Close
New

Medscape is available in 5 Language Editions – Choose your Edition here.

 

Lennox-Gastaut Syndrome Workup

  • Author: Koshi A Cherian, MD; Chief Editor: Amy Kao, MD  more...
 
Updated: Jul 27, 2016
 

Approach Considerations

Electroencephalography (EEG) is an essential part of the workup for Lennox-Gastaut syndrome (LGS). To date, there are no known laboratory investigations to aid in the diagnosis of LGS. Neuroimaging is an important part of the search for an underlying etiology in a patient with LGS.

Next

Electroencephalography

Always perform an EEG in patients with suspected LGS, since the diagnosis depends on the presence of specific EEG findings. A routine 20-minute EEG may not capture the patient both awake and asleep and thus may miss specific important EEG findings. Instead, obtain prolonged video/EEG telemetry, if possible. Record both waking and sleep EEG, to assist in confirming a suspected diagnosis and to capture and classify each of the patient's multiple seizure types.

Video recordings can also be used to educate the parents on which of the patient's "events" are seizures and which are nonepileptic behavioral events. Parental ability to correctly recognize and identify atypical absences is poor. In one study using video/EEG monitoring in a cohort of children with LGS, parental recognition was 27% for atypical absences, while the sensitivity was as high as 80% for myoclonic seizures and 100% for tonic, atonic, tonic-clonic, clonic, and complex partial seizures.[7]

Go to EEG in Common Epilepsy Syndromes, Epileptiform Normal Variants on EEG, and Generalized Epilepsies on EEG for more information on these topics.

Interictal electroencephalography

Interictal EEG is characterized by a slow background that can be constant or transient. Permanent slowing of the background is associated with poor cognitive prognosis.

The hallmark of the awake interictal EEG in patients with LGS is the diffuse slow spike wave (see the image below). This pattern consists of bursts of irregular and generalized spikes or sharp waves followed by a sinusoidal 35-400-millisecond slow wave with an amplitude of 200-800 microvolts, which can be symmetric or asymmetric.

The amplitude often is higher in the anterior region or in the frontal or frontocentral areas, but in some patients the activity may dominate in the posterior head regions. The frequency of the slow spike wave activity commonly is found at 1.5-2.5 Hz.

Slow spike wave pattern in a 24-year-old awake mal Slow spike wave pattern in a 24-year-old awake male with Lennox-Gastaut syndrome. The slow posterior background rhythm has frequent periods of 2- to 2.5-Hz discharges, maximal in the bifrontocentral areas, occurring in trains as long as 8 seconds without any clinical accompaniment.

Slow spike waves usually are not activated by photic stimulation. Hyperventilation rarely induces slow spike waves, although mental retardation prevents adequate cooperation in many patients. During non–rapid eye movement (REM) sleep, discharges are more generalized, more frequent, and consist of polyspikes and slow waves. In REM sleep, spike waves decrease. During periods of frequent seizures, the total duration of REM sleep is reduced.

Ictal electroencephalography

During a tonic seizure, the EEG is characterized by a diffuse, rapid (10-13 Hz), low-amplitude activity pattern, mainly in the anterior and vertex areas ("recruiting rhythm") that progressively decreases in frequency and increases in amplitude.

A brief generalized discharge of slow spike waves or flattening of the recording may precede this pattern. Diffuse slow waves and slow spike waves may follow it.

These fast discharges are common during non-REM sleep. Unlike tonic-clonic seizures, no postictal flattening occurs with these seizures. Clinical manifestations appear 0.5-1 second after the onset of EEG manifestations and last several seconds longer than the discharge.

During an atypical absence seizure, the EEG is characterized by diffuse, slow (2-2.5 Hz), and irregular spike waves, which may be difficult to differentiate from interictal bursts. Occasionally, discharges of rapid rhythms may be observed preceded by flattening of the record for 1-2 seconds, followed by progressive development of irregular fast rhythm in the anterior and central regions, and ending with brief spike waves.

During atonic, massive myoclonic, and myoclonic-atonic seizures, the EEG is characterized by slow spike waves, polyspike waves, or rapid diffuse rhythms. Simultaneous video/EEG recording can help differentiate these seizure types. In most patients, these 3 types of seizures coexist.

The EEG during absence status epilepticus reveals continuous spike wave discharges, usually at a lower frequency than at baseline, and rapid rhythms during tonic status epilepticus.

Previous
Next

Neuroimaging Studies

In general, a magnetic resonance imaging (MRI) scan is the preferred neuroimaging study for a patient with LGS, rather than a CT scan. CT scans may be preferred in selected situations (eg, evaluation of suspected intracranial injury and/or hematoma in a patient with head trauma resulting from a seizure).

Abnormalities revealed by neuroimaging associated with LGS include tuberous sclerosis, brain malformations (eg, cortical dysplasias), hypoxia-ischemia injury, or frontal lobe lesions.

No current indication exists for routine positron emission tomography (PET) or single-photon emission computed tomography (SPECT) scanning in patients with LGS. However, PET or SPECT scans may be useful in patients undergoing evaluation as candidates for epilepsy surgery.

Previous
 
 
Contributor Information and Disclosures
Author

Koshi A Cherian, MD Assistant Professor, Department of Neurology and Pediatrics, Albert Einstein College of Medicine; Attending Physician, Department of Neurology, Division of Child Neurology and Epilepsy, Montefiore Medical Center; Attending Physician, Department of Pediatrics, Division of Child Neurology, Jacobi Medical Center; Staff Physician (Courtesy), Department of Pediatrics, Division of Child Neurology, St Barnabas Hospital

Koshi A Cherian, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Pediatrics, American Epilepsy Society, American Medical Association, Child Neurology Society, Medical Society of the State of New York

Disclosure: Nothing to disclose.

Coauthor(s)

Tracy A Glauser, MD Professor, Departments of Pediatrics and Neurology, University of Cincinnati College of Medicine; Director, Comprehensive Epilepsy Center, Co-Director, Genetic Pharmacology Service, Cincinnati Children's Hospital Medical Center

Tracy A Glauser, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Pediatrics, American Epilepsy Society, Child Neurology Society

Disclosure: Received consulting fee from Eisai for consulting; Received consulting fee from Lundbeck for consulting; Received consulting fee from Questcor for consulting; Received consulting fee from ucb Pharma for consulting; Received consulting fee from Supernus for consulting; Received honoraria from Supernus for speaking and teaching; Received consulting fee from Sunovion for consulting; Received royalty from AssureRx for license; Received consulting fee from Upsher-Smith for consulting; Received consul.

Diego A Morita, MD Assistant Professor of Pediatrics and Neurology, Department of Pediatrics, Division of Neurology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine

Diego A Morita, MD is a member of the following medical societies: American Academy of Neurology, American Academy of Pediatrics, American Epilepsy Society, American Medical Association

Disclosure: Nothing to disclose.

Karen Mary Stannard, MD FRCPC

Karen Mary Stannard, MD is a member of the following medical societies: American Academy of Neurology, Child Neurology Society, Royal College of Physicians and Surgeons of Canada

Disclosure: Nothing to disclose.

Chief Editor

Amy Kao, MD Attending Neurologist, Children's National Medical Center

Amy Kao, MD is a member of the following medical societies: American Academy of Neurology, American Epilepsy Society, Child Neurology Society

Disclosure: Have stock from Cellectar Biosciences; have stock from Varian medical systems; have stock from Express Scripts.

Acknowledgements

David A Griesemer, MD Professor, Departments of Neuroscience and Pediatrics, Medical University of South Carolina

David A Griesemer, MD is a member of the following medical societies: American Academy for Cerebral Palsy and Developmental Medicine, American Academy of Neurology, American Epilepsy Society, Child Neurology Society, and Society for Neuroscience

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

References
  1. Trevathan E, Murphy CC, Yeargin-Allsopp M. Prevalence and descriptive epidemiology of Lennox-Gastaut syndrome among Atlanta children. Epilepsia. 1997 Dec. 38(12):1283-8. [Medline].

  2. Arzimanoglou A, French J, Blume WT, Cross JH, Ernst JP, Feucht M, et al. Lennox-Gastaut syndrome: a consensus approach on diagnosis, assessment, management, and trial methodology. Lancet Neurol. 2009 Jan. 8(1):82-93. [Medline]. [Full Text].

  3. Engel J Jr; International League Against Epilepsy (ILAE). A proposed diagnostic scheme for people with epileptic seizures and with epilepsy: report of the ILAE Task Force on Classification and Terminology. Epilepsia. 2001 Jun. 42(6):796-803. [Medline].

  4. Heiskala H. Community-based study of Lennox-Gastaut syndrome. Epilepsia. 1997 May. 38(5):526-31. [Medline].

  5. Oguni H, Hayashi K, Osawa M. Long-term prognosis of Lennox-Gastaut syndrome. Epilepsia. 1996. 37 Suppl 3:44-7. [Medline].

  6. Ohtsuka Y, Amano R, Mizukawa M, Ohtahara S. Long-term prognosis of the Lennox-Gastaut syndrome. Jpn J Psychiatry Neurol. 1990 Jun. 44(2):257-64. [Medline].

  7. Bare MA, Glauser TA, Strawsburg RH. Need for electroencephalogram video confirmation of atypical absence seizures in children with Lennox-Gastaut syndrome. J Child Neurol. 1998 Oct. 13(10):498-500. [Medline].

  8. Al-Banji MH, Zahr DK, Jan MM. Lennox-Gastaut syndrome. Management update. Neurosciences (Riyadh). 2015 Jul. 20 (3):207-12. [Medline].

  9. van Rijckevorsel K. Treatment of Lennox-Gastaut syndrome: overview and recent findings. Neuropsychiatr Dis Treat. 2008 Dec. 4(6):1001-19. [Medline]. [Full Text].

  10. Wheless JW, Clarke DF, Arzimanoglou A, Carpenter D. Treatment of pediatric epilepsy: European expert opinion, 2007. Epileptic Disord. 2007 Dec. 9(4):353-412. [Medline].

  11. Conry JA, Ng YT, Paolicchi JM, Kernitsky L, Mitchell WG, Ritter FJ, et al. Clobazam in the treatment of Lennox-Gastaut syndrome. Epilepsia. 2009 May. 50(5):1158-66. [Medline].

  12. Ng YT, Collins SD. Clobazam. Neurotherapeutics. 2007 Jan. 4(1):138-44. [Medline].

  13. Ng YT, Conry JA, Drummond R, Stolle J, Weinberg MA. Randomized, phase III study results of clobazam in Lennox-Gastaut syndrome. Neurology. 2011 Oct 11. 77(15):1473-1481. [Medline].

  14. Feucht M, Brantner-Inthaler S. Gamma-vinyl-GABA (vigabatrin) in the therapy of Lennox-Gastaut syndrome: an open study. Epilepsia. 1994 Sep-Oct. 35(5):993-8. [Medline].

  15. You SJ, Kang HC, Kim HD, Lee HS, Ko TS. Clinical efficacy of zonisamide in Lennox-Gastaut syndrome: Korean multicentric experience. Brain Dev. 2008 Apr. 30(4):287-90. [Medline].

  16. Motte J, Trevathan E, Arvidsson JF, Barrera MN, Mullens EL, Manasco P. Lamotrigine for generalized seizures associated with the Lennox-Gastaut syndrome. Lamictal Lennox-Gastaut Study Group. N Engl J Med. 1997 Dec 18. 337(25):1807-12. [Medline].

  17. Glauser TA. Topiramate. Epilepsia. 1999. 40 Suppl 5:S71-80. [Medline].

  18. Glauser TA, Levisohn PM, Ritter F, Sachdeo RC. Topiramate in Lennox-Gastaut syndrome: open-label treatment of patients completing a randomized controlled trial. Topiramate YL Study Group. Epilepsia. 2000. 41 Suppl 1:S86-90. [Medline].

  19. Sachdeo RC, Glauser TA, Ritter F, Reife R, Lim P, Pledger G. A double-blind, randomized trial of topiramate in Lennox-Gastaut syndrome. Topiramate YL Study Group. Neurology. 1999 Jun 10. 52(9):1882-7. [Medline].

  20. Pellock JM. Felbamate. Epilepsia. 1999. 40 Suppl 5:S57-62. [Medline].

  21. Glauser T, Kluger G, Sachdeo R, Krauss G, Perdomo C, Arroyo S. Rufinamide for generalized seizures associated with Lennox-Gastaut syndrome. Neurology. 2008 May 20. 70(21):1950-8. [Medline].

  22. Kluger G, Kurlemann G, Haberlandt E, Ernst JP, Runge U, Schneider F, et al. Effectiveness and tolerability of rufinamide in children and adults with refractory epilepsy: first European experience. Epilepsy Behav. 2009 Mar. 14(3):491-5. [Medline].

  23. Perucca E, Cloyd J, Critchley D, Fuseau E. Rufinamide: clinical pharmacokinetics and concentration-response relationships in patients with epilepsy. Epilepsia. 2008 Jul. 49(7):1123-41. [Medline].

  24. Ferrie CD, Patel A. Treatment of Lennox-Gastaut Syndrome (LGS). Eur J Paediatr Neurol. 2009 Nov. 13(6):493-504. [Medline].

  25. Lerner JT, Salamon N, Sankar R. Clinical profile of vigabatrin as monotherapy for treatment of infantile spasms. Neuropsychiatr Dis Treat. 2010 Nov 8. 6:731-40. [Medline]. [Full Text].

  26. Ohtsuka Y, Yoshinaga H, Shirasaka Y, Takayama R, Takano H, Iyoda K. Rufinamide as an adjunctive therapy for Lennox-Gastaut syndrome: A randomized double-blind placebo-controlled trial in Japan. Epilepsy Res. 2014 Nov. 108(9):1627-36. [Medline].

  27. Banzel (rufinamide) [package insert]. Woodcliff Lake, NJ: Eisai Inc. 2/2015. Available at [Full Text].

  28. Wheless JW, Isojarvi J, Lee D, Drummond R, Benbadis SR. Clobazam is efficacious for patients across the spectrum of disease severity of Lennox-Gastaut syndrome: Post hoc analyses of clinical trial results by baseline seizure-frequency quartiles and VNS experience. Epilepsy Behav. 2014 Oct 2. 41C:47-52. [Medline].

  29. Lowes R. Clobazam (Onfi) can cause serious skin reactions, FDA warns. Medscape Medical News. December 3, 2013. Available at http://www.medscape.com/viewarticle/815303. Accessed: December 8, 2013.

  30. FDA Drug Safety Communication. FDA warns of serious skin reactions with the anti-seizure drug Onfi (clobazam) and has approved label changes. December 3, 2013. Available at http://www.fda.gov/Drugs/DrugSafety/ucm377204.htm. Accessed: December 8, 2013.

  31. Cukiert A, Burattini JA, Mariani PP, Câmara RB, Seda L, Baldauf CM, et al. Extended, one-stage callosal section for treatment of refractory secondarily generalized epilepsy in patients with Lennox-Gastaut and Lennox-like syndromes. Epilepsia. 2006 Feb. 47(2):371-4. [Medline].

  32. Ben-Menachem E, Hellström K, Waldton C, Augustinsson LE. Evaluation of refractory epilepsy treated with vagus nerve stimulation for up to 5 years. Neurology. 1999 Apr 12. 52(6):1265-7. [Medline].

  33. Neal EG, Chaffe H, Schwartz RH, Lawson MS, Edwards N, Fitzsimmons G, et al. The ketogenic diet for the treatment of childhood epilepsy: a randomised controlled trial. Lancet Neurol. 2008 Jun. 7(6):500-6. [Medline].

  34. Freeman JM, Vining EP, Kossoff EH, Pyzik PL, Ye X, Goodman SN. A blinded, crossover study of the efficacy of the ketogenic diet. Epilepsia. 2009 Feb. 50(2):322-5. [Medline].

  35. De Los Reyes EC, Sharp GB, Williams JP, Hale SE. Levetiracetam in the treatment of Lennox-Gastaut syndrome. Pediatr Neurol. 2004 Apr. 30(4):254-6. [Medline].

 
Previous
Next
 
Patient with Lennox-Gastaut syndrome wearing a helmet with face guard to protect against facial injury from atonic seizures
Slow spike wave pattern in a 24-year-old awake male with Lennox-Gastaut syndrome. The slow posterior background rhythm has frequent periods of 2- to 2.5-Hz discharges, maximal in the bifrontocentral areas, occurring in trains as long as 8 seconds without any clinical accompaniment.
 
 
 
All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.