1. On 29 July 2025 the Byron Shire Council, the appellant, lodged an Application to Appeal Against the Decision of a Medical Assessor. The medical dispute was assessed by

Dr Himanshu Singh, a Medical Assessor, who issued a Medical Assessment Certificate (MAC) on 1 July 2025. 2. The appellant relies on the following grounds of appeal under s 327(3) of the Workplace Injury Management and Workers Compensation Act 1998 (the 1998 Act): * the assessment was made on the basis of incorrect criteria, and * the MAC contains a demonstrable error. 3. 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. 4. Rule 128 of the Personal Injury Commission Rules 2021 (the PIC Rules) and Procedural Direction PIC7 - Appeals, reviews, reconsiderations and correction of obvious errors in medical disputes 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 r 128(1) of the PIC Rules. 5. The assessment of permanent impairment is conducted in accordance with the SIRA NSW Workers Compensation Guidelines for the Evaluation of Permanent Impairment, 4th ed

1. The appellant employed Craig Bridge, the respondent, as a community enforcement coordinator from January 2021. The respondent's last day of work for the appellant was on 22 September 2023. Due to several matters that occurred during his employment the respondent suffered a psychological injury that has been variously diagnosed as post-traumatic stress disorder and major depressive disorder.
2. The respondent claimed compensation from the appellant's insurer for permanent impairment from his injury. He relied on a report of psychiatrist Dr Richa Rastogi dated

1 September 2024 that his solicitors had obtained and wherein Dr Rastogi advised she diagnosed the respondent's injury as post-traumatic stress disorder and further advised she assessed the degree of the respondent's permanent impairment from his injury as 22% whole person impairment (WPI). Dr Rastogi noted within her report that the respondent had a previous history of post-traumatic stress disorder for which he had been treated with psychological counselling and from which he had made a "recovery". Dr Rastogi did not make any deduction when assessing the degree of the respondent's permanent impairment from his injury for any proportion of the respondent's permanent impairment due to his prior history of post-traumatic stress disorder. It can be inferred therefore that Dr Rastogi considered that the respondent's prior post-traumatic stress disorder did not contribute to the respondent's permanent impairment from the injury he suffered due to his employment with the appellant. 3. The Appeal Panel observes at this point that the respondent was previously employed between 1990 and 2010 by the State of New South Wales as a police officer. He suffered an injury in the form of post-traumatic stress disorder due to matters that occurred within that employment. He instituted proceedings in the former Workers Compensation Commission (WCC) seeking the WCC determine a disputed claim he had made against the State of New South Wales for compensation for permanent impairment from that injury. The WCC referred the matter to Approved Medical Specialist Dr Robert Gertler who assessed the respondent's permanent impairment from the injury he suffered from his employment as a police officer resulted in his having a degree of permanent impairment of 17% WPI. 4. Returning to the narrative regarding the respondent's current claim, the appellant denied it was liable to pay compensation to the respondent for permanent impairment. It relied on a report its solicitors obtained from psychiatrist Dr Abhishek Nagesh dated 22 January 2025. Dr Nagesh diagnosed the respondent's injury as post-traumatic stress disorder and major depressive disorder. Dr Nagesh assessed the degree of the respondent's permanent impairment from those psychiatric illnesses as 24% WPI. Dr Nagesh however considered that 40% of this permanent impairment is due to the respondent's pre-existing post-traumatic stress disorder and hence made a deduction of that order when assessing the degree of the respondent's permanent impairment from his injury due to his employment with the appellant. Hence, Dr Nagesh advised in his report he assessed the degree of the respondent's permanent impairment from his injury with the appellant is 14% WPI. That is beneath the threshold imposed by s 65A(3) of the Workers Compensation Act 1987 for a worker to be entitled to compensation for permanent impairment from a psychiatric injury, and hence the appellant's refusal of the respondent's claim. 5. Following that, the respondent instituted proceedings in the Personal Injury Commission (Commission) by lodging an Application to Resolve a Dispute dated 25 March 2025. The matter found its way to Member Glenn Capel to deal with preliminary issues. The Commission issued a Certificate of Determination that was amended on 16 June 2025 recording determinations that Member Capel made with the parties' consent, one of which included that the matter be remitted to the President for referral to a Medical Assessor to assess the degree of the respondent's permanent impairment from his injury. A delegate of the President duly attended to that task by issuing a referral to the Medical Assessor that was amended on 23 June 2025. 6. As said, the Medical Assessor issued a MAC in response to that referral on 1 July 2025. In that he certified he assessed the degree of the respondent's permanent impairment from his injury is 24% WPI. The Medical Assessor diagnosed the respondent's injury arising from his employment with the appellant is post-traumatic stress disorder. 7. The Medical Assessor noted within the MAC that his assessment was based on his clinical interview with the respondent, his mental state examination of the respondent and documentation received "including previous IME". At the commencement of the MAC under the heading "evidence" the Medical Assessor provided very brief summaries of the reports of "independent medical experts", that included the reports of Dr Rastogi and Dr Nagesh on which the parties relied, and also a brief summary of the Medical Assessment Certificate that Approved Medical Specialist Dr Robert Gertler issued on 26 October 2010. 8. The Medical Assessor recorded within the MAC the respondent's previous diagnosis of post-traumatic stress disorder that was a consequence of his exposure to multiple traumatic events during his policing career. The Medical Assessor noted the respondent received treatment for that until 2010. The Medical Assessor noted that the respondent reported that he had recovered from his symptoms and was symptom free when he commenced his employment with the appellant. 9. The Medical Assessor did not make any deduction under s 323(1) of the 1998 Act for any proportion of the respondent's permanent impairment due to his pre-existing post-traumatic stress disorder. Indeed, at the appropriate place with the approved form for a MAC, the Medical Assessor stated that no proportion of the respondent's permanent impairment is due to his pre-existing posttraumatic stress disorder.

1. The Appeal Panel conducted a preliminary review of the original medical assessment in the absence of the parties and in accordance with the Procedural Direction PIC7.
2. As a result of that preliminary review, the Appeal Panel determined that it was not necessary for the respondent to undergo a further medical examination. This is because the material before the Appeal Panel is sufficient for it to determine the appeal.

1. The Appeal Panel has before it all the documents that were sent to the Medical Assessor for the original medical assessment and has taken them into account in making this determination.

1. Both parties made written submissions. They are not repeated in full, but have been considered by the Appeal Panel.
2. In summary, the appellant submitted that the Medical Assessor erred by not finding that a proportion of the respondent's permanent impairment from his injury is due to his pre-existing condition of post-traumatic stress disorder. The appellant submitted that the Medical Assessor failed to engage with the respondent's history and failed to engage with the evidence. The appellant referred to various pieces of the evidence that was before the Medical Assessor, including the Medical Assessment Certificate that Approved Medical Specialist Dr Gertler issued, several reports of Dr Nagesh, and the reasons for a determination that WCC Arbitrator Nicholl made in the proceedings the respondent previously issued in the WCC.
3. The appellant submitted that the Medical Assessor did not discuss the impact that the respondent's prior injury of post-traumatic stress disorder had on his current injury, including whether as a consequence of his prior injury the respondent had a vulnerability or pre-disposition to developing the injury he suffered whilst working for the appellant or increasing his impairment from that injury.
4. The appellant submitted that the Medical Assessor failed to provide any or any adequate reasons for not making a deduction for a proportion of the respondent's permanent impairment that was due to his pre-existing post-traumatic stress disorder.
5. The appellant submitted that case law establishes a principle that it does not matter whether a prior injury is asymptomatic when assessing whether the prior injury forms a proportion of a worker's permanent impairment and that a prior injury being asymptomatic does not prevent a finding that the prior injury contributes to a permanent impairment the worker has from the injury being assessed. The appellant submitted that it was "an irrelevant finding" for the Medical Assessor to make regarding the respondent's self-report of symptoms that he had recovered from his prior injury. The appellant submitted "as a matter of logic" where the respondent had been assessed as having 17% WPI due to his prior injury. His permanent impairment from that prior injury is severe and permanent.
6. The appellant submitted that a deduction "in excess of the one-tenth assumption" ought to have been made by the Medical Assessor.
7. The appellant referred to various parts of the evidence before the Medical Assessor and submitted that these revealed that the respondent was subject to non-work-related stressors during 2022 and 2023. These matters included the respondent's partner falling from a horse and fracturing a vertebra, the respondent being in a dispute with a neighbour and being in dispute with the owner corporation of the complex in which he and his partner reside, and the respondent having liver biopsies and concerns about his liver. The Appeal Panel notes that all these matters occurred contemporaneously with the respondent's employment with the appellant.
8. The appellant submitted that these matters were inconsistent with the history the Medical Assessor obtained that the respondent did not have any impairments in his function during the time he was employed with the appellant. The appellant acknowledged that it did not dispute that the respondent suffered a compensable psychological injury or that his employment with it was a main contributing factor to that injury. The appellant submitted that the evidence regarding the stressors to which the respondent was subject outside of his employment "ought to have been explored by the [Medical Assessor] in his questioning of the worker". The appellant submitted that this was a failure of the Medical Assessor and amounted to a demonstrable error in the MAC.
9. In reply, the respondent submitted that the Medical Assessor was required to apply paragraph 11.10 of the Guidelines with respect to making a deduction under s 323(1) of the 1998 Act. The respondent referred to several authorities to support that submission, specifically Matheson v Baptist Care NSW & ACT[1] at [7]-[19], Department of Education v Mansfield[2] at [25] - [26], and Quintiliani-Johns v Secretary, Department of Education[3] at [74]-[75]. The respondent submitted that it is clear from the MAC that the Medical Assessor undertook the task imposed upon him by s 323 and paragraph 11.10. The respondent noted that the Medical Assessor was aware he had reported he had no issue with his mental health when he commenced his employment with the appellant, that the Medical Assessor was also aware that he had travelled overseas during the course of his employment, and was aware of the activities he undertook with his partner. The respondent submitted that the Medical Assessor obtaining that history "patently addressed the requirements of Clause 11.10". The respondent submitted that the evidence disclosed that he had no deficit in any of the domains of the psychiatric impairment rating scale (PIRS).
10. The respondent submitted that paragraph 11.10 of the Guidelines only requires reversion to s 323(1) if pre-injury functioning cannot be assessed. The respondent submitted the evidence showed that he had recovered from his prior post-traumatic stress disorder and was able to obtain employment and live his life and he submitted there was no evidence that he was receiving any treatment or taking any medication for his prior injury.
11. The respondent submitted that his having a vulnerability of susceptibility to further relapse or aggravation of his post-traumatic stress disorder is not the equivalent of evidence that his pre-existing condition or previous injury contributes to his current impairment.
12. The respondent submitted that the non-work-related stressors to which the appellant referred do not result in any diagnoseable condition and do not contribute to the degree of his permanent impairment.

1. 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.
2. In Campbelltown City Council v Vegan [2006] NSWCA 284 the Court of Appeal held that the Appeal Panel is obliged to give reasons.
3. Section 323(1) of the 1998 Act requires a Medical Assessor when assessing the degree of a worker's permanent impairment from an injury to make a deduction for any proportion of that impairment that is due to a previous injury, pre-existing condition or abnormality. Section 323(2) of the 1998 Act requires the Medical Assessor to assume that the deductible proportion is to be 10% of the impairment if it is difficult or costly to determine what the deductible proportion is, provided making that assumption is not at odds with the available evidence. Section 323(4) of the 1998 Act permits the State Insurance Regulatory Authority (SIRA) to issue guidelines regarding how a Medical Assessor is to determine the deduction to be made under s 323(1).
4. SIRA has made such guidelines with respect to permanent impairment resulting from a psychiatric injury, and they are contained in paragraph 11.10 of the Guidelines. Therein is detailed the method a Medical Assessor must apply with respect to any deduction to be made under s 323(1). That paragraph reads as follows:

"To measure the impairment caused by a work-related injury or incident, the psychiatrist must measure the proportion of WPI due to a pre-existing condition. Pre-existing impairment is calculated using the same method for calculating current impairment level. The assessing psychiatrist uses all available information to rate the injured worker's pre-injury level of functioning in each of the areas of function. The percentage impairment is calculated using the aggregate score and median class score using the conversion table below. The injured worker's current level of WPI% is then assessed, and the pre-existing WPI% is subtracted from their current level, to obtain the percentage of permanent impairment directly attributable to the work-related injury. If the percentage of pre-existing impairment cannot be assessed, the deduction is 1/10th of the assessed WPI."

1. That paragraph, issued by SIRA pursuant to its authority under ss 323(4) and 376, is valid, and must be applied by a Medical Assessor.[4]
2. There is no controversy in this case that prior to the respondent commencing his employment with the appellant, he suffered a psychiatric injury, in the form of post-traumatic stress disorder, due to the circumstances of his employment between 1990 and 2010 with the NSW Police Force.
3. As the appellant submitted, the fact that a worker is not suffering symptoms from a previous injury or a pre-existing condition at the time the worker suffers the workplace injury in regards to which permanent impairment is being assessed, does not preclude a finding being made that the pre-existing condition or previous injury contributes to the impairment being assessed from the workplace injury. Further, it cannot be assumed that an asymptomatic condition does contribute to the impairment from the injury being assessed.[5]
4. It is also not sufficient for s 323(1) to be engaged that at the time a worker suffers a psychological injury the worker has a pre-disposition or susceptibility to developing a condition subsequent to the injury. The condition must be existing at the time the worker suffers injury for s 323(1) to be engaged with respect to that condition.[6]
5. In the Appeal Panel's view the Medical Assessor was wrong to conclude that the respondent's pre-existing post-traumatic stress disorder did not form a proportion of the permanent impairment from the psychiatric injury the respondent suffered as a consequence of his employment with the appellant, which the Medical Assessor correctly diagnosed, in the Appeal Panel's view, is post-traumatic stress disorder.
6. It is the case that the evidence, including the history the Medical Assessor obtained during his clinical interview of the respondent, reveals that at the time the respondent commenced employment with the appellant in January 2021 the respondent was not suffering any symptoms from his prior injury caused by his work with the New South Wales Police Force. That is to say that at the time at which his exposure commenced to the stressors to which he was subject in his employment with the appellant, and from which his injury precipitated, he was asymptomatic.
7. It is also the case, in the Appeal Panel's view, that the respondent's pre-existing post-traumatic stress disorder did make him vulnerable to suffering an injury of the same type because of the stressors to which he was exposed in his employment with the appellant.
8. However, his prior injury did more than that. That is, it contributes now to the impairment he suffers from the injury arising from stressors to which he was exposed in his employment with the appellant. The stressors to which he was exposed in his employment with the appellant do not meet criterion A for a diagnosis of post-traumatic stress disorder. In other words, the post-traumatic stress disorder that the respondent now suffers as a consequence to the stressors to which he was exposed in his employment with the appellant is not a fresh illness but a recurrence of the illness from which he suffered due to the stressors to which he was the subject in his employment with the New South Wales Police Service. That is to say that the injury he suffered with the New South Wales Police Service, although the symptoms from which were treated successfully, has recurred as a consequence of the stressors to which he was subject in his employment with the appellant. His prior injury has added to the severity of his symptoms he now suffers from his recurrent post-traumatic stress disorder. Saying that in a somewhat reverse way, without his prior injury the respondent's functioning with respect to the PIRS would not be as severe.
9. The Medical Assessor erred by not finding that a proportion of the respondent's permanent impairment from the injury he suffered due to his employment with the appellant is not due to the injury he suffered due to his employment with the New South Wales Police Service. That error is such that the MAC contains a demonstrable error which the Appeal Panel must correct.
10. As noted above, and as the respondent highlighted in his submissions, paragraph 11.10 of the Guidelines applies to determine what the deduction must be pursuant to s 323(1). However, the Appeal Panel does not read paragraph 11.10 of the Guidelines in the manner that the respondent submitted at [31] of his written submissions, which is that s 323(1) is only engaged if a worker's pre-injury functioning cannot be assessed. In the Appeal Panel's view s 323(2) of the 1998 Act must be engaged in the circumstance where, as here,

(a) an Appeal Panel or a Medical Assessor can assess a worker's pre-injury level of functioning in all areas of PIRS and assess that level of functioning as unimpaired, that is 0% WPI, but

(b) the worker's prior injury does contribute to the worker's current level of impairment.

That is, in such circumstance there must be a deduction of one-tenth, in accordance with s 323(2), for the proportion of the worker's permanent impairment that is due to the prior injury, if the evidence reveals that a proportion of the worker's current permanent impairment is due to the previous injury notwithstanding that the worker's pre-injury impairment from the prior injury at the time the worker suffers the subsequent injury is at that time assessed at 0%. That ensures that the final sentence of paragraph of 11.10 is read harmoniously with s 323(2). If it were otherwise, it would be inconsistent with s 323(2).

1. As the Appeal Panel has noted, and indeed as the Medical Assessor noted, the evidence reveals that the respondent was unimpaired with respect to all domains of the PIRS at the time he commenced employment with the appellant.
2. Consequently, the Appeal Panel in correcting the error the Medical Assessor made makes a deduction of one-tenth pursuant to s 323(1) of the 1998 Act for the proportion of the respondent's permanent impairment from his injury that is due to his previous injury that he suffered whilst working for the New South Wales Police Service.
3. With respect to the submission the appellant made that the Medical Assessor did not have regard to or did not properly weigh the evidence relating to "non-work stressors", which the Appeal Panel has noted occurred contemporaneously with the stressors to which the respondent was exposed and resulted in his injury, the Appeal Panel considers that the submission goes nowhere. As the appellant has acknowledged, it did not contest that the stressors to which the respondent was exposed in his employment were the main contributing factor to the occurrence of his injury, that is his post-traumatic stress disorder. The respondent has a permanent impairment from that injury. The respondent did not contend otherwise, and indeed Dr Nagesh upon whose report it relied confirmed that. The medical dispute between the parties related to the degree of the respondent's permanent impairment from that injury and whether any proportion of his permanent impairment is due to a previous injury, but to repeat there was no dispute that the respondent suffered a compensable injury in the form of a post-traumatic stress disorder. A permanent impairment a worker has may result from more than one cause. That is, more than one factor may combine together to cause impairment. [7] Hence, an impairment may be caused both from a work injury and other factors. Both may contribute materially to the worker's permanent impairment.
4. There is no express provision within the 1998 Act that requires, in the circumstance where a worker's permanent impairment is both the consequence of a work injury and other contemporary factors, that an apportionment of impairment be made between the work injury and those factors when assessing the degree of the worker's permanent impairment from his or her injury. In such circumstance, common law principles will apply when assessing the degree of permanent impairment a worker has resulting from the work injury.[8] Thus where both a work injury and other factors combine in an inextricable way to cause the worker's permanent impairment, there will be no deduction or apportionment on account of those other factors when assessing the degree of the worker's permanent impairment from the work injury. It is only where those other factors cause a distinct condition from the work injury and result in a separate permanent impairment that can be discretely assessed where an apportionment would be possible.[9]
5. For these reasons, the Appeal Panel has determined that the MAC issued on 1 July 2025 should be revoked, and a new MAC should be issued. The new certificate is attached to this statement of reasons.

This Certificate is issued pursuant to s 328(5) of the Workplace Injury Management and Workers Compensation Act 1998.

The Appeal Panel revokes the Medical Assessment Certificate of Medical Assessor Himanshu Singh and issues this new Medical Assessment Certificate as to the matters set out in the Table below:

Chapter, page and paragraph number in NSW workers compensation guidelines

Chapter, page, paragraph, figure and table numbers in AMA 5 Guides

Proportion of permanent impairment due to pre-existing injury, abnormality or condition

Sub-total/s % WPI (after any deductions in column 6)

Total % WPI (the Combined Table values of all sub-totals)

[1] [2025] NSWSC 213 (Matheson).

[2] [2025] NSWSC 325.

[3] [2024] NSWSC 1200.

[4] Matheson [22]-[29] and [35].

[5] Elcheikh v Diamond Formwork (NSW) Pty Ltd (in liq) [2013] NSWSC 365 at [95]; Pereira v Siemens Ltd [2015] NSWSC 1133 at [88]- [90].

[6]Cullen Woodbrae Holdings Pty Ltd [2015] NSWSC 1416 at [46].

[7] Calman v Commissioner of Police [1999] HCA 60 at [38]- [30] which dealt with an incapacity resulting from injury but the principle discussed is germane for a permanent impairment resulting from a work injury.

[8] Secretary, NSW Department of Education v Johnson [2019] NSWCA 321 at [49]- [55].