Auditory brainstem response: Difference between revisions

The '''auditory brainstem response''' ('''ABR'''), also called '''brainstem evoked response audiometry''' ('''BERA''') or '''brainstem auditory evoked potentials''' ('''BAEPs''') or '''brainstem auditory evoked responses''' ('''BAERs''')<ref>{{Cite web |date=2022-05-27 |title=Auditory Brainstem Response (ABR) Evaluation |url=https://www.hopkinsmedicine.org/health/conditions-and-diseases/hearing-loss/auditory-brainstem-response-abr-evaluation |access-date=2024-02-16 |website=www.hopkinsmedicine.org |language=en}}</ref><ref>{{Citation |last=Young |first=Allen |title=Auditory Brainstem Response |date=2024 |work=StatPearls |url=http://www.ncbi.nlm.nih.gov/books/NBK564321/ |access-date=2024-02-16 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=33231991 |last2=Cornejo |first2=Jennifer |last3=Spinner |first3=Alycia}}</ref> is an [[auditory evoked potential]] extracted from ongoing electrical activity in the brain and recorded via [[Electrode|electrodes]] placed on the scalp. The measured recording is a series of six to seven vertex positive waves of which I through V are evaluated. These waves, labeled with Roman numerals in ''Jewett'' and ''/Williston'' convention, occur in the first 10 milliseconds after onset of an auditory stimulus. The ABR is consideredtermed an ''exogenous response'' because it is dependent upon external factors.<ref name="Eggermont, 2007">{{cite book |author1=Eggermont, Jos J. |author2=Burkard, Robert F. |author3=Manuel Don |title=Auditory evoked potentials: basic principles and clinical application |publisher=Lippincott Williams & Wilkins |location=Hagerstwon, MD |year=2007 |isbn=978-0-7817-5756-0 |oclc=70051359 }}</ref><ref name="Hall, 2007">{{cite book |author=Hall, James W. |title=New handbook of auditory evoked responses |publisher=Pearson |location=Boston |year=2007 |isbn=978-0-205-36104-5 |oclc=71369649 }}</ref><ref>{{cite book |author=Moore, Ernest J |title=Bases of auditory brain stem evoked responses |publisher=Grune & Stratton |location=New York |year=1983 |isbn=978-0-8089-1465-5 |oclc=8451561 |url-access=registration |url=https://archive.org/details/basesofauditoryb0000unse }}</ref>

*'''More in depth location''' – waveWaves I and II originatesoriginate from the distal and proximal [[auditory nerve]] fibers, wave III from the [[cochlear nucleus]], IV showing activity in the [[superior olivary complex]], and wave V is associated with the [[lateral lemniscus]].<ref>{{Cite journal|last1=Møsller|first1=Aage R.|last2=Jannetta|first2=Peter J.|last3=Møsller|first3=Margareta B.|date=November 1981|title=Neural Generators of Brainstem Evoked Potentials Results from Human Intracranial Recordings|url=http://journals.sagepub.com/doi/10.1177/000348948109000616|journal=Annals of Otology, Rhinology & Laryngology|language=en|volume=90|issue=6|pages=591–596|doi=10.1177/000348948109000616|pmid=7316383 |s2cid=11652964 |issn=0003-4894}}</ref>

==History of research==

In 1967, ''Sohmer'' and ''Feinmesser'' were the first to publish human ABRs recorded with surface electrodes, in humans which showedshowing that cochlear potentials could be obtained non-invasively. In 1971, ''Jewett'' and ''Williston'' gave a clear description of the human ABR and correctly interpreted the later waves as arriving from the brainstem. In 1977, ''Selters'' and ''Brackman'' published landmark findingsreported on prolonged inter-peak latencies in tumor cases (greater than 1&nbsp;cm). In 1974, ''Hecox'' and ''Galambos'' showed that the ABR could be used for threshold estimation in adults and infants. In 1975, Starr and Achor were the first to report the effects on the ABR of CNS pathology in the brainstem.<ref name="Hall, 2007" />

Long and Allen were the first to report the abnormal brainstem auditory evoked potentials (BAEPs) in an alcoholic woman who recovered from [[acquired central hypoventilation syndrome]]. These investigators hypothesized that their patient's [[brainstem]] was poisoned, but not destroyed, by her chronic alcoholism.<ref>Long, K.J.; Allen, N. (October 1984). "Abnormal brain-stem auditory evoked potentials following Ondine's curse". ''Arch. Neurol''. '''41''' (10): 1109–10. {{doi|10.1001/archneur.1984.04050210111028}}. [[PubMed Identifier|PMID]] 6477223.</ref>

===Use= Applications ==

One use of the traditionalTraditional ABR is site-of-[[lesion]] testing and it has been shown to be sensitive to large acoustic [[tumors]]. However, it has poor sensitivity to tumors smaller than 1 sub-centimeter in diametertumors. In the 1990s, there were several studies that concludedrecommended that the use ofusing ABRs to detect acoustic tumors should be abandoned. As a result, many practitioners onlyswitched useto MRI for this purpose now.<ref name="Don, 2005" />

The reason the ABR does not identify small tumors canbecause be explained by the fact that ABRsthey rely on latency changes of peak voltage (V). Peak V is primarily influenced by high-frequency fibers,. and tumorsTumors will be missed if those fibers aren'tare affectedunaffected. Although the click stimulates a wide frequency region on the [[cochlea]], phase cancellation of the lower-frequency responses occurs as a result of time delays along the [[basilar membrane]].<ref name="Prout, 2007">{{cite web |url=http://www.audiologyonline.com/askexpert/display_question.asp?question_id=512 |title=Asymmetrical low frequency hearing loss and acoustic neuroma |year=2007|author=Prout, T |work=Audiologyonline }}</ref> IfSmall atumors tumormay isnot small,sufficiently it is possibleaffect those fibers won't be sufficiently affected to be detected by the traditional ABR measure.

PrimaryHowever, reasonsMRI-ing whyevery itpatient is not practical togiven simply send every patient in for an MRI are theits high cost of an MRI, its impact on patient comfort, and limited availability in ruralmany areas and third-world countries. In 1997, Dr. Manuel Don and colleagues published onintroduced the Stacked ABR as a way to enhance the sensitivity of the ABR in detectingto smaller tumors. Their hypothesis was that the new ABR-stacked derived-band ABR amplitude could detect small acoustic tumors missed by standard ABR measuresABRs.<ref name="Don, 1997">{{cite journal |vauthors=Don M, Masuda A, Nelson R, Brackmann D |title=Successful detection of small acoustic tumors using the stacked derived-band auditory brain stem response amplitude |journal=Am J Otol |volume=18 |issue=5 |pages=608–21; discussion 682–5 |date=September 1997 |pmid=9303158 }}</ref> In 2005, heDon stated that it would be clinically valuable to have available an ABR test to screen for small tumors.<ref name="Don, 2005">{{cite journal |vauthors=Don M, Kwong B, Tanaka C, Brackmann D, Nelson R |title=The stacked ABR: a sensitive and specific screening tool for detecting small acoustic tumors |journal=Audiol. Neurootol. |volume=10 |issue=5 |pages=274–90 |year=2005 |pmid=15925862 |doi=10.1159/000086001 |s2cid=43009634 }}</ref> In a 2005 interview in Audiology Online, Dr. Don of House Ear Institute defined theThe Stacked ABR asis "...ansensitive, attemptspecific, towidely recordavailable, thecomfortable, sumand of the neural activity across the entire frequency region of the cochlea in response to a click stimulicost-effective."<ref name="DeBonis, 2008"/>

*Step 1: obtain#Obtain Click-evoked ABR responses to clicks and high-pass pink masking noise (ipsilateral masking)

*Step 2: obtain#Obtain derived-band ABRs (DBR)

*Step 3: shift#Shift & align the wave V peaks of the DBR – thus, "stacking" the waveforms with wave V lined up

*Step 4: add#Add the waveforms together

*Step 5: compare#Compare the amplitude of the Stacked ABR with the click-evoked ABR from the same ear

====Application and effectivenessEffectiveness====

With the intent of screening forScreening and detecting the presence of small (less than or equal to 1&nbsp;cm)sub-centimeter acoustic tumors, the Stacked ABR isoffers:<ref name="Don, 1997"/>

In a 2007 comparative study of ABR abnormalities in acoustic tumor patients, Montaguti, andet.al., colleagues mention the promise of and great scientific interest in thedescribed Stacked ABR. Theas article suggests thathaving the Stacked ABR could make it possiblepotentiasl to identify small acoustic neuromas missed by traditional ABRs.<ref name="Montaguti 2007">{{cite journal |vauthors=Montaguti M, Bergonzoni C, Zanetti MA, Rinaldi Ceroni A |title=Comparative evaluation of ABR abnormalities in patients with and without neurinoma of VIII cranial nerve |journal=Acta Otorhinolaryngol Ital |volume=27 |issue=2 |pages=68–72 |date=April 2007 |pmid=17608133 |pmc=2640003 }}</ref>

Tone-burst ABR is used to obtain thresholds for children who are too young to otherwise reliably respond behaviorally to frequency-specific soundacoustic stimuli. The most common frequencies tested atare 500, 1000, 2000, and 4000&nbsp;Hz, as these frequencies are generally thought to be necessary for hearing aid programming.

In 1981, Galambos and colleagues reported on the "40 Hz auditory potential" which is a continuous 400&nbsp;Hz tone sinusoidally 'amplitude modulated' at 40&nbsp;Hz and at 70&nbsp;dB SPL. This produced a very frequency -specific response, but the response was veryinfluenced susceptible toby state of arousal. In 1991, Cohen and colleagues learned that by presenting at a higher rate of stimulation than 40&nbsp;Hz (>70&nbsp;Hz), the response was smaller, but less affected by sleep. In 1994, Rickards and colleagues showed that it was possible to obtain responses in newborns. In 1995, Lins and Picton found that simultaneous stimuli presented at rates in the 80 to 100&nbsp;Hz range made it possible to obtain auditory thresholds.<ref name="Eggermont, 2007"/>

TheASSR uses the same or similar to traditional recording montages used foras ABR recordings are used for the ASSR. Two active electrodes are placed at or near vertex and at ipsilateral earlobe/mastoid with ground at low forehead. If collectingCollecting from both ears simultaneously, requires a two-channel pre-amplifier is used. When singleSingle channel recordingrecordings system is used tocan detect activity from a binaural presentation,. aA common reference electrode may be located at the [[nape]] of the neck. Transducers can be insert earphones, headphones, a bone oscillator, or sound field. and itIt is preferable iffor the patient isto be asleep. Unlike ABR settings, theThe high pass filter might be approximately 40 to 90&nbsp;Hz and low pass filter might be between 320 and 720&nbsp;Hz with typical filter slopes of 6&nbsp;dB per octave. Gain settings of 10,000 are common, artifact reject is left "on", and it is thought to be advantageous to have manual "override" to allowallows the clinician to make decisions during test and apply course correctionscorrect as neededappropriate.<ref name="Beck, DL 2007">Beck, DL; Speidel, DP; and Petrak, M. (2007) Auditory Steady-State Response (ASSR): A Beginner's Guide. The Hearing Review. 2007; 14(12):34-37.</ref>

===ABR vs. ASSRComparison===

*Both record bioelectric activity from electrodes arranged in similar recording arrays.

*Both areuse auditory evoked potentials.

*Both can be used to estimate thresholdthresholds for patients who cannot or will not participate in traditional behavioral measures.

*ASSR is evoked using repeated sound stimuli presented at a high reprepetition rate rather than an abrupt sound at a relatively low rep rate.

*ABR estimates thresholds basically from 1-4k in typical mild-moderate-severe hearing losses. ASSR can also estimate thresholds in the same range, but offers more frequency specific infoinformation more quickly and can estimate hearing in the severe-to-profound hearing loss ranges.

*ABR depends highly upon a subjective analysis of the amplitude/latency function. The ASSR uses a statistical analysis of the probability of a response (usually at a 95% confidence interval).

*ABR is measured in microvolts (millionths of a volt) and thewhile ASSR is measured in nanovolts (billionths of a volt).<ref name="Beck, DL 2007"/>

===Analysis, normative data, and general trends===

Analysis is mathematically based and dependent upon the fact that related bioelectric events coincide with the stimulus reprepetition rate. The specific methodanalysis of analysismethod is based on the manufacturer's statistical detection algorithm. It occurs in the spectral domain and is composed of specific frequency components that are harmonics of the stimulus repetition rate. Early ASSR systems considered the first harmonic only, but newer systems also incorporate higher harmonics in their detection algorithms.<ref name="Beck, DL 2007"/> Most equipment provides correction tables for converting ASSR thresholds to estimated HL audiograms and are found to be within 10&nbsp;dB to 15&nbsp;dB of audiometric thresholds, although studies vary. Correction data depends on variables such as equipment, frequencies, collection time, subject age, sleep state, and stimulus parameters.<ref name="Picton 2005">{{cite journal |vauthors=Picton TW, Dimitrijevic A, Perez-Abalo MC, Van Roon P |title=Estimating audiometric thresholds using auditory steady-state responses |journal= Journal of the American Academy of Audiology|volume=16 |issue=3 |pages=140–56 |date=March 2005 |pmid=15844740 |doi= 10.3766/jaaa.16.3.3}}</ref>

In certain cases where behavioral thresholds cannot be attained, ABR thresholds can be used for [[hearing aid]] fittings. New fittingFitting formulas such as DSL v5.0 allow the userhearing to base theaid settings into thebe hearing aidbased on the ABR thresholds. Correction factors do exist for converting ABR thresholds to behavioral thresholds, but vary greatly. For example, one set of correction factors involves lowering ABR thresholds from 1000 to 4000&nbsp;Hz by 10&nbsp;dB and lowering the ABR threshold at 500&nbsp;Hz by 15 to 20&nbsp;dB.<ref name="Objective Assessment of Hearing">{{cite book |vauthors=Hall JW, Swanepoel DW | year = 2010| title = Objective Assessment of Hearing | location = San Diego = Arch. Neurol | publisher = Plural Publishing Inc.}}</ref> Previously, brainstem audiometry has beenwas used for hearing aid selection by using normal and pathological intensity-amplitude functions to determine appropriate amplification.<ref>{{cite journal | author= Kiebling J | year = 1982 | title = Hearing Aid Selection by Brainstem Audiometry | journal = Scandinavian Audiology | volume = 11 | issue = 4 | pages = 269–275 | doi = 10.3109/01050398209087478 | pmid = 7163771}}</ref> The principal idea of the selection and fitting of the hearing instrument was based on the assumption that amplitudes of the brainstem potentials were directly related to loudness perception. Under this assumption, the amplitudes of brainstem potentials stimulated by the hearing devices should exhibit close-to-normal values. ABR thresholds do not necessarily improve in the aided condition.<ref>{{cite journal |vauthors=Billings CJ, Tremblay K, Souza PE, Binns MA | year = 2007 | title = Stimulus Intensity and Amplification Effects on Cortical Evoked Potentials | journal = Audiol Neurotol | volume = 12 | issue = 4| pages = 234–246 | pmid = 17389790| doi=10.1159/000101331| s2cid = 2120101 }}</ref> ABR can be an inaccurate indicator of hearing aid benefit due to difficulty processing the appropriate amount of fidelity of the transient stimuli used to evoke a response. Bone conduction ABR thresholds can be used if other limitations are present, but thresholds are not as accurate as ABR thresholds recorded through air conduction.<ref>{{cite journal |vauthors=Rahne T, Ehelebe T, Rasinski C, Gotze G | year = 2010 | title = Auditory Brainstem and Cortical Potentials Following Bone-Anchored Hearing Aid Stimulation| journal = Journal of Neuroscience Methods | volume = 193 | issue = 2| pages = 300–306 | pmid = 20875458| doi=10.1016/j.jneumeth.2010.09.013| s2cid = 42869487 }}</ref>

*no frequency-specific compensation of hearing impairmentcompensation