To study global system for mobile communications (GSM) cellular phone radiofrequency effects on human cerebral activity. The work was based on the investigation of auditory evoked potentials recorded from healthy humans and epileptic patients. Ten variables measured from auditory evoked potentials were employed in the design of a supervised support vector machines classifier.
|Chamber||The subject reclined on a chair in a soundproof Faraday screened room.|
|Setup||Two 24-ms sound stimuli of 500 Hz and 1 kHz in random order (250 times each) were heard through the phone once every second. The experimental sessions consisted of four phases: no RF emission, minimal RF emission, maximum RF emission and again minimal RF emission.|
|Additional info||Every healthy subject took part in two sessions several days apart (with the phone on the right or the left ear). A third session was either supplementary or sham. Epileptic patients had only two sessions (EMF or sham on the side affected by the disease). The type of session was not known to the subject. In this study only phones on the right ear were considered.|
For both groups, the N100 amplitudes were reduced under the influence of GSM radiofrequency (mean attenuation of -0.36 µV for healthy subjects and -0.60 µV for epileptic patients). Healthy subjects showed a N100 latency decrease, which could be consistent with mild, localised heating. The auditory cortical activity in humans was modified by GSM cellular phone radiofrequencies, but an effect on brain functionality has not been proven.