Nguyen v Hycast Metals Pty Limited
[2021] NSWPICMP 18
•12 March 2021
| DETERMINATION OF APPEAL PANEL | |
| CITATION: | Nguyen v Hycast Metals Pty Limited [2021] NSWPICMP 18 |
| APPELLANT: | Luong Van Nguyen |
| RESPONDENT: | Hycast Metals Pty Limited |
| APPEAL PANEL: | Ms Jane Peacock Dr Brian Williams Dr Joseph Scoppa |
| DATE OF DECISION: | 12 March 2021 |
| CATCHWORDS: | WORKERS COMPENSATION- Industrial deafness; the fact that the Medical Assessor’s (MA) approach differs from that of both other experts does not mean he has erred; the MA is required to approach his assessment on an independent basis; Held- the MA clearly explained why his opinion differed; his reasons were not insufficient; considering the nature and duration of the appellant’s occupational noise exposure and the nature and extent of all the hearing losses at 0.5 – 4 kHz, it was open to the MA to find that the losses at 2000 Hz are incompatible with noise induced hearing loss; this is because industrial deafness typically causes a bilaterally symmetrical sensorineural hearing loss from low to high tones with relative sparing of the low tones in comparison to the high tones, with the maximal loss occurring at 4000 and 3000 Hz; thus in industrial deafness the hearing loss at 2000 Hz would be expected to be significantly less severe than the losses at 3000 Hz and 4000 Hz, and this is not the case in the MA’s audiogram, or in the other prior audiograms dating back to 2014 at which time he had 25 years of occupational noise exposure; MAC upheld. |
STATEMENT OF REASONS FOR DECISION OF THE APPEAL PANEL IN RELATION TO A MEDICAL DISPUTE
BACKGROUND TO THE APPLICATION TO APPEAL
On 4 December 2020 Mr Luong Van Nguyen (the appellant) lodged an Application to Appeal Against the Decision of Approved Medical Specialist. The medical dispute was assessed by Dr Henley C Harrison, a Medical Assessor (MA), who issued a Medical Assessment Certificate (MAC) on 6 November 2020.
The appellant relies on the following grounds of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (1998 Act):
· the MAC contains a demonstrable error.
The delegate is satisfied that, on the face of the application, at least one ground of appeal has been made out. The Appeal Panel has conducted a review of the original medical assessment but limited to the ground(s) of appeal on which the appeal is made.
The Workers compensation medical dispute assessment guidelines set out the practice and procedure in relation to the medical appeal process under s 328 of the 1998 Act. An Appeal Panel determines its own procedures in accordance with the Workers compensation medical dispute assessment guidelines.
The assessment of permanent impairment is conducted in accordance with the NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4th ed 1 April 2016 (the Guidelines) and the American Medical Association Guides to the Evaluation of Permanent Impairment, 5th ed (AMA 5).
PRELIMINARY REVIEW
The Appeal Panel conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Workers compensation medical dispute assessment guidelines.
As a result of the Appeal Panel’s preliminary review, the Appeal Panel determined that it was not necessary for the worker to undergo a further medical examination.
EVIDENCE
Documentary evidence
The Appeal Panel has before it all the documents that were sent to the MA for the original medical assessment and has taken them into account in making this determination.
Medical Assessment Certificate
The parts of the medical certificate given by the MA that are relevant to the appeal are set out, where relevant, in the body of this decision.
SUBMISSIONS
Both parties made written submissions. They are not repeated in full but have been considered by the Appeal Panel.
FINDINGS AND REASONS
The procedures on appeal are contained in s 328 of the 1998 Act. The appeal is to be by way of review of the original medical assessment but the review is limited to the grounds of appeal on which the appeal is made.
In Campbelltown City Council v Vegan [2006] NSWCA 284 the Court of Appeal held that the Appeal Panel is obliged to give reasons. Where there are disputes of fact it may be necessary to refer to evidence or other material on which findings are based, but the extent to which this is necessary will vary from case to case. Where more than one conclusion is open, it will be necessary to explain why one conclusion is preferred. On the other hand, the reasons need not be extensive or provide a detailed explanation of the criteria applied by the medical professionals in reaching a professional judgement.
The following matter was referred for assessment (s 319 of the 1998 Act):
· Date of injury: 3 September 2018 (deemed date)
· Body parts/systems referred: Binaural hearing loss
· Method of assessment: Whole person impairment
The MA issued a MAC certifying his assessment as follows:
Injury deemed to have happened on: Frequency Hz Left dB HL
Air Bone %
Right dB HL
Air Bone %Total % BHI Occupational % BHI 3.9.2018
(deemed)500 65 >60 14 100 >60 20 15 0 1000 65 >60 17.5 85 >70 23.9 18.6 0 1500 75 >70 16.9 90 >70 19.7 17.6 0 2000 85 >70 14.3 95 >70 20 14.5 0 3000 85 >70 9.5 115 >70 10 9.6 9.5 4000 75 70 8.2 110 >70 10 8.7 8.2 80.4 103.6 18.7 TOTAL % BHI: 84.0% Less Pre-existing non-related loss: 65.3% Less Presbyacusis correction: 0% Add % of severe tinnitus: 0& Adjusted total % BHI: 18.7% Resultant total BHI of 18.7% = 10% whole person impairment (Table 9.1)
The worker appealed.
In summary, the appellant submitted on appeal as follows:
(a) the deduction for an unrelated hearing loss is excessive notwithstanding the ear infection on the right side, and
(b) the MA has failed to provide adequate reasons in explaining the deduction for non-related hearing loss.
In summary, Hycast Metals Pty Ltd (the respondent) submitted that the MA had not made any demonstrable errors and the MAC should be confirmed.
The role of the MA is to conduct an independent assessment on the day of examination. The MA is required to take a history, conduct a physical examination including an audiogram, review the special investigations, make a diagnosis and have due regard to other evidence and other medical opinion that is before the MA. The MA must bring his clinical expertise to bear and exercise his clinical judgement when making an assessment of impairment and make such assessment in accordance with the criteria in the Guides.
The MA took a history as follows:
“• Brief history of the incident/onset of symptoms and of subsequent related events, including treatment: During his time with the Respondent, Hycast Metals Pty Ltd, the worker was exposed to loud noise with the potential to damage hearing. He has had difficulty hearing since 2004 and watery discharge from the right ear particular for a long time. Treatment has consisted of a right ear operation by Dr M Chin in 2017 and the wearing of hearing aids for about the last five years.
· Present treatment: As stated above the worker wears hearing aids and wore them for the telephone assessment and most of the in person assessment except for the audiometry. He said that he cannot hear without them.
· Present symptoms: The worker has trouble hearing–family friends and other people and, as stated above has to have his hearing aids in or he cannot hear people. The hearing is worse on the right side and is worse in group conversations and background noise. He also has some tinnitus when his hearing aids are in but this has been less since his ear operation and does not seem to trouble him much. In addition, he has watery ear discharge, mainly from the right ear but this has been less since the operation. It is increased by his wearing his hearing aids.
· Details of any previous or subsequent accidents, injuries or condition: Other than possible previous occupational noise exposure in a factory in Cabramatta (see below), there are no previous or subsequent accidents, injuries or conditions.
· General health: The worker appears to be in good health but did have a left parotidectomy in 2004. This however would not have affected hearing and apart from the right ear operation mentioned above, there is nothing relevant to the claim. In particular, there is no other history of previous ear disease, no history of familial deafness, none suggestive of exposure to ototoxic (hearing-damaging) medication and none of significant head injury.
· Work history including previous work history if relevant: The worker came to Australia from his native Laos in 1987. Back there he worked as an apprentice jeweller and was not exposed to loud noise.
In about 1988, he worked for one year in a factory at Cabramatta. I note that his statement which I went over fully with him says that he worked as a process worker but he said that he was a supervisor and contrary to what the statement says, he said that it was not very noisy. So it is not clear to me whether this first job in NSW exposed him to loud noise but certainly the next job with the respondent does seem to have.
He has worked for the respondent since September 1989 until the present time as a process worker until about the last one year when he became a supervisor but still exposed to loud noise. He confirmed that there was a lot of noise from welding, hammering and grinding during most of the working day. This would have had the potential to damage hearing over an eight hour working day. Initially he worked about 10 hours a day, five or sometimes six days a week but now works eight hours a day five days a week. He wears hearing protection – previously plugs but now muffs.
· Social activities/ADL: Apart from the effects of his deafness as described under ’present symptoms’ on his activities of daily living, he avoids noisy or crowded places such as clubs or pubs because of his increased difficulty understanding speech in such circumstances.
He has done no military service and has no noisy pastimes.”
The MA undertook a physical examination and recorded his findings as follows:
“Due to the current Covid-19 pandemic the examination was confined to essentials – an assessment of the ability to understand speech and examination of the ears.
On examination, both eardrum membranes were scarred but appeared to be intact. There was an almost invisible scar behind the right pinna (ear flap) which was consistent with the surgery in 2017.The interpreter, Ms Ngo was able to converse satisfactorily with him with a normal speaking voice over the telephone.”
The audiogram was performed on the day of examination by a qualified audiologist and reviewed by the MA as follows:
“Audiometry was performed on the day of assessment in a quiet environment in a suitable sound proofed booth using a calibrated audiometer. The audiogram was performed by my audiologist, /Mrs Monica Summers a qualified audiologist whose qualifications are: BA DipEd, DipAud, MAud, MAudSA (CC) Clinical Audiologist. Prior to the audiogram being performed, I ascertained that the worker had not been exposed to loud noise in the last 16 hours. The audiogram showed a bilateral deafness, sensorineural on the left side and probably mixed (both conductive and sensorineural) on the right side; I use the word ‘probably’ because the amount of hearing loss was so great that masked bone conduction could not be used - however the appearance of the audiogram and the history of middle ear disease on the right side suggests strongly that there is conductive deafness on that side. The total binaural hearing impairment (BHI) derived from this audiogram is 84.0%. A copy of the audiogram accompanies this report. Please note however that not all of this deafness is occupational deafness (‘industrial deafness).”
The MA summarised his diagnosis as follows:
“• summary of injuries and diagnoses
Bilateral sensori-neural deafness partly due to occupational deafness and partly due to another cause or causes probably at least partly constitutional.
· consistency of presentation
The history, examination and audiogram are consistent with only some of the hearing loss being industrial deafness (an accurate audiogram was easily obtained).”
The MA was of the opinion that “although the worker has been exposed to significant occupational noise not all of the deafness can be due to occupational noise exposure”. He explained his opinion as follows:
“The audiogram shows significantly worse hearing loss on the right side which is not consistent with occupational hearing loss because such hearing loss is usually fairly symmetrical. I have therefore apportioned the occupational hearing loss to the amount of hearing loss affecting the left side. Even on the left side the audiogram is not wholly consistent with occupational hearing loss because the profile of the audiogram in this case is fairly flat; in occupational hearing loss there should be a significant progressive increase in hearing loss with increase in frequency so that the profile of the audiogram slopes downward from left to right, usually with a convex curve upwards. In this case the frequencies 2000 and 3000 on the left side are affected equally and there is little difference between 1500 cps and 3000 cps (10 dB is minimal difference); so the profile of the audiogram below 3000 cps is not consistent with occupational hearing loss even on the left side. I have therefore apportioned the occupational hearing loss to the frequencies 3000 cps and above on the left side.
This apportionment gives 18.7% BHI of occupational hearing loss.
No deduction for presbycusis is appropriate so I have not made any.
The worker does not suffer from severe tinnitus so I have not made an allowance for it.
The above give a resultant total BHI of 18.7% which equals 10% whole person impairment.”
The MA explained his calculations as follows:
“The non-related loss is the difference between the total BHI (84.0%) and the noise induced hearing loss (18.7%); it is therefore 65.3%.”
A MA is required to make an independent assessment on the day of examination. He is not bound to follow the opinions of the other experts whose reports are in evidence before him. Here the MA has clearly had regard to the other medical opinions and explained why his opinion differs as follows:
“The report by Dr Howison dates from 2016 so it is not current. I note that he apportioned the occupational hearing loss to the frequencies 2000 cps and above on the left side. I also note that there is very little difference in the hearing loss on that side between 1000 cps and 4000 cps. I believe that it would have been more appropriate if he had made a similar frequency apportionment to mine.
The report by Dr Seymour dates from 2018 so it also is not really current. I believe that the comments that I have made about the apportionment by Dr Howison also apply to the report by Dr Seymour.”
The appellant has a non-occupational non-noise induced hearing loss component in the right ear because industrial deafness is generally bilaterally symmetrical, affecting both ears to more or less the same extent.
For this reason the MA has used the audiological results from the left ear to assess occupational hearing loss in both ears. This is the same approach the other experts (Dr Howison and Dr Seymour) took. To assess impairment from noise induced hearing loss, the MA took into account the losses at 3000 Hz and 4000 Hz on the left side. That is, he excluded the losses at 2000Hz and below. The MA’s approach differs from that of the other experts because Dr Howison included the loss at 2000Hz and excluded the losses at 1500Hz and below, and Dr Seymour included the losses at 2000Hz and 1500Hz. The fact that the MA’s approach differs from that of both other experts does not mean he has erred. The MA is required to approach his assessment on an independent basis. The MA clearly explains why his opinion differs. His reasons are not insufficient. The Panel notes that in this matter, considering the nature and duration of the appellant’s occupational noise exposure and the nature and extent of all the hearing losses at 0.5 – 4 kHz, it was open to the MA to find that the losses at 2000 Hz are incompatible with noise induced hearing loss. This is because industrial deafness typically causes a bilaterally symmetrical sensorineural hearing loss from low to high tones with relative sparing of the low tones in comparison to the high tones, with the maximal loss occurring at 4000 and 3000 Hz. Thus in industrial deafness the hearing loss at 2000 Hz would be expected to be significantly less severe than the losses at 3000 Hz and 4000 Hz, and this is not the case in the MA’s audiogram, or in the other prior audiograms dating back to 2014 at which time he had 25 years of occupational noise exposure.
The Panel can therefore find no error in the MA’s approach in excluding the losses at 2000Hz and below. Accordingly the MAC will be confirmed.
For these reasons, the Appeal Panel has determined that the MAC issued on 6 November 2020 should be confirmed.
Jane Peacock
Member
Dr Brian Williams
Medical Assessor
Dr Joseph Scoppa
Medical Assessor
12 March 2021