Prognosis of myasthenia gravis: A multicenter follow-up study of 844 patients

Beghi, Ettore; Antozzi, Carlo; Batocchi, Anna Paola; Cornelio, F.; Cosi, V.; Evoli, Amelia; Lombardi, M.; Mantegazza, Renato; Monticelli, M; Piccolo, G.; Tonali, P.; Trevisan, Daniela; Zarrelli, Michele

doi:10.1016/0022-510x(91)90260-e

Cited by 112 publications

(99 citation statements)

References 23 publications

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“…4,5 Nevertheless, up to 46% of patients do not receive the correct diagnosis within the first year of onset. 6,7 The most common ancillary tests include antibody assays, electrophysiological tests (repetitive nerve stimulation, RNS or single-fiber electromyography, SFEMG) and edrophonium test. In isolated ocular MG, however, these tests exhibit a reduced sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Ocular vestibular evoked myogenic potentials as a test for myasthenia gravis

et al. 2016

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OBJECTIVE To explore whether ocular vestibular evoked myogenic potentials (oVEMP) can be used to detect a decrement in the extraocular muscle activity of patients with myasthenia gravis (MG). METHODS Twenty-seven patients with MG, including 13 with isolated ocular and 14 with generalized MG, and 28 healthy controls participated. We applied repetitive vibration stimuli to the forehead and recorded the activity of the inferior oblique muscle with 2 surface electrodes placed beneath the eyes. To identify the oVEMP parameters with the highest sensitivity and specificity, we evaluated the decrement over 10 stimulus repetitions at 3 different repetition rates (3 Hz, 10 Hz, and 20 Hz). RESULTS Repetitive stimulation at 20 Hz yielded the best differentiation between patients with MG and controls with a sensitivity of 89% and a specificity of 64% when using a unilateral decrement of 15.2% as cutoff. When using a bilateral decrement of 20.4% instead, oVEMP allowed differentiation of MG from healthy controls with 100% specificity, but slightly reduced sensitivity of 63%. For both cutoffs, sensitivity was similar in isolated ocular and generalized MG. CONCLUSION Our study demonstrates that the presence of an oVEMP decrement is a sensitive and specific marker for MG. This test allows direct and noninvasive examination of extraocular muscle activity, with similarly good diagnostic accuracy in ocular and generalized MG. Thus, oVEMP represents a promising diagnostic tool for MG. CLASSIFICATION OF EVIDENCE This study provides Class III evidence that oVEMP testing accurately identifies patients with MG with ocular symptoms (sensitivity 89%, specificity 64%). Author contributions:Yulia Valko collected and analyzed the data and wrote the manuscript.Sally Rosengren contributed to the study design, data analysis and writing of the manuscript.Hans Jung contributed to the patient examination and review of the manuscript.Dominik Straumann contributed to the study design, data analysis and review of the manuscript.Klara Landau contributed to the study design, patient examination and review of the manuscript.Konrad Weber designed the study, contributed to data collection, data analysis and writing of the manuscript, and conducted the statistical analysis.Study funding: the study was supported by a research grant of the University of Zurich (Forschungskredit der Universität Zürich).Disclosure Agreement: All authors report no disclosures.Valko et al. 3 AbstractObjective: To explore whether ocular vestibular evoked myogenic potentials (oVEMP)can be used to detect a decrement in the extraocular muscle activity of myasthenia gravis (MG) patients.Methods: Twenty-seven MG patients, including 13 with isolated ocular and 14 with generalized MG and 28 healthy subjects participated. We applied repetitive vibration stimuli to the forehead and recorded the activity of the inferior oblique muscle with two surface electrodes placed beneath the eyes. To identify the oVEMP parameters with the highest sensitivity and specificity, we evaluated th...

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Section: Introductionmentioning

confidence: 99%

Ocular vestibular evoked myogenic potentials as a test for myasthenia gravis

et al. 2016

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“…Articles describing the same cohort are grouped in the same row. The article by Beghi et al 15 describes a subset of the cohort of Mantegazza et al 17 The matched cohort of Buckingham et al 27 likely included subjects described initially by Eaton and Clagett. 35 Authors assembled cohorts from MG patients referred to tertiary care centers or neuromuscular clinics.…”

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confidence: 99%

Practice parameter: Thymectomy for autoimmune myasthenia gravis (an evidence-based review) [RETIRED]

2000

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The Quality Standards Subcommittee of the American Academy of Neurology is charged with developing practice parameters for neurologists for diagnostic procedures, treatment modalities, and clinical disorders. The selection of topics for which practice parameters are used is based on prevalence, frequency of use, economic impact, membership involvement, controversy, urgency, external constraints, and resources required. This paper addresses the role of thymectomy in the treatment of nonthymomatous autoimmune MG.In 1939, Blalock et al. 1 reported the remission of generalized MG in a 21-year-old woman after removal of a cystic thymic tumor. Subsequently, Blalock et al.2,3 performed thymectomy on MG patients without thymoma, found hyperplasia in the thymus glands, and reported improvement in at least half of their patients. Since these reports, thymectomy, with or without the presence of thymoma, has gained widespread acceptance as a form of treatment for MG.Because a definitive study of the effectiveness of thymectomy has never been done, 4,5 the role of thymectomy in the management of MG remains uncertain. Nevertheless, physicians have to advise their patients regarding the benefits of thymectomy based on the existing literature. Our goal is to develop evidence-based recommendations for clinicians considering thymectomy for patients with nonthymomatous autoimmune MG by performing a systematic review and analysis of the literature. Process. Identification and selection of studies.We searched the National Library of Medicine's Medline database from 1966 to February 1998 using the medical subject headings "myasthenia gravis" (restricted to the surgery subheading) and "thymectomy." To identify articles published before 1966, or missed by our original search strategy, we reviewed the references of the identified articles.We classified the resulting articles into the following categories: Class II, controlled but nonrandomized studies describing outcomes in MG patients with and without thymectomy; and Class III, uncontrolled case series describing outcomes in patients with or without thymectomy.Within a given controlled (Class II) study, we planned to describe the therapeutic effect of thymectomy by comparing the rate MG patients receiving thymectomy achieved desirable outcomes with the rate MG patients not receiving thymectomy achieved desirable outcomes. The nonrandomized nature of Class II studies often introduces differences in the baseline characteristics of the thymectomy and nonthymectomy patient groups that can effect MG outcomes independent of thymectomy. To the extent possible, we planned to adjust for these confounding differences in baseline prognostic characteristics. In the absence of randomized controlled trials, such adjustments are critical for estimating the actual therapeutic effect, if any, of thymectomy. 6Between uncontrolled (Class III) studies, comparisons of outcome rates in thymectomy and nonthymectomy MG patients introduce additional confounding baseline differences.6 These additional confounde...

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“…We know that in older patients the pattern of muscle involvement changes, becoming predominantly restricted to the ocular and bulbar groups, as does their response to treatment. 5 Overall older patients have a less favourable outcome in both ocular myasthenia 1 and MG, 6 but we are not aware of any reports that age, per se, increases the severity or rapidity of onset of the disease.…”

Section: Commentmentioning

confidence: 98%

“…Extrapolating from reports on the generalised form of myasthenia, acute severe cases are predicted to do badly. In their review of MG, Beghi et al 6 found that the outcome of myasthenia was directly related to the severity of the disease at presentation. In general there was a poor response to anticholinesterases but a good response to immunosuppressive therapy, as was the case here.…”

Section: Commentmentioning

confidence: 99%