MTHR - Mobile Telecommunications and Health Research

Human Volunteer Studies: General and Special Populations

Chair: Professor M Rugg

Following a joint session with the Dosimetry Workshop to discuss progress on the Standard Human Exposure System, the Workshop moved on to consider progress with the human volunteer studies funded under the Programme. Andrew Parkes described progress with the project Conversations in cars: the relative hazards of mobile phones. This study is currently at the most advanced stage of any in the Programme. Although Dr Parkes was only able to discuss preliminary results at the meeting, he expected that the full analysis would be completed by the end of November and would be seeking to prepare a full report for publication as soon as possible thereafter.

Progress with the three remaining human volunteer studies funded in response to the First Call for Proposals has been slowed by the need to develop a Standard Human Exposure System. The three project leaders each described the background and rationale for their proposed work. It was clear from the presentations that although it had not been possible to commence experimental exposures, the research teams had been carrying out preliminary work such as ensuring that instrumentation would not be affected by radiofrequency fields, or putting in place procedures to recruit subjects. Consequently it is expected that experimental work will get underway promptly once the exposure systems are ready for use. During the ensuing discussion, it became clear that one of the major strengths of the proposed studies would be a comparison between the effects of modulated signals (simulating GSM mobile phones or TETRA emergency services radio, as appropriate) and the unmodulated carrier signal. There was discussion of the problems associated with variation in SAR distribution in the head, which will depend on the model of phone used, the exact position of the phone in relation to the head and the frequency of the emissions. As it was clearly not practical to test all possible combinations of these variables, it was agreed that it would be important to ensure that exposures were consistent across all subjects and studies; this was the reason for developing the Standard Human Exposure System. It was also agreed that a standard approach should be developed for assessing the laterality of phone use in subjects.

The final session of the workshop moved on to a consideration of how to investigate the issue of sensitivity to mobile phones and base stations reported by some people. It was important to assess this sensitivity under tightly controlled conditions. A secondary goal may be to try and determine whether there are any specific characteristics that may be used to define such populations. The Programme already included one study designed to investigate the sensitivity of people characterised by vestibular disturbance and the Programme Management Committee had now decided to fund a second study to investigate the issue of sensitivity to mobile phone signals subject to completion satisfactory contract. Moreover, the draft research specification for the Third Call (announced by Sir William Stewart on the 11th of November) requested a two stage project to examine sensitivity to base stations. The first stage of this project would seek to define the study population, whilst the second would be a provocation study; if necessary technical assistance in terms of exposure and dosimetry could be made available to potential applicants who were otherwise well qualified to conduct this type of study.

Continuing with the theme of sensitive populations, the issue of subject recruitment was discussed. Referral from GPs could not generally be relied upon as most people suffering symptoms do not consult their GP, but instead take personal action. In selecting recruits it would be important to distinguish between those with general sensitivity, and those who were apparently asymptomatic apart from their sensitivity to phones or base stations. It could be relevant to include both populations in any study; those with a general sensitivity would probably be the most likely to develop a disability and thus be a very important group, whilst those with a specific sensitivity would probably be easier to study. It would be important to consult Special Interest Groups about the design of the base station provocation study from an early stage and it is possible that they could have a role to play in the recruitment of subjects. The draft research specification for the base station provocation study does not call for the inclusion of children in the study group as advice from ethical experts had suggested that this would probably he unacceptable.

Summaries of the closed sessions of the MTHR Research Seminar - 11th of November 2002