THREE ABSTRACTS


In: Biomagnetism: Fundamental Research and Clinical Applications. Eds: C. Baumgartner, L. Deecke, G. Stroink and S.J. Williamson. Elsevier/ISO Press, Amsterdam (1995): 16-19

Evocation of Epileptiform Activity by Weak D.C. Magnetic Fields and Iron Biomineralization in the Human Brain

J. Dobson, M. Fuller, S. Moser, H. Gregor Wieser, J.R. Dunn and J. Zoeger

Epileptic patients being evaluated for surgery were implanted with EEG electrodes via the Foramen Ovale (FO) in order to locate the origin of epileptiform activity. A coaxial coil generating D.C. magnetic fields of 0.4 millitesla (mT) to 1.8 mT was fitted around the patient's heads and fields of varying strength were applied. The response of the EEG was monitored during application of these magnetic fields. In three patients, epileptiform activity was apparently evoked, though not each time the field was applied. In one non-epileptic patient with no FO electrodes inserted (electrodes were attached to the scalp only) no response was seen. Magnetic properties of tissue samples from the human hippocampus also were studied and the results indicate a similarity between this tissue and extracellularly produced magnetite found in the GS-15 bacteria strain.


Biochem. Biophys. Res. Comm. (1996) 227(3):718-723

Application of the Ferromagnetic Transduction Model to D.C. and Pulsed Magnetic Fields: Effects on Epileptogenic Tissue & Implications for Cellular Phone Safety

Jon Dobson and Tim St. Pierre

The ferromagnetic transduction model proposed by Kirschvink (1) suggests that the coupling of biogenic magnetite particles in the human brain to mechanosensitive membrane ion gates may provide a mechanism for interactions of environmental magnetic fields with humans. Extremely low frequency alternating magnetic fields primarily were considered, and in the model A.C. fields with frequencies below 10 Hz should have minimal effect. We show that pulsed fields, square waves and D.C. fields also could force open the membrane gates long enough to disrupt normal neurophysiological processes. The model may therefore be extended to explain results obtained in studies of epileptic patients which show effects on the central nervous system from low frequency square wave and D.C. magnetic fields. In addition, the model also may provide a plausible mechanism linking exposure to magnetic fields from discontinuous transmission cellular telephones and disruption of normal cellular processes in the human brain.


Brain Res. Bull. (1995) 36/2: 155-159

On The Sensitivity of the Human Brain to Magnetic Fields: Evocation of Epileptiform Activity

M. Fuller, J. Dobson, H.G. Wieser and S. Moser

FULLER, M., DOBSON, J., WIESER, H.G., and MOSER, S. On the sensitivity of the human brain to magnetic fields: evocation of epileptiform activity BRAIN RES. BULL. - Evocation of epileptiform activity by DC magnetic fields of between 0.9 and 1.8 millitesla (mT) has been demonstrated in six epileptic patients undergoing presurgical evaluation. The activity was monitored by electroencephalography (EEG) recording from both electrodes attached to the scalp as well as from intracranial electrodes inserted via the foramen ovale. Epileptiform activity evoked by the magnetic field application was distinguished from background levels by comparing the number of epileptiform discharges in the ten second intervals before and after field applications. In nearly all cases, a delay of up to several seconds was observed between the application of the magnetic field and the onset of epileptiform firing. Removal of the field also appeared to cause firing in some instances but this has not yet been investigated systematically. In all six patients, subsequent seizures confirmed that the epileptiform activity monitored during the experiments was originating from the primary epileptogenic zones of the patients.


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