicited with different types of external stimuli and are useful in the assessment of myoclonus, excessive startle and stiff person syndrome. However, limitations of the tests should be recognized, and the results should be interpreted together with clinical observations.
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Affiliation(s)
- Kai-Hsiang Stanley Chen
- Department of Neurology, National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, Taiwan
| | - Robert Chen
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada.,Edmond J. Safra Program in Parkinson's Disease, University Health Network, Toronto, ON, Canada
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Tatum W, Rubboli G, Kaplan P, Mirsatari S, Radhakrishnan K, Gloss D, Caboclo L, Drislane F, Koutroumanidis M, Schomer D, Kasteleijn-Nolst Trenite D, Cook M, Beniczky S. Clinical utility of EEG in diagnosing and monitoring epilepsy in adults. Clin Neurophysiol 2018; 129:1056-1082. [DOI: 10.1016/j.clinph.2018.01.019] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 12/28/2017] [Accepted: 01/09/2018] [Indexed: 12/20/2022]
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Sifoglu A, Gunduz A, Kiziltan G, Kiziltan ME. Dopaminergic medication unrelated myoclonus is less related to tremor in idiopathic Parkinson's disease. Neurol Sci 2016; 38:679-682. [PMID: 27990561 DOI: 10.1007/s10072-016-2793-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/02/2016] [Indexed: 11/25/2022]
Abstract
Myoclonus in Parkinson's disease (PD) may be related or unrelated to dopaminergic medication and may share some features of cortical myoclonus. The aim of this study was to analyze clinical and electrophysiological correlates of the dopaminergic treatment unrelated myoclonus in PD patients. We included 17 PD patients with the end-of-dose myoclonus and 16 PD patients without myoclonus between January 2010 and June 2011. Surface electromyography of upper extremity muscles and long latency reflexes (LLRs) were performed. Positive or negative myoclonus with a duration of 35-100 ms was observed. Rest tremor was less frequent in the group with myoclonus. Only one PD patient with myoclonus had C reflex. Mean LLR amplitude was significantly high in PD with myoclonus compared to the group without myoclonus (p = 0.024). Dopaminergic treatment unrelated myoclonus is less related to rest tremor in PD, may be positive or negative, and exhibits similar features to cortical myoclonus.
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Affiliation(s)
- Ayla Sifoglu
- Department of Neurology, Cerrahpaşa School of Medicine, Istanbul University, K.M.Pasa, 34098, Istanbul, Turkey.
| | - Aysegul Gunduz
- Department of Neurology, Cerrahpaşa School of Medicine, Istanbul University, K.M.Pasa, 34098, Istanbul, Turkey
| | - Gunes Kiziltan
- Department of Neurology, Cerrahpaşa School of Medicine, Istanbul University, K.M.Pasa, 34098, Istanbul, Turkey
| | - Meral E Kiziltan
- Department of Neurology, Cerrahpaşa School of Medicine, Istanbul University, K.M.Pasa, 34098, Istanbul, Turkey
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Doden T, Sato H, Hashimoto T. Clinical characteristics and etiology of transient myoclonic state in the elderly. Clin Neurol Neurosurg 2015; 139:192-8. [PMID: 26513432 DOI: 10.1016/j.clineuro.2015.10.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 10/05/2015] [Accepted: 10/06/2015] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To clarify clinical picture of transient myoclonic state in elderly patients. METHODS The Aizawa Hospital database was searched to identify all patients with transient myoclonic state with or without asterixis between April 2006 and June 2013. Medical records, brain images and laboratory data including electroencephalograms and electromyograms were reviewed. RESULTS We found 26 patients: 10 women and 16 men, and their ages ranged from 56 to 96 years (79.7 ± 9.9 years, mean ± standard deviation). The affected sites of the myoclonic jerks were predominantly the lower face, neck and upper extremities. The myoclonus appeared at conscious resting condition, slightly exaggerated by posturing or action. Asterixis was observed in eight patients. Single myoclonic bursts were 1.70 ± 0.94 s long. The interval of myoclonic bursts was 4.47 ± 2.44 s. Single myoclonic bursts were composed of 9.5 ± 2.5 Hz myoclonic contractions, and single myoclonic contractions were 44.4 ± 12.3 ms in duration. Most of the patients suffered from chronic diseases, but they were basically independent in activity of daily living. Oral administration of clonazepam was effective. CONCLUSIONS Transient myoclonic state has relatively stereotyped features. The pathophysiology may include some metabolic abnormality on a background of age-related arteriosclerotic changes. Its prognosis is benign, and prompt oral administration of clonazepam abolishes it. Further investigations will be needed to clarify its cause and pathophysiology.
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Affiliation(s)
- Tadashi Doden
- Department of Neurology, Aizawa Hospital, Matsumoto, Japan.
| | - Hiromasa Sato
- Department of Neurology, Aizawa Hospital, Matsumoto, Japan.
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Yoshimura M, Zhang S, Ueda Y, Matsuda K, Imai K, Takahashi Y, Inoue Y. An analysis of epileptic negative myoclonus by magnetoencephalography. Epilepsy Res 2015; 110:139-45. [PMID: 25616466 DOI: 10.1016/j.eplepsyres.2014.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2014] [Revised: 11/26/2014] [Accepted: 12/03/2014] [Indexed: 10/24/2022]
Abstract
PURPOSE To clarify the neurophysiologic mechanism of epileptic negative myoclonus (ENM), we analyzed the magnetoencephalography (MEG) of a patient with ENM. METHODS The 52-year-old right-handed male had frequent ENM in the right upper limb during awake and monthly seizures with sudden tonic stiffening of the right forearm during sleep. MRI demonstrated a focal cortical dysplasia in the cortex of the posterior portion of the left superior frontal sulcus. Whole-head type MEG, electroencephalography and electromyography were simultaneously recorded during ENM. Single equivalent currents dipoles (ECDs) were calculated for each spike component followed by silent period (SP) in the right deltoid muscle. These MEG spike components were averaged with respect to their peaks, and single ECD was also calculated for the averaged spike component. Furthermore, we analyzed the MEG with the silent-period-locked-averaging (SPLA) method. Twenty MEG signal data were averaged with respect to the onset of SP. Twenty epochs in each of five separate periods of recording were repeatedly averaged. ECDs were calculated for spike components observed in each averaged epoch. RESULTS ECDs of each spike followed by SP were clustered near the cortex of the left central sulcus. In MEG spike averaging and SPLA method, ECDs at the peak of spike components were located near the right shoulder division of the primary sensorimotor cortex reproducibly. ECDs on the ascending phase before the peak were located lateral to the above ECD location in MEG spike averaging method. CONCLUSIONS ENM was produced by an inhibitory action on the primary sensorimotor cortex corresponding to the body segment in which ENM occurs.
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Affiliation(s)
- Masaki Yoshimura
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku 420-8688, Shizuoka, Japan.
| | - Shouwen Zhang
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku 420-8688, Shizuoka, Japan.
| | - Yuki Ueda
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku 420-8688, Shizuoka, Japan.
| | - Kazumi Matsuda
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku 420-8688, Shizuoka, Japan.
| | - Katsumi Imai
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku 420-8688, Shizuoka, Japan.
| | - Yukitoshi Takahashi
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku 420-8688, Shizuoka, Japan.
| | - Yushi Inoue
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Urushiyama 886, Aoi-ku 420-8688, Shizuoka, Japan.
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Matsumoto H, Saito K, Konoma Y, Okabe S, Ugawa Y, Ishibashi Y. Motor cortical excitability in peritoneal dialysis: a single-pulse TMS study. J Physiol Sci 2015; 65:113-9. [PMID: 25376928 PMCID: PMC10717939 DOI: 10.1007/s12576-014-0347-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 10/23/2014] [Indexed: 10/24/2022]
Abstract
The aim of this paper is to investigate cortical excitability in patients with end-stage renal disease receiving peritoneal dialysis (PD) without any symptoms suggestive of uremic encephalopathy. We performed transcranial magnetic stimulation for 52 PD patients and 28 normal subjects. We compared the active motor threshold (AMT), resting motor threshold (RMT), root latency, central motor conduction time (CMCT), and cortical silent period (CSP) in PD patients to those in normal subjects. AMT, RMT, CMCT, and CSP were not significantly different between PD patients and normal subjects. However, root latency was significantly prolonged in PD patients compared to normal subjects. The root latency correlated linearly with HbA1c or duration of PD in the patients. The results suggest that the corticospinal tract and the cortical and spinal excitabilities are preserved but the peripheral nerves are disturbed in PD patients. The severity of peripheral neuropathy corresponds to the severity of DM and the duration of PD. We uncovered no evidence suggestive of any subclinical abnormality of the motor cortical excitability in PD patients.
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Affiliation(s)
- Hideyuki Matsumoto
- Department of Neurology, Japanese Red Cross Medical Center, 4-1-22 Hiroo, Shibuya-ku, Tokyo, 150-8935, Japan,
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Butz M, Timmermann L, Gross J, Pollok B, Südmeyer M, Kircheis G, Häussinger D, Schnitzler A. Cortical activation associated with asterixis in manifest hepatic encephalopathy. Acta Neurol Scand 2014; 130:260-7. [PMID: 24372275 DOI: 10.1111/ane.12217] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVES Severe hepatic encephalopathy gives rise to asterixis, a striking motor symptom also called flapping tremor, which is characterized by a sudden ceasing of muscle tone in all muscles of a limb. In this study, we aimed at scrutinizing the cortical activation associated with asterixis and unraveling the underlying pathophysiological mechanisms. MATERIAL AND METHODS We recorded simultaneously neural activity with magnetoencephalography (MEG) and muscle activity with surface EMG in nine patients with manifest hepatic encephalopathy showing asterixis. Asterixis events were detected semiautomatically and served as triggers for averaging MEG signals. Evoked responses averaged time-locked to asterixis events were subjected to equivalent current dipole (ECD) modeling. Additionally, we localized the strongest cortico-muscular coherence in the frequency of the co-occurring tremulousness. RESULTS Evoked fields averaged time-locked to asterixis events were best explained by a single dipolar source in the contralateral primary motor cortex (M1, Talairach coordinates of mean localization: -40, -20, and 64; Brodmann area 4). This dipole showed a twofold field reversal, that is biphasic wave, with frontal dipole orientation at 49 ms before flap onset and 99 ms after flap onset. Conversely, two maxima with occipital dipole orientation were observed 2 ms and 160 ms after flap onset. Cortico-muscular coherence for the tremulousness was likewise localized in the contralateral M1 confirming earlier findings in the present patient cohort. CONCLUSIONS Our results reveal an involvement of M1 in the generation of asterixis. As also tremulousness, also called mini-asterixis, was shown to originate in M1, asterixis and mini-asterixis may share common pathophysiological mechanisms.
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Affiliation(s)
- M. Butz
- Medical Faculty; Institute of Clinical Neuroscience and Medical Psychology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
- Sobell Department of Motor Neuroscience and Movement Disorders; UCL Institute of Neurology; London UK
- Centre for Cognitive Neuroimaging (CCNi); Institute of Neuroscience and Psychology; University of Glasgow; Glasgow UK
| | - L. Timmermann
- Department of Neurology; University of Cologne; Cologne Germany
| | - J. Gross
- Centre for Cognitive Neuroimaging (CCNi); Institute of Neuroscience and Psychology; University of Glasgow; Glasgow UK
| | - B. Pollok
- Medical Faculty; Institute of Clinical Neuroscience and Medical Psychology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
| | - M. Südmeyer
- Medical Faculty; Institute of Clinical Neuroscience and Medical Psychology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
| | - G. Kircheis
- Medical Faculty; Department of Gastroenterology, Hepatology and Infectiology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
| | - D. Häussinger
- Medical Faculty; Department of Gastroenterology, Hepatology and Infectiology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
| | - A. Schnitzler
- Medical Faculty; Institute of Clinical Neuroscience and Medical Psychology; Heinrich Heine University Düsseldorf; Düsseldorf Germany
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Abstract
In 1949, asterixis was first described in patients with hepatic encephalopathy. It was quickly recognized that this phenomenon also occurs in other generalized encephalopathies and sometimes results from structural brain lesions. This paper is a study of asterixis in the general neurology clinic and on the inpatient neurology consultation service. The neurologists recorded the findings on inpatients and clinic patients for 12 consecutive months. Of the 1,109 inpatients with adequate examination, asterixis was documented in 97. Eighteen of the 97 cases were unilateral (18.6%) and 79 cases were bilateral (81.4%). Of the 614 outpatient visits with well documented examination, 6 (1%) individuals had asterixis. Since a small number of patients were examined more than once, the study yielded 103 individuals with adequate data for analysis. Asterixis resulted from varied causes: medications, renal disorder, hepatic dysfunction, pulmonary insufficiency, stroke and other brain lesions (including malignancy, subdural hematoma, and epidural abscess). Asterixis occurred in various patterns: in some cases it was easier to elicit in the upper extremities, in some it was easier to elicit in the lower limbs, and some it was solely or predominantly unilateral. The findings are discussed in light of the literature on asterixis with regard to its varied causes, patterns and presentations. Lastly, asterixis is examined from a historical perspective and the terminology is elucidated.
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Affiliation(s)
- Gian Pal
- Department of Neurology, Medstar Washington Hospital Center, 110 Irving Street N.W., Washington, DC, 20010, USA,
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Inoue M, Kojima Y, Mima T, Sawamoto N, Matsuhashi M, Fumuro T, Kinboshi M, Koganemaru S, Kanda M, Shibasaki H. Pathophysiology of unilateral asterixis due to thalamic lesion. Clin Neurophysiol 2012; 123:1858-64. [DOI: 10.1016/j.clinph.2012.01.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/14/2012] [Accepted: 01/19/2012] [Indexed: 10/28/2022]
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Matsumoto H, Ugawa Y. Neurophysiological analyses of asterixis utilizing innovative approaches. Clin Neurophysiol 2012; 123:1695-6. [PMID: 22406313 DOI: 10.1016/j.clinph.2012.02.063] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 02/03/2012] [Accepted: 02/04/2012] [Indexed: 11/29/2022]
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Abstract
This review examines some of the advances in understanding myoclonus over the last 25 years. The classification of myoclonus into cortical, brainstem, and spinal forms has been consolidated, each with distinctive clinical characteristics and physiological mechanisms. New genetic causes of myoclonus have been identified, and the molecular basis of several of these conditions has been discovered. It is increasingly apparent that disease of the cerebellum is particularly important in the genesis of cortical reflex myoclonus. However, the precise mechanism and origin of myoclonus in many situations remain uncertain. Effective treatment of myoclonus remains limited, and the challenge lies ahead to develop more therapeutic options.
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Affiliation(s)
- Hiroshi Shibasaki
- Kyoto University Graduate School of Medicine and Takeda General Hospital, Kyoto, Japan
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LaBuzetta JN, Yao JZ, Bourque DL, Zivin J. Adult nonhepatic hyperammonemia: a case report and differential diagnosis. Am J Med 2010; 123:885-91. [PMID: 20920686 DOI: 10.1016/j.amjmed.2010.02.029] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 02/03/2010] [Accepted: 02/04/2010] [Indexed: 12/11/2022]
Abstract
This article presents a case report of nonhepatic hyperammonemia, i.e., elevated serum ammonia secondary to a nonhepatic etiology. It then discusses the importance of broadening one's differential diagnosis to include such nonhepatic causes of elevated ammonia levels, and provides a short review of rarer causes of hyperammonemia in the adult population. Treating the underlying condition is the best way to prevent recurrence of hyperammonemia. However, symptomatic treatment should not be delayed while investigating the underlying source.
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Epileptic negative myoclonus: A combined study of EEG and [123I]iomazenil (123I-IMZ) single photon emission computed tomography indicating involvement of medial frontal area. Epilepsy Res 2010; 89:220-6. [PMID: 20133106 DOI: 10.1016/j.eplepsyres.2010.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 10/20/2009] [Accepted: 01/10/2010] [Indexed: 11/21/2022]
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Vetrugno R, D'Angelo R, Moghadam KK, Vandi S, Franceschini C, Mignot E, Montagna P, Plazzi G. Behavioural and neurophysiological correlates of human cataplexy: a video-polygraphic study. Clin Neurophysiol 2009; 121:153-62. [PMID: 19955018 DOI: 10.1016/j.clinph.2009.10.012] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 10/06/2009] [Accepted: 10/25/2009] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To investigate the behavioural and neurophysiological pattern of cataplexy. METHODS Seven narcolepsy with cataplexy patients underwent daytime videopolygraphy using humorous movies or/and jokes to trigger cataplectic attacks. RESULTS During segmental cataplectic attacks, EMG showed brief and irregular periods of silencing focally involving facial, neck, axial or limb muscles, sometimes coinciding with bursts of rapid eye movements. All patients enacted intentional movements in response to these segmental postural lapses. During global cataplectic attacks, EMG showed suppression of activity alternated with patterned enhancement, enhanced EMG activity in neck muscles preceding that of other cranial, axial and lower limb muscles. This waxing and waning EMG pattern ended with a complete body collapse and persistent muscle atonia. Breathing irregularities, heart rate (HR) instability and EEG desynchronization were observed during global cataplectic attacks without any appreciable blood pressure changes, but with HR deceleration and silencing of sympathetic skin response while in complete atonia. Patients subjectively perceived the involuntary postural lapses as startling and alarming. CONCLUSIONS Cataplexy in our patients showed many of the features of tonic REM sleep. SIGNIFICANCE Cataplexy can be construed as a "freezing-like" perturbation of the orienting response with transient impairment of posture and movements resulting in a "patchwork-compromise-behaviour".
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Affiliation(s)
- Roberto Vetrugno
- Department of Neurological Sciences, University of Bologna, Bologna, Italy.
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Rubboli G, Tassinari CA. Negative myoclonus. An overview of its clinical features, pathophysiological mechanisms, and management. Neurophysiol Clin 2007; 36:337-43. [PMID: 17336779 DOI: 10.1016/j.neucli.2006.12.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Negative myoclonus (NM) is an unspecific motor disorder that can characterize a variety of neurological conditions. From the clinical point of view, NM appears as a shock-like involuntary jerky movement caused by a sudden, brief interruption of muscle activity. Asterixis is a type of NM that occurs typically in toxic-metabolic encephalopathies. NM of epileptic nature, or epileptic negative myoclonus (ENM), is defined as an interruption of tonic muscle activity, which is time-locked to an epileptic EEG abnormality, without evidence of an antecedent positive myoclonia in the agonist-antagonist muscles. ENM can be observed in idiopathic, cryptogenic, and symptomatic epileptic disorders. Pathophysiological hypotheses on the origin of NM involve subcortical as well as cortical mechanisms. Recent neuroimaging and neurophysiologic investigations, including intracerebral recordings and electrical stimulation procedures in epileptic patients, suggest the participation of premotor, primary motor, primary sensory, and supplementary motor areas in the genesis of NM. Polygraphic monitoring is essential for the diagnosis of NM, allowing the demonstration of brief interruptions of a tonic EMG activity, not preceded by a positive myoclonus in the agonist and antagonist muscles of the affected limb. Simultaneous EEG-EMG monitoring demonstrating the association of NM with an epileptic potential is consistent with the diagnosis of ENM. Evolution and prognosis of NM is mainly related to aetiology. In childhood idiopathic partial epilepsy, ENM can respond to some drugs (in particular, ethosuximide), whereas other medications (such as carbamazepine or phenytoin) have been reported to induce or worsen it.
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Affiliation(s)
- G Rubboli
- Neurology Unit, Department of Neurosciences, Bellaria Hospital, University of Bologna, Via Altura, 3-40139 Bologna, Italy.
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Rubboli G, Mai R, Meletti S, Francione S, Cardinale F, Tassi L, Lo Russo G, Stanzani-Maserati M, Cantalupo G, Tassinari CA. Negative myoclonus induced by cortical electrical stimulation in epileptic patients. Brain 2005; 129:65-81. [PMID: 16272166 DOI: 10.1093/brain/awh661] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Negative myoclonus (NM) is a motor disorder characterized by a sudden and abrupt interruption of muscular activity. The EMG correlate of NM is a brief (<500 ms) silent period (SP) not preceded by any enhancement of EMG activity (i.e. myoclonus). This study investigated the role of premotor cortex (PMC), primary motor cortex (MI), primary somatosensory area (SI) and supplementary motor area (SMA) in the pathophysiology of cortical NM by means of intracerebral low frequency (1 Hz) electrical stimulation. In three drug-resistant epileptic patients undergoing presurgical evaluation, we delivered single electric pulses (stimulus duration: 3 ms; stimulus intensity ranging from 0.4 to 3 mA) to PMC (2 patients), MI (1 patient), SI and SMA through stereo-EEG electrodes; surface EMG was collected from both deltoids. The results showed that (i) the stimulation of PMC or MI could evoke a motor evoked potential (MEP) either at rest or during contraction, in this latter case followed by an SP; however, in two patients, at the lowest stimulus intensities (0.4 mA), 50% of stimuli could induce a pure SP, i.e. not preceded by an MEP; raising the intensity of stimulation (0.6 mA), the SPs showed an antecedent MEP in >80% of stimuli; (ii) the stimulation of SI at low stimulus intensities (from 0.4 to 0.8 mA) induced in two patients only SPs, never associated with an antecedent MEP, whereas in the third subject the SPs could be inconstantly preceded by an MEP; by incrementing the stimulus intensity (up to 3 mA), in all three patients the SPs tended to be preceded, although not constantly, by an MEP; stimulus intensity affected SP duration (i.e. the higher the intensity, the longer the SP), without influencing the latency of onset of the SPs; (iii) the stimulation of SMA induced only pure SPs, at all stimulus intensities up to 3 mA; as for SI, increment of stimulus intensity was paralleled by an increase in SP duration, without influencing the onset latency of SPs. We conclude that single electric pulse stimulation of PMC, MI, SI and SMA through stereo-EEG electrodes can induce pure SPs, not preceded by an MEP, which clinically appear as NM, suggesting therefore that these cortical areas may be involved in the genesis of this motor phenomenon. However, it must be pointed out that SMA stimulation induced only pure SPs, regardless of the stimulus intensity, whereas occurrence of pure SPs following stimulation of PMC, MI, and SI depended mainly on the intensity of stimulation.
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Affiliation(s)
- Guido Rubboli
- Department of Neurological Sciences, Bellaria Hospital, University of Bologna, Bologna, Italy.
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Abstract
As myoclonus is often associated with abnormally increased excitability of cortical structures, electrophysiological studies provide useful information for its diagnosis and classification, and about its generator mechanisms. The electroencephalogram-electromyogram polygraph reveals the most important information about the myoclonus of interest. Jerk-locked back-averaging and evoked potential studies combined with recording of the long-latency, long-loop reflexes are useful to investigate the pathophysiology of myoclonus further, especially that of cortical myoclonus. Recent advances in magnetoencephalography and transcranial magnetic stimulation have contributed significantly to the understanding of some of the cortical mechanisms underlying myoclonus. Elucidation of physiological mechanisms underlying myoclonus in individual patients is important for selecting the most appropriate treatment.
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Affiliation(s)
- Hiroshi Shibasaki
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 10, Room 5C432A, Bethesda, MD 20892-1428, USA.
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Kristeva R, Popa T, Chakarov V, Hummel S. Cortico-muscular coupling in a patient with postural myoclonus. Neurosci Lett 2004; 366:259-63. [PMID: 15288430 DOI: 10.1016/j.neulet.2004.05.114] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Revised: 05/11/2004] [Accepted: 05/19/2004] [Indexed: 10/26/2022]
Abstract
We investigated the cortico-muscular coherence in a patient with posturally induced cortically originating negative myoclonus. We recorded simultaneously 50 channels EEG and EMG from quadriceps and biceps femoris muscles of the left upper leg. Three experimental conditions were investigated with the patient in a seated position: (i) recording during rest (Rest), (ii) recording while the patient had to hold his left leg horizontally stretched out (Postural), and (iii) recording while the patient had to hold his left leg horizontally stretched out against a vertical force (Postural against force). Coherence, phase difference and cumulant density were computed as indicators for cortico-muscular coupling. The cortical component preceding the silent period was shown by averaging and was reconstructed. During postural and postural against force conditions, the EEG over the vertex was significantly coherent with EMG, in alpha (7-15 Hz) and beta range (15-30 Hz). The strongest coherence peak was at 21 Hz. No high-frequency coherence was observed. The phase difference and the cumulant density estimate corresponded to a 32 ms time lag between motor cortex and muscles, with EEG leading. The broadening of the coherence spectrum at which the motor cortex drives the muscles together with the excessive coherence levels and the giant SEP could reflect the hyperexcitability of the sensorimotor cortex. The frequency content of the coherence may be characteristic for this type of myoclonus. The results lend support to the view that the frequency analysis may have some diagnostic potential in cortical myoclonus.
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Affiliation(s)
- Rumyana Kristeva
- Neurological Clinic, University of Freiburg, Breisacherstrasse 64, 79106 Freiburg, Germany.
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21
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Ugawa Y, Hanajima R, Terao Y, Kanazawa I. Exaggerated 16-20 Hz motor cortical oscillation in patients with positive or negative myoclonus. Clin Neurophysiol 2003; 114:1278-84. [PMID: 12842726 DOI: 10.1016/s1388-2457(03)00126-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Muscle jerks and their cortical correlates usually occur abruptly and arrhythmically in patients with positive or negative myoclonus. However, there have been several reports in which oscillatory pre-myoclonic cortical discharges occur in patients with repetitive myoclonus (Mov Disord 6 (1994) 633; Brain 119 (1996) 1307; Brain 124 (2001) 2459; Brain 126 (2003) 326). In the present paper, we describe 4 patients with non-repetitive positive or negative myoclonus whose jerks were preceded by 16-20 Hz oscillatory EEG potentials over the contralateral sensorimotor cortex. METHODS Jerk-locked averaging (JLA) was performed in 3 patients with positive myoclonus two of which had benign familial myoclonus epilepsy whilst the other had tuberculous meningitis. Silent period locked averaging (SPLA) was performed in a patient with hepatic encephalopathy and asterixis. RESULTS In the 3 patients with positive myoclonus, JLA revealed a sequence of 20 Hz EEG potentials preceding the myoclonus. The positive peak of the last oscillation preceded the onset of myoclonus by the cortico-muscular latency. In the patient with hepatic encephalopahty, SPLA showed that 16 Hz EEG oscillations over the contralateral motor cortex were associated with small EMG oscillations, and that the largest EEG wave of the oscillation preceded the onset of a large EMG discharge just prior to the EMG silence. These oscillatory activities are similar in frequency to the motor cortical oscillations seen in monkeys and humans during voluntary contraction. CONCLUSIONS Abnormally enhanced rhythmic (16-20 Hz) activities in the motor cortex are associated with arrhythmic positive or negative myoclonus. The rhythmic activities may also be responsible for the generation of the tremulousness (or mini-asterixis) in metabolic encephalopahty.
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Affiliation(s)
- Yoshikazu Ugawa
- Department of Neurology, Division of Neuroscience, Graduate School of Medicine, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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Pranzatelli MR. Infantile spasms versus myoclonus: is there a connection? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2002; 49:285-314. [PMID: 12040898 DOI: 10.1016/s0074-7742(02)49018-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Infantile spasms (IS) is usually classified as a form of "myoclonic epilepsy," but the nosology of this whole group of disorders is unclear. Evidence suggests that the spasms are subcortically mediated, but can be modified by input from the cortex, which is believed to be abnormally excitable and disorganized. The latter features may give rise to hypsarrhythmia. The whole issue of myoclonus rests on the phenotype of IS and precise measurements of the length of electromyographic (EMG) bursts. Based on scant EMG data, it would appear that the bursts during flexor spasms are too long for epileptic myoclonus. The nature of tonic spasms of even longer duration is not myoclonic. However, the infrequent spontaneous myoclonic jerks, which can occur without spasms, and head nodding could represent positive and negative myoclonus, respectively. Data can be collected easily through techniques such as back-averaging to resolve the issue of classification and localization of motor phenomena.
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Affiliation(s)
- Michael R Pranzatelli
- Departments of Neurology and Pediatrics, Southern Illinois University School of Medicine, Springfield, Illinois 62702, USA
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Tatu L, Moulin T, Martin V, Monnier G, Rumbach L. Unilateral pure thalamic asterixis: clinical, electromyographic, and topographic patterns. Neurology 2000; 54:2339-42. [PMID: 10881268 DOI: 10.1212/wnl.54.12.2339] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Eleven patients (nine with infarctions and two with primary hematomas) with isolated thalamic lesions and contralateral asterixis were examined using a standard electromyographic and neuroimaging protocol. Asterixis was a short-duration phenomenon associated with a hemiataxia hypesthesia syndrome in all patients. Electromechanical synchronization was constant for the two silent period types. The anatomic data strongly suggest that ventral lateral or lateral posterior thalamus are concerned in the pathophysiology of thalamic asterixis.
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Affiliation(s)
- L Tatu
- Fédération des Sciences Neurologiques, Centre Hospitalier Universitaire Jean Minjoz, Besançon, France.
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25
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Matsunaga K, Uozumi T, Akamatsu N, Nagashio Y, Qingrui L, Hashimoto T, Tsuji S. Negative myoclonus in Creutzfeldt-Jakob disease. Clin Neurophysiol 2000; 111:471-6. [PMID: 10699409 DOI: 10.1016/s1388-2457(99)00277-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
OBJECTIVE To describe electrophysiological findings in a patient with Creutzfeldt-Jakob disease (CJD) showing negative myoclonus. METHODS AND RESULTS We studied this CJD patient electrophysiologically, in comparison with two patients with cortical reflex positive myoclonus due to benign adult familial myoclonic epilepsy (BAFME). Spontaneous negative myoclonus was associated with periodic synchronous discharges (PSDs) on the electroencephalogram, but negative myoclonus could also be induced by electrical stimulation of the median nerve in the CJD patient. This patient showed giant somatosensory evoked potentials (SEPs) and enhanced C reflexes, and the duration of the induced EMG silences was found to be significantly correlated with the amplitude of cortical SEPs. The duration of silent periods (SPs) produced by magnetic stimulation of the motor cortex was extremely long. The study of recovery function of SEPs suggested that the excitability of the somatosensory cortex was decreased during a long post-stimulus period. These findings were clearly different from those of patients with BAFME. CONCLUSIONS This CJD patient had two types of negative myoclonus; one was associated with PSDs and the other was cortical reflex negative myoclonus. The long-lasting decrease in excitability of the sensorimotor cortices after stimulation could be related to the occurrence of both types of negative myoclonus.
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Affiliation(s)
- K Matsunaga
- Department of Neurology, University of Occupational and Environmental Health, School of Medicine, Yahatanishi-ku, Kitakyushu City, Japan.
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26
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Abstract
As myoclonus is often associated with abnormally increased excitability of cortical structures, electrophysiological studies provide useful information for its diagnosis and classification and about its generator mechanisms. The EEG-EMG polygraph provides the most essential information about the myoclonus of interest. Jerk-locked back averaging and evoked potential studies combined with recording of the long latency, long loop reflexes are useful to further investigate the pathophysiology of myoclonus, especially that of cortical myoclonus. A recent advance in magnetoencephalographic techniques has contributed significantly to the elucidation of some of the cortical mechanisms underlying myoclonus. Elucidation of physiological mechanisms underlying myoclonus in each individual patient is important for selecting the most appropriate treatment of choice.
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Affiliation(s)
- H Shibasaki
- Departments of Neurology and Brain Pathophysiology, Kyoto University School of Medicine, Shogoin, Sakyo, Kyoto, 606-8507 Japan
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Activities of the primary and supplementary motor areas increase in preparation and execution of voluntary muscle relaxation: an event-related fMRI study. J Neurosci 1999. [PMID: 10212312 DOI: 10.1523/jneurosci.19-09-03527.1999] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Brain activity associated with voluntary muscle relaxation was examined by applying event-related functional magnetic resonance imaging (fMRI) technique, which enables us to observe change of fMRI signals associated with a single motor trial. The subject voluntarily relaxed or contracted the right upper limb muscles. Each motor mode had two conditions; one required joint movement, and the other did not. Five axial images covering the primary motor area (M1) and supplementary motor area (SMA) were obtained once every second, using an echoplanar 1.5 tesla MRI scanner. One session consisted of 60 dynamic scans (i.e., 60 sec). The subject performed a single motor trial (i.e., relaxation or contraction) during one session in his own time. Ten sessions were done for each task. During fMRI scanning, electromyogram (EMG) was monitored from the right forearm muscles to identify the motor onset. We calculated the correlation between the obtained fMRI signal and the expected hemodynamic response. The muscle relaxation showed transient signal increase time-locked to the EMG offset in the M1 contralateral to the movement and bilateral SMAs, where activation was observed also in the muscle contraction. Activated volume in both the rostral and caudal parts of SMA was significantly larger for the muscle relaxation than for the muscle contraction (p < 0.05). The results suggest that voluntary muscle relaxation occurs as a consequence of excitation of corticospinal projection neurons or intracortical inhibitory interneurons, or both, in the M1 and SMA, and both pre-SMA and SMA proper play an important role in motor inhibition.
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Toma K, Honda M, Hanakawa T, Okada T, Fukuyama H, Ikeda A, Nishizawa S, Konishi J, Shibasaki H. Activities of the primary and supplementary motor areas increase in preparation and execution of voluntary muscle relaxation: an event-related fMRI study. J Neurosci 1999; 19:3527-34. [PMID: 10212312 PMCID: PMC6782247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/1998] [Revised: 02/10/1999] [Accepted: 02/12/1999] [Indexed: 02/12/2023] Open
Abstract
Brain activity associated with voluntary muscle relaxation was examined by applying event-related functional magnetic resonance imaging (fMRI) technique, which enables us to observe change of fMRI signals associated with a single motor trial. The subject voluntarily relaxed or contracted the right upper limb muscles. Each motor mode had two conditions; one required joint movement, and the other did not. Five axial images covering the primary motor area (M1) and supplementary motor area (SMA) were obtained once every second, using an echoplanar 1.5 tesla MRI scanner. One session consisted of 60 dynamic scans (i.e., 60 sec). The subject performed a single motor trial (i.e., relaxation or contraction) during one session in his own time. Ten sessions were done for each task. During fMRI scanning, electromyogram (EMG) was monitored from the right forearm muscles to identify the motor onset. We calculated the correlation between the obtained fMRI signal and the expected hemodynamic response. The muscle relaxation showed transient signal increase time-locked to the EMG offset in the M1 contralateral to the movement and bilateral SMAs, where activation was observed also in the muscle contraction. Activated volume in both the rostral and caudal parts of SMA was significantly larger for the muscle relaxation than for the muscle contraction (p < 0.05). The results suggest that voluntary muscle relaxation occurs as a consequence of excitation of corticospinal projection neurons or intracortical inhibitory interneurons, or both, in the M1 and SMA, and both pre-SMA and SMA proper play an important role in motor inhibition.
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Affiliation(s)
- K Toma
- Department of Brain Pathophysiology, Kyoto University Graduate School of Medicine, Kyoto, 606-8507 Japan
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Tassinari CA, Rubboli G, Shibasaki H. Neurophysiology of positive and negative myoclonus. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1998; 107:181-95. [PMID: 9803948 DOI: 10.1016/s0013-4694(98)00058-3] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Myoclonus is defined as a sudden, brief, jerky, shock-like, involuntary movement, arising from the central nervous system that can be caused by a muscular contraction, i.e. positive myoclonus, or by an interruption of muscular activity, i.e. negative myoclonus. Myoclonus can characterize a variety of neurological disorders, and often both positive and negative myoclonus can coexist. In this paper, we outline some relevant clinical aspects and neurophysiological features of the different types of myoclonus, with particular emphasis on the physiological findings. Indeed, since most myoclonus depend on enhancement of neuronal activities which are inherently present in normal subjects, electrophysiological studies are useful for elucidating the underlying pathophysiological mechanisms and for establishing the correct diagnosis [corrected].
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Affiliation(s)
- C A Tassinari
- Department of Neurology, University of Bologna, Bellaria Hospital, Italy.
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Connemann BJ, Urban PP, Lüttkopf V, Hopf HC. A fully automated system for the evaluation of masseter silent periods. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1997; 105:53-7. [PMID: 9118839 DOI: 10.1016/s0924-980x(96)96549-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Exteroceptive suppression of masseter muscle activity, 'masseter inhibitory reflex', comprises one or 2 silent periods (SP1 and SP2) interrupting the voluntary activation. The main problem when evaluating exteroceptive suppression is the lack of an objective and precise measure for the onset and end of the silent period which so far has not been overcome by various automated systems. We describe a new fully automated system for determining the onset and end of the masseter silent period. The decision approach is essentially based upon deterministic properties of median filters which are used to partition the local variances of the EMG traces into constant segments and edges between them. The system was tested in 13 healthy volunteers with 2 subjects tested serially 10 times each to get estimates of the inter- and intra-individual variability. The performance of the system compared favourably to that of a simpler approach and to earlier results from our laboratory. The inter-individual variability of the SP1 onset was 17 times smaller than when based on a subjective decision process.
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Affiliation(s)
- B J Connemann
- Klinik und Poliklinik für Neurologie, Johannes Gutenberg Universität, Mainz, Germany
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Gambardella A, Aguglia U, Oliveri RL, Pucci F, Zappia M, Quattrone A. Photic-induced epileptic negative myoclonus: a case report. Epilepsia 1996; 37:492-4. [PMID: 8617179 DOI: 10.1111/j.1528-1157.1996.tb00596.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We present the first documented case of photic-induced epileptic negative myoclonus. A 17-year-old girl had experienced two generalized tonic-clonic seizures (GTCS) while watching television. The only EEG abnormality was a photoparoxysmal response (PPR), which was sometimes accompanied by loss of postural tone in both arms. Valproate was effective in abolishing photosensitivity. Negative myoclonus should be included among the ictal phenomena accompanying PPR.
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Affiliation(s)
- A Gambardella
- Institute of Neurology, School of Medicine, Catanzaro, Italy
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Terada K, Ikeda A, Nagamine T, Shibasaki H. Movement-related cortical potentials associated with voluntary muscle relaxation. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1995; 95:335-45. [PMID: 7489662 DOI: 10.1016/0013-4694(95)00098-j] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We recorded movement-related cortical potentials (MRCPs) associated with voluntary muscle relaxation, which was not accompanied by contraction of the antagonist or any other muscles, in 10 normal subjects. Voluntary, self-paced relaxation of the wrist extensors from the extended position was employed as the relaxation task, and wrist flexion by muscle contraction was employed as the contraction task. The accelerogram was used to obtain the trigger signals for both tasks. The electromyograms of the ipsilateral agonist and antagonist, the proximal muscles and the contralateral corresponding muscles were monitored to confirm the absence of muscle contraction for the relaxation task. All MRCP components were identified in both tasks; Bereitschaftspotential (BP), negative slope (NS'), parietal peak of motor potential (ppMP) and frontal peak of motor potential (fpMP). BP started earlier and was larger at the contralateral parietotemporal electrodes for the relaxation than for the contraction task, and the slow positive shift at the bilateral frontopolar electrodes was seen more often in the relaxation task. It is concluded that the voluntary muscle relaxation needs a cortical preparatory process similar to voluntary muscle contraction, and needs a more extensive and longer preparation process in the primary motor area and possibly in other motor areas as compared with the contraction.
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Affiliation(s)
- K Terada
- Department of Brain Pathophysiology, Kyoto University School of Medicine, Japan
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Rubboli G, Parmeggiani L, Tassinari CA. Frontal inhibitory spike component associated with epileptic negative myoclonus. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1995; 95:201-5. [PMID: 7555910 DOI: 10.1016/0013-4694(95)00144-n] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The aim of this study was to characterize paroxysmal EEG activities associated with epileptic negative myoclonus (ENM) in an epileptic patient presenting with ENM. ENM was predominant in the right upper limb and was correlated to a spike in the left central region. Spikes associated with ENM (SaENM) and spikes unrelated to ENM (SuENM) were identified by the temporal relation between the left central spike and the EMG silent period in the right wrist extensor. SaENM showed a significantly longer duration than SuENM (128 +/- 27 msec versus 92 +/- 21 msec, respectively; P < 0.01). SaENM and SuENM were submitted to spike averaging and topographic mapping. Spike averaging was performed averaging the EEG 640 msec before and after the peak of the spike. Both averaged SaENM and SuENM consisted of a negative spike with highest amplitude at C3 and similar topographic characteristics. The discriminant feature between the two types of spikes was the presence, in averaged SaENM, of a second smaller negative spike, 40 msec after the peak of the spike at C3, whose maxima were distributed over the left frontal region. We labeled this second spike as ENM-related component. We conclude that, in our patient, ENM was associated with a frontal cortical potential suggesting the involvement of frontal areas in the generation of negative myoclonus.
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Affiliation(s)
- G Rubboli
- Department of Neurology, University of Bologna, Bellaria Hospital, Italy
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Aguglia U, Gambardella A, Zappia M, Valentino P, Quattrone A. Negative myoclonus during valproate-related stupor. Neurophysiological evidence of a cortical non-epileptic origin. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1995; 94:103-8. [PMID: 7532570 DOI: 10.1016/0013-4694(94)00268-p] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We retrospectively reviewed clinical and neurophysiological data of 6 epileptic patients who developed negative myoclonus and stupor a few days after introduction of valproate (VPA). Prompt remission of clinical signs and symptoms followed valproate withdrawal. We attempted to elucidate the pathophysiological mechanism of VPA-induced stupor and provide further polygraphic and backaveraging EEG documentation of negative myoclonus. During VPA-induced stupor electroencephalograms revealed posterior background slowing in all patients. Interictal epileptiform discharges were present in 3 patients. In all 6 patients close examination using simultaneous video-polygraphic recording showed negative myoclonus which was not time-related to lateralized spike discharges. In 2 of 3 patients with no spikes on conventional EEG who underwent backaveraged EEG recordings we detected a large (5 microV) cortical positive-negative wave time-locked (30-40 msec) with the postural modification of the contralateral wrist. This cortical potential was similar to that observed in patients with asterixis secondary to metabolic or toxic encephalopathies. In one patient i.v. administration of 10 mg diazepam did not modify this cortical potential and did not reverse the clinical manifestations. In all patients the only abnormal laboratory finding was an increased level of venous ammonemia. Our findings are against an epileptic origin of VPA encephalopathy and provide further argument in favour of a cortical non-epileptic mechanism mediating negative myoclonus. Benzodiazepines should be avoided in the management of this condition.
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Affiliation(s)
- U Aguglia
- Institute of Neurology, School of Medicine, Catanzaro, Italy
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Abstract
A patient with myoclonus epilepsy had 2 types of negative myoclonus as well as positive myoclonus at rest. One type followed a large EMG discharge at the end of continuous contraction and the other did not. Both types of negative myoclonus and positive myoclonus were preceded by EEG activity, predominantly distributed in the contralateral central region. It is suggested that an abnormal activity around the motor cortex suppresses a voluntary contraction as well as induces myoclonus. Clonazepam was markedly effective on both positive and negative myoclonus.
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Affiliation(s)
- T Yokota
- Department of Neurology, Tokyo Medical and Dental University, Japan
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37
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Artieda J, Muruzabal J, Larumbe R, García de Casasola C, Obeso JA. Cortical mechanisms mediating asterixis. Mov Disord 1992; 7:209-16. [PMID: 1620137 DOI: 10.1002/mds.870070304] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We describe a patient with chronic renal failure who suffered multifocal action-induced jerks. Electromyography (EMG) recorded the typical silence of asterixis. Back-averaging the EEG activity preceding the EMG silent periods in the forearm showed a biphasic wave antedating the asterixis by 23 ms. Somatosensory evoked potentials (SEPs) after median nerve stimulation were pathologically enlarged on both hemispheres. Brain-mapping of the biphasic wave preceding asterixis and the giant SEPs indicated a common origin in the sensorimotor cortex. This observation provides further documentation of a cortical origin for some types of asterixis in humans.
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Affiliation(s)
- J Artieda
- Department of Neurology, Clinica Universitaria, University of Navarra, Pamplona, Spain
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Ugawa Y, Genba K, Shimpo T, Mannen T. Onset and offset of electromyographic (EMG) silence in asterixis. J Neurol Neurosurg Psychiatry 1990; 53:260-2. [PMID: 2324758 PMCID: PMC1014140 DOI: 10.1136/jnnp.53.3.260] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The onset and offset of electromyographic (EMG) silence were studied physiologically by silent period locked averaging method (SPLA) combined with a computer-assisted method for detecting EMG changes in 11 patients with asterixis of various aetiologies. The onset followed the EMG discharge which was closely associated with a sharp wave probably generated by the motor cortex in three patients. No EEG activity could be shown to be related to the offset of EMG silence in every patient. Jerky movement of asterixis was temporally related to the offset of EMG silence rather than the onset.
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Affiliation(s)
- Y Ugawa
- Department of Neurology, School of Medicine, University of Tokyo, Japan
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