Accident Compensation Act 1985, ss 91(1), (3) and (4).

HJ Heinz Company Australia Ltd v Kotzman [2009] VSC 311 applied; Victorian WorkCover Authority v Elsdon [2013] VSCA 235; (2013) 42 VR 434, Paschalis v Return to Work Corporation of South Australia (2021) 140 SASR 77 referred to.

1. From 1985 until he retired in 2012, Felice Scardamaglia was employed by Amcor PLC ('the employer') in a noisy work environment. In June 2020, he made a claim for an impairment benefit under the Accident Compensation Act 1985 ('the Act'), alleging he had suffered a loss of hearing and tinnitus caused by being exposed to noise in the course of this employment.
2. In March 2021, Mr Scardamaglia was examined by a specialist ear, nose and throat surgeon, Michael Silverstein. Mr Silverstein determined that Mr Scardamaglia has an industrial hearing loss which merits the provision of bilateral hearing aids. He concluded, however, that Mr Scardamaglia's whole person impairment percentage was zero. Relying upon Mr Silverstein's report, the employer (through its claims manager) accepted liability for Mr Scardamaglia's hearing loss, but contended that he was not entitled to an impairment benefit because his whole person permanent impairment was zero per cent.
3. Mr Scardamaglia accepted the employer's liability decision, but disputed the whole person permanent impairment assessment. As a result, the employer referred two medical questions to a medical panel for its opinion. A medical panel comprising Associate Professor Bernard Lyons, an otolaryngologist, was convened to give its opinion in connection with the referred medical questions. On 18 September 2021, the medical panel provided a Certificate of Opinion and a statement of its Reasons for Opinion. The relevant medical questions and the panel's answers were set out in the Certificate of Opinion as follows:

Question a) What is the degree of permanent impairment resulting from industrial deafness assessed in accordance with Section 91 of the Act?

Answer: The Whole Person impairment calculated in accordance with Section 91 of the Act is 0%. The degree of impairment is permanent.

Question b) Does the worker have an accepted injury, which has resulted in a total loss injury mentioned in the table on Section 98E?

Answer: No.

1. On 17 November 2021, Mr Scardamaglia commenced a proceeding in the Trial Division, against the employer and the medical panel, seeking an order that the Certificate of Opinion be quashed and the medical questions remitted to a differently constituted medical panel. Mr Scardamaglia's contention was that the Certificate of Opinion was erroneous because the panel failed to take into account or consider his tinnitus.
2. Mr Scardamaglia's proceeding was heard in the Trial Division by Forbes J on 2 December 2022. At trial, the employer accepted that the medical panel did not make any separate allowance for impairment arising from tinnitus, but submitted that there was no error in the panel's approach because the methods for assessing hearing loss prescribed by the Act did not require the panel to make any separate allowance for tinnitus.
3. On 15 March 2023, the trial judge gave judgment for Mr Scardamaglia, concluding that the medical panel erred by failing to consider the effect of tinnitus.[1] On 12 April 2023, in accordance with the Reasons, her Honour made an order in the nature of certiorari, quashing the medical panel's opinion; and an order in the nature of mandamus, remitting the medical questions to a differently constituted medical panel.
4. The employer now seeks leave to appeal (and, if leave is granted, to appeal) from the orders of the judge on the following proposed ground of appeal:
   1. The primary judge erred in concluding that the ASOHNS Guidelines incorporate Chapter 9.1 of the AMA Guides (4th edition) for the purposes of the assessment of tinnitus in the presence of hearing loss, and/or that the ASOHNS Guidelines permit or require such an assessment.

1. In the Reasons for Opinion, the medical panel records that it conducted an assessment of Mr Scardamaglia on 24 August 2021.
2. The Reasons for Opinion set out Mr Scardamaglia's history of having worn hearing aids for three years and suffering from 'constant annoying tinnitus'. The panel said that an examination of Mr Scardamaglia's ears was 'normal', before setting out its reasons for the answers given to the medical questions in the Certificate of Opinion as follows:

The Panel conducted a hearing test in accordance with the Improved Procedure for Determination of the Percentage Hearing Loss (1988 Edition) published by the National Acoustic Laboratory. The Panel considered the hearing test was accurate and reliable.

The Panel considered that the audiological assessment (copy enclosed) revealed a bilateral sensorineural hearing loss. The Panel was of the opinion that the worker had a significant history of noise exposure. The Panel was not of the opinion that there was evidence to support inclusion of reduced thresholds at frequencies below 2000Hz as being contributed to by noise exposure given the flat low frequency loss from 250-1500Hz likely to be due to degenerative factors. The Panel considered 'the lowest (least hearing loss) reliable thresholds obtained should be used' at all affected frequencies and calculated the hearing loss accordingly. (2kHz-40/45, 3kHz-55/60, 4kHz-60/65).

The Panel calculated a binaural hearing loss of 16.7%, with a 7.5% deduction for presbycusis, resulting in a binaural hearing loss of 9.2% due to occupational noise exposure, relevant to the accepted hearing loss injury.

Based on the worker's history and information in the referral material, the Panel is not positively satisfied that the worker suffered any hearing loss in non-compensable circumstances and therefore the Panel concluded that there is no deduction to be made pursuant to Section 91(3AAA) of the Act.

The whole person impairment calculated in accordance with Section 91 of the Act is 0%. The degree of impairment is permanent.

The Panel acknowledges the report of Mr Michael Silverstein dated 12 March 2021 and agrees with the findings therein of a 0% whole person impairment.

The Panel also concluded that there was no total loss or total loss of use injury when assessed in accordance with Section 98E of the Act.

1. While two medical questions were referred to the medical panel, for the purposes of this proceeding, the relevant medical question is question (a).[2] The expression 'industrial deafness' in question (a) is defined in the Act to mean:

any condition of deafness caused by -

(a) exposure; or

(b) continued exposure; or

(c) periods of continued exposure -

to industrial noise;[3]

1. Section 91 of the Act, referred to in question (a), deals with the way impairment is to be assessed under the Act. Relevantly, s 91 provides:

91 Assessment of impairment

(1) In this Part, a reference to the assessment of a degree of impairment in accordance with this section is a reference to an assessment -

(a) made in accordance with -

(i) the A.M.A Guides as applicable subject to subsections (1A) and (1B); or

(ia) the A.M.A Guides as applicable subject to subsections (1A) and (1B) and guidelines in accordance with subsection (6), (6A) or (6B); or

(ii) methods prescribed for the purposes of this section -

and in accordance with operational guidelines (if any) as to the use of those Guides or methods issued by the Minister; and

(b) ...

...

(3) For the purposes of assessing the degree of impairment of the whole person resulting from diminution of hearing, the percentage of the diminution of hearing determined in accordance with subsection (4) is to be converted as follows -

(a) if the diminution of hearing assessed as a binaural loss of hearing is less than 10 per cent NAL, the degree of impairment is zero;

(b) if the diminution of hearing assessed as a binaural loss of hearing is 10 per cent NAL, the degree of impairment is 10 per cent;

(c) if the diminution of hearing assessed as a binaural loss of hearing is more than 10 per cent NAL, the degree of impairment is the percentage equivalent of the number (rounded up to the next whole number) given by the formula -

10 + [0.278 (NAL − 10)] -

where NAL is the percentage of diminution of hearing determined in accordance with subsection (4).

(3AAA) Impairment from industrial deafness or a proportion of such impairment that occurs in circumstances that do not create a liability to pay compensation under this Act must be excluded from the assessment of deafness for the purposes of assessing the degree of impairment under this section.

...

(4) For the purposes of this section and section 89(3)(a), the percentage of diminution of hearing -

(a) must be assessed as a binaural loss of hearing and determined -

(i) by a person or class of persons approved; and

(ii) in the manner approved -

by the Minister; and

(b) must be assessed as a binaural loss of hearing and determined in accordance with the Improved Procedure for Determination of Percentage Loss of Hearing (1988 Edition or a later prescribed edition) published by the National Acoustic Laboratory.

1. Section 91(1) refers to assessments of impairment being 'made in accordance with ... the A.M.A Guides'. 'A.M.A Guides' (which, for convenience, we will refer to as 'the AMA Guides') is defined in the Act[4] to mean:

the American Medical Association's Guides to the Evaluation of Permanent Impairment (Fourth Edition) (other than Chapter 15) as modified by [the Workplace Injury Rehabilitation and Compensation Act 2013] and the regulations;

1. Section 91(4) requires the percentage of diminution of hearing to be assessed as a binaural loss of hearing and determined in accordance with the Improved Procedure for Determination of Percentage Loss of Hearing (1988 Edition)[5] published by the National Acoustic Laboratory ('the NAL Procedure'). Section 91(4) also requires the percentage of diminution of hearing to be assessed in the manner approved by the Minister for Finance.
2. On 25 October 2018, the then Minister for Finance[6] signed a document headed 'Victorian Worker's Compensation Legislation: Approval of the Manner for Determining the Percentage of Diminution of Hearing' ('the Approval'). The Approval stated that it was made under a number of sections of the Act and the Workplace Injury Rehabilitation and Compensation Act 2013, including s 91(4)(a)(ii) of the Act. The Approval stated that the Minister approved 'the following manner of determining the percentage of diminution of hearing for the purposes of the Victorian Worker's Compensation Legislation', namely:
   1. The compensable hearing loss shall be determined in accordance with the publication Improved Procedure for Determining Percentage Loss of Hearing, NAL report No 118 January 1988 published by the National Acoustic Laboratories including the presbycusis table in the same publication.

...

1. The determination will be made using the Guidelines for the Assessment of Noise Induced Hearing Loss (Revised June 2017) by the Victorian Section of the Australian Society of the Otolaryngology Head and Neck Surgery.

1. By s 91(4)(a)(ii), Mr Scardamaglia's industrial deafness,[7] or percentage of diminution of hearing,[8] was required to be assessed and determined using the guidelines published by the Victorian Section of the Australian Society of the Otolaryngology Head and Neck Surgery referred to in para VI of the Approval ('the ASOHNS Guidelines').
2. The issue in this proceeding is whether the ASOHNS Guidelines incorporate a section of Chapter 9 of the AMA Guides (referred to by the parties, and in the proposed ground of appeal, as Chapter 9.1) for the purposes of the assessment of tinnitus in the presence of hearing loss, such that the ASOHNS Guidelines required the medical panel to assess Mr Scardamaglia's alleged tinnitus in accordance with the AMA Guides in addition to assessing his hearing loss in accordance with the NAL Procedure.
3. While it is the terms of the ASOHNS Guidelines which govern the assessment and determination of hearing loss, it is convenient to refer, first, to the NAL Procedure, and then to the AMA Guides as they are both referred to in the ASOHNS Guidelines.

1. The NAL Procedure is a 1988 document published by the National Acoustic Laboratories. It contains empirical formulae and computer programs which can be used to calculate binaural percentage loss of hearing 'accurately in hearing threshold level steps as small as 0.5 dB or less'. The document notes that the use of computers to carry out routine audiological calculations has become widespread, and that it is desirable to be able to calculate percentage losses of hearing accurately by the use of computers. It is not necessary to say anything further about the document, other than to note that the panel conducted Mr Scardamaglia's hearing test in accordance with it and enclosed a copy of the audiological assessment that was thereby produced.

1. The relevant chapter of the AMA Guides is Chapter 9. It is headed, 'Ear, Nose, Throat, and Related Structures'. Within Chapter 9, there are sections dealing with the assessment of hearing impairments. These sections are headed '9.1 The Ear'; '9.1a Hearing'; and '9.1b Objective Techniques for Determining Hearing Impairments'.
2. Sections 9.1a and 9.1b deal with the assessment and determination of hearing impairments using a pure tone audiometer. It is not necessary to describe the procedures set out in these sections, other than to say that there are differences between them and those described in the NAL Procedure - noting that it is the NAL Procedure which is prescribed by s 91(4)(b) and referred to in s 91(3) of the Act.
3. The reference to tinnitus in Chapter 9 appears in section 9.1 and is as follows:

Disturbances of the ear, such as chronic otorrhea, otalgia, and tinnitus, are not measurable. Therefore, the physician should estimate an impairment percentage based on the severity of those conditions and the degree to which they interfere with functions of the ear, and a percentage that is consistent with established values.[9]

Tinnitus in the presence of unilateral or bilateral hearing loss may impair speech discrimination; therefore, an impairment percentage up to 5% may be added to the impairment for hearing loss.[10]

For convenience, we will refer to these two paragraphs as 'the AMA tinnitus paragraphs'.

1. The ASOHNS Guidelines are divided into seven sections headed:
   • '1. Preamble';
   • '2. Overview';
   • '3. The medical assessment';
   • '4. The audiometrical assessment';
   • '5. Interpretation and preparation of the medical opinion';
   • '6. Special considerations'; and
   • '7. Other considerations'.
2. In the Overview section, the ASOHNS Guidelines state that the percentage loss of hearing 'is determined from [the NAL Procedure]'. The Guidelines give a brief description of the NAL Procedure, before stating that the percentage loss of hearing is then converted to a whole person impairment in accordance with the formula in the Act.[11]
3. Under the heading '7. Other considerations', there is a sub-heading 'a. Tinnitus'. Under this subheading, the following appears:

The 4th edition of the AMA Guides relevant to ENT impairment assessment refers only to the effects of tinnitus on the function of the ear. This means the effect of tinnitus on hearing and any effect on the pure tone audiogram will be accounted for in that evaluation of hearing.

Other symptoms related to tinnitus, which may adversely affect the ability to carry out the activities of daily living including anxiety and sleep disturbance, are responses to the presence of the tinnitus and not directly related to hearing.

The impairment evaluation of these aspects of tinnitus belongs in the field of specialists in psychological medicine. The ENT impairment assessor can make a recommendation that such an assessment be carried out if considered appropriate.

For convenience, we will refer to these three paragraphs as 'the ASOHNS tinnitus paragraphs'.

1. The judge commenced her analysis by saying that the medical panel was required to assess a degree of impairment arising from 'industrial deafness', whether or not tinnitus was separately identified in Amcor's acceptance of injury.[12] Her Honour then said that, industrial deafness being the injury, ss 91(3) and (4) of the Act provide the method for the assessment and determination of the impairment arising from it.[13]
2. The judge said that the percentage hearing loss obtained by the NAL Procedure was 'not the entirety of the determination required by s 91(4) of the Act'.[14] Her Honour said that, if it were, then 'there would be no work for s 91(4)(a)(ii) and the Minister's approval of the ASOHNS Guidelines'.[15] Her Honour noted that the ASOHNS Guidelines address a number of issues that may result in the adjustment of the figure obtained by using the NAL Procedure. These included the use of presbycusis correction tables; the need to consider other pathologic disorders; and the way in which a unilateral compensable hearing loss is to be treated.[16] Her Honour then said:

The ASOHNS Guidelines provide similar assistance for the clinical assessment of tinnitus. Assistance in that regard specifically references an assessment using the AMA Guides. In this way the effect of the ASOHNS Guidelines is to bring into the ENT assessment a specific aspect of the AMA Guides regarding tinnitus.[17]

1. Thus, so her Honour concluded, the ASOHNS Guidelines contemplated that the diminution of hearing - being the relevant percentage arrived at by the full application of ss 91(4)(a) and (b) of the Act - 'will not necessarily be the same figure as the percentage loss of hearing assessed by the NAL Procedure'.[18]
2. The judge then referred to well-known principles of statutory construction: namely, that the ordinary and grammatical sense of statutory words should be interpreted having regard to their context and purpose; and that a court must strive to give meaning to every word of a statutory provision.[19] Her Honour then said:

There is therefore a significance to the distinction between the 'percentage of diminution of hearing' that is arrived at by the steps identified in s 91(4) of the Act and the 'binaural loss of hearing' that is assessed and determined as part of those steps. A binaural loss of hearing under s 91(4)(b) using the NAL Procedure may be adjusted as a relevant binaural loss in accordance with the ASOHNS Guidelines which have the Minister's approval for the purpose of s 91(4)(a)(ii). That figure, if either reduced or augmented in accordance with the ASOHNS Guidelines, then becomes the percentage of diminution of hearing. This interpretation gives work to all parts of s 91(4).

The ASOHNS Guidelines are approved for the use of medical assessors. They are not to be interpreted as if they were statutory provisions. They inform the statutory method for assessing impairment but do not themselves prescribe a method. They are directed at the manner of assessment. The manner considers the use of the NAL Procedure and the use of the AMA Guides where each are relevant. The ASOHNS Guidelines do not remove the AMA Guides from all consideration. The specific reference to the AMA Guides does incorporate them in a limited fashion. The description identifies the ways that the effect of tinnitus is permitted within an ENT impairment assessment and those that are beyond it. A plain reading of the ASOHNS Guidelines in my opinion does not limit the effect of tinnitus on the hearing function of the ear to that recorded by a pure tone audiogram.[20]

1. Having concluded favourably to Mr Scardamaglia that the ASOHNS Guidelines incorporated the AMA Guides in a limited fashion, the judge then rejected an alternative argument made by Mr Scardamaglia that tinnitus is not included in a determination of the percentage of diminution of hearing under s 91(4), but falls to be assessed under s 91(1) using the AMA Guides.[21] Mr Scardamaglia did not file any notice of contention in this Court in respect of the rejection of this argument and appeared in his written case in this Court to accept her Honour's rejection of this alternative argument.
2. The judge concluded the Reasons by saying:

[I]n answering [question (a)], the Panel erred by failing to consider the effect of tinnitus on the hearing function of the ear as provided for by the ASOHNS Guidelines. The ASOHNS Guidelines referred to the ENT assessment under Chapter 9 of the AMA Guides, which remains relevant on the question of any specific allowance to be made for tinnitus in the presence of hearing loss. That measurement is informed by the severity of the condition and the degree to which it interferes with the hearing function of the ear. It permits an additional allowance of up to 5% before conversion to WPI. Under s 91(4) of the Act, that allowance would form part of the percentage diminution of hearing, together with other adjustments to the NAL Procedure required by application of s 91(4)(a)(ii).

Accordingly, in conducting its assessment for industrial deafness, the Panel should have made any additional allowance of up to 5% for the effect of tinnitus as it considered appropriate, in addition to the binaural loss of hearing assessed and determined in accordance with the NAL Procedure. This overall figure constitutes the percentage of diminution of hearing in accordance with s 91(4) of the Act, and it is this figure that should be converted to a degree of whole person impairment in accordance with the formulae in s 91(3) of the Act.[22]

1. The employer contended that, contrary to the conclusion reached by the judge, the plain words of the ASOHNS Guidelines do not prescribe the use of the AMA Guides in the assessment of tinnitus. To the contrary, properly construed, the ASOHNS Guidelines did not incorporate, or permit regard to be had to, the AMA tinnitus paragraphs or any other part of the AMA Guides. In support of these contentions, the employer made the following submissions:

(1) The ASOHNS Guidelines were written by expert medical practitioners, and 'should not be overlaid with legalistic interpretation'.[23]

(2) It is of 'paramount importance' to be faithful to the plain words of the ASOHNS Guidelines.[24]

(3) Section 91(1) of the Act provides that, with respect to most injuries, the assessment of the resulting degree of impairment is made in accordance with the AMA Guides. Sections 91(3) and (4), however, prescribe a different, stand-alone and self-contained methodology, displacing the use of the AMA Guides (and in particular Chapter 9.1) in the assessment of hearing impairments. Thus, the legislative context in which the ASOHNS Guidelines are effected demonstrates that the AMA Guides have no part to play in the assessment of hearing impairments.

(4) A plain reading of the ASOHNS Guidelines does not incorporate Chapter 9 of the AMA Guides 'in a limited fashion',[25] or otherwise.

(5) Properly construed, the ASOHNS Guidelines confirm that the effect of tinnitus on the function of hearing is already taken into account by the assessment carried out in accordance with the ASOHNS Guidelines. Therefore, any assessment of tinnitus under Chapter 9 of the AMA Guides would result in a duplication of the assessment conducted in accordance with the ASOHNS Guidelines. In the alternative, even if the reference to 'that evaluation of hearing' at the end of the first of the ASOHNS tinnitus paragraphs relates to an evaluation conducted under the AMA Guides, it cannot be said that there is any express incorporation of the AMA Guides.

(6) If the purpose of the ASOHNS tinnitus paragraphs was to incorporate or engage the AMA tinnitus paragraphs (or any part of Chapter 9), one would expect that to have been made plain in the ASOHNS Guidelines - both in respect of which part or parts of the AMA Guides might be relevant, and also how any interaction with the ASOHNS Guidelines would operate. While the ASOHNS Guidelines set out various other issues that might be raised in an assessment, in each such case, the Guidelines included some explanation or direction as to the procedure to be followed. The absence of any such explanation or direction in relation to tinnitus tells against any incorporation of the AMA tinnitus paragraphs.

(7) The language in Chapter 9 of the AMA Guides differs materially from that used in ss 91(3) and (4) of the Act and the ASOHNS Guidelines. The various descriptors 'a binaural loss of hearing', 'the percentage of diminution of hearing', and 'percentage loss of hearing', used in the Act and the ASOHNS Guidelines, are not interchangeable with the terms used in the AMA Guides - the AMA Guides using the language of hearing 'impairment', which is then converted to a Whole Person Impairment. Specifically, the differences in terminology reflected the different procedures for the assessment of hearing loss in the AMA Guides and ASOHNS Guidelines. It follows that the additional allowance of up to 5 per cent referred to in the AMA Guides cannot simply be aggregated with a binaural loss of hearing assessed and determined in accordance with the NAL Procedure. These percentages are 'incommensurable'.

(8) The ASOHNS Guidelines confirm that the percentage loss of hearing is determined by the use of the NAL Procedure. While parts of the ASOHNS Guidelines provide direction to the examiner in the proper use of the NAL procedure, nothing in the ASOHNS Guidelines permits modification of the percentage loss of hearing after it has been determined in accordance with the NAL Procedure.

1. Mr Scardamaglia submitted that the orders made by the judge were correct for the reasons given in the Reasons. He then made submissions which he described as 'ancillary and supplementary to her Honour's judgment'.
2. Mr Scardamaglia submitted that tinnitus is not, and cannot be, properly accounted for solely within the NAL Procedure. He submitted that s 91(4)(a)(ii) 'must also have force which in turn requires further considerations that may be raised as part of the assessment of compensable permanent impairment of the ear (scil, diminution of hearing)'. He then said:

It can therefore immediately be seen that there is a real and clear distinction between on the one hand, the percentage loss of hearing assessed by the NAL Procedure, and any assessment made under the ASOHNS Guidelines, which must also form part of the overall assessment of permanent impairment of the ear.

1. Mr Scardamaglia submitted that, while the NAL Procedure dictates some of the relevant considerations for a percentage hearing loss, the ASOHNS Guidelines address a number of issues that may be raised as part of the assessment. Those issues included the need to consider pathological disorders, the use of presbycusis correction tables, and other matters, including the considerations referred to in the ASOHNS tinnitus paragraphs.
2. Next, Mr Scardamaglia submitted that, properly construed, the second sentence of the first of the ASOHNS tinnitus paragraphs referred to the effect of tinnitus on hearing generally, together with any effect of it on the pure tone audiogram, as having to be accounted for in the evaluation of hearing conducted in accordance with the entirety of Chapter 9 of the AMA Guides. Such an evaluation includes, as the AMA Guides state, the possibility of a separate additional allowance for tinnitus, where the tinnitus (in the presence of unilateral or bilateral hearing loss) may impair speech discrimination. He submitted that, in such a case, the mere application of the NAL Procedure may understate the percentage diminution of hearing required to be assessed in the manner approved by the Minister - namely, by using the ASOHNS Guidelines mandated by the Approval.
3. Finally, Mr Scardamaglia submitted that the judge correctly construed and analysed s 91(4) by ensuring that s 91(4)(a)(ii) was given operative effect. Relying upon the proposition that, in interpreting a statutory provision, a court should strive to give meaning to every word of the provision, Mr Scardamaglia submitted that a plain reading of the ASOHNS Guidelines required any diminution of hearing caused by tinnitus to be taken into account in the calculation of the percentage of diminution of hearing assessed in accordance with s 91(4) of the Act.

General principles for interpreting the ASOHNS Guidelines

1. In Heinz,[26] Kyrou J, in considering the AMA Guides as they fell to be applied under s 91(1) of the Act, said in respect of their interpretation:

The interpretation of the Guides is a question of law. The determination of a level of impairment is a question of fact.

It has been said that to the extent that an Act requires determinations of impairment to be made in accordance with the Guides, the Guides has the force of law and is a legislative document.

However, the Guides is, as its title suggests, a guide. It was written by expert medical practitioners and not by statutory draftspeople, and should not be overlaid with legalistic - or a lawyer's precise - interpretation. It is of paramount importance to be faithful to the Guides' plain words. The Guides should not be interpreted as if it was a statute.

The use of the Guides is designed to promote precision, certainty and consistency. Its purpose is to make as objective as possible the process of estimating impairment by reference to sufficient medical and non-medical information to justify the estimate.

If there is any inconsistency between the AC Act and the Guides, the AC Act will prevail. If there is any inconsistency between the text in the Guides and an example which seeks to illustrate what is said in the text, the text will prevail.[27]

1. The observations made, and conclusions drawn, by Kyrou J in relation to the AMA Guides are apposite in considering the ASOHNS Guidelines. While the ASOHNS Guidelines are not to be interpreted as if they were statutory provisions, they form an integral part of the statutory scheme under the Act and should be interpreted according to the same principles as those applied in Heinz with respect to the AMA Guides.[28]

1. The issue in this proceeding is a narrow one. The employer accepts that the medical panel did not make any separate allowance for an impairment or diminution of hearing arising from tinnitus, and that it did not apply the AMA Guides (more particularly, the AMA tinnitus paragraphs) in its assessment of Mr Scardamaglia's diminution of hearing. The narrow issue between the parties is whether the panel erred in this approach.
2. While (as we have said) Mr Scardamaglia filed no notice of contention in this Court seeking to invoke the operation of s 91(1) of the Act, in oral argument he appeared, at one stage, to suggest that, by applying the AMA Guides except in so far as they are inconsistent with the NAL Procedure and the ASOHNS Guidelines, s 91(1) had a role to play in the assessment of his tinnitus. In circumstances where the employer was not on notice of that argument, we decline to entertain it. We proceed on the basis accepted by the judge, namely that the assessment of Mr Scardamaglia's percentage diminution of hearing (including that caused by any tinnitus) fell to be assessed in accordance with s 91(4) of the Act.
3. Section 91(4) of the Act requires the percentage of diminution of hearing to be assessed as a binaural loss of hearing, determined in accordance with the NAL Procedure and in the manner provided in the ASOHNS Guidelines. The narrow issue described above falls to be determined by the proper construction and application of the ASOHNS Guidelines in the context of the legislative scheme of which they are a part.
4. In the preamble of the ASOHNS Guidelines, the purpose of the Guidelines is stated to be:

... to assist hearing loss assessors in assessing compensable hearing loss and the resulting permanent impairment.

1. The ASOHNS Guidelines contain statements which are prescriptive, statements which are suggestive of particular approaches, recommendations and statements of an advisory nature. Plainly, the audience for whom they were primarily written is medical practitioners with expertise in the assessment of hearing loss. Bearing in mind the readership to which it is directed, the document assumes a certain amount of specialist knowledge. On its face, one can see that the document is not sufficiently detailed to permit a person with no relevant medical qualifications to assess a diminution of hearing, even if they were provided with all the necessary equipment.
2. As we have already observed, the ASOHNS tinnitus paragraphs appear under the heading, 'Other considerations'. Under that heading, there is an additional section dealing with acoustic shock syndrome. In respect of acoustic shock syndrome, it is said that any hearing loss is assessed as described in an earlier section of the document. As with the section on tinnitus, there is also a reference to a psychological response not relevant to the assessment of any diminution of hearing.
3. A fair reading of the ASOHNS Guidelines suggests that tinnitus and acoustic shock syndrome are issues ('other considerations') that may be relevant in the assessment of hearing loss. The document then leaves it to the expert medical assessor to give appropriate consideration to those issues, in a way that is otherwise consistent with the balance of the document.
4. The critical passage of the ASOHNS Guidelines for the purposes of this proceeding is in the first of the ASOHNS tinnitus paragraphs. In that paragraph, the reader is immediately referred to 'The Fourth Edition of the AMA Guides'. While the AMA Guides are not described with greater particularity in that paragraph, they are identified with greater precision in the list of source materials at the end of the Guidelines as:

Guides to the Evaluation of Permanent Impairment. Fourth Edition.

American Medical Association.

1. The first sentence of the ASOHNS tinnitus paragraphs then narrows the reference to the AMA Guides to that part 'relevant to ENT Impairment assessment', stating that 'the AMA Guides relevant to ENT Impairment assessment refers only to the effects of tinnitus on the function of the ear'. The next sentence ('This means the effect of tinnitus on hearing and any effect on pure tone audiogram will be accounted for in that evaluation of hearing') acknowledges that tinnitus may have an effect on hearing and an effect on pure tone audiogram - both of which effects 'will be accounted for' in the evaluation of hearing conducted in accordance with the AMA Guides. The contrary submission made by the employer, that the reference to 'that evaluation of hearing' in the second sentence of the ASOHNS tinnitus paragraphs is a reference to an assessment carried out in accordance with the ASOHNS Guidelines, is untenable for the reasons that follow.
2. In oral argument, the employer submitted that 'that evaluation of hearing' referred to in the second sentence of the ASOHNS tinnitus paragraphs was a reference to an evaluation conducted using only a pure tone audiogram. That submission must be rejected. The relevant sentence commences with a statement that tinnitus has an effect on hearing and an effect on pure tone audiogram. Logically, the effect of tinnitus on hearing cannot be entirely coextensive with its effect on the pure tone audiogram; otherwise, the authors of the ASOHNS Guidelines would not have referred to both effects. It is then difficult to see how both the effect on hearing and the effect on pure tone audiogram could sensibly be said to be accounted for by an evaluation of hearing that involves the use of a pure tone audiogram alone. The employer's construction would treat the second sentence of the ASOHNS paragraphs as stating, illogically, that the effect of tinnitus on the pure tone audiogram will be accounted for in the pure tone audiogram. The better construction of the ASOHNS Guidelines appears to us to be that the effect of tinnitus on both hearing and the pure tone audiogram will be accounted for in the evaluation referred to in the AMA tinnitus paragraphs including the pure tone audiogram.
3. The employer correctly submitted that there is no express incorporation of the AMA Guides in the ASOHNS Guidelines, nor any express statement that any part of the AMA Guides is to be applied as part of the assessment of compensable hearing loss. To find those absences determinative, however, would be to take an impermissibly legalistic approach to a document written by expert medical practitioners, not by lawyers drafting legislation.[29] While the ASOHNS Guidelines are a legislative instrument,[30] they need to be considered by reference to the attributes and qualifications of both the writers and those for whom they were written, and the purpose for which they were written.
4. The purpose of ss 91(3) and (4) of the Act is to provide for the assessment of a worker's work-related percentage diminution of hearing, which percentage is then to be converted into a whole person impairment for the purposes of determining what (if any) compensation is payable to the worker under the Act. Clearly, a construction of the ASOHNS Guidelines, as they now form part of the legislative scheme provided for in the Act, which results in the assessment of the entirety of a worker's percentage diminution of hearing is to be preferred over a construction which would involve some part of a work-related diminution of hearing being ignored, or not assessed.
5. The ASOHNS Guidelines note the possibility of an effect of tinnitus on hearing which is additional to an effect of tinnitus on a pure tone audiogram. In context, this additional effect of tinnitus on hearing is not some unspecified enhancement of hearing; but rather, it must be a diminution of hearing. That issue is put beyond doubt when one reads the AMA tinnitus paragraphs, to which the reader of the ASOHNS Guidelines is referred in the first of the ASOHNS tinnitus paragraphs. The relevant effect of tinnitus, in the presence of unilateral or bilateral hearing loss, is the possible impairment of speech discrimination - a circumstance which could only be said to be a diminution of hearing - which may not have been accounted for on a pure tone audiogram. It is in those circumstances that an assessor is given the discretion (to be exercised in his or her independent expert opinion) to add to the impairment percentage, found by reference to the other provisions of the ASOHNS Guidelines, a further amount of up to 5 per cent for such a diminution of hearing.
6. Undoubtedly, the ASOHNS Guidelines could have been written in a more prescriptive manner, directing expert assessors step by step through a process to an ultimate conclusion. As we have already observed, however, it must steadily be borne in mind that the document was written by medical experts for use by other medical experts, and for the purpose of assisting hearing loss assessors assessing the actual compensable hearing loss suffered by those being assessed. The reference to the AMA Guides in the ASOHNS Guidelines should not be regarded as mere surplusage to be ignored in the assessment under the Guidelines. The reference is there to enable the expert assessor to consider whether or not the diminution of hearing assessment needs to take account of a diminution of hearing that might not be fully accounted for in a pure tone audiogram.
7. It follows from what we have said above that the judge was correct when she concluded that the medical panel erred when it failed to consider the effect of tinnitus on Mr Scardamaglia's hearing as provided by the ASOHNS Guidelines.[31] That said, we would make the following additional observations with respect to the employer's submissions:

(1) Contrary to the employer's submissions, the construction we prefer does not involve any duplication in the assessment of diminution of hearing. An expert assessor is given the discretion to add a percentage (up to 5 per cent) for any additional diminution of hearing caused by tinnitus, which diminution is over and above any diminution of hearing that may have been accounted for on the pure tone audiogram.

(2) The differences in language between the AMA Guides and the Act, on the one hand, and the ASOHNS Guidelines, on the other hand, are of little (if any) moment. Sections 91(3) and (4) refer to 'the percentage of the diminution of hearing' which must then be converted into a 'degree of impairment'. The 'percentage diminution of hearing' referred to in the Act and the ASOHNS Guidelines is the 'percentage hearing impairment' referred to in the AMA Guides; and the 'degree of impairment' referred to in s 91(3) of the Act is the 'degree of impairment of the whole person' referred to in the AMA Guides. There are no relevant distinctions between these terms, and no basis for contending that the percentage diminution in hearing obtained using the NAL Procedure in accordance with the ASOHNS Guidelines cannot be aggregated with an additional percentage hearing loss assessed in accordance with the AMA tinnitus paragraphs.

(3) The fact that there is a different assessment regime for impairments other than diminutions of hearing which are governed by the application of the AMA Guides does not tell against a construction of the ASOHNS Guidelines which permits or requires an assessor to have regard to a relevant part of the AMA Guides, provided that such a construction does not conflict with the text of ss 91(3) and (4) of the Act. The construction we favour permits the limited reference to the AMA Guides in the circumstances we have discussed.

(4) While s 91(4)(b) requires the percentage of diminution of hearing to be determined in accordance with the NAL Procedure, the references to 'NAL' in s 91(3) are, as the section specifically provides, references to the percentage of diminution of hearing determined in accordance with s 91(4) - not merely the product of the application of the NAL Procedure. That is, the references to 'NAL' in s 91(3) are references to the result arrived at by the performance of an assessment using the NAL procedure in the manner described in the ASOHNS Guidelines.

1. While the issue in this case is sufficiently arguable to justify a grant of leave to appeal, the appeal must be dismissed.

[1] Scardamaglia v Amcor Pty Ltd [2023] VSC 114, [65]-[66] ('Reasons').

[3] See s 5(2) of the Act and s 3 of the Workplace Injury Rehabilitation and Compensation Act 2013. Those sections also define 'injury' in the Act to include 'industrial deafness'.

[4] See s 5(2) of the Act and s 3 of the Workplace Injury Rehabilitation and Compensation Act 2013.

[5] While s 91(4)(b) refers to the possibility of a later prescribed edition, it is common ground that the relevant edition in this case is the 1988 edition.

[7] See question (a) of the medical questions.

[8] See ss 91(3) and (4) of the Act.

[9] Noble WG, Assessment of Hearing Loss and Handicap in Adults. New York, NY: Academic Press; 1978.

[11] As to which, see s 91(3).

[23] See HJ Heinz Company Australia Ltd v Kotzman [2009] VSC 311, [26] ('Heinz').

[26] [2009] VSC 311.

[27] Ibid [24]-[28] (citations omitted). See also Victorian WorkCover Authority v Elsdon [2013] VSCA 235; (2013) 42 VR 434, 446-7 [49].

[28] See generally, Paschalis v Return to Work Corporation of South Australia (2021) 140 SASR 77, 129 [212].

[29] See Heinz [2009] VSC 311, [26].