Kellow v Return to Work Corporation of South Australia [2026] SAET 1

1. The evidence of Mr Kellow was received predominantly by way of affidavit. There was little by way of cross-examination, and his evidence in chief was not challenged. I accept his evidence to be a sound basis for findings of fact.
2. Mr Kellow was born on 23 April 1956. He referred to two periods of employment where he was exposed to loud noise. Between 1974 and 1986 he was employed by Dean and Keane Opticians as an Optical Mechanic. He was exposed to up to six hours per day to loud noise emanating from edging machinery that was used to cut and grind glass. The exposure to such noise was not continuous.
3. Between 1986 and 2004, Mr Kellow was employed by SOLA International Holdings Limited as a Development Technician. He was exposed to loud noise for up to four to five hours per day whilst he worked as a Development Technician. Again, the exposure was non-continuous. He referred to a generator that he operated and which he described as being "very noisy". He referred to other machines that he would stand close to, which were also noisy but not as much as the generator.
4. Mr Kellow has continued to be employed and, most recently since 2014, has been employed by Goggleman Younger Optics Australia and Tonic Polarised Sunglasses. He referred to the employment since the employment with SOLA International Holdings Limited as either not involving "excessive noise" or not exposing him to significant noise.
5. Mr Kellow deposed to having undergone hearing tests on 10 August 2011 with Adelaide Digital Hearing Solutions, on 19 July 2016 with the same entity, on 11 April 2024 at Amplifon, on 23 April 2024 at Bloom Hearing Specialists, and on 19 November 2024 at Freedom Hearing.
6. Mr Kellow deposed to knowledge of his mother having experienced age-related hearing loss but he was not otherwise aware of a familial history of hearing loss.
7. Mr Kellow provided some detail of his daily experience of hearing loss and its impact upon his ability to engage in the activities of daily living. He also referred to his experience of tinnitus. The assessment of permanent impairment provided by Dr Hunter included an allowance of 2% Binaural Hearing Impairment (BHI) for tinnitus. The Corporation did not challenge the allowance for tinnitus, but submitted that in the event of a referral to an IMA then both the assessment of permanent impairment for noise induced hearing loss and the assessment of permanent impairment for tinnitus should be referred to the IMA.

1. Dr Hunter gave his evidence by way of a series of medical reports and that evidence was supplemented with oral evidence. Dr Hunter was selected to be the assessor of permanent impairment required to be undertaken in accordance with of the RTW Act and the IAG. Dr Hunter examined Mr Kellow on 19 November 2024 and produced a permanent impairment assessment report dated 10 December 2024. He assessed Mr Kellow as having been left with a 12% WPI attributable to exposure to noise in employment. He relied upon the audiogram results prepared by Michelle Kerr who was recorded as having a Diploma in Audiometry and five years' experience. The testing was undertaken on 19 November 2024. Frequencies between 500Hz and 4000hz were tested. That revealed a total BHI of 34.6%. Dr Hunter, in the exercise of his judgement, relied upon the hearing loss recorded consistently across both ears at frequencies between 1500Hz and 4000Hz which produced a total of 25.1% BHI.[3] As required by the IAG, a deduction of 3.8% was made for presbycusis correction. A loading of 2% BHI was then made for tinnitus and that resulted in an adjusted total of 23.3% BHI. Table 9.2 of the IAG was then utilised to convert the 23.3% BHI to a 12% WPI.
2. Chapter 9.5 of the IAG provides that where the assessor uses a frequency outside of the usual range of 2000Hz to 4000Hz, then detailed explanation must be given. In providing an explanation for also using the frequency at 1500Hz Dr Hunter stated:

After considering the descending audiometric pattern, previous medical history, physical examination and extensive exposure to loud noise over many years, often without hearing protection, and the frequency, duration, and sources of noise exposure as noted in the employment history under point three of this report, I believe the frequencies from 1500Hz to 4000Hz have been damaged by noise exposure and should form the basis of my assessment of noise-induced hearing loss. I could not identify any other cause for the loss at these frequencies.

1. Dr Hunter noted that he disregarded any unrelated hearing impairment identified on the audiogram, including any frequency loss at 500Hz to 1000Hz and that additional loss of the left ear at 1500Hz to 4000Hz was also disregarded on the basis that the additional loss was from another cause.
2. Dr Hunter referred to audiograms prepared by Adelaide Digital Hearing Solutions dated 10 August 2011 and 19 July 2016. He had also been provided with an audiogram of Amplifon dated 28 March 2024 and an audiology report of Amplifon dated 11 April 2024. Dr Hunter determined that these audiograms were not reliable because they did not contain complete air conduction thresholds at 1500Hz and 3000Hz nor bone conduction thresholds at most of the frequencies considered by Dr Hunter to be relevant to the assessment of noise induced hearing loss.
3. The permanent assessment report of Dr Hunter also addressed tinnitus. He concluded that Mr Kellow's experience of tinnitus had an adverse impact upon his concentration where there were levels of distraction when completing house chores or work duties, impaired speech discrimination whilst socialising in public places including restaurants, pubs, and clubs, and there was an adverse impact upon mood by experiencing a decrease in the quality of life. Dr Hunter referred to these matters as giving rise to an impact of tinnitus upon Mr Kellow's Activities of Daily Living and that, in accordance with the IAG, it was appropriate to conclude that there was severe tinnitus as required by Chapter 9.11. In a range of allowing up to 5% BHI, he allowed a loading of 2% BHI.
4. Chapter 1.51 of the IAG provides that reports requested by a claims agent for the Corporation should be provided by the Corporation for review of compliance. That occurred in this case and the Corporation wrote to Dr Hunter by letter dated 20 January 2025 seeking a further report. The request related primarily to Dr Hunter's use of impaired hearing at a frequency outside of the usual range of 2000Hz to 4000Hz.
5. Dr Hunter provided a further report dated 10 December 2024. In that report he referred to Mr Kellow as having been exposed to 31 years of intermittent loud noise. He stated that damage to frequencies below 2000Hz can occur following many years of loud noise exposure. He referred to the examples in Chapter 9 at pages 71 to 76 of the IAG as supporting that position.
6. In a subsequent report dated 7 February 2025, Dr Hunter confirmed that he was aware of the exposure to noise in employment over the period of 31 years was intermittent. He also stated that the absence of a record of the frequency loss at 1500Hz in the Adelaide Digital Hearing Solution audiograms rendered them, in his view, unsuitable for compensation evaluation.
7. The Corporation wrote again to Dr Hunter by letter dated 19 February 2025. The Corporation asserted that it remained unclear as to Dr Hunter's clinical reasoning for the apparent progression of hearing loss between the audiograms of 10 August 2011 and 19 July 2016, on the one hand, and the audiogram performed on 19 November 2024, on the other. The letter appears to challenge the appropriateness of using the audiogram of 19 November 2024 where Mr Kellow had last been exposed to occupational noise considered capable of causing hearing loss in 2004. A further report was not requested at that time. The letter also appeared to be an explanation for why the Corporation considered his assessment to be non-compliant.
8. Arrangements had been made by the Corporation for Mr Kellow to be assessed by another ear, nose, and throat surgeon Dr Kym Diamantis, who assessed Mr Kellow on 12 August 2024 and provided a medical report on the same day. By letter dated 16 April 2025 Dr Diamantis was requested to provide a further report. This followed the Corporation's decision that the report of Dr Hunter was not compliant. Dr Diamantis was asked to comment upon Dr Hunter's use of frequencies outside of the usual range of 2000Hz to 4000Hz and he was asked to comment upon Dr Hunter's reasoning for not relying upon earlier audiograms. Dr Diamantis provided a further report dated 28 April 2025. In that report he stated that he could not see indication for using the 1500Hz threshold. Dr Diamantis referred to the "substantial" progression in hearing loss from 2011 until the audiogram of 2024 which he stated could not be explained by workplace exposure to noise and he thereby concluded that the 2011 audiogram should have been utilised.
9. The report of Dr Diamantis dated 28 April 2025 was put, by the nominated agent for the Corporation, to Dr Hunter and he then provided a further report dated 6 August 2025. Dr Hunter maintained the views previously expressed. He referred to a history of 31 years of intermittent loud noise exposure without hearing protection as a proper basis for utilising the 1500Hz frequency. As for the choice of audiograms, Dr Hunter observed that Dr Diamantis had acknowledged in his report that the choice of audiogram utilised by an assessor is within the discretion of the assessor. Dr Hunter maintained that there was no error in his use of that discretion. Dr Hunter was questioned, in cross-examination, about the deterioration in hearing, suggested to be evident from the results of the audiogram of 2011 when compared to the audiogram of 2024. Dr Hunter acknowledged that the results indicated a significant deterioration in hearing between 2011 and 2024, and especially at 2000Hz and 3000Hz.[4]
10. Dr Hunter agreed that hearing loss from exposure to noise does not extend beyond the date of the exposure.[5]
11. Dr Hunter also accepted that the IAG requires that hearing loss from causes other than exposure to noise at work is to be excluded in the assessment of WPI.[6]
12. There was a non-work cause of some additional hearing loss affecting the left ear. Dr Hunter accepted at one point the audiograms indicated there had been a deterioration of hearing, affecting both ears, between 2011 and 2024.[7] This led to the following exchange:

Mr Harms: So is it not the position that you have not excluded the loss, which appears to have occurred between 2011 and 2024, and is not noise-induced hearing loss?

Witness: The tracing points to noise-induced hearing loss, because it's a sloping, high-tone loss. And due to the fact that the patient had been exposed to noise, I felt that there was adequate reason for stating that that exposure had created the deep decrease in hearing from 2011 to 2024. Am I talking in riddles? I'm sorry if I am.[8]

1. Dr Hunter then gave evidence which indicated he had been of the understanding Mr Kellow had been exposed to noise after 2004. However, he did not explain clearly the basis of that understanding. If a notation was made at the time of a consultation, it was not made available to the Tribunal.[9]
2. Dr Hunter accepted that he may have been mistaken in relation to his recollection of Mr Kellow having reported exposure to noise after 2004.[10] When the extent of reported deterioration in audiograms between 2011 and 2024 was revisited, there was some variation in the evidence given by Dr Hunter. Whereas initially his evidence was to the effect that the difference recorded was outside the test/retest range accepted as being consistent with no deterioration, he subsequently indicated that some "audiology people" have suggested that a variation of up to 20 decibels can be acceptable.[11] In his report dated 10 December 2024, Dr Hunter stated that where in the one audiogram there is a difference between the ears greater than 20dB at 3000, 4000, or 6000Hz then additional factors unrelated to occupational noise exposure are operative. He did not refer to this in his oral evidence and it is not clear whether different conditions apply in those circumstances.
3. Dr Hunter accepted that if the variation is outside of the accepted range then he did not exclude hearing loss from causes other than noise in employment.[12]
4. He maintained in his oral evidence that the exposure to noise in employment, albeit intermittently, was over many years and that it was appropriate to include the recorded hearing loss at 1500Hz.[13]
5. In re-examination Dr Hunter was taken to his interpretation of readings that were recorded in the 2011 audiogram. The audiogram itself was read differently by Dr Hunter and Dr Diamantis.[14]

1. Dr Diamantis gave evidence by way of a series of medical reports and he also gave oral evidence. His evidence included the following:
   1. There was no evidence of noise-exposure of significance after around 2004.
   2. Whilst generally the choice of audiogram to be relied upon is that of the assessor of permanent impairment, the degree of progression of hearing loss from 2011 through to 2024 cannot be explained by workplace noise exposure and, in those circumstances, it was inappropriate in this case to utilise the 2024 audiogram. That is notwithstanding the greater impact of the presbycusis factor.
   3. The progression of hearing loss between 2011 and 2024 was substantial. Effectively, there was a total of some 15 to 16 years of workplace noise exposure which is not sufficient to include hearing loss detected at 1500Hz where the examples provided in the IAG that utilise hearing loss at 1500Hz involve exposure to noise of at least 30 years. In the circumstances, the absence of a record of hearing loss at 1500Hz in the 2011 audiogram is not a sufficient reason to disregard it.
   4. Dr Diamantis accepted that the 2011 audiogram, on the right side, at 4000Hz is not clear. His evidence was based upon a presumed extrapolation of the other results that were clearly recorded.[15]
   5. Dr Diamantis did not make enquiry with the audiologist who prepared the 2011 audiogram nor was there any other evidence that assisted him in the extrapolation exercise that he undertook.[16]
   6. Dr Diamantis accepted that he was not aware of any evidence of Mr Kellow having been exposed to any form of noise after 2004 that could explain a substantial degree of hearing loss between 2004 and the time of the audiogram in 2024.[17]
   7. Dr Diamantis also accepted that there was no history of any other possible cause of a substantial deterioration in Mr Kellow's hearing over that period.[18]
   8. Dr Diamantis had arranged his own audiogram in August 2024 and accepted his results were consistent with the audiogram in 2024 that was relied upon by Dr Hunter and demonstrated a pattern of loss consistent with at least an element of noise-injury.[19]
   9. Dr Diamantis gave evidence consistent with Dr Hunter that hearing loss from noise ceases when the noise has stopped.[20]
   10. On the assumption the 2011 audiogram correctly recorded Mr Kellow's hearing loss at the time, notwithstanding the absence of a history or other evidence explaining a substantial deterioration in hearing thereafter, Dr Diamantis maintained that there must be an explanation, other than exposure to noise, for the substantial deterioration in hearing between 2011 and 2024.
   11. Dr Diamantis had not been provided with any information as to whether Mr Kellow had retired or that the deemed date of injury in this case was 30 April 2024.[21]
   12. Dr Diamantis accepted that the history obtained from a worker together with the tests conducted on the day of the assessment will inform the assessor as to the frequencies to be included in the assessment of permanent impairment, that a degree of judgement is involved, and that different assessors may reasonably reach different conclusions as to the range of frequences to be included in the assessment of permanent impairment.[22]
   13. Ultimately in cross-examination Dr Diamantis accepted that Dr Hunter's evaluation of over 30 years of exposure to noise at work was reasonable and the inclusion of the hearing loss at 1500Hz may be reasonable.[23]
   14. Dr Diamantis also accepted that there is an element of clinical judgement in an assessor determining whether an earlier audiogram is reliable.[24]

1. The Corporation submitted that Dr Hunter's permanent impairment assessment report was infected by error because he had not made any attempt to exclude the further hearing loss that is evident when comparing the 2011 audiogram to the audiogram relied upon by Dr Hunter which was prepared in 2024. Mr Harms observed that the basis of Dr Hunter not having relied upon the 2011 audiogram was the exclusion of a reading at 1500Hz. As I understood the submission, Dr Hunter did not challenge the reliability of the hearing loss recorded at the 2000, 3000, and 4000Hz frequencies. The Corporation submitted that the evidence excludes a noise-based explanation for that deterioration.
2. The Corporation submitted that the difference in loss between the 2011 and 2024 audiograms could not be explained on the basis of variation from day to day and represented a further hearing loss which was required to be deducted. Further, so the Corporation submitted, the absence of a record of the loss at 1500Hz in the 2011 audiogram meant that the assessor was required, as best he could upon the evidence available, to determine the amount of that deterioration and to disregard it.
3. The Corporation submitted that the obligation to disregard hearing loss not attributable to exposure to noise in employment arises whether the issue is approached by reference to s 22 or s 188 of the RTW Act.
4. The absence of bone-conduction thresholds in the 2011 audiogram, also referred to by Dr Hunter, as a reason for not relying upon that audiogram, was contended by the Corporation to also be an approach inconsistent with the requirement to disregard hearing loss not attributable to exposure to noise in employment. The Corporation submitted that the inability to identify the reason for the further hearing loss between the audiograms of 2011 and 2024 is not a proper basis to include the portion of hearing loss that was acknowledged by Dr Hunter as not being attributable to exposure to noise in employment.
5. In all the circumstances, the Corporation urged the Tribunal to consider a referral of medical questions related to the assessment of permanent impairment to an IMA. The questions would include what is the percentage of WPI attributable to exposure to noise in employment, whether losses at 1500Hz should be included in the assessment, and the extent to which the 2011 audiogram is to be taken into account in the assessment of permanent impairment. As indicated earlier in these reasons, the Corporation submitted that if there is to be a referral to an IMA, then the IMA should also be asked to assess the loading (if any) attributable to tinnitus.

1. Mr Kellow submitted that the Corporation's submissions were dependent upon a finding that the 2011 audiogram is reliable. It was submitted that Dr Hunter never conceded that the 2011 audiogram is reliable and that Dr Hunter maintained throughout his evidence that he was not prepared to rely upon the 2011 audiogram because it is unreliable. Moreover, he gave reasons for that conclusion. Firstly, he referred to the absence of a record of hearing loss at the 1500Hz level, and, secondly, the audiogram did not include bone-conduction thresholds at relevant frequencies and particularly at 2000Hz.
2. Mr Kellow submitted that, in assessing permanent impairment, it is for the assessor to determine the extent to which the results of a medical investigation are reliable and to be taken into account.
3. Ms Sibree for Mr Kellow also noted that Dr Diamantis had relied upon results of the 2011 audiogram, not as recorded by the audiologist who performed the test, but on the basis of his extrapolation of the limited results that were recorded and presented to him. They were different from Dr Hunter's understanding of the results and it was contended there was not a proper basis to depart from Dr Hunter's understanding of the results recorded in the audiogram. Alternatively, it represented a further reason not to rely upon the 2011 audiogram.
4. Mr Kellow questioned how, in these circumstances, an IMA could provide further evidence that would assist the Tribunal in quelling the dispute between the parties.
5. Mr Kellow also submitted that it had been open for the Corporation to call the audiologist who prepared the 2011 audiogram to give oral evidence. As I understood that submission, that evidence may have been able to address the issues related to the hearing loss at 1500Hz, the absence of recorded bone-conduction results, and where some of the results of the audiogram available to the Tribunal had been whited out and thereby had become illegible.
6. Ms Sibree addressed s 188 of the RTW Act. She submitted that no guidance had been given by the Corporation to either Dr Hunter or to Dr Diamantis about how to apply s 188 where Mr Kellow had last been exposed to noise in employment in 2004, had not retired from employment and has a deemed date of injury of 30 April 2024.
7. Mr Kellow submitted that Dr Hunter was correct to base his assessment of presenting WPI by reference to the audiogram that was performed on the day of the assessment. He accepted that there may be a question of deduction but only if an earlier audiogram is reliable enough for such a deduction to be made.
8. Ms Sibree submitted that s 188(2) of the RTW Act deems the whole of the noise-induced hearing loss to be taken to have occurred immediately before the notice of injury was given.

1. It is convenient to commence with the findings that may be made by reference to evidence that was not contested or where I have otherwise been persuaded that the finding should be made at this time upon the evidence received.
2. Mr Kellow was last exposed to noise in employment capable of producing noise-induced hearing loss in 2004. Since that time, he has not been exposed to noise outside of the workplace capable of producing noise-induced hearing loss. His deemed date of injury, upon application of s 188(2) of the RTW Act, is 30 April 2024. The audiometry testing performed by audiologist Michelle Kerr on 19 November 2024 was in accordance with the requirements of the IAG and the audiogram subsequently produced accurately records the hearing loss experienced by Mr Kellow at the time of the assessment at the various frequencies set out in the audiogram.
3. Mr Kellow was exposed, intermittently during the day, to noise in employment capable of producing noise-induced hearing loss between 1974 and 2004. This constitutes "many years" of exposure to noise for the purposes of including hearing loss at the 1500Hz frequency. The examples set out in Chapter 9 of the IAG, which include hearing loss at 1500Hz, do not state that the exposure to noise is required to be continuous over the relevant period of time. Dr Diamantis did not dispute that in circumstances of an exposure to noise over a period of 30 years or more, it can be appropriate to include hearing loss at the 1500Hz frequency. He was not persuaded that, effectively, Mr Kellow was exposed to such noise over that relevant period because the exposure was not continuous. In my view, such matters do not require an evaluation of mathematical precision. There is an element of judgement to be exercised by the assessor and by reference to the evidence of the extent of the exposure and the period of time over which there was such exposure to noise, I am persuaded that the assessment of noise-induced hearing loss suffered by Mr Kellow from his exposure to noise in employment should include loss recorded at 1500Hz.
4. Dr Diamantis did not appear to challenge the view of Dr Hunter that the 19 July 2016 audiogram report related to audiometry testing performed by Adelaide Digital Hearing Solutions is not reliable for the purpose of determining Mr Kellow's permanent impairment.
5. The evidence does not disclose a reason for a deterioration in hearing, other than on account of presbycusis, between 2011 and 2024. That is relevant to an assessment of the reliability of the audiogram of 10 August 2011 which followed audiometry testing also performed at Adelaide Digital Hearing Solutions. However, I also accept the submission of the Corporation that the absence of evidence of a cause of deterioration in hearing between 2011 and 2024 does not, in itself, exclude a cause.
6. I have set out above the reasons given by Dr Hunter as to why he considers the audiogram of 2011 to be unreliable. The effect of his evidence is that he was not persuaded that there has been a deterioration in hearing, other than for presbycusis between 2004, when Mr Kellow was last exposed to noise capable of producing noise-induced hearing loss, and the date of the audiogram in 2024 relied upon for the assessment of permanent impairment. Put another way, Dr Hunter maintained his assessment is the permanent impairment that arises from Mr Kellow's work injury in accordance with the IAG.
7. Some observations may be made generally where there is a challenge to the correctness of an assessment of permanent impairment by an accredited assessor. Firstly, it is for the Tribunal to determine the appropriate WPI.[25] Secondly, absent material errors of fact or law, the assessment by the accredited assessor is determinative. The Tribunal may consider other expert views in determining whether error is established but it cannot disregard the assessment made by the approved assessor unless error is shown.[26] Thirdly, in determining whether there is error in the assessment, the Tribunal may obtain further evidence by a referral to an IMA. It may do so where potential error has been demonstrated and with a view to either establishing or allaying concerns about that perceived error.[27] Fourthly, the duty required of the assessor is to assess the permanent impairment arising from the work injury. Where either s 22(8)(b) or s 22(8)(g) of the RTW Act apply, the assessor is to ensure that any impairment assessed which is attributable to a cause other than the work injury, is either "disregarded" or "deducted". Both subsections have a purpose that only an impairment to the extent that it is attributable to a work injury, is to be assessed and compensated.[28] Fifthly, assessors are required to note that there may be occasions where it is difficult to quantify the degree of permanent impairment attributable to an unrelated injury or cause, in accordance with the IAG. That, in itself, does not relieve the assessor from undertaking the task of limiting the assessment of the degree of permanent impairment arising from the work injury to the work injury.[29]
8. It is important to note the factual context in which the statements of principle were made by the majority in Paschalis. In that case the assessment of permanent impairment followed a psychiatric work injury. Sub-section 188(2) of the RTW Act was not considered. The psychiatrist who was appointed to be the assessor of permanent impairment, assessed the presenting impairment and then deducted the likely level of impairment which predated the work injury. The assessor had not assessed the worker prior to the work injury and, in those circumstances, was unable to apply the criteria set out in the IAG. Although the assessor was unable to reach a pre-work injury diagnosis he was sufficiently confident in estimating the level of pre-existing impairment. The majority in Paschalis found no error in that approach. They explained:

Dr Begg was not required to make a separate assessment of the degree of impairment arising from the identified, pre-injury causes in accordance with the Guidelines. That process is neither practical nor warranted by GEPIC. Nonetheless, in his evidence Dr Begg explained how he made his 20 per cent assessment in accord with GEPIC. Of course, if a reliable previous WPI assessment were available, then it may well be used. Speaking generally, however, it was sufficient that the worker's WPI was assessed in accord with the Act, the Guidelines and AMA-5 and, as part of that assessment, appropriate allowance for pre-existing impairment was made by way of deduction under GEPIC.[30]

1. There are factual differences between the circumstances addressed by the Full Court in Paschalis and this case. This case involves noise induced hearing loss and thereby requires a consideration of s 188 which was not a feature in Paschalis. In this case, Dr Hunter, as the assessor, has not made a deduction because he has not been satisfied that there is evidence of a non-work-related impairment to be deducted. However, concerns arise as to whether Dr Hunter has correctly evaluated the 2011 audiogram. His evidence suggests the absence of a threshold at 1500Hz may be sufficient to render the audiogram, as a whole, unreliable. That possible position was not sufficiently explained. I refer to the paragraphs above which summarise the evidence given by Dr Hunter. I refer to the variation in his evidence as to whether the increase in hearing loss recorded between 2000Hz and 4000Hz in comparing the 2011 and 2024 audiograms was within the test/retest range. At times he referred to a range of between 10% and 15% and other times he suggested up to 20%. At times his evidence was consistent with a finding of variation within an acceptable range and other times his evidence was consistent with a finding that the differences in the recorded hearing loss at the frequencies of 2000Hz to 4000Hz support a finding of further hearing loss unrelated to the work injury. His evidence in the exchange recorded at paragraph 24 of these reasons was unclear. I also remain unclear as to the extent to which Dr Hunter may have relied upon an erroneous understanding that Mr Kellow was exposed to noise capable of producing noise-induced hearing loss, in employment, after 2004. Dr Hunter accepted that if the variation between the audiograms of 2011 and 2024 record a hearing loss not arising from the work injury, affecting both ears, then he did not deduct the impairment not related to the work injury.
2. I also have some concerns in relation to aspects of the evidence given by Dr Diamantis. Firstly, I have rejected his evidence in relation to Dr Hunter's use of hearing loss at 1500Hz. Secondly, Dr Diamantis relied upon a different figure for the loss of the right ear at 4000Hz in relation to the 2011 audiogram to that utilised by Dr Hunter. In my view this is a factor relevant to whether the Tribunal can be satisfied that the 2011 audiogram is sufficiently reliable for it to be taken into account. That factor is to be combined with the absence of recorded hearing loss at 1500Hz, the absence of complete air conduction thresholds at 1500Hz and 3000Hz, and the possible absence of recorded bone conduction thresholds at some frequencies, and especially at 2000Hz. Further, in his report dated 28 April 2025, Dr Diamantis stated:

The audiology from 2011, used in my IME, is appropriate when there is no basis for using the thresholds at 1500Hz.[31]

There are two points to be made in relation to that statement. Firstly, as already noted, I have found that there was a basis for Dr Hunter using the threshold of hearing at 1500Hz. Secondly, the statement is indicative of an approach that permeated throughout the evidence of Dr Diamantis, that the recorded thresholds at 2000 and 3000Hz and his extrapolated figure on the right side at 4000Hz in the audiogram of 2011, when compared with the threshold results in the 2024 audiograms demonstrates that there has been further significant hearing loss not related to the work injury and which is required to be deducted in order to assess the permanent impairment arising from the work injury. The approach of Dr Diamantis may be too simplistic and may not have adequately considered the issues raised by Dr Hunter. This is not a case where the Corporation sought the opinion of Dr Diamantis solely for the purpose of addressing compliance in relation to Dr Hunter's permanent impairment assessment report. Dr Diamantis provided his first report dated 12 August 2024 before the assessment of permanent impairment was undertaken by Dr Hunter. In his first report, Dr Diamantis referred to audiology from April 2024 together with audiology that was documented on the day of his assessment. He relied only upon the audiogram of 2011 to determine the WPI for hearing loss arising from employment. This was on the basis of his understanding that there had been no noise exposure since 2004 in the workplace. The subsequent reports of Dr Diamantis and his oral evidence were not just an independent review of the assessment of Dr Hunter. He maintained the correctness of his earlier assessment.

1. Dr Diamantis did not provide a loading for tinnitus. His reasoning was that although he obtained a history of at least 15 years of tinnitus which impacted upon Mr Kellow's socialisation and communication, which impacted upon his enjoyment of entertainment, Dr Diamantis was not satisfied that there was an impact upon either daytime or nighttime activities of daily living. The understanding of Dr Diamantis of the impact of the tinnitus experienced by Mr Kellow upon his activities of daily living is different to that of Dr Hunter. No error has been demonstrated in Dr Hunter's assessment by reference to the history he obtained and the evidence given by Mr Kellow. I do not have a concern in relation to Dr Hunter's loading of 2% BHI for tinnitus.
2. The commissioning letters that were sent by the requestor to Dr Diamantis and to Dr Hunter were contained within the trial book. In neither instance was the attention of the doctor drawn to the deeming provision in s 188(2) of the RTW Act. The legal principles relevant to determining which audiogram is to be utilised and to form the basis of the assessment of permanent impairment were not mentioned in either commissioning letter and were not addressed either by Dr Hunter or Dr Diamantis in their reports. I addressed these principles in Van Loggem v Return to Work Corporation of South Australia (Van Loggem)[32] and also the differences in the operation of s 188(2) and (3) of the RTW Act.[33] In Van Loggem, I expressed some tentative views in circumstances of a conclusion reached that Ms Van Loggem should be referred to an IMA and that evidence received before expressing a concluded view. In Van Loggem I decided that whether 188(2) and (3) operate as an exclusive code for the assessment of permanent impairment for hearing loss and tinnitus and whether s 188(2) deems all of hearing loss or only that loss arising from employment to have occurred immediately before notice of injury was given, should await the report of the IMA and decided with the benefit of all of the evidence. I am of the same view in this case, but the relevant text of s 188 should be brought to the attention of the IMA.

1. There should be a referral of medical questions to an IMA. The parties will be afforded an opportunity to be heard in relation to who should be nominated as IMA, the text of the medical questions to be asked of the IMA in conformity with these reasons, the text of the background and other matters that should be brought to the attention of the IMA in the referral document, and the documents that should be attached to the referral document.
2. The parties are to provide their submissions at to the identity of the IMA, the content of the referral document and the documents to be attached to the referral, in writing, by 27 January 2026.

[3] There was some asymmetrical loss recorded and that was excluded by Dr Hunter.

[13] Cross-examination culminating at TR 36 L23.

[25] Paschalis v Return to Work Corporation of South Australia (Paschalis) [2021] SASCFC 44, [158] (Liversey & Bleby JJ).

[27] Sean Luke v Department for Primary Industries and Regions [2025] SAET 24, [112] (Gilchrist, Kelly, & Crawley DPJJ).

[28] Paschalis supra [198] (Livesey and Bleby JJ).

[29] Paschalis supra [201] and reference to Department for Health and Ageing v Neilson [2017] SAET 136.

[30] Paschalis supra [235] (Livesey and Bleby JJ).

[32] [2025] SAET 47 at [88]-[101].