An EEG is a recording of the electrical current potentials spontaneously from nerve cells in the brain onto the skull. Variations in wave characteristics correlate with neurological conditions and are used to diagnose conditions.

Transmission of the EEG by telephone, radio, or cable may be considered medically necessary when the closest medical facilities are located in remote areas which lack trained EEG interpreters for individuals with the following indications:

• Altered consciousness, such as stuporous, semi-comatose, or comatose states; or
• Atypical seizure variants in individuals experiencing bizarre, distressing symptoms as seen with "spike and wave stupor" or other forms of seizure disorders; or
• Head injury, where a subdural hematoma may be identified; or
• Differentiation of complicated migraine with epilepsy-like symptoms (e.g., auras, alterations in level of consciousness) from true seizure disorders.

Radio and cable telemetry of the EEG may be considered medically necessary for:

• EEG recording during provocation testing (e.g., withdrawal of anticonvulsant medications), which can be safely undertaken only in the immediate proximity of emergency medical personnel and technology; and
• EEG recording attempting to localize the seizure focus’ prior to surgery when ambulation is desirable (e.g., when seizures are triggered by specific environmental stimuli or daily events).

Video EEG monitoring may be considered medically necessary for ANY ONE of the following indications and/or conditions:

• The diagnosis cannot be made by neurological examination, standard EEG studies or ambulatory cassette EEG monitoring; or
• Routine surface EEG is not diagnostic of a seizure disorder; or
• Seizure activity is observed clinically but not captured by routine EEG; or
• Seizure activity captured on routine EEG does not yield sufficient qualitative or quantitative data to determine a treatment regimen; or
• Antiepileptic drug (AED) withdrawal is needed; or
• Non-neurological causes of symptoms (e.g., syncope and cardiac arrhythmias) have been ruled out; or
• To differentiate epileptic events from nonepileptic seizures such as psychogenic seizures; or
• Individual with intractable epilepsy is being evaluated for surgical intervention; or
• Seizure monitoring of a neonate or child is needed to develop or modify treatment; or
• To monitor neonates with hypoxic-ischemic encephalopathy (HIE) who are being treated with therapeutic hypothermia (TH)

Note: Monitoring may be performed on an outpatient or inpatient basis, depending on the frequency and duration of seizure activity and length of time necessary to collect data. Individuals with frequent (at least three per week) intractable minor seizures and those individuals being evaluated for efficacy of drug treatment can be evaluated on an outpatient basis, in 3-12 hours. Inpatient monitoring is required for individuals such as those with seizures that only occur at night, are infrequent, are clinically severe (such as prolonged complex partial seizures), or are provoked by drug withdrawal.

Twenty-four hour ambulatory cassette-recorded EEGs may be medically necessary in the following circumstances:

• When used in conjunction with ambulatory electrocardiogram (ECG) recordings for seizures suspected to be of cardiogenic origin; or
• When used in conjunction with electro-oculogram (EOG) and electromyogram (EMG) recordings for suspected seizures of sleep disturbances; or
• When used for quantification of seizures in patients who experience frequent absence seizures; or
• When used in documenting seizures which are precipitated by naturally occurring cyclic events or environmental stimuli which are not reproducible in the hospital or clinic setting; or
• To monitor neonates with HIE who are being treated with TH.

Quantitative electroencephalogram (QEEG) may be considered medically necessary when used as an adjunct to traditional EEG and/or diagnostic evaluation of epilepsy when ANY ONE of the following criteria is met:

• The surface or long-term EEG is inconclusive and additional testing for possible epileptic spikes or seizures is needed; or
• Ambulatory recording is needed to facilitate subsequent visual EEG interpretation; or
• There is need for topographic voltage and dipole analysis in pre-surgical candidates with intractable epilepsy:
  • As continuous monitoring in the operating room for the early detection of an acute intracranial complication during cerebrovascular surgery (i.e., intracranial, carotid endarterectomy); or
  • As monitoring for the detection of nonconvulsive seizures in high risk individuals in the intensive care unit and operating room.

Digital analysis of electroencephalogram (DEEG) is considered not medically necessary as there is no evidence that such additional processing and interpretation has been shown to improve outcomes in individual management.

Twenty-four hour ambulatory cassette-recorded EEGs are considered experimental/investigational and, therefore non-covered in the following circumstances:

• For the study of neonates or unattended, uncooperative individuals; and
• In localization of seizure focus/foci when the seizure symptoms and/or other EEG recordings indicate the presence of bilateral foci or rapid generalization; and
• For final evaluation of individuals who are being considered as candidates for resective surgery.

Scientific evidence does not demonstrate the efficacy of twenty-four hour ambulatory cassette-recorded EEGs in certain instances.

Telephone transmission of the EEG to determine electrocerebral silence, i.e., brain death, is considered experimental/investigational, and therefore non-covered.

Quantitative electroencephalographic-based assessment (QEEG) is considered experimental/investigational and, therefore non-covered when used as a diagnostic aid for attention deficit/hyperactivity disorder.