Video-EEG Monitoring in Childhood Epilepsy

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Video-EEG Monitoring in Childhood Epilepsy

• M. Mohammadi MD
• Professor of Pediatric Neurology (TUMS)
• Former Fellow, Clinical Paediatric
  Neurophysiology, University College of London,
  GOS Hospital, London, UK.
• November 2006

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Major Queries
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Advantages of the Outpatient EEG Study?

• The outpatient "routine" EEG is the most commonly
  performed diagnostic procedure in the individual
  who has a suspected seizure disorder.
• For most patients, the routine EEG is sufficient
  for physicians to classify seizure types and
  initiate medical therapy.

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Advantages of the Outpatient EEG Study?

• The neurologic history and examination and
  routine EEG indicate the probable seizure
  diagnosis in most patients.
• The outpatient sleeping and waking EEG study
  usually identifies interictal EEG activity, in
  patients with seizure disorders.
• Interictal epileptiform activity may be
  satisfactory in many instances to classify the
  seizure types.

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Limitations of the Outpatient EEG Study?

• The brief duration of the EEG recordings may fail
  to identify epileptiform activity.
• The routine EEG may be repetitively normal and
  identify no epileptiform discharges.

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Limitations of the Outpatient EEG Study?

• EEG may record nonspecific and nonepileptiform
  findings that may incorrectly suggest the
  diagnosis of epilepsy.
• Interictal EEG alone may lead to errors in
  diagnostic classification that result in
  ineffective treatment strategies.
• The interictal EEG pattern also may be an
  unreliable indicator of the classification of
  seizure type.

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TYPES

• Outpatient vs. Inpatient Settings
• Ambulatory vs. Non-ambulatory EEG monitoring
• Analog vs. computer assisted digital video EEG
  monitoring

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IMPLICATIONS

• Diagnosis of a seizure disorder
• Classification of seizure types
• Evaluation of precipitating factors
• Quantification of seizures
• Surgical localization

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Does the Patient Have Epilepsy?

• Approximately 20 of patients who are referred to
  comprehensive epilepsy programs because of
  medically refractory "seizures" do not have
  epilepsy.
• Physiological and psychological disorders may
  cause diagnostic confusion with epilepsy and
  result in patients being inappropriately treated
  with antiepileptic medications.
• A normal scalp-recorded EEG during and after a
  "seizure" in an unresponsive patient virtually
  excludes an epileptic clinical event.

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Nonepileptic Phenomena Confused with Epilepsy

• Autonomic Disorders
• Cardiac Arrhythmias
• Cerebrovascular Disease
• Drug Toxicity
• Metabolic Disorders
• Migraine
• Orthostatic Hypotension

• Valvular Heart Disease
• Vasovagal Syncope
• Vestibular Disorders
• Shuddering attacks
• Breath Holding Spells
• Sleep Disorders
• Day Dreaming
• GER

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Nonepileptic Psychologic Phenomena Confused with
Epilepsy

• Anxiety
• Depression
• Panic attacks
• Psychogenic seizures
• Psychosis
• Somatoform disorders
• Rage attacks

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What is the Seizure Type?

• In one study, the diagnostic classification was
  altered in 19 (47.5) of 40 patients by inpatient
  video-EEG monitoring.
• Studies also disclosed previously unrecognized
  seizures in 20 of patients monitored.
• Improved seizure control can occur in 60 to 70
  of patients as a result of videoEEG monitoring.
• Prolonged EEG recordings are clearly superior to
  the routine EEG in detecting seizures (50-70
  with long-term monitoring compared with 2.5-7
  with routine EEG studies).

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Is the Patient a Candidate for Epilepsy Surgery?

• The most effective treatment of intractable
  partial epilepsy is resection of the epileptic
  brain tissue.
• Of the nearly 800,000 patients with partial
  epilepsy in the United States, 45 have medically
  refractory seizure disorders.
• The most commonly performed and most effective
  procedure for treating intractable epilepsy is an
  anterior temporal lobectomy, after which nearly
  60 of patients are seizure-free and 90 are
  substantially improved.

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Is the Patient a Candidate for Epilepsy Surgery?

• The surgically remediable epileptic syndromes
  include medial temporal lobe epilepsy and partial
  epilepsy related to lesional pathology, eg, a
  primary brain tumor.
• Approximately 80 of patients with medial
  temporal lobe epilepsy associated with mesial
  temporal sclerosis have an excellent outcome.

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Is the Patient a Candidate for Epilepsy Surgery?

• Confirmation of the localization of the
  epileptogenic area is critical to identifying
  appropriate candidates.
• An inability to localize the epileptogenic area
  sufficiently with noninvasive monitoring is an
  indication for long-term intracranial EEG
  monitoring, eg, subdural grid or implanted depth
  electrodes.

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Limitations of Video-EEG Monitoring?

• Needs Special Training
• Technicians
• Interpretators
• Maintaining Personnel
• Logistically Difficult (Wi Fi Cordless
  Technology)
• Needs Patients Cooperation
• Needs Interdisciplinary Approach