Video-EEG Monitoring in Video-EEG Monitoring in Childhood EpilepsyChildhood Epilepsy

M. Mohammadi MDM. Mohammadi MDProfessor of Pediatric

Neurology (TUMS)Former Fellow, Clinical Paediatric

Neurophysiology, University College of London, GOS Hospital, London, UK.

November 2006

Major QueriesMajor Queries

What’sWrongWith

OrdinaryEEG?

Advantages

Drawbacks

What isthe

implications?

Types

What isIt?

Video-EEGMonitoring

Advantages of the Outpatient EEG Study?

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.

Advantages of the Outpatient EEG Study?

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.

Limitations of the Outpatient EEG Study?

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.

Limitations of the Outpatient EEG Study?

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.

TYPESTYPES• Outpatient vs. Inpatient

Settings• Ambulatory vs. Non-

ambulatory EEG monitoring• Analog vs. computer

assisted digital video EEG monitoring

IMPLICATIONSIMPLICATIONS

Diagnosis of a seizure disorderClassification of seizure typesEvaluation of precipitating

factorsQuantification of seizuresSurgical localization

Does the Patient Have Does the Patient Have Epilepsy?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.

Nonepileptic Phenomena Confused Nonepileptic Phenomena Confused with Epilepsywith 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

Nonepileptic Psychologic Nonepileptic Psychologic Phenomena Confused with Phenomena Confused with

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

What is the Seizure Type?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).

Is the Patient a Candidate Is the Patient a Candidate for Epilepsy Surgery?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.

Is the Patient a Candidate Is the Patient a Candidate for Epilepsy Surgery?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.

Is the Patient a Candidate Is the Patient a Candidate for Epilepsy Surgery?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.

Limitations of Video-EEG Monitoring?

Limitations of Video-EEG Monitoring?

• Needs Special Training– Technicians– Interpretators– Maintaining Personnel

• Logistically Difficult (Wi Fi Cordless Technology)

• Needs Patients’ Cooperation

• Needs Interdisciplinary Approach