EDITORIAL

Myoclonic atonic epilepsy Another generalized epilepsy syndrome that is “not so” generalized

John M. Zempel, MD, Myoclonic atonic/astatic epilepsy (MAE), first described PhD well by Doose1 (pronounced dough sah: http://www. Tadaaki Mano, MD, PhD youtube.com/watch?v5hNNiWXV2wF0), is a generalized electroclinical syndrome with early onset characterized by myoclonic, atonic/astatic, generalized Correspondence to tonic-clonic, and absence seizures (but not tonic Dr. Zempel: seizures) in association with generalized spike-wave [email protected] (GSW) discharges. Thought to have a genetic component that has proven to be complicated,2 MAE Neurology® 2014;82:1486–1487 sometimes occurs in children who have otherwise been developing normally and has variable outcome. MAE is typically treated with antiseizure medications that are used for generalized epilepsy syndromes, with perhaps a best response to valproate, felbamate, or the ketogenic diet.3,4 In this issue of Neurology®, Moeller et al.5 report on the fMRI correlates of GSW discharges as measured with simultaneous EEG during sleep in children with a clinical diagnosis of MAE. They were able to obtain blood oxygen level–dependent (BOLD) fMRI signal changes in most individual participants. This study, like other EEG-fMRI studies of the generalized epilepsies, shows that fMRI activations involve selective brain networks that are more localized than the widespread EEG discharges associated with generalized epilepsies. Group fMRI analysis showed BOLD signal increases in the thalamus, putamen, and premotor cortex, with BOLD signal decreases in nodes of the default mode network (posterior cingulate/precuneus and lateral parietal cortex/inferior parietal lobule). In addition to the common brain networks highlighted in other generalized epilepsy syndromes with thalamic activation and posterior cingulate/precuneus deactivation, children with MAE have prominent activation of nodes of the motor network, consistent with the motor features of the common myoclonic atonic/astatic seizures seen in this distinctive electroclinical syndrome. More generally, the results of this study are in line with a broadly developing theme in the study of childhood generalized epilepsy syndromes. EEG-fMRI studies of childhood absence epilepsy

have shown predominant thalamic activation and default mode network deactivation.6–8 Even Lennox-Gastaut syndrome, a devastating epileptic encephalopathy with EEG findings of runs of slow spike and wave and paroxysmal higher frequency activity, has fMRI correlates that are more focal than expected in a syndrome with widespread EEG abnormalities.9,10 EEG-fMRI is maturing as a research and clinical technique. Recording scalp EEG in an electrically hostile environment is not an easy task. Substantial technical artifacts, such as changing imaging gradients and ballistocardiogram (ECG-linked artifact observed in the scalp electrodes), contaminate the EEG signal. However, the relatively distinctive EEG discharges in patients with epilepsy have partially circumvented this problem. EEG-fMRI even has applicability to young pediatric populations6–8 and was performed by Moeller et al.5 with chloral hydrate–induced sleep in mostly young children (ages 3–13 years, but mostly 3–5). Clinically, EEG-fMRI is advancing in both technology and utilization across many types of epilepsy. EEG-fMRI localization is used increasingly in focal epilepsies, where more precise localization may lead to successful surgical treatment.11 EEG-fMRI may eventually have clinical utility in the generalized epilepsies, for both treatment and diagnosis. The response to treatment with valproate, for example, is related to the generator of the GSW discharge.12 EEG-fMRI may be particularly helpful diagnostically by providing a biomarker for distinguishing subtypes of these often overlapping generalized epilepsy syndromes. The BOLD signal fingerprint may provide both syndrome- and patient-specific information as the underlying causes of the many related generalized syndromes are better understood.13 AUTHOR CONTRIBUTIONS John M. Zempel: drafting/revising the manuscript, study concept or design. Tadaaki Mano: study concept or design, study supervision.

STUDY FUNDING No targeted funding reported.

See page 1508 From the Department of Neurology and Pediatrics (J.M.Z.), Washington University School of Medicine, St. Louis, MO; and Gifu University of Medical Science (T.M.), Seki, Gifu, Japan. Go to Neurology.org for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the editorial. 1486

© 2014 American Academy of Neurology

DISCLOSURE

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The authors report no disclosures relevant to the manuscript. Go to Neurology.org for full disclosures.

REFERENCES 1. Doose H. Myoclonic-astatic epilepsy. Epilepsy Res Suppl 1992;6:163–168. 2. Tang S, Pal DK. Dissecting the genetic basis of myoclonicastatic epilepsy. Epilepsia 2012;53:1303–1313. 3. Zupanc ML, Roell Werner R, Schwabe MS, et al. Efficacy of felbamate in the treatment of intractable pediatric epilepsy. Pediatr Neurol 2010;42:396–403. 4. Kelley SA, Kossoff EH. Doose syndrome (myoclonicastatic epilepsy): 40 years of progress. Dev Med Child Neurol 2010;52:988–993. 5. Moeller F, Groening K, Moehring J, et al. EEG-fMRI in myoclonic astatic epilepsy (Doose syndrome). Neurology 2014;82:1508–1513. 6. Moeller F, Siebner HR, Wolff S, et al. Simultaneous EEGfMRI in drug-naive children with newly diagnosed absence epilepsy. Epilepsia 2008;49:1510–1519. 7. Bai X, Vestal M, Berman R, et al. Dynamic time course of typical childhood absence seizures: EEG, behavior, and functional magnetic resonance imaging. J Neurosci 2010; 30:5884–5893.

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Carney PW, Masterton RA, Harvey AS, Scheffer IE, Berkovic SF, Jackson GD. The core network in absence epilepsy: differences in cortical and thalamic BOLD response. Neurology 2010;75:904–911. Pillay N, Archer JS, Badawy RA, Flanagan DF, Berkovic SF, Jackson G. Networks underlying paroxysmal fast activity and slow spike and wave in Lennox-Gastaut syndrome. Neurology 2013;81:665–673. Siniatchkin M, Coropceanu D, Moeller F, Boor R, Stephani U. EEG-fMRI reveals activation of brainstem and thalamus in patients with Lennox-Gastaut syndrome. Epilepsia 2011;52:766–774. An D, Fahoum F, Hall J, Olivier A, Gotman J, Dubeau F. Electroencephalography/functional magnetic resonance imaging responses help predict surgical outcome in focal epilepsy. Epilepsia 2013;54:2184–2194. Szaflarski JP, Kay B, Gotman J, Privitera MD, Holland SK. The relationship between the localization of the generalized spike and wave discharge generators and the response to valproate. Epilepsia 2013;54: 471–480. Moeller F, Stephani U, Siniatchkin M. Simultaneous EEG and fMRI recordings (EEG-fMRI) in children with epilepsy. Epilepsia 2013;54:971–982.

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Myoclonic atonic epilepsy: Another generalized epilepsy syndrome that is ''not so'' generalized John M. Zempel and Tadaaki Mano Neurology 2014;82;1486-1487 Published Online before print April 2, 2014 DOI 10.1212/WNL.0000000000000368 This information is current as of April 2, 2014 Updated Information & Services

including high resolution figures, can be found at: http://www.neurology.org/content/82/17/1486.full.html

References

This article cites 13 articles, 4 of which you can access for free at: http://www.neurology.org/content/82/17/1486.full.html##ref-list-1

Subspecialty Collections

This article, along with others on similar topics, appears in the following collection(s): All Epilepsy/Seizures http://www.neurology.org//cgi/collection/all_epilepsy_seizures Generalized seizures http://www.neurology.org//cgi/collection/generalized_seizures Myoclonus; see Movement Disorders/myoclonus http://www.neurology.org//cgi/collection/myoclonus_see_movement_d isorders-myoclonus

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Neurology ® is the official journal of the American Academy of Neurology. Published continuously since 1951, it is now a weekly with 48 issues per year. Copyright © 2014 American Academy of Neurology. All rights reserved. Print ISSN: 0028-3878. Online ISSN: 1526-632X.

Myoclonic atonic epilepsy: another generalized epilepsy syndrome that is "not so" generalized.

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