Deep magnetic brain stimulation--the end of psychiatric electroshock therapy?

The biophysical processes during electroconvulsive therapy (ECT) are discussed. The multilayer head structure causes a shunting and spreading of the major portions of the current all over the extracranial tissues. The final effect is that only a small percentage of the injected current passes into the brain. The second 'side effect' of the ECT is the electrical overstimulation of the cortex layer, with self-sustained after-discharge causing convulsive seizure. Therefore, the stimulus transmission into the neurochemically and physiologically disturbed meso-diencephalic region is the most important problem. The stimulation of the brain with rapid-rate time-varying magnetic field pulses makes this problem soluble. The magnetic field passes through all head structures with no attenuation and can stimulate the brain without discomfort. Our calculations of stimulus parameters have assumed that this inductive method may be able to evoke the same therapeutic effects as ECT, but in a safer way (painless, noninvasive and without motor seizure).