O'Kane v Comcare

Introduction 1 This is an appeal from a decision of the Administrative Appeals Tribunal (the Tribunal) given on 8 October 2013. In matter 2013/0975 the reviewable decision was affirmed and in matter 2012/2313 the decision was set aside and in substitution the Tribunal decided that the applicant was not entitled to compensation for the permanent impairment claim. 2 The notice of appeal invokes not only s 44 of the Administrative Appeals Tribunal Act 1975 (Cth) (the AAT Act) but also, for a reason which is not clear, s 5(1)(e) of the Administrative Decisions (Judicial Review) Act 1977 (Cth) which provides that a person who is aggrieved by a decision to which that Act applies may apply to the Federal Court for an order of review in respect of the decision on the ground "that the making of the decision was an improper exercise of the power conferred by the enactment in pursuance of which it was purported to be made". That paragraph has to be read with s 5(2) of that Act. In oral submissions the reference was to s 5(1) of the Administrative Decisions (Judicial Review) Act more generally and seems to have been directed to any problems arising from a narrow view of s 44 of the AAT Act. I return to this topic at [81] below.

The findings and reasons of the Tribunal 3 The Tribunal said that Mr O'Kane had two claims: for compensation for binaural hearing loss and for tinnitus (Matter 2013/0975); and for permanent impairment due to those conditions (Matter 2013/2313). 4 The first claim was accepted on 10 November 2011, a decision revoked on review on 27 February 2013. Mr O'Kane sought further review by the Tribunal on 6 March 2013. 5 In the second reviewable decision, dated 20 April 2012, Mr O'Kane was found to be entitled to compensation for permanent impairment of $35.11 for hearing loss, but not for tinnitus or non-economic loss in accordance with the Compensation (Commonwealth Government Employees) Act 1971 (Cth) (1971 Act). He sought further review by the Tribunal on 7 June 2012. 6 The Tribunal gave the following background, so far as relevant. The applicant relied in particular on what was said by the Tribunal at [44], [45], [48] and [56]. I have identified those paragraphs in the following summary which reproduces the findings and reasons of the Tribunal. 7 Mr O'Kane commenced work as an ACTION bus driver in the ACT on or about 15 June 1974. No hearing test was conducted prior to his appointment. He received an involuntary redundancy package on 15 January 1996. However, he recommenced as a casual part-time bus driver on 16 January 1996 and became permanent part-time on 16 April 1996. 8 On 7 April 1996, Mr O'Kane was 'king hit' at a local hotel in the ACT. The assault was to his left temple and he fell on his right side on a tiled floor, hitting the right side of his head on the floor. By 1 August 1996, Dr Choong reported Mr O'Kane as being fully recovered 'except for the hearing loss'. Mr O'Kane made a claim for victims compensation in respect of this incident. The claim covered bruising, damage to teeth, and nerve damage to the right ear including hearing loss. 9 On 24 July 1996 Mr O'Kane's loss of hearing was assessed by Dr Hugh Williams, ear, nose and throat surgeon. Dr Williams found that: … the tympanic membranes of his ears appeared satisfactory and tuning fork tests along with audiometry indicated moderately severe right-sided sensorineural deafness which I believe is consistent with the injuries sustained which caused him a traumatic cochleitis at the time of the head injury which has left him with partial deafness in his right ear. … According to Tables put out by the National Acoustic Laboratories [NAL] Report of January 1988 I calculate that Mr O'Kane has a 15.1% loss of total hearing. (emphasis added) 10 On 3 June 2001, Mr O'Kane was assaulted outside the same ACT hotel as the assault in 1996. He suffered concussion and undertook a hearing test following the incident. In a statutory declaration, Mr O'Kane submitted that he had resulting "hearing loss" and that his medical advisers said he "will require hearing aids". He had sought criminal injuries compensation for the cost of hearing aids following the assault. 11 On 8 August 2004, Mr O'Kane ceased driving ACTION buses. 12 On 8 May 2008, Mr O'Kane underwent a hearing test which indicated a binaural hearing loss of 33.9 per cent when corrected for presbyacusis (the effects of ageing). 13 On 2 June 2008, Mr O'Kane underwent a further hearing test which indicated a binaural hearing loss of 15.5 per cent when corrected for presbyacusis. 14 On or about 16 December 2010, Mr O'Kane attended solicitors who lodged a claim for permanent impairment with Comcare in respect of hearing loss and tinnitus. 15 On 31 October 2011, Dr Matison assessed Mr O'Kane to have a 41.3 per cent binaural hearing loss (corrected for presbyacusis). 16 On 10 November 2011, Comcare accepted liability for Mr O'Kane's hearing loss and tinnitus with a date of injury of 23 November 2010. 17 On 3 January 2012, Mr O'Kane received confirmation from Comcare that it would accept liability for the cost of hearing aids. 18 On 13 February 2012, Comcare decided that Mr O'Kane was not entitled to permanent impairment in respect of his hearing loss and tinnitus. 19 On 20 April 2012, Comcare set aside the decision of 13 February 2012 and found that Mr O'Kane was entitled to a permanent impairment assessment under the 1971 Act in respect of his hearing loss of 0.0095 per cent, amounting to an entitlement to $35.11, and nothing in respect of his tinnitus. 20 On 12 July 2012, Mr O'Kane underwent a hearing test indicating a binaural hearing loss of 50.6 per cent (corrected for presbyacusis). 21 On 14 August 2012, Dr Pham produced a report stating Mr O'Kane's hearing loss, corrected for presbyacusis, as at 23 November 2010 was 39.8 per cent binaural hearing loss and binaural hearing loss attributable to noise exposure was 17.4 per cent. 22 On 1 November 2012, Dr Matison provided a further report to Comcare. Dr Matison expressed the view that Mr O'Kane's hearing loss was unlikely to be attributable to the assaults. 23 In a supplementary report dated 21 November 2012, Dr Matison modified his views and indicated that the assault in 1996 may have contributed to the hearing loss in the right ear but could not comment as to the extent. 24 In a further supplementary report dated 29 December 2011, Dr Matison reported that in his opinion, 0.6 per cent loss of hearing by Mr O'Kane was due to acoustic trauma from a burst tyre, the remaining 40.7 per cent hearing was "most likely due to a familial form of deafness unconnected with any employment factor". His conclusion was "based on the audiogram pattern, which is not typical of noise trauma". Thus although he considered that Mr O'Kane may have been exposed to excessive noise in the early years of his career with ACTION, in his opinion, bus driving was not the predominant cause of his hearing loss. 25 In a reviewable decision dated 27 February 2013, Comcare revoked the decision of 10 November 2011 and denied Mr O'Kane's claim for "sensorineural hearing loss" and "tinnitus". 26 The Tribunal referred to the relevant legislation as being the Safety, Rehabilitation and Compensation Act 1988 (Cth) (SRC Act). The Tribunal said that relevant provisions were s 4(1), the definitions provision; s 5A which defines what is a compensable "injury" for the purposes of the Act; s 5B which defines one form of compensable injury as a work-related "disease"; and s 7(4) which describes the date of injury. 27 The Tribunal identified the following issues so far as presently relevant: • Was Mr O'Kane's claim for compensation excluded by s 53 of the SRC Act i.e. did Mr O'Kane notify Comcare of his claim "as soon as practicable"? • Was Mr O'Kane's claimed condition of hearing loss an "injury (other than a disease)", or a "disease" for the purposes of the SRC Act? • Was Mr O'Kane's claimed condition of tinnitus an "injury (other than a disease)", or a "disease" for the purposes of the SRC Act? • Did Mr O'Kane's claimed conditions arise out or, or in the course of his employment with the Australian Capital Territory (ACT) Government? OR • Were Mr O'Kane's claimed conditions contributed to, to the degree relevant, depending on the legislation at the date of injury, to his employment with the ACT Government? • Were the impairments arising from Mr O'Kane's claimed conditions permanent? • Was Mr O'Kane entitled to compensation for permanent impairment and non-economic loss for his claimed conditions? 28 So far as relevant for present purposes, the Tribunal considered these matters as follows. 29 In considering whether Mr O'Kane's claim for compensation was excluded by s 53 of the SRC Act, the Tribunal said at [44] that in an earlier Tribunal decision s 53 was found to be no bar when an applicant had only recently become aware of a possible link between his condition and his employment. Of its nature, hearing loss was often slowly incremental and difficult to detect. The Tribunal referred to the report of the National Institute on Deafness and other Communication Disorders which indicated at paragraph 50 that the symptoms of Noise Induced Hearing Loss increased "gradually over a period of continuous exposure … The individual may not be aware of the loss but it can be detected with a hearing test". In other words, the Tribunal said at [45], the gradual deterioration of the condition may prevent a person becoming aware of the deterioration of their hearing. The evidence suggested this appeared to be the case for Mr O'Kane. In summary, the Tribunal said at [48], the gradually developing nature of the injury, the worsening of his hearing only since Mr O'Kane ceased bus driving in 2004, the paucity of audiometry reports for Mr O'Kane prior to 2010, and the fact that the pre-2010 audiometric evidence did not attribute hearing loss to bus driving, were an adequate explanation for Mr O'Kane's delay between the middle of 2008 and the end of 2010, to notify Comcare of his claim. 30 The Tribunal went on to consider whether Mr O'Kane's claimed condition of hearing loss was an "injury (other than a disease)", or a "disease" for the purposes of the SRC Act. 31 The Tribunal at [50] referred to Re Sandercock and Military Rehabilitation and Compensation Commission [2013] AATA 517 at [25]-[28], another claimed long-standing hearing loss claim. 32 In that case the Tribunal said there was no consistent view in the cases as to whether hearing loss was an "injury" or a "disease" for the purposes of ss 4(1), 5A, 5B and 6 of the SRC Act. However, the Tribunal said, the distinction between an "injury" in its primary sense and a "disease" was described by the High Court in Kennedy Cleaning Services Pty Ltd v Petkoska (2000) 200 CLR 286 at [39] per Gleeson CJ and Kirby J as the difference between "a sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state" as compared with the "underlying pathology" that constitutes a "disease". Applying that distinction, acoustic trauma, if it results in sudden damage to sensitive hair cells of the inner ear as well as the hearing nerve would amount to an "injury"; while presbyacusis, being a slowly degenerative process associated with ageing, would amount to a "disease". 33 The present Tribunal said that, as acknowledged in the cases, "the appropriate characterisation of the cause of the hearing loss [is] generally apparent from the facts of each particular case", citing Re Tralongo and Military Rehabilitation and Compensation Commission [2004] AATA 1242 at [36]. 34 The Tribunal said that in Mr O'Kane's case, the claim was that his hearing loss was due to loud continuous noise from driving buses in combination with the effects of ageing, and possibly a familial disposition to hearing loss, alongside the injury from the assault in 1996. That meant that Mr O'Kane's hearing loss was due to combined effects which were categorised differently. The assault, a "sudden and ascertainable or dramatic physiological change or disturbance of the normal physiological state", and the "loud continuous noise" from driving buses which damages the sensitive hair cells of the inner ear, perpetuated and worsened over the period of his driving noisy buses and the '301' tram would both be "injuries". The age-related and familial predisposition would be characterised as slowly degenerating or congenital conditions and hence, if employment-related, would be "diseases". 35 Since it was the contribution of the former categories including hearing loss from bus driving, which were being considered in the present claim, the Tribunal found that Mr O'Kane's hearing loss related to an "injury", namely, the damage to the sensitive hair cells of the inner ear. 36 The Tribunal then turned to whether Mr O'Kane's claimed condition of tinnitus was an "injury (other than a disease)", or a "disease" for the purposes of the Act. 37 It said that tinnitus was "a noise heard in the ear without any external cause". It was most commonly associated with noise induced hearing loss, but could also be related to trauma or disease. Initially the condition was manifested in Mr O'Kane's right ear. Since then, the condition had deteriorated and was now experienced binaurally as shown in the audiogram of 8 May 2008. 38 Due to the indeterminate nature of the evidence, the Tribunal said it was difficult to make a definitive finding of "injury" or "disease" in relation to Mr O'Kane's tinnitus. There was evidence which the Tribunal accepted that Mr O'Kane first noticed tinnitus following the assault in 1996. The continuing and worsening nature of Mr O'Kane's tinnitus suggested that his condition may also be associated with his noise induced hearing loss or his presbyacusis/familial predisposition, the first possibly being an injury, the second two causes, a disease. 39 On balance, the Tribunal said at [56], it found that although the tinnitus may have been initiated by trauma, the condition had been perpetuated and worsened by association with his general hearing loss, both being characterised as "injuries". Accordingly the Tribunal found that his tinnitus initiated by, and exacerbated by being associated with, an "injury" was itself an "injury". 40 The Tribunal then turned to whether Mr O'Kane's claimed condition of hearing loss was contributed to, to the degree relevant, depending on the legislation at the date of injury, by his employment with the ACT Government. 41 The Tribunal had found that Mr O'Kane's claimed noise-induced hearing loss was categorised as an "injury" which meant for liability to accrue, that element of his condition must "arise out of or in the course of" his employment. A similar test applied to his tinnitus. The Tribunal referred to s 5A(1) of the SRC Act. 42 Mr O'Kane's claim was that his noise-induced hearing loss was due in part to the noise he experienced while driving ACTION buses, particularly those with front mounted engines. He gave evidence that he drove some 11 different vehicles while at ACTION. 43 Mr O'Kane also submitted that ticket validators, placed behind the driver's head, were installed in 1998/9, and if they jammed, let out a high-pitched scream. This noise could not be shut off by drivers until the bus returned to the depot where the supervisors could turn them off. He also submitted that a two-way radio was fitted to the buses in the 1980s. Initially they could not be adjusted by drivers and provided a constant stream of noise. 44 The Tribunal set out a table indicating the percentage of hearing loss (corrected to deduct the effects of ageing) experienced by Mr O'Kane as found by the medical experts and on audiometry. There was no evidence of Mr O'Kane's level of hearing when he started bus driving. 45 The Tribunal considered the evidence of Mr Herbert, a former ACTION driver, who said that if allocated to one of the three '301' trams, the shift would be between 8-10 hours. One of those trams was allocated to the Canberra city route. Two of the trams were noisier than the third. The trams were introduced in 1995 and retired in 1998. Of the 12 drivers of those trams, six of them had put in hearing claims which were accepted by Comcare. 46 The Tribunal considered the evidence of the engineering manager for ACTION who said he was not a noise expert but to his knowledge the noise level on a normal day of driving buses did not exceed the 85 decibel level. He conceded that he did not know whether the '301' trams had been tested, nor the Dennis dart bus. In his view, even the two vehicles which exceeded the 85 decibel level did not do so for 8 hours. In his view exposure was harmful only if over 8 hours. 47 The Tribunal considered the opinion of Dr Matison, from which he did not resile at the hearing, that the audiogram findings were "characteristic of familial forms of sensorineural deafness" at least for the left ear, and were not typical of steady state noise exposure. He favoured this view, even though Mr O'Kane's right ear exhibited a "high tone dip consistent with noise trauma", that is, hearing loss in the 2000hz to 4000hz range, since steady state noise exposure would have had the same impact on both ears. His view was supported by the fact that the 40.7 per cent binaural hearing loss was "much higher than seen in the majority of cases of industrial noise trauma". Dr Matison conceded that there was some work-related element, but noted the difficulty in estimating the quantum of that contribution due to the fact that "there is no contemporaneous report from either his GP or a specialist, no claim and no audiometry". Moreover, as he pointed out, what later audiometry existed was confusing. He said in his report: The June 2008 audiogram shows, after an allowance for presbycusis, a 15.1% binaural hearing impairment, yet the Australian Hearing audiogram done approximately one month previously indicated a 33.9% binaural hearing handicap after an allowance for presbycusis. … There is no incident or factor in the history to account for this disparity. Furthermore, the Audio Clinic audiogram on 10 July 2012 shows a 50.6% binaural hearing handicap after a deduction for presbycusis, significantly greater than the audiometry of 23 November 2010. What it did establish, he said, was: … that the bulk of Mr O'Kane's hearing losses appear to have occurred between 2008 and 2012. This deterioration cannot be attributed to his Commonwealth Government employment which ceased in 2005. [sic]. Noise trauma does not progress once exposure to the offending noise ceases. 48 The Tribunal said that in a supplementary report dated 21 November 2012, Dr Matison conceded that the loss of hearing in the right ear "could be consistent with the injuries received in the assault" in 1996. However, he denied that all the hearing loss could be attributed to that cause since the left ear also had a hearing loss. In the absence of the audiogram at the time, he could not calculate what proportion of hearing loss might be attributed to noise from driving buses as compared with the assault. 49 The Tribunal considered Dr Pham's view that the Robson report indicated that for the two trams referred to, "during acceleration … there was noise level at 94 decibels with a peak reading at 100 decibels" and this would be sufficient to damage hearing. He noted it was difficult to know how often the tram accelerated but it could be inferred that Mr O'Kane was periodically exposed to excessive loud noise. He considered this would have been sufficient to cause employment-related hearing loss. Discounting for periods when the engine was idling or not exceeding the 85 decibel limit, and for presbyacusis, he attributed Mr O'Kane's work-related binaural hearing loss to be 17.4 per cent of the total hearing loss. 50 The Tribunal referred to the oral evidence of Dr Matison who said that a person can withstand 100 decibels of noise per day for no longer than about 15 minutes per day. If the exposure was only for shorter times, it would not cause deafness. He acknowledged that the '301' tram exceeded that noise level when accelerating or braking but said without knowing the average time per day or per shift of Mr O'Kane's exposure, or whether he was in the noisier or the less noisy of the trams, there was no evidence that driving the '301' tram contributed to his deafness. 51 At the hearing, the Tribunal said, the two experts conceded that noise-induced hearing loss and tinnitus are usually permanent. The experts also agreed that employment made some contribution to Mr O'Kane's hearing loss. The experts agreed that the two most consistent audiograms were those in May and June 2008. They were undertaken only four years after Mr O'Kane ceased work with ACTION and probably were sufficiently indicative of his hearing conditions in 2004. 52 They also agreed that the fairest way to estimate his hearing loss was to take an average of the two results for the two 2008 audiograms for the frequencies most likely to be associated with noise induced hearing loss, that is, the hearing loss within the 2000hz to 4000hz range. That produced a figure of 8.55 binaural hearing loss. A deduction needed to be made for age for both audiogram results. That produced a figure, according to Dr Matison, of 4 for the Audio Clinic audiogram and 9 for the Australian Hearing audiogram. Averaging the two led to a figure of 6.6 which divided by two gave a whole person impairment of 3 per cent. Both experts agreed that Mr O'Kane's tinnitus attracted a five per cent hearing loss. 53 Dr Matison also said, following discussions with Dr Pham, that there was not enough evidence to reach a firm conclusion that Mr O'Kane did suffer hearing loss due to work factors. Dr Matison said their findings were on the basis of "possibilities", but not of "probabilities". There was insufficient proof, he said, that Mr O'Kane was exposed to noise from driving ACTION vehicles. However, he acknowledged that they could not rule out noise induced hearing loss since he had suffered binaural hearing loss in the upper 2000hz to 4000hz range, at least in the right ear, typical of noise induced hearing loss. But he said that the pattern of hearing loss shown in the audiograms was not typical of noise induced hearing loss. Each hearing test showed markedly different results from the other, and there was little or no consistency in the readings. Dr Pham said there was a contribution from work, but it was difficult to quantify. 54 The Tribunal said it was hampered because of the paucity of evidence of the hours of driving per day by Mr O'Kane of the vehicles found in the reports to have exceeded safe noise levels, and the frequency of such exposure. He did drive the Hino bus which was said to be noisy, but the 2004 report said the Hino bus did not exceed safe occupational limits and it was not known how often and for what periods he drove the bus. Similarly he did have split shifts on school buses, but the excessive noise levels, according to the Robson reports, occurred for short periods only when the bulk of the children were either entering or exiting the buses, recorded as being for less than 15 minutes. Mr O'Kane did drive '301' trams but there was the same deficiency of information about length of shifts, frequency of shifts and length of excessive noise levels when accelerating, braking, or driving in second/third gears. The average length of time he was exposed to these noises was not known. Any noise level would have been intermittent and it was not known for how long it would have continued. 55 The Tribunal said that given an 8 - 10 hour shift it was unlikely on the evidence for excessive noise levels to continue for an average of 8 hours a day. In addition, the audiometry reports showed that Mr O'Kane's hearing loss was worse on his right than his left ear. That finding was inconsistent with Mr O'Kane's claim of excess noise from engines located to the left of the driver at the front of the vehicle. Finally, it was not known what was the decibel level of the scream from the malfunctioning ticket validators, nor for how long or how frequently Mr O'Kane was exposed to the noise. The Tribunal also noted that it had no information about the period during which the radio noise could not be turned down by the driver, nor of Mr O'Kane's length or frequency of exposure. 56 Whether Mr O'Kane's hearing loss arose out of or in the course of his employment involved both a causal and a temporal test, although there was overlap between the two tests. "Arising out of employment" referred to the work which an employee was employed to do and what was incidental to that work. There was no question that to the extent that Mr O'Kane's hearing loss was due to driving buses, it arose out of, or in the course of his employment. 57 However, the Tribunal found at [81] it was not satisfied on the evidence that Mr O'Kane's hearing loss was due to his work or an incident of that work. There was an absence of evidence about length and frequency of exposure, and the need for continuous exposure at A-weighted levels for an average of 8 hours a day, and for higher frequency noise levels, for example, averaging above 100 decibels, for longer than 15 minutes. In light of medical and other evidence about the contributing effects of injury to Mr O'Kane's ears from two assaults, of his ageing, and the possibility of some familial predisposition as well, the Tribunal was not satisfied that his hearing loss could be attributed to his employment. Both medical experts agreed that the evidence was deficient without the benefit of a report from a sound engineer and this would be difficult to obtain now that the noisiest buses or trams had been sold and were no longer in use. 58 The Tribunal said that that finding was supported by the limited evidence of Mr O'Kane's hearing loss prior to 2004, being confined to the test undertaken in 1996. It was also supported by the fact that two of the noisiest vehicles Mr O'Kane drove, the Leyland crash gear box bus and the '301' trams, were decommissioned by 1978 and 1998 respectively, some time prior to Mr O'Kane's ceasing work with ACTION. In addition, his hearing loss was worse in his right ear, when the engine noises to which he said he was exposed were closer to his left ear. The evidence that his hearing had worsened since leaving work was also significant. 59 The Tribunal accepted Dr Matison's evidence which was that after exposure to excessive noise ceased, noise induced hearing loss ceases. So the worsening of Mr O'Kane's hearing after he ceased working for ACTION indicated that his worsening hearing loss, as reflected in audiograms of 2010 and 2012, must be due to other causes. The post-employment worsening of his hearing was supported by the fact that Mr O'Kane did not seek medical treatment for the condition until 2008, a finding consistent with the audiometry reports. Finally, although Dr Pham was prepared, prior to the hearing, to attribute 17.4 per cent of Mr O'Kane's hearing loss to employment, at the hearing, he acknowledged that it was not possible to know what amount could be attributed to his employment. Dr Matison was only prepared to allocate 0.6 per cent hearing loss to employment and although both experts considered the fairest method of estimation in the unsatisfactory state of the evidence was to average the results from the audiometric tests in 2008, that option only applied if the Tribunal accepted, as it had not done, that the hearing loss arose out of or during the course of Mr O'Kane's employment. 60 The Tribunal then turned to consider whether Mr O'Kane's claimed condition of tinnitus was contributed to, to the degree relevant, depending on the legislation at the date of injury, by his employment with the ACT Government. 61 The Tribunal referred to Mr O'Kane's evidence that his tinnitus was severe, continuous and interfering with his sleep. 62 The Tribunal then referred to Dr Matison's initial view which was that it was "highly unlikely that Mr O'Kane suffered any tinnitus from [the assaults]". At the hearing Dr Matison conceded the evidence indicated that Mr O'Kane did not have tinnitus prior to 1996, the condition was compatible with the effects of an assault, and this suggested it was the trauma, not noise which contributed to his tinnitus. At the same time he acknowledged that tinnitus can be either of gradual onset or of sudden onset, although it was usually sudden. He noted the confusion from the Audio Clinical reports which indicated that "tinnitus was either absent, intermittent or mild". He could not explain why it was bilateral in Mr O'Kane's case. 63 The Tribunal referred to Dr Pham's view in his report of 14 August 2012 which was that "the level of noise exposure could contribute or aggravate tinnitus". However, at the hearing, he said it was hard to say what caused Mr O'Kane's tinnitus and there was no way to know. 64 In this state of the evidence, the Tribunal found it was not satisfied that Mr O'Kane's tinnitus was sufficiently associated with his hearing loss for it to have "arisen out of or in the course of his employment". 65 The Tribunal concluded its reasons by saying it was satisfied that the injuries did not arise out of or in the course of employment. This also meant, the Tribunal said, it was not necessary to consider further the issues relating to the permanent impairment claim.