Clinical UM Guideline
|Subject:||Auditory Brainstem Responses (ABRs) and Evoked Otoacoustic Emissions (OAEs) for Hearing Disorders|
|Guideline #:||CG-MED-49||Current Effective Date:||10/06/2015|
|Status:||Revised||Last Review Date:||08/06/2015|
This document addresses the use of auditory brainstem responses (ABRs) and evoked otoacoustic emissions (OAEs) for the evaluation of hearing disorders. This document does not address ABR or OAE for neurologic conditions, such as multiple sclerosis (MS), or when used as part of intra-operative monitoring (for example, during surgery for acoustic neuroma).
ABR and OAE testing are noninvasive methods used to detect hearing disorders. OAE measures the preneural status of the peripheral auditory system to the outer hair cells of the inner ear (cochlea). OAE may be used to assess hearing disorders as the result of cochlear dysfunction or detect irregularities to the pathway of the inner ear. ABR measures the neural status of the cochlea, the auditory nerve, and assess auditory neuropathy. ABR testing may be used to assess central nervous system issues such as eighth cranial nerve dysfunction from vascular compression or tumors and brainstem dysfunction. ABR is also referred to as auditory evoked response (AER) auditory evoked potential (AEP), brainstem evoked auditory potential (EAP), brainstem auditory evoked potential (BAEP), brainstem auditory evoked response (BAER), and evoked response audiometry.
Automated ABR, OAE, or OAE followed by ABR testing is considered medically necessary to screen for hearing disorders for any of the following indications:
ABR with or without OAE testing is considered medically necessary to diagnose hearing disorders for any of the following indications:
Not Medically Necessary:
ABR or OAE for hearing disorders is considered not medically necessary when the above criteria are not met, or for the evaluation of suspected presbycusis, or for the evaluation of suspected otosclerosis, or for individuals able to undergo standard audiometry.
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.
|92558||Evoked otoacoustic emissions, screening (qualitative measurement of distortion product or transient evoked otoacoustic emissions), automated analysis. [screening test]|
|92585||Auditory evoked potentials for evoked response audiometry and/or testing of the central nervous system, comprehensive|
|92586||Auditory evoked potentials for evoked response audiometry and/or testing of the central nervous system, limited|
|92587||Distortion product evoked otoacoustic emissions, limited evaluation (to confirm the presence or absence of hearing disorder, 3‐6 frequencies) or transient evoked otoacoustic emissions, with interpretation and report|
|92588||Distortion product evoked otoacoustic emissions; comprehensive diagnostic evaluation (quantitative analysis of outer hair cell function by cochlear mapping, minimum of 12 frequencies), with interpretation and report|
|ICD-10 Diagnosis||[For dates of service on or after 10/01/2015]|
|H90.0-H90.8||Conductive and sensorineural hearing loss|
|H91.01-H91.93||Other and unspecified hearing loss|
|H93.011-H93.93||Other disorders of ear, not elsewhere classified|
|P36.0-P36.9||Bacterial sepsis of newborn|
|P55.0-P55.9||Hemolytic disease of newborn|
|P58.0-P58.9||Neonatal jaundice due to other excessive hemolysis|
|R62.0||Delayed milestone in childhood|
|R94.120||Abnormal auditory function study|
|T36.0X1A-T36.96||Poisoning by, adverse effect of and underdosing of systemic antibiotics|
|T45.1X1A-T45.1X5S||Poisoning by, adverse effect of and underdosing of antineoplastic and immunosuppressive drugs|
|T56.0X1A-T56.94||Toxic effect of metals|
|Z01.110-Z01.118||Encounter for examination of ears and hearing with abnormal findings|
|Z82.2||Family history of deafness and hearing loss|
|Z86.69||Personal history of other diseases of the nervous system|
|ICD-9 Diagnosis||[For dates of service prior to 10/01/2015]|
|388.00-388.9||Other disorders of ear|
|771.81||Septicemia [sepsis] of newborn|
|773.0-773.2||Hemolytic disease of fetus or newborn, due to isoimmunization [jaundice]|
|774.1||Perinatal jaundice from other excessive hemolysis|
|794.15||Abnormal auditory function studies|
|960.0-960.9||Poisoning by antibiotics|
|963.1||Poisoning by antineoplastic and immunosuppressive drugs|
|984.0-985.9||Toxic effect of lead, other metals|
|V12.49||Personal history of other disorders of nervous system and sense organs|
|V19.2||Family history of deafness or hearing loss|
|V41.2||Problems with hearing|
|V72.11||Encounter for hearing examination following failed hearing screening|
|V72.19||Other examination of ears and hearing [this diagnosis accepted for screening tests only]|
ABR measurements reflect the status of the auditory (cranial) nerve and pathways, and peripheral auditory system. ABR responses allow for the identification of normal cochlear function and neurophysiological competency of the acoustic pathway in test subjects. The test involves placing electrodes on the scalp and earlobes. Auditory stimuli, such as tones or clicking noises are delivered to one ear. The sound stimulation moves through the outer ear (canal), through the middle ear (tympanic membrane and ossicles) to the inner ear (cochlea), through the vestibular and eighth cranial nerve to the brain. An electrical response from the brainstem is sensed by the electrodes that have been strategically placed on the subject's scalp. During automated ABR screening, this response is recorded and analyzed by a computer and, based on the computer algorithm, the subject either passes or fails the screening. A non-automated ABR requires interpretation by an audiologist. A diagnostic ABR provides information such as "no response", thresholds prediction, auditory neuropathy, or central auditory brainstem abnormality. Any individual who fails the screening is usually referred for additional testing.
Otoacoustic emissions (OAEs) are used to assess cochlear integrity and preneural function, and are physiologic measurements of the response of the cochlear outer hair cells to acoustic stimuli. This test may only detect hearing disorders that affect the cochlea and the pathway to the inner ear. OAEs do not diagnosis hearing loss; they reflect inner ear mechanics and provide information that further defines auditory system condition and sensitivity. OAEs recorded in the absence of stimulation are known as spontaneous OAEs. OAEs that are recorded in response to auditory signals are known as evoked OAEs. OAE testing involves the insertion of a small probe into the ear canal, and the introduction of soft tones or click stimuli. The sound moves along the pathway from the outer ear, through the middle ear and into the cochlea. When the cochlea is functioning properly, an otoacoustic emission is produced that travels back out through the middle and the outer ear. This emission is calculated by the probe and analyzed by a computer. When an emission is adequate, "pass" is displayed on the monitor. In instances of dysfunction or blockage along the pathway to the cochlea, the equipment will be unable to measure the emission, and the monitor will display "fail" or "refer." When used in conjunction with ABR, OAEs are not only useful in the differential diagnosis of cochlear hearing disorders, but also in the identification of children with neurological dysfunction (AAA, 2011; ASHA, 2004).
Two types of OAEs are generally performed in the clinical setting; transient evoked OAEs (TEOAEs) and distortion product OAEs (DPOAEs). TEOAEs are elicited with brief sounds (clicks or tone bursts) that have an intensity level of 80 dB SPL. TEOAEs reflecting cochlear (outer hair cell) activity are generally recorded across a frequency range of 500 to approximately 4000 Hz. In contrast, DPOAEs are elicited with sets of two pure tone frequencies that are closely spaced and presented simultaneously at an intensity level 55 and 65 dB SPL. DPOAEs can be recorded over the frequency region of 500 to 8,000 Hz and sometimes even higher frequencies. TEOAEs may be used to access cochlear function and to validate other tests. DPOAEs are generally used to assess cochlear damage, ototoxicity, and noise-induced damage.
Bone conduction ABR using a click stimulus provides a differential diagnosis for the type of hearing disorder if air conduction thresholds are elevated. It is one method of identifying infants who may have conductive hearing loss, such as in cranial-facial anomalies (for example, aural atresia). According to the ASHA, when air-conduction thresholds obtained by behavioral or physiologic methods are found to be abnormal, estimates of bone-conduction sensitivity should be completed (ASHA, 2004).
Another auditory evoked potential test with emerging clinical applications is the auditory steady-state response (ASSR). This technology is being investigated as a method of estimating frequency-specific hearing sensitivity in individuals who cannot or will not provide reliable or valid behavioral thresholds (Dimitrijevic, 2002; Vander, 2002). According to the ASHA, "research in this area is ongoing and improvements in methodology are expected. As with all developing clinical procedures, audiologists are expected to monitor the literature for methodological improvements in ASSR" (ASHA, 2004). The Joint Committee on Infant Hearing (JCIH) which includes organizations such as the American Academy of Pediatrics (AAP), the American Academy of Audiology (AAA), the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) and the American Speech-Language-Hearing Association (ASHA), has stated that "At this time, there is insufficient evidence for use of the auditory steady-state response as the sole measure of auditory status in newborn and infant populations." The JCIH indicates that the test could be used to supplement the other screening tests or could be included at older ages and that "clinical research is being performed to investigate its potential use in the standard pediatric diagnostic test battery" (AAP, 2007).
ABRs and OAEs provide physiologic measures that may be used to screen newborns, infants, young children, or any age individual who cannot be evaluated with behavioral techniques, for hearing disorders.
During neonatal screening, a limited (automated) ABR test is usually performed in the nursery using a significantly low intensity level (35 to 40 dB) to rule out hearing disorders ranging from moderate, to severe, or profound. If the infant fails testing at this level, he/she is typically referred to an audiologic laboratory for a comprehensive ABR which involves testing measurements at several different intensity levels and frequencies.
OAEs can be measured in almost all individuals who have normal hearing sensitivity and normal functioning of the middle ear system (provided that the ear canal is clear and the recording conditions are suitable). Evoked OAEs are generally not present in ears with hearing loss that is of a moderate degree or greater. The test causes no discomfort and only requires the subject to remain quiet and reasonably still for a few minutes. Because no behavioral response is required, the information can be obtained from individuals who are sleeping, comatose or not developmentally mature enough to provide a behavioral response to sound. OAE is particularly useful when screening is required in individuals under the age of 4 years when risk factors are present, and when the child is essentially unable to cooperate with a screening audiogram in the office. Uses for OAE include, but are not limited to, the screening of newborns, infants and children for hearing disorders, assisting in the diagnosis of hearing disorders in infants and children who did not pass the initial hearing screening, evaluating infants and children suspected of having hearing disorders when behavioral audiometric tests are judged to be unreliable, ear-specific thresholds cannot be obtained, or when results are inconclusive regarding the type, degree, or configuration of hearing levels (ASHA, 2004).
The American Academy of Pediatrics (AAP) emphasizes that ABR and OAE are not true tests of hearing and in fact are tests of auditory pathway structural integrity. OAE testing does not assess the integrity of the neural transmission of sound from the eighth nerve to the brainstem and, therefore, will miss auditory neuropathy and other neuronal abnormalities. In these instances, individuals with such abnormalities will have normal OAE test results but abnormal ABR test results. Even if ABR or OAE test results are normal, hearing cannot be definitively considered normal until a child is developmentally mature enough for a reliable behavioral audiogram to be obtained. Behavioral pure tone audiometry is the standard for hearing evaluation (Cunningham, 2003).
According to the AAP, ABR or OAE testing is appropriate to make a confirmatory diagnosis of hearing disorders in infants and children (developmental age of birth to 36 months) who did not pass the initial hearing screening. When a permanent hearing deficit is detected, frequency-specific ABR testing is appropriate to determine the degree and configuration of hearing deficiency in each ear for fitting of amplification devices. When there are risk indicators for neural hearing disorders (auditory neuropathy/auditory dyssynchrony, also known as auditory neuropathy spectrum disorder ([ANSD]) such as hyperbilirubinemia or anoxia, click-evoked ABR testing using both condensation and rarefaction single-polarity stimulus are needed to determine if a cochlear microphonic is present (AAP, 2007).
Studies have demonstrated the benefits of the early identification of hearing disorders in children and the success of early interventions. The Wessex Universal Neonatal Hearing Screening Trial (1998) was a nonrandomized, controlled trial carried out in the United Kingdom that explored whether the addition of universal neonatal hearing screening to usual care screening at 7 to 8 months of age versus usual care screening alone, increases identification and improved the early management of infants with congenital permanent childhood hearing impairment (PCHI). The study included newborns (25,609) that were born during periods when universal newborn hearing screening was conducted, and infants (28,172) not screened as newborns. The researchers screened infants using TEOAE and, in infants who failed this test, ABR testing was performed on the same day. Participants were also screened using the Health Visitor Distraction Test at 7 to 8 months of age as usual care. Infants with abnormal newborn screening test results, abnormal Health Visitor Distraction Tests, or when there were additional concerns regarding hearing impairment, were referred to audiology services. Neonatal screening achieved 87% coverage of births, with a false-alarm rate of 1.5%, and an overall yield of 90 cases of bilateral PCHI of 40 dB or more relative to hearing threshold level per 100,000 target population. This value is equivalent to 80% of the expected prevalence of the disorder in the population. Seventy-one more infants with moderate or severe PCHI per 100,000 target population were referred before age 6 months during periods with neonatal screening compared to periods without this screening. Early confirmation and management of PCHI were significantly increased. The rate of false-negative results from neonatal screening was significantly lower than that for the distraction test (4% vs. 27% p=0.041). The authors concluded that neonatal screening is effective in the early identification of congenital PCHI and may be particularly useful for infants with moderate and severe PCHI for whom early management may have the most benefit.
Kennedy and colleagues (2006) evaluated children with bilateral permanent hearing impairment identified from a large birth cohort in southern England. Of the 120 participants in the study, 61 were born during periods with universal newborn screening and 57 had hearing impairment that was confirmed by nine months of age. The primary outcomes were language versus nonverbal ability and speech (expressed as a z score). Confirmation of hearing impairment by nine months of age was associated with higher adjusted mean z scores for language as compared with nonverbal ability. Birth during periods with universal newborn screening was also associated with higher adjusted z scores for receptive language as compared with nonverbal ability, although the z scores for expressive language as compared with nonverbal ability were not significantly higher. Speech scores did not differ significantly between those who were exposed to newborn screening or early confirmation and those who were not.
Nelson and colleagues (2008) completed an updated review for the US Preventive Services Task Force on universal newborn hearing screening. The systematic review focused on observational studies and controlled trials addressing the outcomes of infants screened for hearing loss by 6 months of age. The research addressed three questions: (1) Among infants identified by universal screening who would not be identified by targeted screening, does initiating treatment before 6 months of age improve language and communication outcomes? (2) Compared with targeted screening, does universal screening increase the chance that treatment will be initiated by 6 months of age for infants at average risk or for those at high risk? (3) What are the adverse effects of screening and early treatment? The authors found that children with hearing loss who undergo universal newborn hearing screening have better language outcomes at school age than children not screened. Infants identified with hearing loss through universal screening receive intervention (referral, diagnosis, and treatment) earlier than those identified in other ways.
Because approximately half of the children with hearing loss have no identifiable risk factors, universal screening (instead of targeted screening) has been proposed to identify children with permanent congenital hearing loss. According to the United States Preventive Services Task Force (USPSTF, 2008), newborn hearing screening testing is highly accurate and leads to earlier identification and treatment of infants with hearing loss. Several professional societies and governmental organizations have published guidelines emphasizing the importance of hearing screening in infants and children. While these bodies all agree that ABR and OAE testing are useful screening tools in the identification of hearing loss, there is still a lack of consensus with regard to the frequency of screening, which tests are most appropriate for the different age groups, and when ABR or OAE testing is appropriate outside of the screening setting.
According to the ASHA, OAEs and ABRs are appropriate tools to assess for hearing disorders in children who are chronologically/developmentally between 0 to 4 months of age (age adjusted for prematurity). For children who have a developmental or chronological age from 5 to 60 months, evoked OAEs and/or ABR testing should be completed when behavioral audiometric tests are judged to be unreliable, ear-specific thresholds cannot be obtained, or when results are inconclusive regarding type, degree, or configuration of hearing levels. In addition, if the neurological integrity of the auditory system through the level of the brainstem is in question, ABR testing should be conducted (ASHA, 2004).
The JCIH published a position statement titled "Principles and Guidelines for Early Hearing Detection and Intervention Programs. According to this guideline, "both OAE and automated ABR technologies provide noninvasive recordings of physiologic activity underlying normal auditory function, both are easily performed in neonates and infants." To maximize the outcome for infants who are deaf or hard of hearing, all infants should be screened at no later than 1 month of age. Infants in the well-infant nursery should be screened for hearing loss using either OAE or automated ABR and receive an additional screening prior to discharge. The hospital may choose to use the same technology for both screenings (OAE followed by OAE or automated ABR followed by a second ABR prior to discharge) or may opt to use OAE for the initial screening followed by automated ABR prior to discharge. Infants who do not pass the initial OAE screening but subsequently pass an automated ABR test are considered a screening "pass." Infants in the well-infant nursery who fail automated ABR testing should not be rescreened by OAE testing and "passed," because such infants are presumed to be at risk of having a subsequent diagnosis of auditory neuropathy/dyssynchrony. The JCIH recommends automated ABR technology as the only appropriate technique for screening infants in the neonatal intensive care unit (NICU). Infants who do not pass automated ABR testing in the NICU, should be referred to an audiologist for rescreening and, when indicated, comprehensive evaluation, including diagnostic ABR testing, rather than for general outpatient rescreening. Infants with confirmed hearing loss should receive appropriate intervention at no later than 6 months of age from education and health care professionals with expertise in hearing loss and deafness in infants and young children. According to the American Academy of Pediatrics (AAP, 2007):
Early and more frequent assessment may be indicated for children with cytomegalovirus (CMV) infection, syndromes associated with progressive hearing loss, neurodegenerative disorders, trauma, or culture positive postnatal infections associated with sensorineural hearing loss, for children who have received extracorporeal membrane oxygenation (ECMO) or chemotherapy; and when there is caregiver concern or a family history of hearing loss.
The United States Preventive Services Task Force (UPSTF) recommends that newborn hearing screening programs include a 1- or 2-step validated protocol which includes OAEs followed by ABR in those who failed the first test. Infants with positive screening test results should receive appropriate audiologic evaluation and follow-up after discharge. All infants should undergo hearing screening before 1 month of age. Any infant who does not pass the newborn screening should undergo audiologic and medical evaluation before 3 month of age (USPSTF, 2008).
According to the American Academy of Pediatrics (AAP) guideline titled "Hearing Assessment in Infants and Children: Recommendations Beyond Neonatal Screening", the technology used for hearing screening should be age appropriate. Evoked OAE testing is appropriate for children of any developmental age and automate ABR testing is appropriate for infants with a developmental age between birth to 9 months. Behavioral audiological testing for infants and children between the developmental ages of 9 months to 2½ years is generally performed using visual reinforcement audiometry and play audiometry is generally used for children with a developmental age between 2½ to 4 years (Harlor, 2009).
The American Academy of Audiology (2011) endorses the detection of hearing disorders in early childhood and school‐aged populations using evidence‐based hearing screening methods. OAEs are recommended for preschool and school age children for whom pure tone screening is not developmentally appropriate (ability levels less than 3 years).
Diagnosis of Acoustic Neuroma (vestibular schwannoma)
Vestibular schwannomas (acoustic neuromas, acoustic schwannomas, acoustic neurinomas, and vestibular neurilemomas) are Schwann cell-derived tumors that commonly arise from the vestibular portion of the eighth cranial nerve.
Historically, other auditory tests have been used to diagnose acoustic neuromas (vestibular schwannomas), including but not limited to, acoustic reflex testing and impedance audiometry. Prior to emergence of the use of MRI in the diagnosis of retrocochlear pathology (e.g., acoustic neuroma), ABR was the method of choice. With the increased availability of MRI, ABR is not utilized as much in the routine evaluation of individuals suspected of having retrocochlear pathology. However, if an individual has a contraindication to undergoing MRI, for example, has a pacemaker, then ABR may be utilized for diagnostic purposes. Similarly, if MRI results are equivocal, ABR may be utilized for confirmation of diagnosis.
According to the American College of Radiology (ACR) 2008 guideline titled ACR Appropriateness Criteria® vertigo and hearing loss, ABR and gadolinium-enhanced MRI are used to discriminate among idiopathic, viral, and other causes of sensorineural hearing loss (Angtuaco, 2013).
Common drugs including but not limited to aminoglycosides (for example, gentamicin, kanamycin, neomycin and tobramycin), chemotherapeutic agents (primarily cisplatin and its analogue carboplatin), and heavy metals are known for their ototoxic potential. The goal of monitoring for ototoxicity is to identify cochlear dysfunction early in an effort to reduce or prevent further auditory damage. Pure tone audiometry or ABR is useful in documenting changes in hearing associated with ototoxic drug treatment but do not provide the ability to predict forthcoming hearing loss. Conversely, because OAEs originate from the outer hair cells of the cochlea; virtually any insult to the cochlea ranging from anoxia to ototoxic damage of outer hair cells may be visualized in the OAE outcomes in the form of amplitude reduction or loss of OAEs. Therefore, OAEs can provide information regarding hair cell damage before it becomes apparent in the results of pure tone threshold measurements. When OAEs are abolished, however, behavioral and electrophysiologic measurements must be used to track hearing changes (Katbamna, 2008).
The AAA and the ASHA support the use of OAEs or ABRs to monitor for ototoxicity in individuals undergoing treatment with an ototoxic agent (for example, aminoglycosides, chemotherapy agents, and heavy metals.) Both organizations indicate that ototoxicity monitoring tests require a baseline evaluation which is ideally performed prior to the administration of any ototoxic drugs, and with tests that will be used later for monitoring, so that later results have the clearest basis for interpretation. Baseline testing should be fairly comprehensive and may include the testing of OAEs (AAA, 2009; Konrad-Martin, 2005).
Auditory Brainstem Response (ABR): A test which measures the electrical activity in cochlea and auditory pathways of the brain in response to clicks or certain tones. ABR is also referred to as auditory evoked response (AER), auditory evoked potential (AEP), evoked auditory potential (EAP), brainstem auditory evoked potential (BAEP), brainstem auditory evoked response (BAER), and evoked response audiometry (ERA).
Auditory neuropathy: A type of hearing impairment where outer hair cell function is normal but neural transmission in the auditory pathway is impaired, also known as auditory dys-synchrony, auditory neural hearing loss and auditory neuropathy spectrum disorder (ANSD).
Cochlea: Part of the inner ear that processes sound.
Distortion Product Otoacoustic Emissions (DPOAEs): Sounds emitted in response to 2 simultaneous tones of different frequencies.
Evoked Otoacoustic Emissions (OAE): Sounds measured in the external ear canal that are a reflection of the functioning of the cochlea.
Evoked Responses (also known as evoked potentials): Electrical responses produced by the nervous system in response to a stimulus (auditory, somatosensory, or visual).
Neonatal Intensive Care Unit (NICU): A facility in which a neonatologist provides primary care for the infant. Newborn units are divided into 3 categories: Level I - well infant nurseries; Level II - specialty care by a neonatologist for infants at moderate risk of serious complications; Level III – specialty and subspecialty care including the provision of life support.
Transient Evoked Otoacoustic Emissions (TEOAEs): Sounds emitted in response to acoustic stimuli of very short duration; usually tone-bursts or clicks; Also known as transient otoacoustic emissions (TOAEs).
Peer Reviewed Publications:
Government Agency, Medical Society, and Other Authoritative Publications:
Auditory Brainstem Response (ABR)
Auditory Evoked Potential (AEP)
Brainstem Auditory Evoked Potential (BAEP)
Brainstem Auditory Evoked Response (BAER)
Distortion Product Otoacoustic Emissions (DPOAEs)
Evoked Auditory Potential (EAP)
Evoked Otoacoustic Emission
Evoked Response Audiometry (ERA)
Otoacoustic Emission (OAE)
Transient Evoked Otoacoustic Emissions (TEOAEs)
|Revised||08/06/2015||Medical Policy & Technology Assessment Committee (MPTAC) review. In the Position Statement section, changed "eg." to "for example. Updated the review date, Rationale and History sections of the document.|
|Reviewed||08/14/2014||Medical Policy & Technology Assessment Committee (MPTAC) review. Updated the Description, References and History sections of the document.|
|Revised||08/08/2013||MPTAC review. Title of document changed to "Auditory Brainstem Responses (ABRs) and Evoked Otoacoustic Emissions (OAEs) for Hearing Disorders". Medically necessary criteria revised to address automated ABR. The term "hearing loss" was replaced with "hearing disorder" when appropriate. Revisions to the not medically necessary criteria included the removal of diagnostic testing and the addition of evaluation for suspected presbycusis, suspected otosclerosis and individuals able to undergo standard audiometry. Coding was updated.|
|New||05/09/2013||MPTAC review. Initial document development.|