History/Background and/or General Information
An electroencephalogram (EEG) is a diagnostic test that measures the electrical activity of the brain (brainwaves) using highly sensitive recording equipment attached to the scalp by fine electrodes. It is used to diagnose neurological conditions.
EEGs can be recorded by 24-hour ambulatory cassette. Twenty-four hour ambulatory cassette-recorded EEGs offer the ability to record the EEG on a long-term, outpatient basis. Ambulatory or 24-hour electroencephalographic (EEG) monitoring is accomplished by a cassette recorder that continuously records brain wave patterns during 24 hours of a patient's routine daily activities and sleep. The monitoring equipment consists of an electrode set, preamplifiers, and a cassette recorder. The electrodes attach to the scalp, and their leads are connected to a recorder, usually worn on a belt.
For additional information regarding Ambulatory EEG, please refer to CMS IOM Publication 100-03, Medicare National Coverage Determinations (NCD) Manual, Chapter 1, Part 2, Section 160.22 Ambulatory EEG Monitoring.
Ambulatory monitoring is not necessary to evaluate most seizures which are usually readily diagnosed by routine EEG studies, patient examination and history. Monitoring for identification and lateralization of cerebral seizure foci by ambulatory or continuous 24-hour Electroencephalogram (EEG) may be necessary in patients where epilepsy is suspected but not confirmed by clinical manifestations or resting EEG. Ambulatory EEG should always be preceded by an awake and sleep study. The combination of electroencephalographic and video monitoring of a patient is useful and medically necessary in the initial diagnosis of epilepsy, particularly where previous attempts to define or characterize the seizure activity have proven inconclusive. Beyond the initial diagnosis of epilepsy the combination is useful in uncharacterized events, confirmation and/or differentiation between epileptic and non-epileptic.
Ambulatory EEG may also be medically necessary in the differentiation of psychogenic seizures from epilepsy and in the localization of a seizure focus prior to a surgical intervention for intractable epilepsy. It is anticipated that clinical examination and routine electroencephalographic studies be utilized before employing electroencephalographic and video monitoring, and that this study be essential to the establishment of an appropriate treatment regimen.
Additionally, the study may be used in pediatric beneficiaries where history and clinical descriptions of seizure activity are difficult to obtain. It is anticipated that many of these outpatient studies will not provide the diagnosis within the first 24 hours, but expects that 72 hours of monitoring will be diagnostic in most circumstances. Occasionally patients may require more extensive monitoring, and medical necessity must be documented for review in these circumstances. This 72-hour limitation does not apply to the inpatient setting where patients are frequently withdrawn from their anti-epileptic regimens, and where precise presurgical localization of epileptic foci is often conducted.
It is anticipated that once the diagnosis has been established, this study will not be repeated, nor will it be used in the monitoring of a therapeutic regimen. Again, this expectation will not be applied to patients readmitted for inpatient care of their seizure disorder.
Additionally, ambulatory EEG monitoring may facilitate the differential diagnosis between seizures and syncopal attacks, sleep apnea, cardiac arrhythmias or hysterical episodes. The test may also allow the investigator to identify the epileptic nature of some episodic periods of disturbed consciousness, mild confusion, or peculiar behavior, where resting EEG is not conclusive. It may also allow an estimate of seizure frequency, which may at times help to evaluate the effectiveness of a drug and determine its appropriate dosage.
Digital analysis of an electroencephalogram (EEG) is used to diagnose neurological conditions when routine EEG outcomes and neurological imaging are inconclusive to confirm diagnostic symptoms. Digital analysis of an electroencephalogram (EEG) requires the analysis of an EEG using quantitative analytical techniques such as data selection, quantitative software processing, and dipole source analysis.
Covered Indications
Covered Indications for monitoring for identification and lateralization or localization of cerebral seizure focus
- Inconclusive EEGs;
- Experiencing episodic events where you suspect epilepsy but the history, examination, and routine EEG do not resolve the diagnosis uncertainties;
- Patients with confirmed epilepsy who are experiencing suspected non-epileptic events or for classification of seizure type (only ictal recordings can reliably be used to classify seizure type [or types] which is important in selecting appropriate anti-epileptic drug therapy);
- Differentiating between neurological and cardiac related problems;
- Adjusting anti-epileptic medication levels;
- Localizing seizure focus for enhanced patient management;
- Identifying and medicating absence seizures;
- For suspected seizures of sleep disturbances;
- Seizures which are precipitated by naturally occurring cyclic events or environmental stimuli which are not reproducible in the hospital or clinic setting.
Covered Indications for digital analysis of an electroencephalogram (EEG)
Digital analysis of an electroencephalogram (EEG) meets the definition of medical necessity when performed as an adjunct to traditional EEG for the following conditions:
Epilepsy, when ANY of the following are met:
- The long-term EEG is inconclusive and additional testing for possible epileptic spikes or seizures is needed;
- For topographic voltage and dipole analysis in presurgical candidates with intractable epilepsy.
Cerebral vascular disease:
- When routine EEG outcomes and neurological imaging are inconclusive to confirm diagnostic symptoms.
Limitations
Limitations for monitoring for identification and lateralization or localization of cerebral seizure focus
The following indications are not covered as they are not considered medically reasonable and necessary:
- Study of neonates or unattended, non-cooperative patients;
- Localization of seizure focus/foci when the seizure symptoms and/or other EEG recordings indicate the presence of bilateral foci or rapid generalization; and
- Final evaluation of patients being considered as candidates for respective surgery.
Electroencephalographic (EEG) video monitoring is medically necessary when the diagnosis cannot be made by neurological examination, standard EEG studies, and ambulatory EEG monitoring, and non-neurological causes of symptoms (e.g., syncope, cardiac arrhythmias) have been ruled out.
Video recording with EEG is usually an inpatient procedure. Inpatient setting is required when stopping medications for pre-surgical planning.
Monitoring beyond 72 hours must be supported by written documentation for each additional 24 hours of monitoring and be made available upon request.
It would not be expected to see more than three services (three of one or three of any combination of services) billed in most circumstances within a one-year period. It is anticipated that once the diagnosis has been established, this study will not be repeated, nor will it be used in the monitoring of a therapeutic regimen (this expectation will not be applied to patients readmitted for inpatient care of their seizure disorder or characterization of seizure changes in any setting).
The following items represent the number of 24-hour segments of recordings for testing:
- For diagnostic testing: 2-3 days is usually sufficient when looking for seizures or interictal activity.
- For pre-surgical evaluation: 7-10 days to capture at least 3 or 4 seizures may be required in order to be sure of seizure onset location reliability. For follow-up, 2-3 days is usually sufficient.
Limitations for digital analysis of electroencephalogram (EEG)
The following indications are not covered as they are not considered medically reasonable and necessary:
- Anxiety
- Attention deficit disorder
- Attention-deficit hyperactivity disorder
- Autism spectrum disorders
- Depression
- Learning disorders
- Schizophrenia
- Substance abuse.
It is not routinely appropriate to perform and report digital analysis of EEG when there are no spikes to analyze (eg, when the video –EEG monitoring is normal). If digital analysis of an electroencephalogram (EEG) is reported for reasons other than three- dimensional spike analysis, the patient’s record must clearly reflect why the digital analysis was needed and address how it assisted with the reading of the data. Digital analysis requires that the neurologist or technician conduct the analysis using quantitative analytical techniques such as data selection, quantitative software processing, and dipole source analysis. Evidence of such analysis should be evident in the medical record (typically, three-dimensional spike localization).
Digital analysis of electroencephalogram (EEG) is reported when substantial additional digital analysis was medically necessary and was performed, such as 3D dipole localization.
Digital analysis would be more commonly used at specialty centers, e.g. epilepsy surgery programs. Note that the codes for "monitoring for identification and lateralization of cerebral seizure focus" already include epileptic spike analysis.
As published in the CMS IOM Publication 100-08, Medicare Program Integrity Manual, Chapter 13, Section 13.5.4, an item or service may be covered by a contractor LCD if it is reasonable and necessary under the Social Security Act Section 1862 (a)(1)(A). Contractors shall determine and describe the circumstances under which the item or service is considered reasonable and necessary.
Provider Qualifications
A qualified physician for this service/procedure is defined as follows: A) Physician properly enrolled in Medicare. B) Training and expertise must have been acquired within the framework of an accredited residency and/or fellowship program in the applicable specialty/subspecialty in the United States or must reflect equivalent education, training, and expertise endorsed by an academic institution in the United States and/or by the applicable specialty/subspecialty society in the United States.
The accuracy of non-invasive diagnostic studies depends on the knowledge, skill and experience of the technologist and the physician performing the supervision and/or interpretation of the study. Consequently, the technologist and the physician must maintain proof of training and experience. All non-invasive diagnostic studies must be: (1) performed by a qualified physician, or (2) performed under the general supervision of a qualified physician in the office setting. For EEG studies performed in a IDTF setting, the supervising physician must be a Board Certified (ABMS) Neurologist, and the technician qualification must include credentialing by ABRET Neurodiagnostic Credentialing and Accreditation for Registered Electroencephalographic Technologist (R. EEG T.).
