LCD L33405: Polysomnography and Sleep Testing

History/Background and/or General Information

About 40 million people in the United States suffer from sleep problems every year. Not getting enough sleep for a long time can cause health problems. Many sleep disorders can be managed by primary care physicians; however, when abnormal sleep patterns are not easily explainable and further evaluation is necessary, expert opinion and sleep studies may be needed.

Sleep consists of two distinct states: rapid eye movement (REM), and non-rapid eye movement (NREM). REM sleep is when we dream. NREM sleep is further divided into three stages. Stages one and two are referred to as light sleep and stage three as deep sleep. The first sleep cycles each night contain relatively short REM periods and long periods of deep sleep. As the night progresses, REM sleep periods increase in length while deep sleep decreases. By morning, people spend nearly all their sleep time in stages one, two, and REM.

Polysomnography (PSG) refers to the continuous and simultaneous monitoring and recording of various physiological and pathophysiological parameters of sleep furnished in a sleep laboratory facility that includes physician review, interpretation and report. A technologist supervises the recording during sleep time and has the ability to intervene, if needed. The studies are performed to diagnose a variety of sleep disorders and to evaluate a patient’s response to therapies such as continuous positive airway pressure (CPAP). PSG is distinguished from sleep studies by the inclusion of sleep staging, which requires electroencepholograpm (EEG), electroculogram (EOG), and electromyography (EMG).

Parameters 1-3 are required for a basic PSG. Additional parameters that may be monitored include, but are not limited to, the following:

• At minimum, a 3 lead electroencephalogram (EEG) to measure global neural encephalographic activity using electrodes placed on the scalp.

• Electrooculogram (EOG) to measure eye movements using electrodes placed near the outer canthus of each eye.

• A submental electromyogram (EMG) to measure submental electromyographic activity using electrodes placed over the mentalis, submentalis muscle, and/or masseter regions.

• Rhythm electrocardiogram (ECG).

• Nasal and oral airflow via both thermistor and nasal pressure sensor for PSG sleep staging with 4 or more additional parameters of sleep.

• Airflow in the mask if positive airway pressure for PSG sleep staging with 4 or more additional parameters of sleep, with initiation of continuous positive airway pressure therapy or bilevel ventilation.

• Respiratory effort by chest-wall and abdominal movement measured using respiratory inductive plethysmography, endoesophageal pressure or by intercostal EMG or validated Polyvinylidene Fluoride (PVDF) impedance belt.

• Oxygen saturation (SpO2) by oximetry or transcutaneous monitoring.

• Bilateral anterior tibialis muscle activity, motor activity-movement using EMG.

• Body positions by directly applied sensors or by direct observation.

• Sound recordings to measure snoring.

• Continuous video monitoring.

Optional parameters that can be monitored in a sleep study include the following:

• Core body temperature

• Incident light intensity

• Penile tumescence

• Pressure and pH at various esophageal levels

PSG and other sleep test monitoring devices are generally classified based on the number of biologic sensors applied and physiologic parameters recorded.

• Type I PSG is covered when used to aid the diagnosis of obstructive sleep apnea (OSA) in beneficiaries who have clinical signs and symptoms indicative of OSA if performed attended in a sleep lab facility. Type I devices are capable of recordings of all of the physiologic parameters and signals defined for PSG. The recording is furnished in a sleep laboratory facility in which a technologist is physically present to supervise the recording during sleep time and has the ability to intervene if needed. Minimal requirements include recording of EEG, EOG, chin EMG, anterior tibialis EMG, ECG, airflow, respiratory effort and oxygen saturation. Body position must be documented or objectively measured. Trained personnel must be in constant attendance and able to intervene.

• A Type II sleep testing device is covered when used to aid the diagnosis of OSA in beneficiaries who have clinical signs and symptoms indicative of OSA if performed unattended in or out of a sleep lab facility or attended in a sleep lab facility. Type II devices are portable devices that may measure the same channels as type I testing, except that a heart-rate monitor can replace the ECG. This device has a minimum of 7 channels (e.g., EEG, EOG, EMG, ECG-heart rate, airflow, respiratory effort, and oxygen saturation – this type of device monitors sleep staging). A sleep technician is not necessarily in constant attendance in Type II studies but is needed for preparation.

• A Type III sleep testing device is covered when used to aid the diagnosis of OSA in beneficiaries who have clinical signs and symptoms indicative of OSA if performed unattended in or out of a sleep lab facility or attended in a sleep lab facility. Type III devices monitor and record a minimum of 4 channels and must record ventilation or airflow, heart rate or ECG, and oxygen saturation. A sleep technician is not necessarily in constant attendance in Type III studies but is needed for preparation.

• A Type IV sleep testing device measuring three or more channels, one of which is airflow, is covered when used to aid the diagnosis of OSA in beneficiaries who have signs and symptoms indicative of OSA if performed unattended in or out of a sleep lab facility or attended in a sleep lab facility. Type IV devices must include airflow as one of the required 3 channels. Other measurements may include oximetry and heart rate. A sleep technician is not necessarily in constant attendance in Type IV studies but is needed for preparation.

• A sleep testing device measuring three or more channels that include actigraphy, oximetry, and peripheral arterial tone is covered when used to aid the diagnosis of OSA in beneficiaries who have signs and symptoms indicative of OSA if performed unattended in or out of a sleep lab facility or attended in a sleep lab facility. A sleep technician is not necessarily in constant attendance in such studies but is needed in preparation.

Multiple sleep latency testing (MSLT) involves four or five 20-minute nap opportunities offered at 2-hour intervals. MSLT objectively assesses sleep tendency by measuring the number of minutes it takes the patient to fall asleep. Conversely, the maintenance of wakefulness test (MWT) requires the patient to try to stay awake. MSLT is the better test for demonstration of sleep-onset REM periods, a determination that is important in establishing the diagnosis of narcolepsy. To insure validity, proper interpretation of the MSLT can only be made following a polysomnography performed on the preceding night.

Normally, sleep studies and PSG for sleep disorders are performed in sleep centers or laboratories. However, the diagnosis of OSA for coverage of CPAP may also be established by home sleep testing (HST) as indicated under Sleep Apnea below.

If HST is used, they may be tested in the home environment after application of the sensors and receiving education regarding a monitoring device from the technical, professional, or appropriately trained staff of the sleep center or laboratory. The overnight stay in the sleep center or laboratory is considered an integral part of PSG, MSLT, and MWT but not for HST.

Covered Indications

Please refer to CMS IOM Publication 100-02, Medicare Benefit Policy Manual , Chapter 15, Section 70 for sleep disorder clinics definitions and criteria for coverage of diagnostic tests, and medical conditions for which testing is covered.

1. Sleep Apnea:

Please refer to CMS IOM Publication 100-02, Medicare Benefit Policy Manual , Chapter 15, Section 70 B. Medical Conditions for Which Testing is Covered.

Please refer to CMS IOM Publication 100-03, Medicare National Coverage Determinations (NCD) Manual , Chapter 1, Part 4, Section 240.4 Continuous Positive Airway Pressure (CPAP) Therapy For Obstructive Sleep Apnea (OSA) and Section 240.4.1 Sleep Testing for Obstructive Sleep Apnea (OSA) for indications and limitations.

Abnormal breathing events in sleep apnea syndromes include apnea, hypopnea and respiratory effort related arousals (RERA). Apnea is a cessation of airflow for at least 10 seconds. Hypopnea is an abnormal respiratory event lasting at least 10 seconds with at least a 30% reduction in thoracoabdominal movement or airflow as compared to baseline, and with at least a 4% decrease in oxyhemoglobin saturation. RERA is defined as a period during sleep lasting at least 10 seconds during which severe narrowing of the upper airways with increasing respiratory efforts leads to electroencephalographic arousal from sleep without an appreciable reduction in airflow and oxygen saturation.

Apneas can be classified as central, obstructive or mixed based on the presence of respiratory effort during the event. In obstructive apnea events, respiratory effort continues in the absence of airflow while in central apnea events, both airflow and respiratory effort are simultaneously absent. Mixed apnea events contain respiratory effort only during a portion of the apnea event.

For a diagnosis of OSA to be made, the following criteria must be met:

A. Prior to sleep testing, the patient has a face-to-face clinical evaluation by the treating physician to assess the patient for OSA which must include, at a minimum, the following:

• Sleep history and symptoms including, but not limited to, snoring, daytime sleepiness, observed apneas, choking or gasping during sleep, morning headaches; and,

• Epworth Sleepiness Scale; and,

• Physical examination that documents body mass index, neck circumference and a focused cardiopulmonary and upper airway system evaluation.

B. The patient has a covered sleep test that meets either of the following criteria:

• The apnea-hypopnea index (AHI) or Respiratory Disturbance Index (RDI) is greater than or equal to 15 events per hour with a minimum of 30 events; or,

• The AHI or RDI is greater than or equal to 5 and less than or equal to 14 events per hour with a minimum of 10 events and documentation of:

• Excessive daytime sleepiness, impaired cognition, mood disorders, or insomnia; or,

• Hypertension, ischemic heart disease, or history of stroke

OSA occurs when the muscles relax during sleep, causing soft tissue in the back of the throat to collapse and block the upper airway. This leads to partial reductions (hypopneas) and complete pauses (apneas) in breathing during sleep. Most pauses last between 10 and 30 seconds, but some may persist for one minute or longer. This can lead to abrupt reductions in blood oxygen saturation. OSA characterized by RERA events has been called upper airway resistance syndrome. In central sleep apnea, the airway is not blocked but respiratory coordination is impaired such that the brain does not signal the muscles of respiration to contract. All sleep apnea syndromes disrupt sleep, leading to excessive daytime sleepiness, fatigue and cognitive disturbances. OSA has also been associated with elevated risk for arterial hypertension, cardiac ischemic events, cerebral vascular accidents, insulin resistance and obesity.

The diagnosis and severity of sleep apnea syndromes is established by the clinical evaluation and a positive PSG or HST. Staging of the severity of sleep apnea can be accomplished by utilization of the apnea-hypopnea index (AHI) which is defined as the average number of apneas and hypopneas per hour of sleep. The respiratory disturbance index (RDI) is another term used to establish the diagnosis of sleep apnea and stage its severity, which in sleep tests that measure sleep with EEG is defined as the average number of apneas and hypopneas, and RERA per hour of sleep. In Type III, Type IV HST, and in HST devices measuring three or more channels that include actigraphy, oximetry, and peripheral arterial tone where sleep is not measured, the RDI is defined as the average number of apneas and hypopneas per hour of recording.

Positive airway pressure (PAP) therapy is a non-invasive technique for providing continuous (CPAP) or variable levels of air pressure from a flow generator, via a nose mask, through the nares. The purpose is to prevent the collapse of the oropharyngeal walls and the obstruction of airflow during sleep, which occurs in OSA. CPAP is the most commonly used treatment for OSA. The appropriate level for CPAP is best determined during a CPAP titration PSG. A titration PSG provides useful information on the appropriate level of CPAP during one single night in a dedicated environment. Other factors, such as body and neck or mandibular position, weight changes, and nasal obstruction may affect the appropriate CPAP level. Since these effects may change over time, automatically-adjusting positive airway pressure devices (APAP) were developed. APAP devices are designed to automatically match the treatment pressure to the patient's needs. APAP devices react to perceived treatment pressure needs by manufacturer specific processes such that the information derived from APAP may differ by device and manufacturer. Certain APAP devices may be used in an unattended way to determine a fixed CPAP treatment pressure for patients with moderate to severe OSA without significant co-morbidities such as congestive heart failure, chronic obstructive pulmonary disease, central sleep apnea syndromes and hypoventilation syndromes. Similarly, certain APAP devices may be initiated and used in the self-adjusting mode for unattended treatment of patients previously diagnosed with moderate to severe OSA without the significant co-morbidities earlier described. A clear patient preference for APAP over manual CPAP has not been demonstrated by studies addressing the issue.

Bilevel positive airway pressure (BPAP) is a positive pressure treatment alternative to CPAP that delivers different pressures during exhalation and inhalation. The inhalation pressure does not adapt to the patient's changing needs, as in the APAP, but the exhalation pressure can be adjusted lower. The ability to set different inhalation and exhalation pressures results in lower average airway pressures than those delivered by CPAP. Using lower pressures may reduce the incidence of side effects, such as the sensation of suffocation, difficulty exhaling, nasal congestion, etc. which contribute to patient noncompliance. A clear patient preference for BPAP over CPAP has not been demonstrated by studies addressing the issue.

Split-Night Studies

Split-night studies involve polysomnography in the first half of the night followed, if there is an abnormal frequency of apneas and hypopneas, by PAP titration for the remainder of the night. Polysomnography with PAP titration is indicated in patients with sleep apnea previously diagnosed by a clinical evaluation and either a positive PSG or a positive HST. Typically split-night studies are performed for two major reasons:

• When a positive diagnosis (described below) of sleep apnea (obstructive, central or mixed) can be made within the first 4 hours of polysomnography. This could include emergency protocols where patient’s apnea is not safe to continue testing without PAP treatment

• In patients with a prior history of OSA who need an updated polysomnography and PAP titration.

For Positive Airway Pressure (PAP) titration, a split-night study (initial diagnostic polysomnogram followed by PAP titration during polysomnography on the same night) is an alternative to one full night of diagnostic polysomnography, followed by a second night of titration for the treatment of obstructive sleep apnea (OSA) if the following criteria are met:

A positive test for OSA is established if either of the following criteria using the Apnea-Hypopnea Index (AHI) or Respiratory Disturbance Index (RDI) is met:

• AHI or RDI greater than or equal to 15 events per hour, or

• AHI or RDI greater than or equal to 5 and less than or equal to 14 events per hour with documented symptoms of excessive daytime sleepiness, impaired cognition, mood disorders or insomnia, or documented hypertension, ischemic heart disease, or history of

• There are at least three hours for PAP titration prior to the end of the test.

2. Narcolepsy:

Please refer to CMS IOM Publication 100-02, Medicare Benefit Policy Manual , Chapter 15, Section 70 B. Medical Conditions for Which Testing is Covered.

Narcolepsy can occur with and without cataplexy (sudden, brief loss of muscle tone with retained consciousness precipitated by strong emotion).

A clinical history, sleep diaries, PSG, and MSLT are key items in the evaluation of narcolepsy. PSG followed by MSLT is useful in confirming the clinical impression. Narcoleptic patients often report disrupted sleep, and PSG often confirms fragmented sleep patterns. Ordinarily, a diagnosis of narcolepsy can be confirmed by demonstrating mean sleep latency of 8 minutes or less and two or more sleep onset sleep periods on prior night PSG and MSLT.

The diagnosis of narcolepsy is usually confirmed by PSG followed by a MSLT. The following measurements are normally required to diagnose narcolepsy:

• PSG assessment of the quality and quantity of nighttime sleep and to exclude alternate pathology such as

• OSA;

• MSLT derived mean sleep latency;

• The number of REM onset sleep episodes on the PSG and MSLT.

Initial PSG and MSLT occasionally fail to identify narcolepsy. Repeat PSG may be indicated if:

• The first study is technically inadequate due to equipment failure;

• The subject could not sleep or slept for an insufficient amount of time to allow a clinical diagnosis;

• Initiation of therapy or confirmation of the efficacy of prescribed therapy is needed; or

• The results were inconclusive or ambiguous.

3. Other Respiratory Disorders:

This diagnostic category includes breathing disorders that are not principally defined by obstructive or central apnea/hypopnea or the upper airways resistance syndrome.

PSG is indicated for patients with neuromuscular disorder and sleep-related symptoms to evaluate symptoms of sleep disorder that are not adequately diagnosed by obtaining a sleep history, assessing sleep hygiene, and reviewing sleep diaries.

PSG and HST are not indicated to diagnose chronic lung disease. Nocturnal hypoxemia in patients with chronic obstructive, restrictive, or reactive lung disease is usually adequately evaluated by oximetry and does not require PSG or HST. However, if the patient’s symptoms suggest a diagnosis of obstructive sleep apnea or periodic limb movement disorder, indications for PSG are the same as for those disorders in patients without chronic lung disease.

4. Parasomnia:

Please refer to CMS IOM Publication 100-02, Medicare Benefit Policy Manual , Chapter 15, Section 70 B. Medical Conditions for Which Testing is Covered.

In parasomnia, PSG is routinely indicated:

• To assist with the diagnosis of paroxysmal arousals or other sleep disruptions that are thought to be seizure related when the initial clinical evaluation and results of a standard EEG are inconclusive.

• In evaluating sleep-related behaviors that are violent or otherwise potentially injurious to the patient or

• When evaluating patients with sleep behaviors suggestive of parasomnias that are unusual or atypical because of the patient's age at onset; the time, duration, or frequency of occurrence of the behavior; or the specifics of the particular motor patterns in question (e.g. stereotypical, repetitive, or focal).

In parasomnia, PSG may be indicated under the following circumstances:

• In situations with forensic considerations (e.g., if onset follows trauma or if the events themselves have been associated with personal injury).

• When the presumed parasomnia or sleep-related epilepsy does not respond to conventional therapy.

• PSG is not routinely indicated in cases of typical, uncomplicated, and non-injurious parasomnias when the diagnosis is clearly delineated.

5. Restless Legs Syndrome and Periodic Limb Movement Disorder:

N/A