Are we being poisoned by pesticides?

Press, 22 July 1986, Page 25

Are we being poisoned by pesticides?

Task force rules on the Dermatron

Almost a year ago, Dr Matthew Tizard, of Auckland, began notifying the Department of Health about cases of alleged herbicide poisoning he had diagnosed with an electroacupuncture device called the Dermatron. A task force inquiry into chemical poisoning has raised questions about the diagnostic method, which lacks a controlled scientific test. STAN DARLING reports:

Dr Keith Scott, an Auckland general practitioner and homeopath, has no reservations about recent Department of Health task force inquiry findings on a controversial diagnostic technique that lacks scientific testing. Last week, the Accident Compensation Corporation confirmed its earlier decision to deny future payments for the diagnosis of alleged effects of chemical poisoning, or for certain treatments based on such a diagnosis. Dr Matthew lizard, an Auckland homeopath, has reported cases of alleged poisoning to the Department of Health. The medical task force, which had co-opted Dr Scott and a medical electronics expert, decided that the effectiveness of the Dermatron — an electroacupuncture device which helps to diagnose chronic agricultural poisoning — was questionable. Dr Scott says he considered using the German-manufactured instrument about six years ago, but he thinks it is unreliable.

■t the diagnosis is correct,” says Dr Scott “I am very anti the extensive use of pesticides, too, but if you have pesticides in your blood, that doesn’t mean they are causing the illness. “I don’t necessarily say the instrument doesn’t work, but it has not been properly tested.” Dr Tizard refused a task force suggestion that a proper scientific test could be organised with his participation. Peter Duncan, the Accident Compensation Corporation’s chief legal adviser, says that Dr Tizard’s diagnosis of chemical poisoning in some patients was brought to the corporation’s attention late last year.

alleged chemical poisoning. Dr Blackmore would not comment further on any aspect of the inquiry’s findings. When the task force report was released last month, he said that he would like to see a “properly set up” scientific trial of the Dermatron, .but that did not mean the "cold, callous do this-do that" kind of experiment proposed by the Health Department

The task force says that that is the only type of trial that would be scientifically valid. “My great concern is that the general public should realise that science has a lot to offer,” says Dr Tim Maling, chairman of the task force and senior lecturer in clinical pharmacology at the Wellington Clinical School of Medicine.

Suspension confirmed

“The scientific approach is the only way to assess these problems. Unless one operates critically, one is not doing the best for the patients.” In an April reply to the task force on'its proposal of a “double blind assessment” of electroacupuncture diagnosis, Dr Tizard said: “It is well known that acupuncture point measurement is a delicate procedure, subject to observer error.. It is also dependent on the state of the operator who is also ‘in the circuit’ so to speak.” According to the task force the only scientifically acceptable way to evaluate the technique would be a double-blind study to measure how precise and specific the diagnosis is. In such a study — involving Dr

“It was suggested that we should investigate it because it may not necessarily stand up to expected diagnosis standards," he says of the Dermatron procedure.

“I am not saying that it’s useless,” he adds, but an experienced operator quoted in the task force report says that the Dermatron should not be used diagnostically. “It might be an aid,” says Dr Scott, “but it is not an absolute answer. There is so much margin of error.”

At the end of February, the A.C.C. informed Dr Tizard that payments for treatment as a result of such diagnoses would be suspended after March 5. This week’s ruling confirms that temporary suspension. * The A.C.C.’s general policy of refusing payments extends to any New Zealand doctor using the diagnostic device. Dr Robert Blackmore, of Christchurch, has used the same method to detect

He says that you cannot use treatment results to determine whether it is reliable. In some cases, patients would have got better without treatment. “Just because a treatment works, that doesn’t mean to say

Tizard and, it was hoped, other New Zealand practitioners of the technique — the machine would be used on several patients while the operators were “blind” to the nature of the homeopathic preparation in a metal container. That container is connected to the machine in series, between the Dermatron and a hand-held electrode. The task force says that an adequately-designed test “would give a clear indication of the repeatability of diagnoses by the same practitioner, and consistency between practitioners.” But Dr Tizard replied that a • double-blind trail “with a series of unknown ampoules being handled by examiners is an artificial situation, far removed from the normal tranquil setting

of everyday testing where the operator knows what he is testing with.” Any such trial could produce false results, he told the task force: The task force report says that “most medical devices would not be expected to be capable of achieving the same high level of accuracy as claimed for his technique by Dr Tizard. Furthermore, other devices would be subjected to rigorously-controlled clinical trials to evaluate their diagnostic validity.” In the absence of proof of diagnostic accuracy, the task force could not comment on the apparent preponderance of diagnoses of paraquat poisoning in the three Auckland health districts (Auckland, South Auckland,

and Takapuna) and the predominantly 2,4,5-T diagnoses in Christchurch.

No consistent

symptoms

The task force looked at 95 reported cases. Of the 34 2,4,5-T diagnoses, 17 were in Christchurch. Of the 43 paraquat diagnoses, only three were in Christchurch. No consistent diagnostic pattern of symptoms could be discerned in the 95 cases. Of the 95 patients, 78 said they had no history of known exposure to agricultural chemicals. Seven said they had, and three said previous contact was pos-

sible. The other seven were not investigated. The task force accepted that it was “impossible to exclude completely the possibility of exposure to pesticides in any of the 78 persons with no proven history of contact.” Dr Tizard had acknowledged that nearly all his patients living in urban areas, and about a third of rural cases, had no history of contact with agricultural chemicals. Since being diagnosed, a proportion of Dr Tlzard’s patients might have noticed improvement in their symptoms whether they had been treated or not "Such spontaneous improvement over time is a well recognised feature of many chronic diseases running a fluctuating

course,” says the inquiry report For many patients, “the mere fact of receiving treatment — any treatment even coloured water — will be beneficial,” says the report “This is well-known phenomenon known as the placebo effect but there is little agreement as to how it works.” If the diagnostic technique is unreliable, “as indeed there appears to be every reason to believe,” says the report, “Dr Tizard has, at the least, a responsibility to alert his patients to the uncertainty of their previous diagnoses.” The task force says he has nothing to fear from a controlled trial of the Dermatron if the technique is valid, and “he would be making a significant contribution to resolving this issue.”