| Action | Amend Regulation as Result of Periodic Review |
| Stage | NOIRA |
| Comment Period | Ended on 9/1/2011 |
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7 comments
This is very interesting
Thank goodness for common sense.
The Pro-Choice groups need to get together and take this to Federal court. Virginia is attempting to enact laws which circumvent a LEGAL procedure which the Supreme courts have recognized as legal whether they like it or not. Every single representative that voted yes should be charged with obstruction. McDonnell claims he saved Virgina while taking Federal stimulus AND CUTTING EDUCATION. They want people to be uneducated, poor, and having no choice but to introduce more children into an already over burdened welfare system. People need to wake up.
Little bit undertain in terms of the process being unconstitutional.
If this can pass its absolutly brilliant.
The audiologists and other professionals at Pediatrix Audiology Services, which operates at INOVA Fairfax Hospital, appreciate the efforts involved in updating the guidelines and recommendations for diagnostic testing on neonates. We have some general concerns, and specific items that we believe should be changed if the guidance is issued.
We believe that protocol manuals should be developed by individual clinics in order to reflect the level of care they provide as well as to document standard operating procedures. In contrast, a similar guidance issued by the State may be interpreted as setting a standard of care to which all practitioners must adhere, in order to be considered as providing the usual and customary level of patient care. An audiologist who deviates from these procedures could be construed as engaging in malpractice because he or she is not adhering to the State’s standard of care guidance. Therefore, we believe that great care should be taken when recommending specific procedures. Textbooks can be used as reference documents by those who need the level of specificity in these guidelines. Because of this, we recommend that the state withdraw this guidance and substitute more general goal statements that recognize the challenges of testing patients in diverse settings and with different types of equipment.
If the guidance is put forward, the following 12 items merit specific reconsideration and illustrate our concern that the document is overly prescriptive.
Item 1. Stimulus level for click evoked response testing to rule out Auditory Neuropathy Spectrum Disorder (ANSD). (Page 4 of guidance)
Guidance: Recommends use of 80-90 dB HL click stimuli.
Rationale: The audiologist should have discretion on the intensity level of the click stimulus to use. A commonly used intensity is 70 dB nHL, which we utilize because it permits comparison to the Issa and Ross (1995) normative data for infant absolute and interpeak latencies, as reprinted in Hall’s (2007) New Handbook of Auditory Evoked Responses. If the infant is sleeping, and if the audiologist does not suspect severe hearing loss, then 70 dB nHL stimuli minimize the chance that the infant will awaken. Other audiologists may use 65 dB nHL, also due to concern of awakening the infant. If results are not within normal limits and are not sufficient to rule out ANSD, testing at a higher level would be appropriate; 90 dB nHL may be insufficient in some cases.
Item 2. Use of click stimuli in diagnostic evaluations in air- and bone-conduction testing. (Page 4 and 5 of guidance.)
Guidance: Our interpretation of the guidance is that the click threshold is to be established for air-conducted stimuli and for bone-conduction testing.
Rationale: INOVA uses click ABR testing in infant hearing screening and in ruling out ANSD, but threshold estimation testing is conducted only using tone-burst stimuli. The audiologist determines the frequency or frequencies at which to test bone conduction on a case-by-case basis. 1000 Hz is generally favored because of the technical difficulties recording 500 Hz responses. Oates & Stapells (1998; Seminars in Hearing) argue convincingly that click-evoked potentials testing lacks frequency specificity and as such, the click threshold is more weakly correlated to high-frequency pure-tone thresholds than when tone-bursts are used as stimuli. They provide examples of patients with hearing loss who had normal click-evoked responses. For these reasons, spending time finding a click threshold is inappropriate, as the time could be better used in finding tonal thresholds.
Item 3. Use of two-channel ABR system for bone-conduction testing (page 5-6)
Guidance: Calls for examination of ipsilateral and contralateral channel recordings and observation of wave I in each channel to determine if loss may be unilateral.
Rationale:
We recognize that some audiologists advocate using two channel recordings for bone-conduction testing because the presence of wave I, and an earlier wave V in one channel, is consistent with the corresponding ear providing the response. This requires that all ABR systems used in testing infants have two channels, which increases equipment expense. However, proper use of masked unilateral testing permits identification of the ear that is responding to the stimulus, and single channel recordings minimize the number of waveforms to manage, which can increase test efficiency. We recommend that the audiologist have discretion of whether or not to use a two-channel recording for bone-conduction testing.
Item 4. Location of non-inverting electrode (page 6).
Guidance: The guidance calls for vertex (Cz) electrode location, although high forehead is called for during bone-conduction testing (page 5).
Rationale: We avoid placing electrodes on or near the fontanel and instead use the high forehead (Fpz) electrode location. We prefer the high forehead as it does not require attaching an electrode to hair, which could impede electrode adherence and/or could cause the baby discomfort on removing the electrode. We do not anticipate a significant morphology change with these two electrode locations.
Item 5. Use of high frequency immittance probe tones in all testing situations for those under age 4 months. (page 5)
Guidance: The guidance calls for testing those under 4 months of age with 660 or 800 Hz probe tones. The wording could be construed to indicate that all audiologists must do this testing on all patients and in all clinics.
Rationale: Ensuring that all clinics that conduct electrophysiologic evaluations have high frequency probe tone immittance testing equipment available requires resource expenditures, and limits capital resources that could be allocated to other equipment needs. Guidance could be written to reflect that this testing is an important component during the complete evaluation procedure, so that it is not presumed to occur at each site, and with each evaluation. For example, when electrophysiology findings are abnormal, our reports could recommend follow-up immittance testing using high-frequency tympanometry and reflex testing in conjunction with the recommended behavioral response testing.
The guidance calls for a 660 or 800 Hz probe tone, and as such would preclude use of a 1000 Hz probe tone, which we prefer to use on all children less than six (rather than four) months of age.
Item 6. Stimulus polarity. (page 6)
Guidance: Use of alternating polarity stimuli to cancel stimulus artifacts during tone-burst testing.
Rationale: Our audiologists record separate rarefaction and condensation runs if significant stimulus artifact is present, and use one polarity when artifacts are not present. Rarefaction and condensation polarity stimuli yield very similar latency wave peaks when clicks and high-frequency stimuli are used; however, at lower frequencies, latency differences are sometimes elicited. In theory, the ABR peaks should delay by one-half cycle when changing stimulus polarity, since shearing cilia towards stria vascularis is excitatory. (To simplify, assume a 500 Hz single cycle wave were the stimulus. If a rarefaction cycle triggered hair cell depolarization, then switching to condensation causes the rarefaction portion of the wave to begin 1 ms later; the wave V should be delayed by 1 ms, or after one-half cycle delay. All wave peaks should be delayed by 1 ms.)
An example of this is inserted below.
Traces 5 and 6 are elicited by condensation and rarefaction tone bursts, respectively. The summation (wave 10) is equivalent to having used an alternating polarity, and cancels the stimulus artifact. (It may also oblate waves I and III if present). We are not aware of any scholarly literature that shows evidence of an electrophysiologic threshold difference occurring as a result of using alternating versus single-polarity stimuli. This could be used to argue for use of alternating polarity signals. However, testing this comparison calls for “proving the null” – proving that no difference exists between single and alternating polarity responses -- which is difficult. We are concerned that in some patients, the 1 ms difference between the responses to rarefaction and condensation stimuli that occurs when using an alternating polarity stimulus may cause a decrease in wave V amplitude and reduce the readability of responses. Therefore when artifact problems are not evident, we prefer use of a single polarity stimulus.
Item 7. Use of ipsilateral notched noise. (Page 6)
Guidance: Stapell’s ipsilateral notched noise is referenced in the document.
Rationale: We recognize that use of ipsilateral notched noise masks spectral splatter and can increase frequency specificity of the response in certain rare circumstances. However, the Blackman gated stimulus used by INOVA is highly frequency specific and unlikely to create significant spectral splatter. The manufacturer of the equipment we use informs us that the “side lobes” (the unintended frequency energy) one octave away from the stimulus frequency is at worst 58 dB lower than the peak energy. The audiogram would have to slope at a rate of more than 60 dB per octave for this energy to plausibly affect the ABR interpretation. As such, we do not believe it is necessary to use ipsilateral band-reject noise.
Item 8. Stimulus repetition rate (page 6)
Guidance: Use of 39.1 tone bursts per second and 21.1 clicks per second repetition rates
Rationale: The rates included in the protocol are highly prescriptive. While a rate of 39.1 may be adequate for some children; better morphology may be found with slower rates in other cases. A rate as slow as 21.1 second is not required if the purpose of click ABR testing is primarily to rule out auditory neuropathy spectrum disorder. Differentiating between a normal ABR and a cochlear microphonic can be achieved at a higher repetition rate. We recommend that audiologists have discretion to use the rates that provide the greatest efficiency and best diagnostic results for that child.
Item 9. Low- and high-pass filter settings (pages 5 and 6)
Guidance: The guidance prescribes the use of 20 or 30 Hz high-pass settings for air conduction, and 30 Hz for bone conduction. The low-pass is set at 1500 Hz for bone conduction and 1500-3000 Hz for air conduction.
Rationale: We concur that in most situations the most prudent filter setting is 20-30 as the high-pass setting, as eliminating the slow component of the response can alter response threshold, particularly for the youngest children and for testing with low-frequency tone bursts. However, this setting brings in myogenic activity. When a child is not asleep, we believe the audiologist may wish to use a setting such as 100-1500 Hz at times when he or she is faced with the choice of collecting highly noise contaminated responses (using a 20 Hz filter setting) or those of compromised morphology (100 Hz setting).
The choice of 1500 Hz or 3000Hz low-pass settings does not affect response threshold and should be left to the discretion of the audiologist.
Item 10. Requirement that responses be recorded down to threshold for bone conduction (page 6).
Guidance: The guidance prescribes finding the bone conduction threshold of the response.
Rationale: This may often be desirable; however, the presence of a response within normal hearing limits and below the air-conduction threshold may be sufficient to document conductive loss, in which case finding the precise threshold would not be necessary.
Item 11. Requirement for behavioral observation and visual reinforcement audiometry
Guidance: Behavioral observation audiometry for speech and 500 and 2000 Hz stimuli is minimally required, as is visual reinforcement audiometry (VRA) for infants age 6 months and older (page 5).
Rationale: This guidance would appear to suggest that behavioral observation or visual reinforcement audiometry must be conducted in conjunction with electrophysiologic evaluation. That may not be practical, e.g. when a patient is scheduled for electrophysiologic testing in a sedation unit. It requires testing in a sound booth, which may not be practical in all settings. Further, behavioral observation audiometry does not have a sufficiently robust history of accurately aiding in the diagnosis of hearing loss in children that it should be mandated. Parent description of infant responsiveness to sound, and audiologist observation (e.g. of HearKit sound toy responses) can provide insight and help establish starting levels for testing without conducting other billable tests.
We unequivocably agree that a typically developing child of age 6 months or older should have VRA testing to augment electrophysiologic findings; however, the guidance can be construed to indicate that it must be conducted in conjunction with electrophysiologic testing. The age limit may not be appropriate for children who are not typically developing; those whose loss is detected at a much older age may not be candidates for this testing.
Item 12. No reference to auditory steady-state testing.
Guidance: The guidance does not discuss ASSR testing.
Rationale: As technology changes, guidance documents written with great specificity would require updating. As written, it appears to not allow ASSR testing. While INOVA is not presently sufficiently convinced that ASSR testing is appropriate for our generally neonatal test population, we would prefer if the guidance had flexibility to permit use of this, and other technology that may emerge over time.
In summary, these 12 items are examples where we believe the existing guidance is overly prescriptive. We presume that it is intended to act as a helpful guidance, but because it is authored by the State, and without a preamble that discusses legitimate alternative methods, it has the effect of setting highly prescriptive standards of practice that are not uniformly supported by the preponderance of the professional literature. We recommend the citation of articles, such as those by Oates and Stapells, as well as the recommendation of other textbooks in auditory electrophysiology, and the provision of links to the materials of Dr Stapells, whom we highly respect. We do not believe it is the role of the State to make specific recommendations in their guidance, as this may be construed as setting a rigid standard of care. Attempts to adhere narrowly to the guidance document may prevent audiologists from using their knowledge and skills to adapt testing procedures as necessary given prior testing results, the state of the child, and the unique capabilities of the clinic.