Clinical UM Guideline
|Guideline #:||CG-MED-46||Current Effective Date:||07/15/2014|
|Status:||Reviewed||Last Review Date:||05/15/2014|
This document addresses ambulatory electroencephalography monitoring in the outpatient (home) setting. This test records continuous and prolonged electrical activity of the brain to assist in the evaluation and diagnosis of seizure disorders, epilepsy syndromes, and other conditions.
Ambulatory electroencephalography (EEG) testing is considered medically necessary for any of the following indications:
Not Medically Necessary:
The use of ambulatory EEG is considered not medically necessary in all of the following circumstances:
The following codes for treatments and procedures applicable to this guideline are included below for informational purposes. Inclusion or exclusion of a procedure, diagnosis or device code(s) does not constitute or imply member coverage or provider reimbursement policy. Please refer to the member's contract benefits in effect at the time of service to determine coverage or non-coverage of these services as it applies to an individual member.
|95950||Monitoring for identification and lateralization of cerebral seizure focus, electroencephalographic (eg, 8 channel EEG) recording and interpretation, each 24 hours|
|95953||Monitoring for localization of cerebral seizure focus by computerized portable 16 or more channel EEG, electro-encephalographic (EEG) recording and interpretation, each 24 hours, unattended|
|95956||Monitoring for localization of cerebral seizure focus by cable or radio, 16 or more channel EEG, electroencephalographic (EEG) recording and interpretation, each 24 hours, attended by a technologist or nurse|
|ICD-9 Diagnosis||[For dates of service prior to 10/01/2015]|
|436||Acute, but ill-defined, cerebrovascular disease|
|779.0||Convulsions in newborn|
|780.01-780.09||Alteration of consciousness|
|780.2||Syncope and collapse|
|781.0||Abnormal involuntary movements|
|V12.54||Personal history of transient ischemic attack (TIA), cerebral infarction w/o residual deficit|
|ICD-10 Diagnosis||[For dates of service on or after 10/01/2015]|
|F44.5||Conversion disorder with seizures or convulsions|
|F48.8||Other specified nonpsychotic mental disorders (psychogenic syncope)|
|G40.001-G40.919||Epilepsy and recurrent seizures|
|G40.A01-G40.A19||Absence epileptic syndrome|
|G40.B01-G40.B19||Juvenile myoclonic epilepsy (impulsive petit mal)|
|I67.81-I67.89||Other specified cerebrovascular diseases|
|P90||Convulsions of newborn|
|R25.0-R25.9||Abnormal involuntary movements|
|R55||Syncope and collapse|
|R56.00-R56.9||Convulsions, not elsewhere classified|
|Z86.73||Personal history of transient ischemic attack (TIA), cerebral infarction w/o residual deficit|
According to the Epilepsy Foundation, epilepsy affects three million people in the United States. Epileptic seizures may be related to a brain injury or genetics, but for 70% of individuals with epilepsy, the cause is unknown. Epilepsy affects more than 300,000 children under the age of 15, and more than 90,000 young people in this group have seizures that cannot be adequately treated. The onset rate increases with aging, particularly if an older adult experiences a stroke or develops a brain tumor or Alzheimer's disease, all of which may result in seizures or epilepsy. Reports indicate that more than 570,000 adults over the age of 65 suffer from the disorder. The Epilepsy Therapy Project notes that 10% of the population will have a seizure in their lifetime. In addition, the National Institute of Neurological Disorders and Stroke (NINDS) reports that 20% of persons with epilepsy have intractable seizures (seizures that do not respond to treatment).
Ambulatory EEG monitoring in the outpatient setting (home environment) is a diagnostic test used to evaluate an individual in whom a seizure disorder is suspected but undefined by the person's medical history, physical examination, or a routine (standard/resting) EEG. Ambulatory EEG recordings are utilized in the evaluation and differential diagnosis of other conditions including cardiac arrhythmias, hysterical episodes, sleep apnea, syncopal episodes, and transient ischemic attacks if these episodes are not identified by conventional studies. In most instances, a routine EEG performed at a clinic or outpatient epilepsy facility can identify brain activity specific to seizures; however, when routine EEG is inconclusive and the clinical history strongly suggests seizure activity, an ambulatory EEG may be indicated. A National Institute for Health and Clinical Excellence (NICE, 2012) clinical guideline on the diagnosis and management of the epilepsies in adults and children in primary and secondary care recommends use of ambulatory EEG in the assessment of children, young people and adults who present diagnostic difficulties after clinical assessment and routine EEG.
Ambulatory EEG testing provides a continuous recording of the brain's electrical activity that can range from several hours to several days (typically 48 hours to 72 hours). In the outpatient setting (physician office, clinic), a set of electrodes with leads are secured to the person's scalp and a recording unit is attached by a belt to the waist or on a shoulder harness. The technology has evolved such that portable recordings of up to 32 channels can record computer-assisted spike and seizure detection rates over several days. The computer software is designed with the goal to increase the chance of recording an ictal event or interictal (the period of time between seizures) epileptiform discharges (IEDs) during the person's routine daily activities and sleep. The person being monitored and observers (family member, caregiver) have the opportunity to "tag" portions of the recording during clinical events using a push button device. Some systems can be configured for polysomnography, with inputs available for monitoring simultaneous electrocardiogram (ECG), oximetry, pulse, respiratory, synchronous video recording, and other parameters. The gold standard for evaluating the large amount of data collected by a computer-assisted system is visual analysis at the end of the testing period by a highly trained individual (Foley, 2000; Seneviratne, 2013; Waterhouse, 2003).
According to the American Association of Neurological Surgeons (AANS, 2013) seizures vary to such an extent that epilepsy specialists frequently re-classify seizure types. Current classifications include two basic categories: primary generalized seizures and focal seizures (previously referred to as partial seizures). Classifying the type of seizure assists the physician in diagnosing whether or not an individual has epilepsy or another condition and is important in the selection of appropriate anti-epileptic drug treatment. Generalized seizures are produced by electrical impulses throughout the entire brain, while focal seizures are produced (at least initially) by electrical impulses in a relatively small area of the brain (focus). The most common types of generalized seizures include: absence seizures (petit mal), atonic seizures, clonic seizures, generalized tonic-clonic (grand mal), myoclonic seizures, and tonic seizures. Focal seizures can be "simple" (not affecting awareness or memory) or "complex" (affecting awareness, memory, or behavior before, during, and immediately after the seizure). Seizure syndromes are specific to adults and children of all ages. Epilepsy syndromes in adults include, but are not limited to: temporal lobe epilepsy, primary generalized epilepsy, idiopathic focal epilepsy, and progressive myoclonic epilepsy. Epilepsy syndromes in children include, but are not limited to: febrile seizures, Landau-Kleffner Syndrome, Lennox-Gastaut Syndrome, and benign occipital epilepsy.
Routine EEG in persons with epilepsy may fail to demonstrate epileptiform activity. Ambulatory EEG is useful in documenting seizures when routine EEG is non-diagnostic. Confirmation of the clinical suspicion of epilepsy is most likely to occur when the person is experiencing daily to almost daily seizures. Studies looking at the diagnostic yield of ambulatory EEG indicate that 6% to 15% of ambulatory EEG recordings identify seizures (Waterhouse, 2003). Morris and colleagues (1994) retrospectively studied the ambulatory EEG results of 344 individuals referred to a community-based outpatient EEG service for further diagnostic evaluation using a 16-channel bipolar recording system. Ambulatory EEG was reviewed for the presence of user identified events, computer identified interictal and ictal abnormalities, and periodic time samples. A push-button recording that signified a clinical event was obtained in 166 individuals (48.3%); 41 (11.9%) of these recordings included a seizure and 125 (36.3%) showed no EEG changes during the habitual event. An EEG abnormality was identified by the computer in an additional 90 recordings (26.2%), for an overall clinical usefulness of 74.4%. Among the 191 individuals referred with previously normal routine EEGs, a total of 129 (67.5%) of these recordings were useful; 48 (25.1%) of these tracings were abnormal and an additional 81 push-button events (42.4%) showed no changes from were recorded from background EEG. Tatum and colleagues (2001) retrospectively studied 502 participants evaluated with a computer-assisted 16-channel ambulatory EEG, identifying that 38.3% of seizures went unreported by participants with 8.5% demonstrating seizure activity during the recording period (mean=28.5 hours). Faulkner and colleagues (2012a) studied the value of outpatient ambulatory EEG in the diagnosis and classification of epilepsy. When compared to routine EEG, ambulatory EEG demonstrated a higher yield and diagnostic sensitivity.
Recognition of IEDs in the absence of recorded seizures can provide evidence to support a clinical diagnosis of epilepsy. Ambulatory EEG is highly specific in identifying the occurrence of electrical spikes in persons in whom the diagnosis of seizures is being considered. Schachter and colleagues (1998) evaluated the incidence of spikes and paroxysmal rhythmic events (PREs) using a computer-assisted ambulatory EEG monitoring system in a multicenter study of asymptomatic adults (n=135) without a history of migraine or a family history of epilepsy. Spikes and PREs were evident in the overnight ambulatory EEG of only one asymptomatic adult (0.7%). The incidences of spikes in 24 other subjects with a history of migraine and/or a family history of epilepsy were 12.5% and 13.3%, respectively. The ambulatory EEGs of these subjects were significantly more likely to show spikes than the ambulatory EEGs of subjects without migraine or a family history of epilepsy. Olson (2001) reviewed ambulatory EEGs of 167 children when seizure-like events occurred at least three days per week to determine why the ambulatory EEGs were performed and whether typical seizures were recorded. Most ambulatory EEGs were performed to discriminate between epileptic and non-epileptic seizures. Ten children were recorded to determine if they were having frequent subtle seizures or frequent IEDs. The remaining 157 children had discrete events. A total of 140 children (89%) had their typical spells recorded while 107 of these children (76%) had non-epileptic events. Average duration of recording was 1.9 days. Ambulatory EEG was successful in recording children's seizure-like events when parents reported events occurring at least three days per week. The procedure was well tolerated and there were few technical problems with prolonged recording time.
Additional case series and retrospective studies compare and confirm higher yields of epileptiform abnormalities and clinical events captured by ambulatory EEG compared to routine EEG (Saravanan, 2001). Investigators suggest that ambulatory EEG is superior to routine EEG in identifying both IEDs and seizures. Studies involving children and adults report a moderate to high diagnostic yield with ambulatory EEG in differentiating between seizures and non-epileptic events, quantifying seizure activity, and characterizing seizure type and location (Dash, 2012; Faulkner, 2012b; Hussain, 2013; Wirrell, 2008). Stefan and colleagues (2009; 2011) proposed the utility of outpatient ambulatory EEG (using a portable video camera in a domestic environment) as a more reliable, objective method of measuring seizure frequency to evaluate response to antiepileptic drug therapy in persons with medically refractory epilepsy.
Some persons in whom epilepsy is suspected have a normal routine or sleep-deprived EEG. An ambulatory EEG may increase the chance of detecting an epileptiform abnormality in these individuals and significantly impact clinical management. An estimated 12% to 25% of individuals who previously had a normal or non-diagnostic routine EEG have epileptiform activity on ambulatory EEG (Waterhouse, 2003). Liporace and colleagues (1998) conducted a multicenter prospective study comparing the usefulness of a sleep-deprived EEG versus a computer-assisted 16-channel ambulatory EEG in individuals with historical information consistent with epilepsy but with a normal or non-diagnostic initial routine EEG. A total of 46 participants had both a 30 to 60 minute sleep-deprived EEG and a computer-assisted ambulatory 24 hour EEG. Sleep-deprived EEG improved detection of epileptiform discharges by 24%, where ambulatory EEG improved detection of epileptiform discharges by 33%. Ambulatory EEG detected seizures in 7 of 46 (15%) participants, and in three participants the seizures were solely detected by the computer. Ambulatory EEG is invaluable in assessing nocturnal or sleep-related events because of its capacity to record an entire night of sleep and children can be monitored at home (Foley, 2000). In addition, an individual's medical history may not reliably differentiate sleep-related events or disorders from epilepsy. An ambulatory EEG may record frequent arousals, suggesting sleep apnea, sustained daytime somnolence, or decreased rapid eye movement sleep latency (as in narcolepsy) and can assist in differentiating between an unsuspected sleep-related disorder and epilepsy (Waterhouse, 2003).
Ambulatory EEG is helpful at identifying seizures that are unrecognized or unreported by the individual and is easily accomplished on an outpatient basis. In both absence and focal seizures, individuals may experience brief alterations in the level of consciousness and impaired reaction time yet be unaware they are experiencing a seizure (Waterhouse, 2003). Keilson and colleagues (1987) studied 15 children, ages 5 to 16 years, with absence epilepsy using an 8-channel ambulatory cassette EEG. All 15 children demonstrated multiple paroxysms of generalized spike-and-wave discharges, most of which were asymptomatic. Therefore, ambulatory EEG may be useful in documenting the success or failure of a therapy in the treatment of absence seizures. In these situations, an ambulatory EEG of an untreated individual may show numerous daily seizures, yet normalize with adequate treatment.
Clinical events known as pseudoseizures are non-epileptic seizures where the person perceives altered movement, emotion, sensation, or an experience similar to those involved with epilepsy. These events are without an EEG documented ictal association. Pseudoseizures occur in as many as 20% of persons evaluated at inpatient epilepsy monitoring centers and in 5% to 20% of outpatient populations. Both pseudoseizures and epileptic seizures are concurrent in an estimated 10% to 60% of individuals with epilepsy (Waterhouse, 2003). In a retrospective review conducted by Morris and colleagues (1994), 36% (125 of 344) of participants in an outpatient study of ambulatory EEG activated the ambulatory event marker for events that were not associated with EEG changes. However, since some seizures are associated with minimal EEG changes or with movement and muscle artifacts that obscure the EEG, an ambulatory EEG is considered clinically appropriate as the initial screening procedure for non-epileptic events. Inpatient video EEG remains the gold standard to definitively diagnose non-epileptic pseudoseizures (LaFrance, 2013; Waterhouse, 2003).
Syncope or near-syncopal episodes may be evaluated with an ambulatory EEG if an ECG lead replaces one of the EEG channels (Lai, 1981). Although the underlying pathophysiological processes are distinct, seizures and syncope share some clinical characteristics which may lead to diagnostic confusion in addition to the fact that seizures and syncope may coexist in a given individual (Zaidi, 2000). Although arrhythmias have been diagnosed with continuous ambulatory EEG/ECG recording, a retrospective record review of epileptiform abnormalities in 500 individuals found epileptiform abnormalities in 1.5% of individuals with syncope and in none without a clear history of episodic complaints (Bridgers and Ebersole, 1985).
Evaluating adequate ictal and interictal EEG data is vital in facilitating localization of seizures in localization-related epilepsy (Kelly, 2011). The peer-reviewed literature reviewing the use of outpatient ambulatory EEG monitoring as the sole EEG modality in the presurgical evaluation of persons with medically refractory epilepsy consists of a single case study (Schomer, 1999) and a small case series (Chang, 2002) from the same treatment center. Chang and colleagues (2002) reported on seven persons who underwent surgery for temporal lobe epilepsy after presurgical EEG monitoring was performed exclusively in the home setting. When compared to a group of 14 persons with similar characteristics (including age, epilepsy, duration, seizure frequency and number of antiepileptic drugs tried before evaluation) who underwent inpatient video EEG monitoring, the number of seizures captured and mean recording duration were less in the seven persons who were evaluated with ambulatory EEG. The small, nonrandomized sample from a single institution and the retrospective design of the study make it difficult to draw conclusions regarding optimal criteria for selecting persons for ambulatory EEG in the presurgical workup. Ambulatory EEG, even with concomitant video recording, has major limitations in the outpatient setting, including the inability to taper antiepileptic drugs due to safety concerns in the home setting and lack of assessment/supervision by an experienced observer if or when a seizure occurs (Velis, 2007). Inpatient video EEG monitoring is considered the preferred mode and gold standard of practice in presurgical EEG testing by most epilepsy treatment centers because it accurately differentiates epileptic from non-epileptic events and provides data to localize the epileptogenic zone in candidates for epilepsy surgery (Seneviratne, 2013; Wirrell, 2008). In summary, the peer-reviewed literature discussing the selection process of appropriate candidates for temporal lobe epilepsy resection surgery consistently recommends that surgery is only undertaken after long-term video EEG monitoring in an epilepsy unit. Ambulatory EEG in the outpatient setting provides insufficient information for localizing both interictal and ictal onset zones and does not allow for the person to be subjected to provocative measures such as medication tapering or reinstitution, sleep deprivation, hyperventilation, or photic stimulation in a controlled environment, all techniques that increase the likelihood of capturing reliable presurgical epileptiform activity (Mansouri, 2012).
In summary, ambulatory EEG is an outpatient test measuring the electrical activity in the brain and has been used for many years in the evaluation and diagnosis of seizure disorders, epilepsy syndromes, and other conditions. It is considered a safe procedure in the home setting and the test causes no discomfort to the individual as the electrodes only record activity and do not produce any electrical current.
Absence seizure: A staring spell, usually brief (less than 15 seconds) in duration due to abnormal electrical activity of the brain; commonly called a petit mal seizure.
Electroencephalography (EEG): A test that involves recording of the electrical activity of the brain (brain waves).
Epilepsy: A condition of the brain where an individual is prone to repeated seizures.
Epileptic seizure: A brief occurrence of signs and/or symptoms such as sudden and involuntary jerk of a hand, arm, or whole body, a strange smell (such as burnt rubber), a sensation in the stomach, a ringing sound that keeps increasing in volume, staring into space, or convulsive movements as a result of a primary change to the electrical activity (abnormally excessive) in the brain.
Epileptiform activity: Changes in the brain's electrical activity that are commonly seen in people who have epilepsy.
Focal seizure: A seizure that begins with an electrical discharge in a relatively small area (called the focus) of the brain; previously referred to as a partial or localization-related seizure. In most cases, the cause is unknown, but may be related to a brain infection, head injury, stroke, or a brain tumor.
Generalized seizure: A seizure that begins with a widespread electrical discharge involving both sides of the brain at once.
Lennox-Gastaut Syndrome: An epilepsy syndrome with an age of onset of 3-10 years characterized by multiple seizure types (including atonic, tonic, tonic-clonic and atypical absence seizures), cognitive impairment and specific EEG features of diffuse slow spike and wave as well as paroxysmal fast activity during sleep.
Medically refractory (intractable) epilepsy: An individual with uncontrolled epilepsy who has seizures that fail to remain controlled despite treatment with two consecutive first-line antiepileptic medications over two years (Engel, 2003).
Myoclonic seizure: Sudden, brief (less than 100 millisecond) and almost shock-like involuntary single or multiple jerks due to abnormal or excessive or synchronous neuronal activity; associated with polyspikes on EEG.
Primary generalized seizure: A seizure that results from abnormal electrical activity of both sides of the brain at the same time.
Pseudoseizure: A non-epileptic event that imitates a seizure and may include rhythmic movements, unresponsiveness, or other symptoms similar to those caused by epilepsy, but without an electrographic association.
Routine (resting/standard) electroencephalography (EEG): A test that measures and records the electrical activity of the brain and is the most common test for epilepsy conducted in the clinical setting (inpatient or outpatient facility).
Seizure: An excessive surge of electrical activity in the brain, usually lasting from a few seconds up to a few minutes, causing a wide range of symptoms or effects depending on which parts of the brain are involved in the abnormal electrical activity.
Tonic seizures: An epileptic seizure characterized by abrupt generalized muscle stiffening than can result in a fall, usually lasting less than a minute with rapid recovery.
Tonic-clonic seizure: A seizure of sudden onset involving generalized stiffening and subsequent rhythmic jerking of the limbs.
Peer Reviewed Publications:
Government Agency, Medical Society and Other Authoritative Publications:
|Websites for Additional Information|
|Reviewed||05/15/2014||Medical Policy & Technology Assessment Committee (MPTAC) review. Updated Discussion/General Information, References, and Websites for Additional Information sections.|
|08/08/2013||Clarified Discussion and Definitions concerning pseudoseizures. Updated References and Websites for Additional Information sections.|
|New||05/09/2013||MPTAC review. Initial document development.|