51
|
Jitter analysis with concentric needle electrodes in the extensor digitorum communis for the diagnosis of myasthenia gravis: a pilot study. Chin Med J (Engl) 2014. [DOI: 10.1097/00029330-201409200-00003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
52
|
Allen MD, Stashuk DW, Kimpinski K, Doherty TJ, Hourigan ML, Rice CL. Increased neuromuscular transmission instability and motor unit remodelling with diabetic neuropathy as assessed using novel near fibre motor unit potential parameters. Clin Neurophysiol 2014; 126:794-802. [PMID: 25240249 DOI: 10.1016/j.clinph.2014.07.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 06/19/2014] [Accepted: 07/08/2014] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To assess the degree of neuromuscular transmission variability and motor unit (MU) remodelling in patients with diabetic polyneuropathy (DPN) using decomposition-based quantitative electromyography (DQEMG) and near fibre (NF) motor unit potential (MUP) parameters. METHODS The tibialis anterior (TA) muscle was tested in 12 patients with DPN (65 ± 15 years) and 12 controls (63 ± 15 years). DQEMG was used to analyze electromyographic (EMG) signals collected during voluntary contractions. MUP and NF MUP parameters were analyzed. NF MUPs were obtained by high-pass filtering MUP template waveforms, which isolates contributions of fibres that are close to the needle detection surface. NF MUP parameters provided assessment of motor unit size (NF area), fibre density (NF fibre count) and contribution dispersion (NF dispersion) and neuromuscular transmission instability (NF jiggle). RESULTS DPN patients had larger (+45% NF area), more complex (+30% NF fibre count), and less stable (+30% NF jiggle) NF MUPs (p<0.05). No significant relationships were found between NF MUP stability and denervation, or strength; however NF MUP complexity was positively related to TA denervation in the DPN group (r=0.63; p<0.05). NF MUP complexity and instability were positively related in DPN patients (r=0.46; p<0.05). CONCLUSIONS DPN is associated with neuromuscular transmission instability and MU remodelling that can be assessed using DQEMG. SIGNIFICANCE DQEMG-derived NF MUP parameters may be useful in identifying patients in early stages of neuromuscular dysfunction related to DPN.
Collapse
Affiliation(s)
- Matti D Allen
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada.
| | | | - Kurt Kimpinski
- Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Timothy J Doherty
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada; Department of Clinical Neurological Sciences, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada; Department of Physical Medicine and Rehabilitation, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Maddison L Hourigan
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Charles L Rice
- School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada; Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
53
|
Gwathmey K, Balogun RA, Burns T. Neurologic indications for therapeutic plasma exchange: 2013 update. J Clin Apher 2014; 29:211-9. [DOI: 10.1002/jca.21331] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 05/01/2014] [Indexed: 12/28/2022]
Affiliation(s)
- Kelly Gwathmey
- Department of Neurology; The University of Virginia; Charlottesville Virginia
| | - Rasheed A. Balogun
- Division of Nephrology; Department of Medicine; University of Virginia Health System; Charlottesville Virginia
| | - Ted Burns
- Department of Neurology; The University of Virginia; Charlottesville Virginia
| |
Collapse
|
54
|
Katzberg HD, Barnett C, Merkies IS, Bril V. Minimal clinically important difference in myasthenia gravis: Outcomes from a randomized trial. Muscle Nerve 2014; 49:661-5. [DOI: 10.1002/mus.23988] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2013] [Indexed: 01/22/2023]
Affiliation(s)
- Hans D. Katzberg
- University Health Network, Division of Neurology; Toronto General Hospital; 200 Elizabeth Street, 5ES-306 Toronto Ontario M5G 2C4 Canada
| | - Carolina Barnett
- University Health Network, Division of Neurology; Toronto General Hospital; 200 Elizabeth Street, 5ES-306 Toronto Ontario M5G 2C4 Canada
| | - Ingemar S.J. Merkies
- Department of Neurology; Spaarne Hospital, Hoofddorp and Maastricht University Medical Centre; Maastricht The Netherlands
| | - Vera Bril
- University Health Network, Division of Neurology; Toronto General Hospital; 200 Elizabeth Street, 5ES-306 Toronto Ontario M5G 2C4 Canada
| |
Collapse
|
55
|
Padua L, Caliandro P, Di Iasi G, Pazzaglia C, Ciaraffa F, Evoli A. Reliability of SFEMG in diagnosing myasthenia gravis: sensitivity and specificity calculated on 100 prospective cases. Clin Neurophysiol 2013; 125:1270-3. [PMID: 24296278 DOI: 10.1016/j.clinph.2013.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 10/16/2013] [Accepted: 11/02/2013] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The study aimed to determine the utility of single-fibre electromyography (SFEMG) in the diagnosis of myasthenia gravis (MG) in subjects with a clinical suspicion of the disease. METHODS We performed a prospective, single-blinded study on 100 consecutive patients. SFEMG was not considered a criterion in making the MG diagnosis. For all cases, a different physician than the one performing SFEMG made the diagnosis of MG. All subjects underwent standard SFEMG of a single muscle, the orbicularis oculi. RESULTS SFEMG was abnormal in 67 of 100 patients. A final diagnosis of definite MG was made in 54 patients (30 men/24 women). SFEMG was positive in 53 of 54 patients diagnosed with MG. The sensitivity of SFEMG in diagnosing MG was 98% (95% CI: 0.94-1.02), while the specificity was 70% (95% CI: 0.54-0.86), with a positive predictive value of 79% (95% CI: 0.74-0.79) and a negative predictive value of 97% (95% CI: 0.94-0.99). CONCLUSIONS In this cohort of patients, normal SFEMG findings were unlikely to occur in patients with MG. SIGNIFICANCE SFEMG is not a confirmatory test for the diagnosis of MG, but it has a high negative predictive value in identifying patients without MG.
Collapse
Affiliation(s)
- L Padua
- Institute of Neurology, Catholic University, Rome, Italy; Don Carlo Gnocchi Onlus Foundation, Milan, Italy.
| | - P Caliandro
- Institute of Neurology, Catholic University, Rome, Italy
| | - G Di Iasi
- 1st Division of Neurology, Department of Neuroscience, Seconda Università, Napoli, Italy
| | - C Pazzaglia
- Don Carlo Gnocchi Onlus Foundation, Milan, Italy
| | - F Ciaraffa
- Institute of Neurology, Catholic University, Rome, Italy
| | - A Evoli
- Institute of Neurology, Catholic University, Rome, Italy
| |
Collapse
|
56
|
Papathanasiou ES, Zamba-Papanicolaou E. Single fiber electromyography: What type of needle should I use? Clin Neurophysiol 2013; 124:2077-8. [DOI: 10.1016/j.clinph.2013.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 05/25/2013] [Accepted: 05/28/2013] [Indexed: 10/26/2022]
|
57
|
Arora Y, Li Y. Overview of myasthenia gravis. Hosp Pract (1995) 2013; 41:40-50. [PMID: 24145588 DOI: 10.3810/hp.2013.10.1079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Myasthenia gravis is an antibody-mediated disorder of neuromuscular transmission that is characterized by weakness and fatigue of voluntary muscles. Weakness may be ocular, bulbar, or generalized. Diagnostic evaluation of patients consists of bedside assessment, antibody testing, and electrophysiologic studies. Various therapeutic options are available, which consist of anticholinesterase inhibitors for symptomatic management, immunosuppressive agents as maintenance therapy, and thymectomy. Plasmapheresis and intravenous immunoglobulin are used in patients in crisis or those with rapidly worsening or refractory symptoms. In our article, we elaborate on key aspects of the epidemiology, pathogenesis, diagnostic evaluation, and therapeutic options for patients with myasthenia gravis.
Collapse
Affiliation(s)
- Yeeshu Arora
- Division of the Neuromuscular Center, Department of Neurology, Cleveland Clinic, Cleveland, OH
| | | |
Collapse
|
58
|
Gulbas G, Kaplan Y, Kamisli O, Ermis H, Kamisli S, Ozcan C. Neuromuscular transmission in hypoxemic patients with chronic obstructive pulmonary disease. Respir Physiol Neurobiol 2013; 189:112-6. [PMID: 23886635 DOI: 10.1016/j.resp.2013.07.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Revised: 07/16/2013] [Accepted: 07/16/2013] [Indexed: 11/18/2022]
Abstract
Many studies have focused on the systemic effects of chronic obstructive pulmonary disease (COPD), but none has examined neuromuscular junction transmission (NMT). We evaluated NMT dysfunction using single-fiber electromyography (SFEMG) in patients with COPD. Twenty patients with COPD and 20 age-matched healthy controls were included in the study. All patients and controls underwent SFEMG. Abnormal NMT was found in seven of 20 patients (35%), but in none of the control subjects. The COPD patients were subgrouped according to the presence of hypoxemia. The patients with normoxemia were classified as Group 1, and the patients with hypoxemia were classified as Group 2. Abnormal NMT was found in six patients in Group 2 and in one in Group 1. While there was significant difference in terms of abnormal NMT between Group 2 and the controls, there was none between Group 1 and the controls. Our results show that NMT abnormalities can be present in hypoxemic patients with COPD.
Collapse
Affiliation(s)
- Gazi Gulbas
- Inonu University, Department of Pulmonary Diseases, Turkey.
| | | | | | | | | | | |
Collapse
|
59
|
Liu M, Cui L, Guan Y, Li B, Du H. Single-fiber electromyography in amyotrophic lateral sclerosis and cervical spondylosis. Muscle Nerve 2013; 48:137-9. [PMID: 23696493 DOI: 10.1002/mus.23767] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Mingsheng Liu
- Department of Neurology; Peking Union Medical College Hospital, Chinese Academy of Medical Sciences; Beijing 100730 China
| | - Liying Cui
- Department of Neurology; Peking Union Medical College Hospital, Chinese Academy of Medical Sciences; Beijing 100730 China
| | - Yuzhou Guan
- Department of Neurology; Peking Union Medical College Hospital, Chinese Academy of Medical Sciences; Beijing 100730 China
| | - Benhong Li
- Department of Neurology; Peking Union Medical College Hospital, Chinese Academy of Medical Sciences; Beijing 100730 China
| | - Hua Du
- Department of Neurology; Peking Union Medical College Hospital, Chinese Academy of Medical Sciences; Beijing 100730 China
| |
Collapse
|
60
|
Cherian A, Baheti NN, Iype T. Electrophysiological study in neuromuscular junction disorders. Ann Indian Acad Neurol 2013; 16:34-41. [PMID: 23661960 PMCID: PMC3644779 DOI: 10.4103/0972-2327.107690] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 11/13/2011] [Accepted: 07/01/2012] [Indexed: 11/20/2022] Open
Abstract
This review is on ultrastructure and subcellular physiology at normal and abnormal neuromuscular junctions. The clinical and electrophysiological findings in myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes, and botulinum intoxication are discussed. Single fiber electromyography (SFEMG) helps to explain the basis of testing neuromuscular junction function by repetitive nerve stimulation (RNS). SFEMG requires skill and patience and its availability is limited to a few centers. For RNS supramaximal stimulation is essential and so is display of the whole waveform of each muscle response at maximum amplitude. The amplitudes of the negative phase of the first and fourth responses are measured from baseline to negative peak, and the percent change of the fourth response compared with the first represents the decrement or increment. A decrement greater than 10% is accepted as abnormal and smooth progression of response amplitude train and reproducibility form the crux. In suspected LEMS the effect of fast rates of stimulation should be determined after RNS response to slow rates of stimulation. Caution is required to avoid misinterpretation of potentiation and pseudofacilitation.
Collapse
Affiliation(s)
- Ajith Cherian
- Department of Neurology, Government Medical College, Trivandrum, Kerala, India
| | | | | |
Collapse
|
61
|
Kouyoumdjian JA, Stålberg E. Stimulated jitter with concentric needle in 42 myasthenia gravis patients. ARQUIVOS DE NEURO-PSIQUIATRIA 2013; 71:237-43. [DOI: 10.1590/0004-282x20130008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 10/26/2012] [Indexed: 11/22/2022]
Abstract
Objective: To estimate jitter parameters in myasthenia gravis in stimulated frontalis and extensor digitorum muscles using the concentric needle electrode. Methods: Forty-two confirmed myasthenia gravis patients, being 22 males (aged 45.6±17.2 years-old) were studied. Jitter was expressed as the mean consecutive difference (MCD). Results: MCD in extensor digitorum was 61.6 µs (abnormal in 85.7%) and in frontalis 57.3 µs (abnormal in 88.1%). Outliers represented 90.5% for extensor digitorum and 88.1% for frontalis. At least one jitter parameter was abnormal in 90.5% of the combined studies. Acetylcholine receptor antibody was abnormal in 85.7% of the cases. Conclusions: Stimulated jitter recordings measured from muscles using concentric needle electrode can be used for myasthenia gravis diagnosis with high sensitivity. Extensive normative studies are still lacking and, therefore, borderline findings should be judged with great caution.
Collapse
Affiliation(s)
- João Aris Kouyoumdjian
- Faculdade de Medicina de São José do Rio Preto (FAMERP); Neuromuscular Investigation Laboratory, Brazil
| | | |
Collapse
|
62
|
Evoli A, Padua L. Diagnosis and therapy of myasthenia gravis with antibodies to muscle-specific kinase. Autoimmun Rev 2013; 12:931-5. [PMID: 23535158 DOI: 10.1016/j.autrev.2013.03.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 01/01/2023]
Abstract
Myasthenia gravis (MG) with antibodies to the muscle-specific receptor tyrosine kinase (MuSK-MG) is a rare disease which covers 5-8% of all MG patients. Symptoms are nearly always generalized, though more focal than in MG with anti-acetylcholine receptor antibodies, with predominant involvement of cranial, bulbar and axial muscles; early respiratory crises are frequent. Focal atrophy, mostly of facial, masseter and tongue muscles, occurs in a proportion of patients. Diagnosis is often challenging on account of atypical presentation with little or no symptom fluctuations, lack of response to acetylcholinesterase inhibitors in a high proportion of patients and negative results of electrodiagnostic studies when performed on limb muscles. Immunosuppression is the mainstay of treatment, since the response to acetylcholinesterase inhibitors is generally unsatisfactory and thymectomy does not appear to improve the course of the disease. Although corticosteroids result in marked improvement, disease flares are frequent during prednisone dosage tapering and most patients remain dependent on treatment. Since treatment with rituximab, in uncontrolled studies, induced sustained benefit in patients with refractory disease, B cell depletion is an attractive option for MuSK-MG patients unresponsive to conventional immunosuppressants.
Collapse
Affiliation(s)
- Amelia Evoli
- Institute of Neurology, Catholic University, Largo F. Vito 1, 00168 Roma, Italy.
| | | |
Collapse
|
63
|
Abstract
Disorders of the neuromuscular junction, such as myasthenia gravis and Lambert-Eaton myasthenic syndrome, constitute an important and treatable class of diseases. Both disorders are typically caused by an immunologically mediated attack on discrete components of the neuromuscular junction, compromise the efficacy of neurotransmitter transmission, and produce clinically distinct syndromes of fatigable muscle weakness. Although the history, clinical examination, and routine antibody testing can be diagnostic in many cases, specialized neurophysiological tests, such as repetitive nerve stimulation and single-fiber electromyography, are essential tools in the diagnostic evaluation of patients with more complicated or atypical conditions. In this review, we introduce primary disorders of the neuromuscular junction, and discuss the salient clinical and laboratory workup appropriate for recognizing these disorders, and the typical findings seen on electrodiagnostic testing with repetitive nerve stimulation and single-fiber electromyography.
Collapse
|
64
|
Abstract
Electromyography (EMG) is an important diagnostic tool for the assessment of individuals with various neuromuscular diseases. It should be an extension of a thorough history and physical examination. Some prototypical characteristics and findings of EMG and nerve conduction studies are discussed; however, a more thorough discussion can be found in the textbooks and resources sited in the article. With an increase in molecular genetic diagnostics, EMG continues to play an important role in the diagnosis and management of patients with neuromuscular diseases and also provides a cost-effective diagnostic workup before ordering a battery of costly genetic tests.
Collapse
Affiliation(s)
- Bethany M Lipa
- Department of Physical Medicine and Rehabilitation, University of California Davis School of Medicine, 4860 Y Street, Suite 1700, Sacramento, CA 95817, USA.
| | | |
Collapse
|
65
|
Neuromuscular medicine competency in physical medicine and rehabilitation residents: a method of development and assessment. Am J Phys Med Rehabil 2012; 92:258-66. [PMID: 23128327 DOI: 10.1097/phm.0b013e3182745ed9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This project endeavored to create an educational module including methodology to instruct physical medicine and rehabilitation residents in the evaluation and appropriate treatment of patients with neuromuscular disorders. It further sought to verify acquired competencies in neuromuscular rehabilitation through objective evaluation methodology. An American Association of Neuromuscular and Electrodiagnostic Medicine board-certified physician with 10 yrs of clinical experience in neuromuscular and general rehabilitation trained 19 residents using a standardized competency-based module. The residents were trained through clinical training, lectures, and review of self-assessment examination concepts from the American Academy of Physical Medicine & Rehabilitation syllabus provided in the Archives of Physical Medicine and Rehabilitation. After delivery of the educational module, knowledge acquisition and skill proficiency were measured in (1) completion of neuromuscular history and physical examination satisfactorily, (2) diagnosis and ability to design a patient care management plan via chart stimulated recall examinations, (3) physician-patient interaction via patient surveys, (4) physician-staff interaction via 360-degree global ratings, and (5) ability to write a comprehensive patient care report and to document a patient care management plan in accordance with Medicare guidelines via written patient reports. Assessment tools developed for this program address the basic competencies outlined by the Accreditation Council for Graduate Medical Education. To test the success of the standardized educational module, data were collected on an ongoing basis. The objective measures compared resident self-assessment examination scores in neuromuscular rehabilitation before and after the institution of the comprehensive neuromuscular competency module in the residency program. Nineteen (100%) of 19 residents successfully demonstrated proficiency in every segment of the evaluation module by the end of the postgraduate year 2 inpatient neuromuscular rehabilitation rotation. Furthermore, the residents' proficiency, as demonstrated by the evaluation after the implementation of the standardized educational module, positively correlated with an increase in the residents' self-assessment examination scores in neuromuscular rehabilitation compared with the residents' scores before the educational module implementation throughout all 3 yrs of training. Resident proficiency in the skills and knowledge pertaining to neuromuscular rehabilitation were objectively verified after completion of the standardized educational module. Validation of the assessment tool is evidenced by the collected data correlating with significantly improved self-assessment examination scores, as outlined in the "RESULTS" section. In addition, the clinical development tool was validated by the residents being individually observed performing history and physical examinations and being deemed competent by the American Association of Neuromuscular and Electrodiagnostic Medicine board-certified physical medicine and rehabilitation physician. The standardized educational module and evaluation methodology provide a potential framework for the definition of baseline competency in the clinical training area of neuromuscular rehabilitation.
Collapse
|
66
|
Laryngeal electromyography: a proposal for guidelines of the European Laryngological Society. Eur Arch Otorhinolaryngol 2012; 269:2227-45. [DOI: 10.1007/s00405-012-2036-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 04/24/2012] [Indexed: 10/28/2022]
|
67
|
Narayanaswami P, Pantoja-Galicia N, Betensky RA, Rutkove SB. Application of futility analysis to refine jitter recordings in myasthenia gravis. Muscle Nerve 2012; 45:486-91. [PMID: 22431080 DOI: 10.1002/mus.22340] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
INTRODUCTION The current practice of single-fiber electromyography (SFEMG) requires that 20 fiber pairs with normal jitter be collected to exclude myasthenia gravis (MG). We applied principles of futility analysis from clinical trials in an attempt to reduce that requirement. METHODS We utilized conditional power futility analysis to assess the probability of an abnormal 20-pair SFEMG based on ongoing analysis of jitter as each pair is collected. Rules for early test termination in the presence of 0, 1, or 2 abnormal pairs were identified. These rules were then applied to previously collected SFEMG data. RESULTS SFEMG could be stopped at just 12 pairs if all are normal and at 17 pairs if 1 is abnormal. The rules successfully determined when SFEMG could be stopped in 104 of 106 (98%) studies originally reported to be normal. CONCLUSIONS If the first 12 SFEMG pairs have normal jitter, the study can be terminated and interpreted as normal.
Collapse
Affiliation(s)
- Pushpa Narayanaswami
- Department of Neurology, Harvard Medical School, Beth Israel Deaconess Medical Center, TCC-8, 330 Brookline Avenue, Boston, Massachusetts 02215, USA.
| | | | | | | |
Collapse
|
68
|
Gwathmey K, Balogun RA, Burns T. Neurologic indications for therapeutic plasma exchange: 2011 update. J Clin Apher 2012; 27:138-45. [DOI: 10.1002/jca.21219] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 02/21/2012] [Indexed: 12/17/2022]
|
69
|
Concurrent chronic motor axonal polyneuropathy and synaptic impairment of neuromuscular junction. J Clin Neuromuscul Dis 2012; 12:223-6. [PMID: 22361520 DOI: 10.1097/cnd.0b013e3181df2b18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Polyneuropathies may exhibits clinical, electrophysiologic signs of neuromuscular junction impairment. Distal motor nerve terminals and neuromuscular junction contain pre or postsynaptically specific targets for circulating autoantibodies, if present in neuropathies. Motor nerve terminal blockade either reversible or permanent is a putative factor of muscle weakness. A 59-year-old patient exhibited oropharyngeal, facial, extremity weakness, fluctuating fatigability, and areflexia. Elecectrophysiologic studies showed purely motor axonal polyneuropathy. Thenar, facial slow rate repetitive stimulation revealed up to 47% decrement of compound muscle action potential size. Single fiber electromyography on voluntary activation confirmed increased jitter and impulse blocking in all muscles examined in one third of the fibers. Repeated testings for antibodies to gangliosides, acetylcholine, muscle tyrosine kinase receptors, voltage-gated calcium channels were negative. Oral pyridostigmine bromide improved bulbar symptoms. Pulse intravenous immunoglobulin, oral steroids, and azathioprine had steady benefit. Impairment of neuromuscular transmission if occurring in chronic axonal neuropathies highlights mechanisms and significance of neuromuscular chronic "synaptopathies."
Collapse
|
70
|
Techniques and applications of EMG: measuring motor units from structure to function. J Neurol 2012; 259:585-94. [DOI: 10.1007/s00415-011-6350-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 11/30/2011] [Indexed: 12/14/2022]
|
71
|
Chroni E, Punga AR. Neurophysiological characteristics of MuSK antibody positive myasthenia gravis mice: focal denervation and hypersensitivity to acetylcholinesterase inhibitors. J Neurol Sci 2012; 316:150-7. [PMID: 22251934 DOI: 10.1016/j.jns.2011.12.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 12/20/2011] [Accepted: 12/22/2011] [Indexed: 11/17/2022]
Abstract
Myasthenia Gravis (MG) patients with antibodies against the muscle specific tyrosine kinase (MuSK+) typically present with focal fatigue and atrophy of the facial and bulbar muscles, along with unbeneficial reactions upon administration of acetylcholinesterase inhibitors (AChEIs). This study addresses the neurophysiological characteristics in facial versus limb muscles, before and after intraperitoneal injection of AChEIs, in mice immunized with MuSK. We performed in-vivo neurophysiological examinations in the masseter and gastrocnemius muscles of mice with MuSK+experimental autoimmune MG (EAMG) and in healthy control mice before and after administration of AChEIs. Abnormal spontaneous activity (fibrillations) was observed in the masseter muscle of MuSK+mice. Furthermore, 94% of MuSK-immunized mice displayed so called extra discharges (EDs) upon administration of a therapeutic AChEI dose, in contrast to 22% of the control mice, indicating neuromuscular hyperactivity. These findings support functional denervation in the masseter muscle and neuromuscular hypersensitivity already at a standard dose of AChEIs in MuSK+EAMG.
Collapse
Affiliation(s)
- Elisabeth Chroni
- Department of Neurology, School of Medicine, University of Patras, Patras, Greece
| | | |
Collapse
|
72
|
Kornegay JN, Bogan JR, Bogan DJ, Childers MK, Li J, Nghiem P, Detwiler DA, Larsen CA, Grange RW, Bhavaraju-Sanka RK, Tou S, Keene BP, Howard JF, Wang J, Fan Z, Schatzberg SJ, Styner MA, Flanigan KM, Xiao X, Hoffman EP. Canine models of Duchenne muscular dystrophy and their use in therapeutic strategies. Mamm Genome 2012; 23:85-108. [PMID: 22218699 DOI: 10.1007/s00335-011-9382-y] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 11/29/2011] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder in which the loss of dystrophin causes progressive degeneration of skeletal and cardiac muscle. Potential therapies that carry substantial risk, such as gene- and cell-based approaches, must first be tested in animal models, notably the mdx mouse and several dystrophin-deficient breeds of dogs, including golden retriever muscular dystrophy (GRMD). Affected dogs have a more severe phenotype, in keeping with that of DMD, so may better predict disease pathogenesis and treatment efficacy. Various phenotypic tests have been developed to characterize disease progression in the GRMD model. These biomarkers range from measures of strength and joint contractures to magnetic resonance imaging. Some of these tests are routinely used in clinical veterinary practice, while others require specialized equipment and expertise. By comparing serial measurements from treated and untreated groups, one can document improvement or delayed progression of disease. Potential treatments for DMD may be broadly categorized as molecular, cellular, or pharmacologic. The GRMD model has increasingly been used to assess efficacy of a range of these therapies. A number of these studies have provided largely general proof-of-concept for the treatment under study. Others have demonstrated efficacy using the biomarkers discussed. Importantly, just as symptoms in DMD vary among patients, GRMD dogs display remarkable phenotypic variation. Though confounding statistical analysis in preclinical trials, this variation offers insight regarding the role that modifier genes play in disease pathogenesis. By correlating functional and mRNA profiling results, gene targets for therapy development can be identified.
Collapse
Affiliation(s)
- Joe N Kornegay
- Department of Pathology and Laboratory Medicine, University of North Carolina-Chapel Hill, Chapel Hill, NC 27599, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
73
|
Bocci T, Pecori C, Giorli E, Briscese L, Tognazzi S, Caleo M, Sartucci F. Differential motor neuron impairment and axonal regeneration in sporadic and familiar amyotrophic lateral sclerosis with SOD-1 mutations: lessons from neurophysiology. Int J Mol Sci 2011; 12:9203-15. [PMID: 22272128 PMCID: PMC3257125 DOI: 10.3390/ijms12129203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2011] [Revised: 11/11/2011] [Accepted: 11/29/2011] [Indexed: 11/22/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a degenerative disorder of the motor system. About 10% of cases are familial and 20% of these families have point mutations in the Cu/Zn superoxide dismutase 1 (SOD-1) gene. SOD-1 catalyses the superoxide radical (O−2) into hydrogen peroxide and molecular oxygen. The clinical neurophysiology in ALS plays a fundamental role in differential diagnosis between the familial and sporadic forms and in the assessment of its severity and progression. Sixty ALS patients (34 males; 26 females) were enrolled in the study and examined basally (T0) and every 4 months (T1, T2, and T3). Fifteen of these patients are SOD-1 symptomatic mutation carriers (nine males, six females). We used Macro-EMG and Motor Unit Number Estimation (MUNE) in order to evaluate the neuronal loss and the re-innervation process at the onset of disease and during follow-up period. Results and Discussion: SOD-1 mutation carriers have a higher number of motor units at the moment of diagnosis when compared with the sporadic form, despite a more dramatic drop in later stages. Moreover, in familiar SOD-1 ALS there is not a specific time interval in which the axonal regeneration can balance the neuronal damage. Taken together, these results strengthen the idea of a different pathogenetic mechanism at the base of sALS and fALS.
Collapse
Affiliation(s)
- Tommaso Bocci
- Unit of Neurology, Department of Neuroscience, Pisa University Medical School, Pisa 56126, Italy; E-Mails: (T.B.); (C.P.); (E.G.); (L.B.); (S.T.)
- Department of Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Siena 53100, Italy
| | - Chiara Pecori
- Unit of Neurology, Department of Neuroscience, Pisa University Medical School, Pisa 56126, Italy; E-Mails: (T.B.); (C.P.); (E.G.); (L.B.); (S.T.)
| | - Elisa Giorli
- Unit of Neurology, Department of Neuroscience, Pisa University Medical School, Pisa 56126, Italy; E-Mails: (T.B.); (C.P.); (E.G.); (L.B.); (S.T.)
- Department of Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Siena 53100, Italy
| | - Lucia Briscese
- Unit of Neurology, Department of Neuroscience, Pisa University Medical School, Pisa 56126, Italy; E-Mails: (T.B.); (C.P.); (E.G.); (L.B.); (S.T.)
| | - Silvia Tognazzi
- Unit of Neurology, Department of Neuroscience, Pisa University Medical School, Pisa 56126, Italy; E-Mails: (T.B.); (C.P.); (E.G.); (L.B.); (S.T.)
| | - Matteo Caleo
- CNR Neuroscience Institute, Pisa 56124, Italy; E-Mail:
| | - Ferdinando Sartucci
- Unit of Neurology, Department of Neuroscience, Pisa University Medical School, Pisa 56126, Italy; E-Mails: (T.B.); (C.P.); (E.G.); (L.B.); (S.T.)
- CNR Neuroscience Institute, Pisa 56124, Italy; E-Mail:
- Department of Neuroscience, SD of Neurology, Cisanello Hospital, Pisa University Medical School, Pisa 56124, Italy
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-050-996760; Fax: +39-050-996767
| |
Collapse
|
74
|
Concentric needle jitter on stimulated frontalis and extensor digitorum in 20 myasthenia gravis patients. Muscle Nerve 2011; 44:912-8. [DOI: 10.1002/mus.22203] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
75
|
Single-fiber electromyography in hyperCKemia: the value of fiber density. Neurol Sci 2011; 33:819-24. [PMID: 22068218 DOI: 10.1007/s10072-011-0836-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2011] [Accepted: 10/21/2011] [Indexed: 10/15/2022]
Abstract
Although persistently raised serum creatine kinase (sCK), or hyperCKemia, is considered the biological hallmark of neuromuscular diseases, pauci- or asymptomatic- or isolated-hyperCKemia can often be found. Single-fiber electromyography (SFEMG) is an electrophysiological technique of great value in the assessment of neuromuscular, neuropathic and myopathic disorders. We hypothesize that SFEMG fiber density (FD) evaluation is able to detect subclinical electrophysiological abnormalities indicating a myopathic process in subjects with hyperCKemia. Nineteen subjects with hyperCKemia without evident clinical signs of muscle involvement and 15 healthy controls were studied. Electrophysiological investigations including nerve conduction studies (NCS), quantitative EMG (QEMG), SFEMG with focus on FD measurements, and muscle biopsy were performed. NCS, QEMG, SFEMG were normal in all controls. In subjects with hyperCKemia, NCS were normal; QEMG was abnormal in 5, while both SFEMG and muscle biopsy disclosed abnormalities in 12 subjects. The mean FD value was 2.6 ± 0.5 in the control and 4 ± 1.4 (p = 0.003) in the hyperCKemia group. SFEMG revealed subclinical changes in the majority of subjects with hyperCKemia. To the best of our knowledge, this is the first study demonstrating that SFEMG FD evaluation is able to detect the presence of muscle diseases, which are in a subclinical phase and would remain unidentified otherwise. SFEMG may be used to distinguish hyperCKemia associated to asymptomatic muscle disorders from idiopathic hyperCKemia. We believe that SFEMG FD evaluation should be added to the routine examinations in the screening of idiopathic hyperCKemia.
Collapse
|
76
|
Gwathmey K, Balogun RA, Burns T. Neurologic indications for therapeutic plasma exchange: An update. J Clin Apher 2011; 26:261-8. [DOI: 10.1002/jca.20298] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 07/05/2011] [Indexed: 12/18/2022]
|
77
|
Witoonpanich R, Dejthevaporn C, Sriphrapradang A, Pulkes T. Electrophysiological and immunological study in myasthenia gravis: Diagnostic sensitivity and correlation. Clin Neurophysiol 2011; 122:1873-7. [DOI: 10.1016/j.clinph.2011.02.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2010] [Revised: 02/09/2011] [Accepted: 02/21/2011] [Indexed: 11/16/2022]
|
78
|
Wijnberg ID, Sleutjens J, Van Der Kolk JH, Back W. Effect of head and neck position on outcome of quantitative neuromuscular diagnostic techniques in Warmblood riding horses directly following moderate exercise. Equine Vet J 2011:261-7. [PMID: 21059016 DOI: 10.1111/j.2042-3306.2010.00224.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
REASONS FOR PERFORMING STUDY There has been growing interest in training techniques with respect to the head and neck position (HNP) of the equine athlete. Little is known about the influence of HNP on neuromuscular transmission in neck muscles. OBJECTIVE To test the hypothesis that different HNPs have effect on single fibre (SF), quantitative electromyographic (QEMG) examination and muscle enzyme activity directly after moderate exercise. METHODS Seven Warmblood horses were studied using a standard exercise protocol in 5 HNPs: HNP1: unrestrained; HNP2: neck raised; bridge of nose around the vertical; HNP4: neck lowered and considerably flexed, bridge of nose pointing towards the chest; HNP5: neck raised and considerably extended; bridge of nose in front of the vertical; HNP7: neck lowered and flexed; bridge of nose pointing towards the carpus. Mean consecutive difference (MCD) of single muscle fibre potentials and motor unit action potential (MUP) variables (amplitude, duration, area, turns and phases) were recorded in each fixed position directly after exercise at rest using commercial EMG equipment. Muscle enzyme activity was measured before and 4, 6 and 24 h after exercise. RESULTS Mean consecutive difference in all HNPs was higher than in HNP1 (22 µs, P < 0.001) of which HNP4 was highest with 39 µs compared to 30 µs in HNP2 (P = 0.04); MCD in HNP 5,7 was with 25 µs lower than in HNP 2 and 4 (P < 0.001). Odds ratio for MCD suggestive for conduction delay or block was 13.6 in HNP4 compared to HNP1 (P < 0.001). Motion unit action potential variables followed the same pattern as MCD. Lactate dehydrogenase (LDH) activity increased in HNP4 at 4 h (P = 0.014), 6 h (P = 0.017) and 24 h (P = 0.038) post exercise and in HNP5 and HNP7 at 4 h (P = 0.037; 0.029). CONCLUSIONS AND CLINICAL RELEVANCE HNP4 in particular leads to a higher rise in LDH activity, MCD and MUP variables, indicating that HNPs have effect on variables characterising neuromuscular functionality.
Collapse
Affiliation(s)
- I D Wijnberg
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
| | | | | | | |
Collapse
|
79
|
Selvan VA. Single-fiber EMG: A review. Ann Indian Acad Neurol 2011; 14:64-7. [PMID: 21654930 PMCID: PMC3108086 DOI: 10.4103/0972-2327.78058] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 02/01/2011] [Accepted: 02/05/2011] [Indexed: 11/05/2022] Open
Affiliation(s)
- V Arul Selvan
- Walton Center for Neurology and Neurosurgery, Lower Lane, Fazakerley, L9 7LJ, Liverpool, UK
| |
Collapse
|
80
|
Activity-dependent changes in impulse conduction of single human motor axons: a stimulated single fiber electromyography study. Clin Neurophysiol 2011; 122:2512-7. [PMID: 21664178 DOI: 10.1016/j.clinph.2011.05.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Revised: 04/30/2011] [Accepted: 05/04/2011] [Indexed: 11/23/2022]
Abstract
OBJECTIVE The aim of this study is to develop a novel method to assess activity-dependent hyperpolarization in human single motor axons at a constant stimulus frequency by using intra-muscular axonal stimulating single fiber electromyography (s-SFEMG). METHODS We performed s-SFEMG in the extensor digitorum communis (EDC) muscle of 10 normal subjects, and measured changes in latencies for single muscle fiber action potentials (MAPs) during 500 stimuli delivered at 5, 10 and 20 Hz. The data were analyzed with a repeated measurement analysis, and multiple comparisons were performed. RESULTS A total of 585 MAPs were examined at 5 Hz (n=190), 10 Hz (n=210), and 20 Hz (n=185) steady stimulation. There was a progressive linear prolongation of latencies, as the stimulus rate increased (F=95.6, p<0.001); the least square means (SEM) of latency change were 100.7 (0.28)% at 5 Hz, 102.3 (0.27)% at 10 Hz and 105.3 (0.28)% at 20 Hz. There were statistically significant differences between frequencies by Tukey-Kramer's method. Despite the significant latency prolongation, no activity-dependent conduction block developed. A 20 Hz electric stimulation to intramuscular axons was well-tolerated in all the subjects. CONCLUSIONS Tetanic stimulation at a constant rate results in significant latency increase in single human motor axons, the extent of which depends on the stimulus frequency. The findings imply that physiological discharge rates will activate the Na(+)/K(+) pump and thereby produce axonal hyperpolarization in single motor axons. SIGNIFICANCE This technique may detect activity-dependent conduction block if the safety margin of impulse transmission is significantly reduced by demyelination or increased branching due to collateral sprouting in a variety of neuromuscular disorders.
Collapse
|
81
|
Riley DA, Burns AS, Carrion-Jones M, Dillingham TR. Electrophysiological Dysfunction in the Peripheral Nervous System Following Spinal Cord Injury. PM R 2011; 3:419-25; quiz 425. [DOI: 10.1016/j.pmrj.2010.12.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 11/20/2010] [Accepted: 12/22/2010] [Indexed: 10/18/2022]
|
82
|
Kouyoumdjian JA, Stålberg EV. Concentric needle jitter on stimulated Orbicularis Oculi in 50 healthy subjects. Clin Neurophysiol 2011; 122:617-622. [DOI: 10.1016/j.clinph.2010.07.012] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Revised: 07/05/2010] [Accepted: 07/09/2010] [Indexed: 11/24/2022]
|
83
|
Witoonpanich R, Pulkes T, Dejthevaporn C, Yodnopklao P, Witoonpanich P, Wetchaphanphesat S, Brengman JM, Engel AG. Phenotypic heterogeneity in a large Thai slow-channel congenital myasthenic syndrome kinship. Neuromuscul Disord 2011; 21:214-8. [PMID: 21316238 PMCID: PMC3327811 DOI: 10.1016/j.nmd.2010.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Revised: 10/20/2010] [Accepted: 12/13/2010] [Indexed: 11/28/2022]
Abstract
The slow-channel congenital myasthenic syndrome (SCCMS) is an autosomal dominant neuromuscular disorder caused by mutations in different subunits of the acetylcholine receptor (AChR). We here report our clinical findings in three generations of a large Thai kinship suffering from SCCMS and trace the disease to the p.Gly153Ser mutation in the AChR α subunit. The same mutation had previously been reported only in Caucasian but not in Asian patients. The clinical features include ptosis, ophthalmoparesis, and weakness of the cervical and finger extensor muscles as well as marked phenotypic heterogeneity.
Collapse
Affiliation(s)
- Rawiphan Witoonpanich
- Division of Neurology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand.
| | | | | | | | | | | | | | | |
Collapse
|
84
|
Sartucci F, Moscato G, Rossi C, Caleo M, Bocci T, Murri L, Giannini F, Rossi A. Macro-EMG and MUNE Changes in Patients with Amyotrophic Lateral Sclerosis: One-Year Follow Up. Int J Neurosci 2011; 121:257-66. [DOI: 10.3109/00207454.2010.550404] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
85
|
Mercelis R, Merckaert V. Diagnostic utility of stimulated single-fiber electromyography of the orbicularis oculi muscle in patients with suspected ocular myasthenia. Muscle Nerve 2011; 43:168-70. [PMID: 21254079 DOI: 10.1002/mus.21853] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Stimulated single-fiber electromyography (SSFEMG) is a valuable diagnostic tool in cases of myasthenia gravis with limited disease. From 1990 to 2008 SSFEMG in the orbicularis oculi muscle (OO) was performed in a cohort of 456 patients referred with clinical suspicion of myasthenia gravis (MG) and exclusively ocular symptoms. A diagnosis of MG was made on clinical grounds in 103 patients. In this patient cohort, the specificity of SSFEMG for myasthenia was 97%, and the sensitivity was 80%. MG patients with a normal SSFEMG had a benign clinical course. This study confirms a high specificity and sensitivity of SSFEMG when it is performed on patients suspected to have ocular MG. In such patients, a normal SSFEMG of the OO predicts a benign clinical course.
Collapse
Affiliation(s)
- Rudy Mercelis
- Department of Neurology, Antwerp University Hospital, Wilrijkstraat 10, Antwerp B2650, Belgium.
| | | |
Collapse
|
86
|
Argov Z. Current approach to seronegative myasthenia. J Neurol 2010; 258:14-8. [PMID: 20852878 DOI: 10.1007/s00415-010-5746-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 09/03/2010] [Indexed: 10/19/2022]
|
87
|
No Increased Neuromuscular Jitter at Rabbit Skeletal Muscle Trigger Spot Spontaneous Electrical Activity Sites. ACTA ACUST UNITED AC 2010. [DOI: 10.1300/j094v08n03_06] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
88
|
Abstract
Neuromuscular jitter is generally recorded with a single fiber (SF) electromyography (EMG) electrode. Due to concern about using reusable needle electrodes, an acceptable alternative for the SF electrode has been sought. This is a review of the issues involved in using disposable concentric needle (CN) electrodes to measure jitter. Signals recorded with CN electrodes frequently represent the summation of many single fiber action potentials, which will decrease the apparent jitter. The influence of these artifacts on the final result also depends on the analysis method. Reference values obtained with CN electrodes correlate with SF EMG values, but they are a few microseconds lower. Overall results show that the CN method is a good alternative to SFEMG and will facilitate the use of jitter analysis. The results must be interpreted with caution, particularly in borderline cases, but they may be acceptable for clinical use when SF electrodes cannot be used.
Collapse
Affiliation(s)
- Erik V Stålberg
- Department of Clinical Neurophysiology, University Hospital, Uppsala, S-751 85 Sweden.
| | | |
Collapse
|
89
|
Lukács M, Vécsei L, Beniczky S. Fiber density of the motor units recruited at high and low force output. Muscle Nerve 2009; 40:112-4. [PMID: 19533643 DOI: 10.1002/mus.21241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Motor units (MUs) are recruited according to the size principle. At low force output, macro-motor unit potentials (macro-MUPs) with small amplitude and area are recorded; MUs with large electrical size fire at high force output. Our objective was to elucidate whether this difference is caused by a higher fiber density (FD) of the MUs recruited at high force output. We measured the FD and respectively the amplitude and the area of the macro-MUPs via single-fiber macro electromyography (EMG) recorded at low and high force output in 48 healthy subjects. The macro-MUPs were significantly larger at high force output than at low force. The FD did not differ at the two force levels. Our findings suggest that the larger electrical size of the high recruitment threshold MUs is due not to a higher FD, but to a larger territory. FD is a robust EMG parameter, independent of the level of the force output.
Collapse
Affiliation(s)
- Miklós Lukács
- Department of Neurology, University of Szeged, Semmelweis u. 6, H-6725, Szeged, Hungary.
| | | | | |
Collapse
|
90
|
Changes in muscle fiber density following a stroke. Clin Neurophysiol 2009; 120:1539-42. [PMID: 19564129 DOI: 10.1016/j.clinph.2009.06.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2009] [Revised: 05/30/2009] [Accepted: 06/03/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Previous studies have revealed a selective functional loss of the large, high-threshold motor units in the paretic muscles after lesion of the upper motor neuron. We set out to study the degree and the time course of the reorganization of the motor units following a stroke. METHODS Examinations were performed on 59 patients with a unilateral ischemic stroke in the territory of the middle cerebral artery, and on 42 healthy controls. The duration of hemiparesis ranged from 2 weeks to 48 months. The fiber density (FD) in the abductor digiti minimi muscle was determined by means of single-fiber electromyography on both the hemiparetic and the unaffected side in the patients, and unilaterally in the control subjects. RESULTS The FD was increased on the hemiparetic side relative to the unaffected side and the control group. This change correlated with the severity of the clinical signs. The FD increased during the first 10 months following the stroke and subsequently remained stable. CONCLUSIONS The process of reinnervation in the muscles takes place in the acute phase after stroke. These changes are related to the severity of the symptoms. SIGNIFICANCE Our findings suggest that trans-synaptic degeneration of the spinal motor neurons occurs shortly after the lesion of the upper motor neurons.
Collapse
|
91
|
Blitzer A, Crumley RL, Dailey SH, Ford CN, Floeter MK, Hillel AD, Hoffman HT, Ludlow CL, Merati A, Munin MC, Robinson LR, Rosen C, Saxon KG, Sulica L, Thibeault SL, Titze I, Woo P, Woodson GE. Recommendations of the Neurolaryngology Study Group on laryngeal electromyography. Otolaryngol Head Neck Surg 2009; 140:782-793. [PMID: 19467391 PMCID: PMC2758662 DOI: 10.1016/j.otohns.2009.01.026] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 12/08/2008] [Accepted: 01/15/2009] [Indexed: 11/17/2022]
Abstract
The Neurolaryngology Study Group convened a multidisciplinary panel of experts in neuromuscular physiology, electromyography, physical medicine and rehabilitation, neurology, and laryngology to meet with interested members from the American Academy of Otolaryngology Head and Neck Surgery, the Neurolaryngology Subcommittee and the Neurolaryngology Study Group to address the use of laryngeal electromyography (LEMG) for electrodiagnosis of laryngeal disorders. The panel addressed the use of LEMG for: 1) diagnosis of vocal fold paresis, 2) best practice application of equipment and techniques for LEMG, 3) estimation of time of injury and prediction of recovery of neural injuries, 4) diagnosis of neuromuscular diseases of the laryngeal muscles, and, 5) differentiation between central nervous system and behaviorally based laryngeal disorders. The panel also addressed establishing standardized techniques and methods for future assessment of LEMG sensitivity, specificity and reliability for identification, assessment and prognosis of neurolaryngeal disorders. Previously an evidence-based review of the clinical utility of LEMG published in 2004 only found evidence supported that LEMG was possibly useful for guiding injections of botulinum toxin into the laryngeal muscles. An updated traditional/narrative literature review and expert opinions were used to direct discussion and format conclusions. In current clinical practice, LEMG is a qualitative and not a quantitative examination. Specific recommendations were made to standardize electrode types, muscles to be sampled, sampling techniques, and reporting requirements. Prospective studies are needed to determine the clinical utility of LEMG. Use of the standardized methods and reporting will support future studies correlating electro-diagnostic findings with voice and upper airway function.
Collapse
Affiliation(s)
| | - Roger L. Crumley
- Department of Otolaryngology-Head and neck Surgery, University of California-Irvine, CA
| | - Seth H. Dailey
- Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Charles N. Ford
- Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Mary Kay Floeter
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Allen D. Hillel
- Department of Otolaryngology – Head and Neck Surgery, University of Washington School of Medicine, Seattle, WA
| | - Henry T. Hoffman
- Department of Otolaryngology-Head and Neck Surgery, University of Iowa, Iowa City, IA
| | - Christy L. Ludlow
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD
| | - Albert Merati
- Department of Otolaryngology – Head and Neck Surgery, University of Washington School of Medicine, Seattle, WA
| | - Michael C. Munin
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Lawrence R. Robinson
- Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, WA
| | - Clark Rosen
- Department of Otolaryngology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Keith G. Saxon
- Department of Surgery, Division of Otolaryngology, Harvard Medical School, Boston MA
| | - Lucian Sulica
- Department of Otorhinolaryngology, Weill Medical College of Cornell University, NYC, NY
| | - Susan L. Thibeault
- Division of Otolaryngology-Head and Neck Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | | | - Peak Woo
- Department of Otolaryngology, Mt Sinai School of Medicine, New York, NY
| | - Gayle E. Woodson
- Department of Otolaryngology-Head and Neck Surgery, Southern Illinois University, Springfield, IL
| |
Collapse
|
92
|
Zivari Adab H, Firoozabadi SMP, Chalavi S, Maghooli K. Simulation and analysis of needle electromyogram in Emery-Dreifuss muscular dystrophy by using line source model. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2009; 2008:338-42. [PMID: 19162662 DOI: 10.1109/iembs.2008.4649159] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Electromyography (EMG) is a valuable clinical test in detection of muscle and nerve pathology and distinguishing between myogenic and neurogenic conditions from normal condition. By using EMG, one assesses the pathophysiology on the basis of the waveform characteristics of the recorded signal. This requires detailed knowledge of the relationship between the waveform generators and the waveform measurements. In this study, we manipulated parameters of improved line source model for normal EMG generation to simulate Emery-Dreifuss Muscular Dystrophy (EDMD) disease. Common features of simulated signals in normal and EDMD conditions were extracted and quantitative analyses were performed. Finally, the simulation results and clinical results were compared and discussed. The results indicate the ability and validity of line source model in simulation EDMD disease and also confirm that EMG recordings in EDMD generally fulfill the criteria for myopathy.
Collapse
Affiliation(s)
- H Zivari Adab
- Biomedical Engineering School, Islamic Azad University, Tehran, Iran.
| | | | | | | |
Collapse
|
93
|
Farrugia ME, Weir AI, Cleary M, Cooper S, Metcalfe R, Mallik A. Concentric and single fiber needle electrodes yield comparable jitter results in myasthenia gravis. Muscle Nerve 2009; 39:579-85. [DOI: 10.1002/mus.21151] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
94
|
Jayawardane P, Senanayake N, Dawson A. Electrophysiological correlates of intermediate syndrome following acute organophosphate poisoning. Clin Toxicol (Phila) 2009; 47:193-205. [DOI: 10.1080/15563650902832608] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
95
|
Kaux JF, Ongena F, Wang F, Crielaard JM, Foidart-Dessalle M. Sudden dysphagia in an elderly, quadriparetic patient. Ann Phys Rehabil Med 2009; 52:59-65. [PMID: 19419659 DOI: 10.1016/j.rehab.2008.11.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2008] [Accepted: 11/20/2008] [Indexed: 11/25/2022]
|
96
|
Kouyoumdjian JA, Stålberg EV. Reference jitter values for concentric needle electrodes in voluntarily activated extensor digitorum communis and orbicularis oculi muscles. Muscle Nerve 2008; 37:694-9. [PMID: 18506720 DOI: 10.1002/mus.21043] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The aim of this study was to estimate normal jitter in voluntarily activated extensor digitorum communis (EDC) and orbicularis oculi (OOc) muscles using a disposable concentric needle electrode (CNE). The EDC of 67 normal subjects (22 males and 45 females, mean age 35.5 +/- 10.2 years) and the OOc of 50 normal subjects (13 males and 37 females, mean age 37.9 +/- 9.6 years) were studied. Jitter values were expressed as the mean consecutive difference (MCD) of 20 potential pairs. The mean MCD for EDC was 23.6 +/- 3.1 micros (upper 95% confidence limit [CL]: 29.7 micros). The mean MCD of all potential pairs (n = 1340) was 23.5 +/- 7.3 micros (95% CL: 38.2 micros). The mean MCD for the 18th highest value was 31.4 +/- 4.9 micros (95% CL: 41.2 micros). The mean MCD for OOc was 24.7 +/- 3.1 micros (95% CL: 31.0 micros). The mean MCD of all potential pairs (n = 1000) was 24.7 +/- 7.1 micros (95% CL: 39.0 micros). The mean MCD for the 18th highest value was 32.7 +/- 4.1 micros (95% CL: 40.9 micros). Our reported CNE jitter values obtained during voluntary activation represent the largest series currently available. The suggested practical limit in the EDC for mean MCD was 30 mus and for outliers was 42 micros, and in the OOc for mean MCD was 31 micros and 41 micros for outliers. The present study confirms that CNE can be used to assess jitter values, although certain precautions must be taken.
Collapse
Affiliation(s)
- João Aris Kouyoumdjian
- Faculdade de Medicina de São José do Rio Preto, Department of Neurological Sciences, Neuromuscular Investigation Laboratory, Rua Luiz Antonio Silveira 1661, São Paulo 15025-020, Brazil.
| | | |
Collapse
|
97
|
Concentric needle single fiber electromyography: Comparative jitter on voluntary-activated and stimulated Extensor Digitorum Communis. Clin Neurophysiol 2008; 119:1614-8. [DOI: 10.1016/j.clinph.2008.03.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2007] [Revised: 01/26/2008] [Accepted: 03/06/2008] [Indexed: 11/24/2022]
|
98
|
Abstract
PURPOSE OF REVIEW Increasing rigor is being applied to medical decision making, but myasthenia gravis, commonly considered the best understood autoimmune disorder from a pathophysiological basis, lags other disciplines in the evidence base used to make clinical decisions. The review attempts to provide a focused, practical guideline for the diagnosis and treatment of ocular myasthenia within the limits of largely retrospective case series and expert opinion. RECENT FINDINGS Confirmation of clinical diagnosis continues to be challenging for ocular myasthenia. Despite the recognition of a new autoantigen, the muscle-specific kinase protein in generalized myasthenia gravis, it has been found to be only rarely identified in ocular myasthenia patients and therefore the majority of patients lack detectable autoantibodies and confirmation of a neuromuscular transmission disorder relies on specialized testing of single-fiber electromyography. The visual compromise of ocular myasthenia responds poorly to nonpharmacological and cholinesterase inhibitor therapy, and although corticosteroids are thought to be extremely effective, their toxicity is poorly defined in ocular myasthenia patients and whether they reduce the risk of development of generalized disease is not known. SUMMARY Rigorous clinical trials or large databases with outcome assessments are necessary in order to allow development of rational treatment strategies.
Collapse
|
99
|
Sener H, Yaman A. Effect of High Temperature on Neuromuscular Jitter in Myasthenia Gravis. Eur Neurol 2008; 59:179-82. [DOI: 10.1159/000114039] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Accepted: 08/17/2007] [Indexed: 11/19/2022]
|
100
|
Harper CM. Electromyographic aspects of neuromuscular junction disorders. HANDBOOK OF CLINICAL NEUROLOGY 2008; 91:149-68. [PMID: 18631842 DOI: 10.1016/s0072-9752(07)01504-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- C Michel Harper
- Mayo Clinic College of Medicine, Department of Neurology, Mayo Clinic, Rochester, MN, USA.
| |
Collapse
|