Evidence - evaluation of expert medical evidence - conflict in expert opinion - function of court.

Powell v. Streatham Manor Nursing Home (1935) AC 243

Ruiz v. Canberra Rex Hotel Pty. Limited (1974) 5 ACTR1

David Jones (Australia) Pty. Limited v. Arauner (unreported, Federal Court of Australia 9 November 1982)

Warren v. Coombes [1979] HCA 9; (1979) 142 CLR 531

Uranerz (Aust.) Pty. Ltd. v. Hale (1980) 30 ALR 193

Baker v. Thorpe (1985) 62 ACTR 1

Adelaide Stevedoring Co. Ltd. v. Forst [1940] HCA 45; (1940) 64 CLR 538 at p.563

The appeal be dismissed and the findings and award of the Chief Magistrate be confirmed.

The appellant employer pay the respondent worker's costs.

On 16 November 1983 the respondent worker was driving a station wagon in the course of her employment with the appellant employer. She inhaled fumes from tins of adhesive which were in the back of the vehicle and became ill. She was totally incapacitated for a period of some ten days following the incident and then returned to work until 15 February 1984. She then ceased work and had not resumed at the time of the hearing of her application for compensation pursuant to the Workmens Compensation Ordinance 1951. On 16 December 1985 the Chief Magistrate sitting in the then Canberra Court of Petty Sessions found that the worker had been totally incapacitated for work from 16 February 1984 to the date of hearing. He further found that such incapacity was occasioned by "personal injury by accident" within s.7 of the Ordinance, namely the inhalation of fumes on 16 November 1983.

2. From the decision of the learned Chief Magistrate the employer appeals, substantially on the ground that the Chief Magistrate should not have found that there was a causal relationship between the inhalation of the fumes and the incapacity of the worker beyond 15 February 1984. Counsel for the parties stated that the factual issue was a particularly difficult one, as was acknowledged by the Chief Magistrate. As his Worship observed, however, it is not for a court to resolve doubts about controversial scientific problems. The function of a court is to determine the matter before it according to law, and questions of fact, such as those arising in the present appeal, are to be decided by giving proper weight to the whole of the evidence and having regard to the onus and standard of proof. It was for the worker to establish on the balance of probabilities that she suffered from an incapacity for work, and that that incapacity was causally related to her injury. Although other grounds are set out in the Notice of Appeal, it is agreed that no question arises on the appeal as to the extent and duration of the worker's incapacity; the Chief Magistrate was entitled to find as he did that she was totally incapacitated for the period in question and the finding is not challenged. The parties accept that the only question for determination at this stage is whether the worker has discharged the onus of showing that her incapacity was related to the injury in a causal sense.

3. A threshold question is the nature of the appeal to this Court. S. 26(1) of the Workmen's Compensation Ordinance 1951 provides for appeals from the Magistrates Court to the Supreme Court and s. 26(2) provides:

Jurisdiction) Ordinance 1982 applies in relation

to an appeal under sub-section (1) -

(a) as if it were an appeal from a judgment or

order of a kind specified in sub-section

282C(2) of that Ordinance; . . .

4. These provisions bring into operation s. 282G of the Magistrates Court (Civil Jurisdiction) Ordinance 1982. That section is in these terms:

"282G. In an appeal, the Supreme Court shall

have regard to the evidence given in the

proceedings out of which the appeal arose, and has

power to draw inferences of fact and, in its

discretion, to receive further evidence."

5. The terms of s. 282G (which came into force on 13 December 1984) are similar to but not identical with s. 214(2) of the Magistrates Court Ordinance 1930. The similarity is such that in my view there is no distinction to be drawn between the nature of an appeal to this Court under the Magistrates Court Ordinance 1930 and an appeal under the Magistrates Court (Civil Jurisdiction) Ordinance 1982. Neither of these two Ordinances makes any express reference to the appeal being by way of rehearing, and in any event the word "rehearing" has no fixed meaning: Powell v. Streatham Manor Nursing Home (1935) AC 243 per Viscount Sankey L.C. at 249. It was accepted by both sides to the present appeal that it is a "rehearing". The express provision in both Ordinances that the Supreme Court may draw inferences of fact and in its discretion receive further evidence, and the wide variety of powers available to the Supreme Court in disposing of the appeal (Magistrates Court Ordinance 1930, s. 218; Magistrates Court (Civil Jurisdiction) Ordinance 1982, s. 282J) all point to the likelihood that something more than an appeal in the strict sense was intended. However, counsel for the respondent submitted that the practice in this Court in workers' compensation appeals has been not to interfere with the decision of the court below on questions of fact unless it is shown that the magistrate had wrongly taken extraneous matters into consideration or wrongly failed to take material matters into consideration or reached a conclusion against the weight of evidence. The practice was said to have been followed ever since the decision of Woodward J. in Ruiz v. Canberra Rex Hotel Pty. Limited (1974) 5 ACTR 1. That decision was approved and applied by a Full Court of the Federal Court in David Jones (Australia) Pty. Limited v. Arauner (unreported, Federal Court of Australia, 9 November 1982). In the Supreme Court Blackburn CJ., whose decision was under appeal, had said:

"My duty in this appeal is to decide what is the

proper inference to be drawn from all the

evidence, and in doing that, I must give respect

and weight to the conclusion of the learned

arbitrator, but once having reached my own

conclusion, I must not shrink from giving effect

to it."

The Federal Court said that an appeal to the Supreme Court from a magistrate under the Workmens Compensation Ordinance 1951 was properly described as a rehearing and that the Supreme Court was entitled to draw its own inferences of fact from the evidence given before the magistrate. The Federal Court nevertheless dismissed the appeal to that Court on the ground that it could not be said that the magistrate's conclusion was "against the weight of the evidence" (as Ruiz's case required). At the same time the Federal Court acknowledged that Blackburn CJ. had been correct in his approach to the appeal to the Supreme Court.

6. It is to be observed that both Ruiz's case and Arauner's case were decided prior to the present provisions of s. 26 of the Workmens Compensation Ordinance 1951 and of the Magistrates Court (Civil Jurisdiction) Ordinance 1982. Ruiz's case was also prior to Warren v. Coombes [1979] HCA 9; (1979) 142 CLR 531 and Arauner's case seems to have been decided without reference to that decision of the High Court, a decision which is of the highest authority on the nature of an appeal by way of rehearing. In the majority judgment of Gibbs ACJ., Jacobs and Murphy JJ. at p. 551 it was said:

"Shortly expressed, the established principles

are, we think, that in general an appellate court

is in as good a position as the trial judge to

decide on the proper inference to be drawn from

facts which are undisputed or which, having been

disputed, are established by the findings of the

trial judge. In deciding what is the proper

inference to be drawn, the appellate court will

give respect and weight to the conclusion of the

trial judge, but, once having reached its own

conclusion, will not shrink from giving effect to

it."

7. The words of Blackburn CJ. quoted above echo this passage. Insofar as Ruiz's case speaks of the need to show factual error in the sense of taking extraneous matters into account or failing to take material matters into account, I doubt whether it can still be regarded as correctly decided. Insofar as both Ruiz's case and Arauner's case speak of the need to show that the decision appealed against is "against the weight of the evidence", I take those cases to mean, in the light of Warren v. Coombes, that the appellant must satisfy the appellate court that the decision appealed against is wrong and that the appellate court will set aside that decision only after giving due consideration to the decision, and the reasons for it. Warren v. Coombes recognises that where factual findings depend on the credibility of witnesses, the appellate court does not have the advantage of the court at first instance. The appellate court will defer to a decision of the lower court based on credibility of witnesses only when that decision can be shown to be wrong on grounds other than credibility, such as inconsistency with established facts or accepted evidence, inherent improbability or error of fact or law: Uranerz (Aust.) Pty. Ltd. v. Hale (1980) 30 ALR 193 and see Baker v. Thorpe (1985) 62 ACTR 1.

8. It should be observed that the resolution of factual issues raised in an appeal may involve an examination of findings based on the credit of witnesses and also of findings which have nothing to do with the credit of witnesses. In accordance with Warren v. Coombes the appellate court must, after giving due consideration to the lower court's decision, give effect to its own findings insofar as they fall into the latter category of findings. If the ultimate effect of those findings leads to a conclusion that, despite the findings of the lower court which are based on the credit of witnesses, the decision appealed against is wrong then the appellate court must allow the appeal.

9. I return to the matters raised in the present appeal. The learned Chief Magistrate stated that he found the worker to be an honest and acceptable witness. There can be no challenge to his Worship's assessment in that regard. He found further, as I have already stated, that she was totally incapacitated for work from 15 February 1984 until the date of the hearing. There is no challenge at this stage to that finding. The appeal must proceed with those two propositions firmly established.

10. Some of the other findings of the learned Chief Magistrate are not in dispute and in my view they are clearly justified by the evidence. On the afternoon of the day in question the worker had collected two four-litre cans of an adhesive called "Kwik Grip" from a hardware store at Phillip. The tins were damaged. The adhesive was leaking from the tins into a cardboard carton in which they had been placed. She placed the tins and the carton in the station wagon immediately behind the driving seat. She noticed an odour which she recognized by experience as being that of fumes from the adhesive. For the remainder of the afternoon, some four hours or so, she drove the vehicle in the course of her duties with the air-conditioner re-circulating the air and the fumes within the vehicle. During the course of the afternoon she noticed watering of the eyes, numbness of the face and nausea. She attempted work the following day but ceased after she found that she was having difficulty driving and breathing. The next day she sought medical attention from her local practitioner and during the next few days was referred to the Royal Canberra Hospital where she came under the attention of a consultant physician, Dr Denborough. She remained off work until about 2 December 1983. She resumed work but continued to have the symptoms just described in addition to clumsiness and a feeling of being disoriented. She also developed cramps in the stomach, irritable bowel symptoms, and had difficulty with the vision in her right eye. She ceased work on 15 February 1984 and remained off work. She was referred to Dr Danta, a neurologist. She became depressed and in March 1984 underwent some tests of a neuro-psychological nature. At about that time she attended occupational and relaxation therapy at the Royal Canberra Hospital and rehabilitative measures of a similar nature were later continued at the Woden Valley Hospital. That appears to have been in early 1984. At the time of the hearing before the Chief Magistrate she was still complaining of nausea and light-headedness, lack of concentration, difficulty sleeping, anxiety, irritation and blurring in the right eye and swelling and numbness of the right cheek. She considered that she was not able to work by reason of these factors as at the date on which she gave evidence, namely 4 March 1985.

11. Medical evidence was given on behalf of the worker by De Denborough, who saw the worker on fourteen occasions between 23 November 1983 and 11 February 1985, and also by Dr Danta, a neurologist, who saw the plaintiff on 27 February and 9 August 1986. Evidence was given for the appellant by Dr Duggin, a consultant physician specializing in toxicology and renal medicine at the Royal Prince Alfred Hospital and Royal Alexandria Hospital for Children, who saw the worker once on 20 June 1984.

12. Before an informed decision can be made as to the relationship, if any, between the inhalation of fumes on 16 November 1983 and the worker's subsequent incapacity, it is necessary to determine the nature of the incapacity. On the other hand, the two questions are not entirely separate. In order to determine the nature of the incapacity, it is relevant to ask what it was that could possibly have brought on the symptoms. That, it seems to me, is a common-sense approach and is also the approach adopted by the doctors. In the early stages investigations revealed that the worker might have been suffering from a brain tumour, and if that were in fact the case, it might well go to explain the origin of the incapacitating symptoms of which the worker complained. However, by the time of the hearing before the Chief Magistrate, the doctors were agreed that what showed up on a CAT scan was not a tumour which might have had its effect upon the behaviour and well being of the worker but a vascular malformation or haematoma present for many years and which is not capable of increasing in size.

13. Dr Denborough and Dr Duggin saw the question as being essentially whether the worker had continued to suffer the toxic effect of the inhalation of the fumes by reason of brain dysfunction or brain damage or both. Dr Danta was not concerned with toxicity but with observable neurological signs which would themselves be indicative of brain dysfunction or damage. He introduced, however, a further factor, one of a psychiatric or psychological nature and one associated with the worker's anxiety and depression. The effect of the evidence of the three doctors may, I think, be summarised in the following way. Dr Denborough considered the question as to whether the worker's condition was caused by brain damage resulting from the inhalation of fumes and came to the conclusion that it was so caused. He also considered whether there was a psychiatric component in the worker's incapacity, and concluded that there was not. Dr Duggin considered the question as to whether the worker's continuing incapacity was caused by brain damage or dysfunction brought about by the inhalation of the fumes and concluded that it could not have been so caused and was not so caused. He did not address himself to the psychiatric or psychological aspects of the case. Dr Danta considered the question as to whether the worker had suffered from brain dysfunction and concluded that she had so suffered for a period of some few days but that her condition thereafter became complicated by an anxiety state. He further concluded that by August 1984 the anxiety state had ceased to be incapacitating.

14. In the end I do not think it necessary to set out the evidence in detail nor to discuss it at length. In my view this has been done perfectly adequately in the reasons for judgment of the learned Chief Magistrate. However it is necessary to say something about the medical issues.

15. It was urged on behalf of the appellant employer that the Magistrate should have preferred the evidence of Dr Duggin to that of Dr Denborough simply upon the basis that the former was more qualified to express an opinion on the essential question in the case than the latter. Alternatively, it was submitted that as the appellate tribunal I should prefer the views of Dr Duggin as recorded in the transcript of evidence and supported by some other documentary material in the case which consisted of copies of articles in learned medical journals and the like. However, these articles were not in evidence and were simply marked for identification before the Magistrate. Neither counsel in the appeal asked me to read them and indeed it was said that it was unnecessary that I should. Dr Duggin's qualifications in the field of toxicology are indeed extremely impressive. The most relevant of his appointments is that of consultant to the Poisons Information Centre located at the Royal Alexandria Hospital for Children in Sydney, which is a well known and respected institution and indeed is the only one of its type in New South Wales. There is nothing similar in the Australian Capital Territory. It is sufficient to say that in any case of serious poisoning in New South Wales, and it seems in the Australian Capital Territory, the patient is transferred to the care of Dr Duggin, who has highly qualified staff and resources at his disposal. It may be mentioned that in addition to his skills and experience in the field of toxicology, Dr Duggin has long had an interest in renal medicine and most of the publications of which he has been the author or with which he has been associated are concerned with renal medicine rather than directly with toxicology.

16. The qualifications of Dr Denborough, on the other hand, are not directly concerned with toxicology. Nevertheless, he holds several advanced qualifications and appointments as a consultant physician. He holds doctorates in philosophy and science and at the time of the hearing was a consultant physician at the Royal Canberra Hospital as well as a professorial fellow in medical and clinical science at the John Curtin School of Medical Research. His particular area of research interest is in biochemical and genetic disorders in human beings. In my view, it could not be said that the difference in the qualifications and experience of these two doctors is such that one must necessarily be accepted in preference to the other, or that in the end, after a consideration of all the evidence, the case is in such a state of balance that the scales are tipped by a consideration of whose qualifications are superior.

17. The fumes from the adhesive which the plaintiff inhaled contain a highly toxic substance called toluene. Toluene is an aromatic hydrocarbon. It is a solvent which is in common use, and increasingly common use in the community. It is one of the substances which causes brain damage to people who are addicted to glue-sniffing.

18. The exact pathology or aetiology was not explained in the evidence but according to Dr Duggin, studies of human beings and experiments with animals exposed to short-term inhalation of toluene have led to the conclusion that during the time of exposure there is inco-ordination and disturbance of various fine psycho-motor functions. The materials which remain in the body after exposure by inhalation are metabolised and excreted as harmless products over a period of up to seventy-two hours, by which time the subject returns to normal behaviour. He gave the following evidence in relation to the longer term effect of short-term exposure:

"Well, in your research or knowledge of the

material, in personal experience, have you ever

experienced someone who has inhaled these

substances and continued to have brain damage months

after the exposure, when one is dealing with one

exposure over a period of two to two and a half

hours? - No, I have not personally seen a case and

I have not personally heard of any cases after a

single exposure and I have not seen any cases

reported in the literature following a single

exposure in the medical literature."

19. This question and answer implies, so it seems to me, an assumption that the organic effect of toluene inhalation cannot continue for a period of months unless it is associated with brain damage. That assumption seems to be consistent with the rest of the evidence of Dr Duggin. He said, for instance, that brain damage is usually associated with peripheral nerve damage, and that the worker in question displayed no such signs of peripheral nerve damage. Dr Duggin's view was that brain damage was likely to be caused only by long-term chronic exposure every day for many years, and that a single exposure of the type experienced by the worker in question simply could not have had that result. As the learned Chief Magistrate observed, however, there has been very little research on the question of single exposures to toluene, possibly because of the dangers associated with such research.

20. Dr Denborough's view was that a single exposure to toluene may, if sufficiently massive, lead to sudden death or brain damage, although it must be observed that he did not indicate what the level of exposure would have to be if it was likely to bring about such results. Furthermore, Dr Denborough stated that brain damage need not necessarily be demonstrated by peripheral nerve damage. This latter proposition is broadly in accordance with the evidence of Dr Duggin and, in my view, the absence of peripheral nerve damage may be regarded as non-determinative. Dr Denborough considered that the evidence of psychometric testing of the worker indicated that she had suffered sudden and acute brain damage, although initially he suspected that this might have been brought about by a tumour. Dr Denborough thought that a second lot of psychometric tests administered in February 1985 were indicative that there was still some degree of minor brain malfunction, and whilst anxiety might play some part in malfunction, he did not believe that the worker's symptoms when he last saw her were solely due to causes of a psychiatric nature. He maintained there was still an organic base, and that there was still objective clinical signs that the worker suffered from eye trouble, skin damage and gastro-intestinal symptoms. Although Dr Denborough discounted a "psychiatric problem" it is, I think, significant that he mentioned that the worker had been subject to a great deal of stress, contributed to by her being told that she was possibly suffering from a brain tumour and had been subject to a number of medical tests which further contributed to her "feeling a nervous wreck". Despite all this Dr Denborough felt that by the time of the hearing the worker was probably ready to start work again, an assessment which was accepted by the learned Magistrate and which is not challenged on this appeal.

21. Dr Danta's view was that neuro-psychological tests administered in March 1984 indicated that there was some brain dysfunction at that stage, which was probably contributed to, if not wholly due to anxiety rather than physical causes. Similar tests administered, however, in February 1985 showed no neurological abnormality at all and when the worker was last seen by Dr Danta in August 1984 he formed the view that any anxiety or stress no longer resulted in an incapacity for work.

22. In summary then, I think that the medical evidence may be briefly stated in a number of propositions. One begins with the initial premise that the plaintiff was incapacitated during the relevant period. There are then three separate views expressed by the medical witnesses. These are:

1. The view of Dr Denborough that throughout the period

the worker's incapacity was due to lasting brain

damage.

2. The view of Dr Duggin that for a limited period the

incapacity was due to temporary brain dysfunction and

thereafter due to unknown causes.

3. The view of Dr Danta that for a limited period the

incapacity was due to temporary brain dysfunction and

for a further limited period thereafter due to

temporary psychological factors and was thereafter due

to unknown causes.

23. The ultimate question is whether the Magistrate was correct in distilling from the alternative and separate view points of each of the three doctors a fourth approach, namely, that the worker's incapacity was probably explicable by a combination of what he called "organic and psychological effects". I think that the Chief Magistrate was not only entitled to adopt that approach but was correct in doing so. The Chief Magistrate in his reasons for judgment referred appropriately to the well known passage of Rich A.C.J. in Adelaide Stevedoring Co. Ltd. v. Forst [1940] HCA 45; (1940) 64 CLR 538 at p 563:

"I do not see why a court should not begin its

investigation, i.e., before hearing any medical

testimony, from the standpoint of the presumptive

inference which this sequence of events would

naturally inspire in the mind of any common-sense

person uninstructed in pathology. When he finds

that a workman of the not-so-young standing

attempts in a posture calculated by reason of the

pressure on the stomach to disturb or arrest the

rhythm of the heart a very strenuous task not

forming part of his ordinary work and then

collapses almost immediately and dies from a heart

condition, why should not a court say that here is

strong ground for a preliminary presumption of

fact in favour of the view that the work

materially contributed to the cause of death?

From this standpoint the investigation of

physiological and pathological opinion shows no

more than the current medical views find

insufficient reason for connecting coronary

thrombosis with effort. Be it so. That to my

mind is not enough to overturn or rebut the

presumption which flows from the observed sequence

of events. If medical knowledge develops strong

positive reasons for saying that the lay commonsense

presumption is wrong, the courts, no doubt,

would gladly give effect to this affirmative

information."

His Worship also referred to the passage in the judgment of Dixon J., as he then was, at p.570:

"Tempting as it always is, particularly in matters

of bodily health, to argue from a sequence of

external events, such reasoning is justified only

when positive knowledge or common experience

supplies some adequate ground for believing that

the events are naturally associated. The evidence

upon which the special magistrate acted is to the

effect that there is no such ground."

24. In my view, even with the adoption of the caution urged by Dixon J., common experience, supplemented by the evidence in the case, leads to the conclusion that the worker's established incapacity demands explanation in terms of her injury rather than that it should go unexplained. It is likely that the explanation is that she sustained temporary brain dysfunction upon which was grafted a condition of anxiety which increased as the brain dysfunction grew less, so that between February and August 1984 the plaintiff's condition became due solely or substantially to the psychological factors. The psychological factors themselves were partly associated with the worker's personality and pre-injury history and were probably contributed to by her being told (incorrectly as it turned out) that investigations of her condition had revealed a brain tumour. In any event there is, in my view, overall sufficient connection between the psychological condition and the initial injury so as to give rise to responsibility on the part of the employer for that condition.

25. There is a further matter which I think should be mentioned although it played no active part in the case and it has not been taken into account for the purpose of my reaching the above conclusion. The case was conducted on the basis that the worker suffered a single and solitary exposure to toluene on the afternoon of 16 November 1983. However the plaintiff said in her evidence-in-chief that part of her duties included the collection of "damaged chemicals" and that there had been "a bit of trouble with damaged tins", from which I would think that it might be inferred that the occasion in question was not the first time during which the worker had been exposed to toluene fumes.

26. The appeal is dismissed and the Chief Magistrate's findings and award confirmed. The appellant employer is to pay the respondent worker's costs.