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Pathophysiology of Myoclonic Seizures

  • Pasquale Striano
  • Federico Zara

Introduction and Definitions

Myoclonic seizures (MS) are characterized by sudden, brief (<350 ms), shock-like contractions that vary in their distribution and intensity of manifestations (Leppik 2003). They may be generalized or confined to the face and trunk, or to extremities, or individual muscles or groups of muscles. MS can occur unilaterally or bilaterally, and if bilaterally, symmetrically or asymmetrically. They may also be rhythmic or arrhythmic, and, in terms of amplitude, they can be small (e.g., no joint movement) or massive contractions (e.g., movement of extremities, trunk, and/or head) (Video 1, 2)(Leppik 2003; Browne and Holmes 2004). Myoclonic jerks may originate in the form of brief electromyographic (EMG) burst (i.e., positive myoclonus) or, more rarely, from brief interruptions of EMG activity (i.e., negative myoclonus) (Genton et al. 2005; Guerrini et al. 2005). MS may be very subtle or extremely dramatic and can be present in several different epilepsy syndromes,...

Keywords

Transcranial Magnetic Stimulation Myoclonic Epilepsy Epilepsy Syndrome Juvenile Myoclonic Epilepsy Myoclonic Seizure 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of Abbreviations

CJD

Creutzfeldt–Jakob disease

CSTB

Cystatin B

EEG

Electroencephalography

EMG

Electromyographic

JLA

Jerk-locked averaging

LLRI

Long-loop reflex I

MERRF

Myoclonic epilepsy with ragged-red fibers

MS

Myoclonic seizures

SEPs

Somatosensory-evoked potentials

ULD

Unverricht–Lundborg disease

Notes

Acknowledgment

We are grateful to Professor Salvatore Striano and Dr. Giuseppe Capovilla for revising the text and kindly contributing to the illustrations.

Supplementary material

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mpeg file: 32711 kB

References

  1. Browne TR, Holmes GL (2004) Handbook of epilepsy, 3rd edn. Lippincott Williams Wilkins, Philadelphia, pp 37–38Google Scholar
  2. Genton P, Roger J, Guerrini R, Medina MT, Bureau M, Dravet C, Delgado-Escueta AV (2005) History and classification of “myoclonic” epilepsies: from seizures to syndromes to diseases. Adv Neurol 95:1–14PubMedGoogle Scholar
  3. Guerrini R, Bonanni P, Parmeggiani L, Hallett M, Oguni H (2005) Pathophysiology of myoclonic epilepsies. Adv Neurol 95:23–46PubMedGoogle Scholar
  4. Leppik IE (2003) Classification of the myoclonic epilepsies. Epilepsia 44(Suppl 11):2–6CrossRefPubMedGoogle Scholar
  5. Marsden CD, Hallett M, Fahn S (1985) The nosology and pathophysiology of myoclonus. In: Marsden CD, Fahn S (eds) Movement disorders, 2nd edn. Butterworth Scientific, London, pp 198–248Google Scholar
  6. Shibasaki H (2006) Neurophysiological classification of myoclonus. Clin Neurophysiol 36:267–269CrossRefGoogle Scholar
  7. Shibasaki H, Hallett M (2005) Electrophysiological studies of myoclonus. Muscle Nerve 31:157–174CrossRefPubMedGoogle Scholar

Copyright information

© Springer-Verlag London Limited 2010

Authors and Affiliations

  • Pasquale Striano
    • 1
  • Federico Zara
    • 1
  1. 1.Unit of Muscular and Neurodegenerative DiseasesInstitute G. GasliniGenovaItaly

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