Partial Amnesia for a Narrative Following Application of Theta Frequency Electromagnetic Fields?

Abstract

Twenty-four university students were Instructed to listen to a three-minute narrative whose propositional and syntactic structure had been standardized. During either the first, second, or third minute of the narrative, subjects (n = 6/group) were exposed to a 5-llz electromagnetic field (Relaxit) that was applied to either the left or right side of the head at the level of the temporal lobe. Subjects then retold the story within 5 minutes. Discourse analysis of each subject's transcript was completed by an expert who was not familiar with the condition of the subjects. There was a significant field condition effect that accounted for 40% of the variance in verbal measures. Subjects that had been exposed to the 5-Hz field during the first minute of the narrative displayed less than half the number of references to the narrative compared to the control group. There was a significant type of reference (recall vs inference) by field condition interaction. The field applied during the first minute reduced the number of Inferences substantially more than the number of direct recalls relative to these values for the control group. These results suggest that the application of ELF fields near the temporal lobe during the electrically labile stage of consolidation for a complex verbal behavior may have affected the memory for this material.