BlueCross and BlueShield of Montana Medical Policy/Codes
Chapter: Medicine: Tests
Current Effective Date: February 15, 2014
Original Effective Date: October 25, 2013
Publish Date: January 31, 2014
Revised Dates: January 31, 2014

Ambulatory electroencephalography (AEEG) monitoring allows a prolonged electroencephalographic (EEG) recording of the electrical current potential or brain activity through the skull. The procedure for an EEG involves placing a series of electrodes, with at least four recording channels on the patient. A very low electrical current is sent through the electrodes and the baseline brain energy is recorded on a diagnostic machine. Electrical activity is recorded and analyzed through an audio amplifier system. Patients are then exposed to a variety of external stimuli, including bright or flashing light, noise or certain drugs, or are asked to open and close their eyes, or to change breathing patterns. The electrodes transmit the resulting changes in brain wave patterns. Variations in wave characteristics correlate with neurological conditions and are used to diagnose specific medical conditions. With identification and classification of brain waves, the analysis of data provides information useful in mapping the brain and various areas involved with body function in relation to disease status. Since movement and nervousness can change brain wave patterns, patients usually recline in a chair or on a bed during the test, which takes up to an hour. Testing for certain disorders may also require an EEG during sleep. An AEEG has the ability to record continuously for up to 72 hours which increases the opportunity of recording an ictal event (during a seizure), or interictal (between seizures) epileptiform discharge (4). This method of recording offers the ability to gather data on a long term, outpatient basis.

In the past decade, computer technology has enabled portable recording of up to 36 channels with sampling rates of up to 400 Hz. AEEG'S can be transmitted by telephone, in which the electrical brain activity is recorded and transmitted to an offsite center for analysis and reporting. The AEEG can also be transmitted by radio or wire in the diagnosis of complex seizure variants which require inpatient monitoring, but do not require the patient to be bed bound. Virtually all contemporary EEG recordings use digital recording methods. There are few, if any, paper analog EEG recordings carried out in current medical practice. There is a distinction between digital recording and digital analysis of EEG data.

Digital recording uses a digital EEG recorder (machine); but it still involves visual analysis of the wave forms. It is digital to the extent that an analog, close-ended paper recorder is not used at the time of wave form (data) capture. This type of reading-by-eye represents the typical EEG interpretation in most clinical situations.

Digital analysis requires the use of quantitative analytical techniques. Data selection, quantitative software processing and dipole source analysis are some of the techniques utilized.

EEG video monitoring (VEEG) is the simultaneous recording of the EEG and video monitoring of patient behavior. This allows for correlation of ictal and interictal electrical events with demonstrated or recorded seizure symptomology. The combined image of EEG tracings and visible behavior helps the physician diagnose the epilepsy and identify affected areas of the brain. Intensive closed circuit TV and EEG monitoring of this type also helps distinguish between true epileptic seizures caused by electrical discharge and non-epileptic seizures caused by psychological factors.

Various ictal (during a seizure) and interictal (between seizure) EEG patterns correspond to specific seizure types and types of epilepsy. While the EEG is almost always abnormal during a seizure, it may be normal between seizures. Thus, lack of interictal EEG abnormalities does not exclude a diagnosis of epilepsy. However, at some time, most epilepsy patients have abnormal EEG discharges. In contrast, some persons with EEG'S that show epilepsy-like activity never have seizures. Thus physicians interpret EEG results within the context of other information they are gathering. Apart from the patient history and the neurological exam, the EEG is the most influential tool in the diagnosis of seizures and epilepsy. (5)


Each benefit plan or contract defines which services are covered, which are excluded, and which are subject to dollar caps or other limits.  Members and their providers have the responsibility for consulting the member's benefit plan or contract to determine if there is any exclusion or other benefit limitations applicable to this service or supply.  If there is a discrepancy between a Medical Policy and a member's benefit plan or contract, the benefit plan or contract will govern.

Medically Necessary

Ambulatory cassette recorded electroencephalogram (AEEG), completed over 24 hours, may be considered medically necessary when used:

  1. In conjunction with ambulatory electrocardiogram (ECG) recordings for seizures suspected to be of cardiogenic origin (i.e., cardiac arrhythmias and transient ischemic attacks etc.) not diagnosed by conventional studies;
  2. To determine classification and quantification of seizures in a patient who experiences frequent  absence, or petit mal seizures;
  3. To determine characterization (lateralization, localization, distribution) of EEG abnormalities, both ictal and interictal, associated with seizure disorders in the evaluation of patients with intractable epilepsy for surgical evaluation

Ambulatory casette recorded electroencephalogram (AEEG) completed over 24 hours is considered not medically necessary when used in the following circumstances:

  • 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;  
  • For final evaluation of patients who are being considered as candidates for resective surgery when the medically necessary criteria listed above has not been met.

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 patient management.

EEG video monitoring (VEEG) may be considered medically necessary to diagnosis seizure type and epilepsy syndrome in individuals who present diagnostic difficulties following clinical assessment and standard EEG.


The electroencephalogram (EEG) is a key tool in the diagnosis and management of epilepsy and other seizure disorders. It is also used to assist in the diagnosis of brain damage and disease (e.g., stroke, tumors, and encephalitis), mental retardation/intellectual disability, sleep disorders, degenerative diseases such as Alzheimer's disease and Parkinson's disease, and certain mental disorders (e.g., alcoholism, schizophrenia, and autism).

The Agency for Healthcare Research and Quality (AHRQ) has stated that information provided by video EEG monitoring has improved patient outcomes by permitting accurate diagnosis and modified therapy. Furthermore, the American Electroencephalographic Society noted that this procedure is widely regarded as safe and effective for evaluating seizures disorders.

The American Epilepsy Society has stated that this technique is the method of choice for the evaluation of intractable and/or undiagnosed seizure disorders. Additionally, many studies have reported the usefulness of this technique, and recommended its use for the diagnosis of psychogenic seizures.

Literature suggests that ambulatory electroencephalogram (AEEG) and video electroencephalogram (VEEG) are also useful in the diagnosis in young children, in patients with poorly characterized seizure types, and in those with suspected psychogenic seizures, especially if episodes are frequent.

V-EEG monitoring may be used to evaluate an individual for presumed seizure disorders that cannot be differentially diagnosed by regular surface EEG. Surface EEG monitoring usually lasts approximately 45 minutes and captures mostly interictal brain-wave activity. 

2013 Update

In 2010, Van Rooij et. al. studied the effect of treatment of subclinical neonatal seizures detected with amplitude-integrated EEG. This was a randomized, multicenter controlled trial of 33 infants. The goal was to investigate how many subclinical seizures in full-term neonates with hypoxic-ischemic encephalopathy (HIE) would be missed without continuous EEG and whether immediate treatment of both clinical and subclinical seizures would result in a reduction in the total duration of seizures and a decrease in brain injury, as seen on magnetic resonance imaging (MRI) scans. Term infants with moderate to severe HIE and subclinical seizures were assigned randomly to either treatment of both clinical seizures and subclinical seizure patterns (group A) or blinding of the amplitude-integrated EEG registration and treatment of clinical seizures only (group B). All recordings were reviewed with respect to the duration of seizure patterns and the use of antiepileptic drugs (AEDs). MRI scans were scored for the severity of brain injury. Nineteen infants in group A and 14 infants in group B were available for comparison. The median duration of seizure patterns in group A was 196 minutes, compared with 503 minutes in group B (not statistically significant). No significant differences in the number of AEDs were seen. Five infants in group B received AEDs when no seizure discharges were seen on amplitude-integrated EEG traces. Six of 19 infants in group A and 7 of 14 infants in group B died during the neonatal period. A significant correlation between the duration of seizure patterns and the severity of brain injury in the blinded group, as well as in the whole group, was found. In this small group of infants with neonatal HIE and seizures, there was a trend for a reduction in seizure duration when clinical and subclinical seizures were treated. The severity of brain injury seen on MRI scans was associated with a longer duration of seizure patterns. (6)

In 2013, Sanchez et al. evaluated survey data that indicated that continuous EEG (CEEG) monitoring is used with increased frequency to identify electrographic seizures in critically ill children. Eleven North American centers retrospectively enrolled 550 critically ill children who underwent CEEG. Indications were encephalopathy with possible seizures in 67% of subjects, event characterization in 38% of subjects, and management of refractory status epilepticus in 11% of subjects. CEEG was initiated outside routine work hours in 47% of subjects. CEEG duration was <12 h in 16%, 12-24 h in 34%, and >24 h in 48%. Substantial variability existed among sites in CEEG indications and neurologic diagnoses, yet within each acute neurologic diagnosis category a similar proportion of subjects at each site had electrographic seizures. Electrographic seizure characteristics including distribution and duration varied across sites and neurologic diagnoses. This indicated variability in practice. The results suggest that multicenter studies are feasible if CEEG monitoring pathways can be standardized. However, the data also indicate that electrographic seizure variability must be considered when designing studies that address the impact of electrographic seizures. (7)

In 2012, Dash AEEG and the cost effectiveness as an alternative to inpatient

VEEG in adult patients. This evaluated EEG activity when patients are at home, without the necessity of admission to the hospital for prolonged VEEG monitoring. This was a prospective, cohort study performed in a Canadian academic center in order to assess the yield and tolerability of AEEG in the adult population. Over a period of three years, 101 patients were included (45 males, 56 females). Most of the patients had at least one previous routine EEG (93%). The primary reasons for the AEEGs were subdivided into four categories: to differentiate between seizures and non-epileptic events; to determine the frequency of seizures and epileptiform discharges; to characterize seizure type or localization; and to potentially diagnose epilepsy. The mean duration of AEEG recording was 15-96 hours. For 73 (72%) patients, the AEEG provided information that was useful for patient management. For 28 (28%) patients, the AEEG did not provide information on diagnosis because no events or epileptiform activity occurred. In only 1 patient was the AEEG inconclusive due to non-physiological artifacts. Three patients were referred for epilepsy surgery without the necessity of VEEG. The main use of AEEG is the characterization of patients with non-epileptic events and in patients with a diagnosis of epilepsy that is not clear. Quantification of spikes and seizures continue to improve the medical management of these patients. AEEG is a cost-effective solution for increasing demands for in-hospital VEEG monitoring of adult patients. (8)

In 2012 Faulkner et al. completed a study due to the International League Against Epilepsy (ILAE) guidelines recommend the use of prolonged EEG where the diagnosis of epilepsy or the classification of the seizure syndrome is proving difficult. Due to its limited provision, VEEG monitoring is unavailable to many patients. This study examined the utility of the alternate of outpatient AEEG. This retrospective study analyzed 324 consecutive prolonged outpatient AEEGs lasting 72-96 hours, without medication withdrawal. EEG data and the clinical records of 324 studies were examined. Two Hundred Nineteen (68%) studies gave positive data, 116 (36%) showed interictal epileptiform discharges (IEDs), 167 (52%) had events. One Hundred Five (32%) studies were normal. Overall 51% of studies changed management of which 22% of studies changed the diagnosis and 29% of studies refined the diagnosis by classifying the epilepsy into focal or generalized. In conclusion, this study confirmed the diagnostic utility of outpatient AEEG in the diagnosis of paroxysmal events. (9)

Society Guidelines and Recommendations

Guidelines were published by the American Clinical Neurophysiology Society (ACNS) in 2008 for long term monitoring for epilepsy (LTME) in order to diagnose, classify, and quantify Epileptic seizures. The ACNS determined LTME should be used for the identification of epileptic paroxysmal electrographic and/or behavioral abnormalities. These include epileptic seizures, overt and subclinical, and documentation of interictal epileptiform discharges. EEG and/or behavioral abnormalities may assist in the differential diagnosis between epileptic disorders and conditions associated with intermittent symptoms due to nonepileptic mechanisms (e.g., syncope, cardiac arrhythmias, transient ischemic attacks, narcolepsy, other sleep disturbances, psychogenic seizures, and other behavioral disorders) and to verify the epileptic nature of the new “spells” in a patient with previously documented controlled seizures. LTME aids in the classification and characterization (lateralization, localization, distribution) of clinical seizure type(s) in patients with documented but poorly characterized epilepsy. Characterization of ictal and interictal epileptiform EEG features are essential in the evaluation of patients with intractable epilepsy for surgical intervention. LTME can determine the relationship of seizures to specific precipitating circumstances or stimuli (e.g., nocturnal, catamenial, situation-related, activity-related). LTME allows quantification of the number or frequency of seizures and/or interictal discharges and their relationship to naturally occurring events or cycles and can aid to appropriate documentation of the EEG response to a therapeutic intervention or modification (e.g., drug alteration). Monitoring objective EEG features are useful in patients with frequent seizures, particularly with absence and other seizures having indiscernible or minimal behavioral manifestations. (1)


Disclaimer for coding information on Medical Policies

Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.

The presence or absence of procedure, service, supply, device or diagnosis codes in a Medical Policy document has no relevance for determination of benefit coverage for members or reimbursement for providers. Only the written coverage position in a medical policy should be used for such determinations.

Benefit coverage determinations based on written Medical Policy coverage positions must include review of the member’s benefit contract or Summary Plan Description (SPD) for defined coverage vs. non-coverage, benefit exclusions, and benefit limitations such as dollar or duration caps. 

ICD-9 Codes

Refer to the ICD-9-CM manual.

ICD-10 Codes

Refer to the ICD-10-CM manual.

Procedural Codes: 95812, 95813, 95816, 95819, 95822, 95824, 95827, 95950, 95951, 95953, 95954, 95956, 95957, S9015
  1. American clinical neurophysiology society, guideline twelve: Guidelines for long term monitoring for epilepsy (2008). Available at (accessed November 14, 2013).
  2. CMS-Local Coverage Determination (LCD): Special EEG tests (L33699). (October. 7, 2013) Centers for Medicare and Medicaid Services. Available at (accessed November 20, 2013).
  3. National Institute for Health and Clinical Excellence (NICE). The Epilepsies: The diagnosis and management of the epilepsies in adults and children in primary and secondary care. Guideline 20 section 8.2.4 (January 2012). Available at (accessed November 18, 2013).
  4. Neurological diagnostic tests and procedures, National Institute of Neurological Disorders and Stroke, (March 2005). Available at (accessed Nov.18, 2013).
  5. The EEG test: The EEG is the most important clinical tool in evaluating patients with suspected seizures, Epilepsy foundation. Landover, Maryland. Available at (accessed November. 21, 2013).
  6. Van Rooij, Linda G.M.., et al. Effect of treatment of subclinical neonatal seizures detected with aEEG: randomized, controlled trial, Pediatrics 2010; 125; e358
  7. Sánchez SM, et al. Electroencephalography monitoring in critically ill children: current practice and implications for future study design, Epilepsia. (August 2013); 54(8):1419-27.
  8. Dash D. et al. Ambulatory EEG: a cost-effective alternative to inpatient video-EEG in adult patients. Epileptic Disord. (Sepember 2012); 14(3):290-7.
  9. Faulkner H. et al, The utility of prolonged outpatient ambulatory EEG. Seizure (September 2012); 21(7):491-5.
  10. Long Term Monitoring for Epilepsy. Electroencephalography and Clinical Neurophysiology (1993) 87: 437-458.
  11. Nuwer, M. Assessment of digital EEG, quantitative EEG, and EEG brain mapping: report of the American Academy of Neurology and the American Clinical Neurophysiology Society. Neurology (July 1997) 49(1): 277-292.
  12. Bigler, Ed, Lajiness-O'Neill, R., et al. Technology in the assessment of learning disability. Journal of Learning Disability (January-February 1998) 31(1):67-82.
  13. Matsuzaka, T., Ono K., et al. Quantitative EEG analyses and surgical outcome after corpus callosotomy. Epilepsia (September 1999) 40(9):1269-1278.
  14. Holschneider, D.P., Leuchter, A.F., et al. Clinical neurophysiology using electroencephalography in geriatric psychiatry: neurobiologic implications and clinical utility. Journal of Geriatric Psychiatry Neurology (1999 fall) 12(3): 150-164.
  15. Drake, M.E., Padamadan, H., et al. Interictal quantitative EEG in epilepsy. Seizure (February 1998) 7(1): 39-42.
  16. Claus, J.J., Kwa, V.I., et al. Slowing on quantitative spectral EEG is a marker for rate of subsequent cognitive and functional decline in early Alzheimer disease. Alzheimer Disease Association Disorder. (September 1998) 12(3): 167-174.
  17. Ricker, J.H., Zafonte, R.D., et al. Functional Neuroimaging and Quantitative Electroencephalography in Adult Traumatic Head Injury: Clinical Applications and Interpretive Cautions. Journal of Head Trauma Rehabilitation (April 2000) 15(2): 859-868.
  18. Wallace, B.E., Wagner, A.K., et al. A History and Review of Quantitative Electroencephalography in Traumatic Brain Injury. Journal of Head Trauma Rehabilitation (April 2001) 16(2): 165-190.
  19. Procaccio F., Polo, et al. Electrophysiologic monitoring in neuro intensive care. Current Opinion in Critical Care (April 2001) 7(2): 74-80.
  20. Electroencephalograms (EEGs)-Archived. Chicago, Illinois: Blue Cross Blue Shield Association Consortium Health Plan Medical Policy Reference Manual (April 15, 2002) Medicine: 2.01.14.
  21. Topographic Brain Mapping-Archived. Chicago, Illinois: Blue Cross Blue Shield Association Consortium Health Plan Medical Policy Reference Manual (July 12, 2002) Medicine: 2.01.10.
July 2013  New 2013 BCBSMT medical policy.
February 2014 Document updated with literature review. The following was changed in coverage: 1) Ambulatory cassette recorded electroencephalogram (AEEG), completed over 24 hours, may be considered medically necessary when used: a) To classify seizure type in individuals with epilepsy after a routine EEG is non-diagnostic and classification will be used to select drug therapy;  b)  To determine characterization (lateralization, localization, distribution) of EEG abnormalities, both ictal and interictal, associated with seizure disorders in the evaluation of patients with intractable epilepsy for surgical evaluation. 2.)  EEG video monitoring (VEEG) may be considered medically necessary to diagnosis seizure type and epilepsy syndrome in individuals who present diagnostic difficulties following clinical assessment and standard EEG. CPT/HCPCS code(s) updated.  CPT 95830 removed from policy.
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