Increases in the Peak Frequency of the EEG Alpha Rhythm on Presentation of Own Names during Deep Anesthesia

The perception of emotionally significant sounds by patients with depression of consciousness remains a relevant topic. Published data indicate that subjects’ own names presented as sound signals constitute stimuli able to have an activatory effect on subjects in an unconscious state. This study examined the electrophysiological responses of patients under deep anesthesia during neurosurgical procedures to assess the influence of the depth of anesthesia on the perception of sounds, including own names, and to investigate the areas of the brain involved in their analysis. Synchronous EEG recordings were made from 12 scalp electrodes and at the level of the midbrain using two deep electrodes at rest and on presentation of sound stimuli (own name, other people’s names, and noise) in 11 patients immediately after removal of tumors from the posterior parts of the third ventricle or the fourth ventricle. The results showed that patients under deep anesthesia were able to mount responses to their own names in the form of increases in the peak frequency of the α rhythm as compared with recordings on presentation of other people’s names and noise, as well as compared with the resting EEG, both at the levels of the scalp EEG in the temporal areas and at the level of the midbrain.