Positive Emotional Experience: Induced by Vibroacoustic Stimulation Using a Body Monochord in Patients with Psychosomatic Disorders: Is Associated with an Increase in EEG-Theta and a Decrease in EEG-Alpha Power

Relaxation and meditation techniques are generally characterized by focusing attention, which is associated with an increase of frontal EEG Theta. Some studies on music perception suggest an activation of Frontal Midline Theta during emotionally positive attribution, others display a lateralization of electrocortical processes in the attribution of music induced emotion of different valence. The present study examined the effects of vibroacoustic stimulation using a Body Monochord and the conventional relaxation music from an audio CD on the spontaneous EEG of patients suffering from psychosomatic disorders (N = 60). Each treatment took about 20 min and was presented to the patients in random order. Subjective experience was recorded via self-rating scale. EEG power spectra of the Theta, Alpha-1 and Alpha-2 bands were analysed and compard between the two treatment conditions. There was no lateralization of electrocortical activity in terms of the emotional experience of the musical pieces. A reduction in Alpha-2 power occurred during both treatments. An emotionally positive attribution of the experience of the vibroacoustically induced relaxation state is characterized by a more pronounced release of control. In the context of focused attention this is interpreted as flow experience. The spontaneous EEG showed an increase in Theta power, particularly in the frontal medial and central medial area, and a greater reduction in Alpha-2 power. The intensity of positive emotional feelings during the CD music showed no significant effect on the increase in Theta power.

Changes in spontaneous EEG activity indicate a special kind of information processing in concept learning

Some findings in the literature suggest that a high amount of spectral power in spontaneous EEG alpha 1 band (7.5-10.0 Hz) may be associated with tasks demanding extensive monitoring of stimulus information and combining features for a match with internal concepts ("exploration"). EEG recordings were obtained from 9 subjects involved in a concept-learning task. They had to match visually presented objects with a concept built up by hypothesis and to respond by pressing a "yes" or "no" key. Epochs of EEG data were analyzed with epoch center-times at 500 and 250 ms before response execution. In the case of "yes" responses, when subjects could match their hypothesis positively with combined features of the presented object increased alpha 1 spectral power was found. Also alpha 1 power was larger immediately after disconfirming feedback than after confirming feedback. Additionally, alpha 2 spectral power (10.5-12.5 Hz) was found to be larger 250 ms after confirming feedback than after disconfirming feedback. It is argued that alpha 1 power seems to reflect those mental processes which are involving in combining features and matching them to a concept in mind. The increase in alpha 2 power after confirming feedback is interpreted in terms of general processing demands imposed during task performance.