The Hearing Loss in the Young Infants: Aid - Case Study Example

Comparative analysis of two reports (a,b) on the topic of: “Should ABR or SSAEPs be used to obtain auditory information for hearing aid selection in children under six months of age?” Introduction to the comparative analysis While both reports aim at finding the right method and correct “auditory evoked potential” tools to measure the hearing loss threshold in the young infants, report ‘b’ is a well organized and structured paper giving the report essay outline and table of contents separately. The table of abbreviations follows this neatly, which enables the reader to understand the meaning of various terms as detailed in the report. In the introduction part of both reports, a reference is made to the age, for determining the neuro-sensual hearing quality in an infant who is less than six months old. While both the reports cite “Bamford” to highlight the requirement of a hearing aid in an infant, report ‘a’ says that this age can be as early as four weeks, and the report ‘b’ puts this age as a median age of four months (Bamford et el ,2005 and 2006). However, the report ‘b’ has given the further information that the identification of infants with the permanent hearing loss disability can start from as early as ten weeks, which has been found after the introduction of ‘new born hearing screening program” (NHSP) during the year 2001. Detection of the permanent hearing disability during childhood As this is the most important part of the study, proper importance has been given to this issue in the report ‘b’, which has analyzed the “Permanent Childhood Hearing Impairment, (PCHI). The definition given for the same in this report is technically sound as it has defined it in the terms of ‘better ear hearing standards of 500Hz to 4K Hz, with more than 40dB-HL.levels. This report has cited (Fortnum et al 2001) saying that it includes the sensorineural and permanent hear losses. However, citing (Davis at el 2004), the report says that PCHI excludes the temporary and unilateral hearing loss and the causes of the PCHI are not known, although it can be congenial or acquired. While report ‘a’ points to the electrophysiological methods that include ABR and ASSR to determine the exact condition of the pediatric audiology, report ‘b’ is more elaborative as it has given details in “appendix-1”, towards the introduction of care pathways for screening the hearing of infants, within its first few weeks after the birth. This report further informs that under “NHS-NHSP” program an audiologist can monitor such screening and decide on the fitting of the hearing aid to the infant. Report ‘a’ has cited (Hall—2006) saying that ASSRs have a unique place in determining the requirement time and age as same have a guaranteed place in the ‘pediatric test battery’. However, it has left this issue open for the debate saying that there is a lack of consensuses to which ”evoked potential technique” can be used for determining the necessity for hearing aids in very young infants. Report ‘b’ is again explanatory as it has highlighted the “auditory evoked potentials” (AEP) , for using it as a tool to determine this age on a more objective and accurate basis. This report further explains the technical parameters of AEP, while emphasizing the use of very sensitive amplifiers and computer averaging equipment to overcome the signal versus noise ratio difficulty. The report has cited (Steppels-2004) for this purpose. The Auditory Evoked Potential (AEP) While report ‘a’ has mentioned that ABR is the most widely used technique as an auditory evoked potential (AEP) tool to estimate the audilogical parameters, it cites the (Cunningum et al 2008) for using Frequency specific tone-burst ABR for determining the hearing aid fitting methodology and timing for the young infants. However, report ‘b’ is more specific technically as it explains the behaviour of brain structures originated by the AEPs, like auditory cortex, auditory 8th. Cranial nerve and structures for auditory brainstem, while mentioning that the ABR response can be found when such tests are conducted at very low voltage, measuring often less than one microvolt. It has also cited the references of (Feinsod et al.,1973) and (Galambos & Hecox, 1977) to highlight the AEPs as an objective test for measuring the infant hearing disabilities, particularly with neurological and sensory disorders. Further, the report has referred to (Stockard & Rossiter, 1977) for defining the brain-stem lesions and their respective location. The Auditory Brainstem Response (ABR) Report ‘a’ has described the ABR as an auditory brainstem function neurological test that shows responses to a brief transducer click or tone. Citing the findings of (Jewett and Williston—1971) the report says that the responses thus obtained were first labelled as seven distinct waveforms. Giving the clinical and laboratory details on these tests, the report further informs about the gadgets and equipment as well as the filters used to detect these waveforms, while also informing that ABR response occurs between one to ten milliseconds of the presentation of stimulus. Describing the waveform structure the report mentions about the seven peaks formation and amplitudes of waveform responses to be less than 0.5 microvolt as it is displayed as a function of time. While the report ‘b’ is also indicative of seven peak waveform responses of ABR, it details about the response representation to the high frequency stimulus of around 2000 to 4000 HZ (Katz et al., 2001).This report is more specific as it mentions that the ABR responses occur within the 10 minutes of stimulus presentation. Both the reports have given the graph of waveform with the highest peak being that of waveform ‘V’, with two axes as amplitude in microvolt and time in msecs. However, the report ‘b’ is again more specific as it gives the source of the graphic information. (Parthasarthy—2006). It also explains the time axis as ‘latency’ in the normal waveform morphology. Report ‘a’ gives the details of the stimulus used for getting the responses, as it describes about both the forms of stimulus, tone and click. This report is more informative and can be useful for the clinical purposes where the choice of click or tone based response is the major criteria. It also explains that the clicks are less frequency-specific than tone based stimulus. It further says that clicks can provide a better-defined response as they have wider frequency range, being broad banded. This report has also given the table outlining the generator site for each ABR wave in the seven-waveform test, which can help in understanding the viability of these tests and the response waveforms thus formed. Steady State Auditory Evoked Potential (SSAEP) While report ‘a’ has documented the Auditory steady State Response (ASSR) in place of SSAEP, the report ‘b’ is more logical as it presents the analytical review of the clinical tests using such SSAEP techniques. The clinical utility and credibility is well documented in the report ’b’ that gives in detail the method of using SSAEP technique for recording neuro-electric activity caused by electrodes that deliver acoustic stimuli through headphones or inserts. This report has further explained with the help of relevant graphs the output response to modulated tones at 70 and 90 Hz., thus giving the response modulation frequency and not the test frequency which will be several times higher. While report ‘a’ correctly mentions that both the ABR and SSAEP are similar to a large extant, as both are auditory evoked potentials. However, the report ‘b’ is elaborative on the clinical test procedure, that uses amplitude modulated stimulus as well as the frequency-modulated stimulus. While explaining the clinical test examples using SSAEP method, it has cited (Scherf et al., 2006, Shapells et al., 2005 & Plourde et al., 1991).ffor stating that SSAEP is a frequency specific measure although the accuracy may be lower with the frequency modulation. Report ‘a’ has given the details of ASSRs, along with the graphic representation of response based on objective statistical tests for assessing the presence or absence of response. However, the report ‘a’ clearly indicates that these tests are largely based on animal research using brain electric source analysis technique (BESA) that can be tried on humans as well. In addition, this report does not mention the test utility for younger infants, in any case. Hence, the report ‘b’ is more viable that has clinical creditability and utility for the correct usage of Auditory Evoked Potential techniques, using SSAEP method. Further more, the acoustic signals and tools like inserts or headphones used in SSAEP are more reliable and test-worthy than use of pure tones’ stimulus modulation in the ASSR technique. However, report ‘a’ says that this method is based on the use of stimulus that can be modulated by amplitude and frequency. It has also highlighted the use of these techniques in clinical test with 100% amplitude and frequency modulation of 20 to 25 percent. But, report ‘a’ has not provided the statistical and logical facts on the clinical tests using ASSR as report ‘b’ has tabled the same in a detailed manner, using SSAEP technique. Threshold estimation Whereas the report ‘a’ gives the details on the frequency-specific thresholds, with reference to the behavioral gold standard, the report cites(Hall-2006) mentioning that it is difficult to obtain such standards in young infants as the respondent infant shall be too young to volunteer a valid behavioral response. This report further mentions about the accuracy of the thresholds Response. The report cites (Sininger and Hyde –2009) note mentioning that the threshold measurement accuracy can be biased, when the test threshold is constantly in disagreement with the true threshold, thereby necessitating the requirement of corrective means. This report has further detailed on the efficiency factor, which affects the ABR or ASSR test accuracy that can be increased by increasing the number of sweeps during the test. However, as more number of sweeps means increased test time, the infant may get disturbed due to the same and this can jeopardize the whole test result. Nevertheless, report ‘b’ is more specific as it has tabulated the summary of criteria for threshold estimation with regard to the frequency and ear specific thresholds, while detailing on the type of loss and test efficiency as well. While comparing the accuracy of the threshold estimates for ABR and SSAEP, the table is informative on the various aspects of the accuracy parameters. It mentions the accuracy estimates of both ABR and SSAEP like the need of an established protocol in ABR while SSAEP may require variable protocol. Similarly, it says that ABR has limited intensity of stimuli whereas; SSAEP can present stimuli up to 120dB. The table further adds that the test measures of SSAEP are objective and measured automatically by a computer, where-as in ABR, there are chances of subjective interpretation of the response. With regard to ear-specific threshold estimates, the table mentions that, while ABR records one ear at a time, there is the provision of dichotic recording in SSAEP tests. It further details that the duration of test needs to be up to 2 hours in case of ABR as the same can be lesser by two to three times for SSAEP tests. Report ‘b’ is more specific as it has given its conclusions also at the end of each specific threshold testing details and procedures. Hearing aid and fitting Report ’b’ gives the details of hearing aid calculations, while citing (Seewald at el -2005), when describing about the output obtained from a computer software on the clinical audiometric thresholds inputs. Report ‘b’ has further specified the criteria requirements for a clinical test for estimation of hearing thresholds, with the aim of fitting a hearing aid to the infant. While describing various “specific-threshold” estimates, the report has vividly detailed on the efficient method for collecting the hearing data. The report specifically suggests here that the tests should be conducted when the child is asleep and the test should take as little time as possible. Conclusion and Summary While report ‘a’ has compared the ABR and ASSR methods of auditory evoked potential, for estimation of infant child hearing aid. It suggests the advantage of ASSR over the ABR on several points. However, the report mentions that due to the ASSR being a recent technology, It may not be clinically viable and credible. This report is slightly bent on using the ABR method , although the report also mentions of less time taken by the ASSR procedure. Report ‘b’ is again more specific and mentions about the technological edge of SSAEP aver the ABR. However, it also cautions about the need for further evidence supporting the technique. Accordingly, this report has suggested the use of ABR for mild to severe hearing losses. In addition,, the report mentions, that with the more ‘normative data in infants’ available and BC threshold measuring problems resolved, SSAEP may be the preferred choice. The report ‘b’ is more affirmative that use of SSAEP is the right option for severe to profound hearing losses. Hence, the comparison of the two reports can be summarized and concluded with the opinion; that while SSAEP is certainly the better AEP method, time is needed to prove its clinical viability and creditability. Comparative evaluation of strength and weakness of the two reports Strengths Report ‘a’ Report ‘b’ This report has documented the Auditory Evoked potential in terms of ABR and ASSR. It has given the separated details for physiology and stimulus with respect to both ABR and ASSR method of AEP. It has given the standards in terms of “gold standards” for determining the test quality of TB-ABR and ASSR It has highlighted the efficiency and accuracy steps taken to conduct the tests for ABR and ASSR with specific details on the test procedure. The relationship between the two methods is clearly indicated with details given separately for frequency-specific thresholds, and behavioral thresholds. Maturation for infant hearing aid assessment and fitting has been detailed in the form of various tests, for both ABR and ASSR The interpretation of the results has been provided with details of the utility of the tests given in the report. The report has given its recommendations while concluding the findings, which has detailed ABR as time tested method .But ASSR has been acknowledged as having an edge over the ABR, The recommendations further suggest use of ASSR with ABR for more profound cases of infant hearing disability. This report is more organized, systematic and reader-friendly, as it has given the table of contents and abbreviations in the beginning of the report. While giving separate details on the detection methods for assessment of hearing malfunction in the young infants, this report has described the use of AEP in finding and treating this disability. The report has put both ABR and SSAEP in the category of AEPs, the modulation and stimulus description is given in the subheading of ABR and SSAEP itself. There are separate and clearly defined estimation reports with regard to the frequency-specific, accuracy-specific and ear-specific thresholds. These estimates are supported by the test procedures for each method, ABR and SSAAEP, separately, accompanied by the conclusion given for each estimation Similatrly efficient methods of collecting hearing data and identification of hearing loss estimate has been described individually for both ABR and SSAEP again with conclusion for the same. To summarize it has tabulated and identified the strength and weakness of both the methods, ABR and SSAEP with respect to the clearly defined overall criteria. Weaknesses Report ‘a’ Report ‘b’ While this report is informative on the established AEPs like ABR and ASSR, it does not mention anything about SSAEP. The report lacks the overall summarized observation to highlight the strength and weakness of two methods as is done in the other report. This report does not carry a separate description of stimuli and physiology related to both SSAEP and ABR Comparative analysis of supporting evidence cited Report ‘a’ Report ‘b’ This report has cited Cone-Wesson (2003) for understanding the electro psychological methods for determining the hearing defects in young infants. Further on the subject, it has cited Bramford (2006) and Hall (2006) for pointing out that the hearing defects can be found in infants of less than four weeks age. However, the report mentions about the lack of consensus on the method, ABR or SSAEP as an AEP can be used for detecting this abnormality. Hence more evidence is required in the form of research finings. There are supporting citation references like (Cunningum, 2008) and (Williston, 1971) that mention on the waveform formation for this purpose. While describing the stimuli of ASSR thresholds, the report has cited (John and Picton 2000, 2005) to highlight that such tests can be done, simultaneously, using a combination of frequency and amplitude modulation, up to eight thresholds. However, the report has suggested lack of evidence to prove the testing accuracy of ASSR due it being a recent technology. The report has recommended more time to establish the advantages of ASSR over the ABR. This report is more specific in determining the permanent childhood hearing impairment, within the first few weeks of he infant’s birth. It has cited (Davis et al 2004) for this purpose. The report has also referred to (NHS—New born hearing screening program –2008) for conducting tests to determine the disability in young infants at very early age. The report has also cited (Stapells, 2004) for the test and use of amplifiers and computer technology to determine the defect. It also cites (Feinsod et al.,1973) to highlight the objective test methods using AEP for sensory disorders and (Galambos & Hecox, 1977) for evaluation of hearing in infants. The citation referred to (Stockard & Rossiter, 1977) is to determine and define the brain stem lesions. The report has many citation references like (Hood-1998) for ABR and many others for SSAEP like (Stappells 2005) which have been provided in this report as an evidence to the tests conducted and findings arrived during such tests with both ABR and SSAEP, with reference to various hearing thresholds, that are frequency or accuracy specific etc.. Further recommendations required for both AEPs in the two reports While both the reports are specific on the tests conducted and their clinical utility and credibility on ABR and ASSR/SSAEP, the recommendations suggested in the report ‘b’ is more specific. These recommendations are given in the earlier pages here. The clinical procedure is more formulated as it is submitted in a logical fashion in the report ‘b’. Report ‘a’ has suggested at many points during the conduction of tests for ABR and ASSR, the need for further clinical tests and evidence to prove the utility of a particular method. However, report ‘b’ is more specific to the application of ABR and SSAEP for utilization of any or both the methods to determine the hearing disorders in infants. It has categorized the cases from mild to sever to profound hearing disabilities, for this purpose. Clarity of presentation As it detailed in this comparative analysis, several times, report ‘b’ is very well presented and it has given the details of clinical tests, with well-defined logics and statistics to prove the point and describe any test prodedure. Although report ‘a’ is also well detailed, but it lacks the clarity of the testing and clinical utilization procedure, which have been left open for further discussion, particularly in the case of ASSR. Clinical utility As both the documents have given their own version of clinical tests with regard to the accuracy-specific or frequency –specific threshold modules as well as the tests on Tone based (TB) or click based clinical experiments, both the reports can be utilized, while deciding the need for a particular clinical utility and its credibility. Improvement required in report ‘a’, compared to report ‘b’ As mentioned in the earlier pages of this comparative analysis, report ‘b’ is more specific, organized and well structured. The improvement in the report ‘a’ can be incorporated in the form of making clearly defined statements, as given in the conclusion and recommendation part of the report ‘b’, towards the utility of ABR or SSAEP with reference to the case history of the hearing disorder. Report ‘a’ also needs improvement in the form of more research to be conducted for finding better and credible references that leave no clue for further test findings. The conclusion part of this comparative analysis should also be utilized to make ways for improving the presentation style of report ‘a’. Last, but not the least, report ‘a’ lacks in giving direct reference to SSAEP as an AEP method or procedure, while it has highlighted the relevant properties of ASSR in this connection, which may confuse a non-professional reader. --------------------------------------------------------------------------------------------------------- Primary References Bamford, J., Uus, K., Davis, A. (2005). 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