Long-term Eyes-closed Alpha-enhancement Training: Effects on Alpha Amplitudes and on Experiential State.

In order to determine the effects of long-term alpha-enhancement training on EEG alpha amplitudes and on experiential states, a 2 × 2 factorial design was employed with two levels of Sensory Deprivation (high and low) and two of Feedback-Electrode Placement (O2-F4 and O2-ear). Twelve research participants (3 per cell) engaged in 10 52-mm sessions of eyes-closed alpha-enhancement training with proportional auditory feedback of integrated alpha amplitudes. The results led to five major conclusions: 1) even long-term alpha-enhancement training (with proportional feedback of alpha strength) does not result in the learned enhancement of alpha strength significantly above optimal eyes-closed baseline levels; 2) in some cases, alpha-enhancement training does result in the maintenance of optimal alpha levels; 3) sub-baseline increases in alpha production during alpha training are most often the result of the gradual dissipation or neutralization of alpha-inhibitory influences (disinhibition or habituation versus enhancement); 4) the occurrences of unusual experiences during alpha training are partly due to the sensory deprivation conditions of the experimental procedures, and partly due to the effects of suggestion and the experience of success; and 5) alpha feedback from the O2-F4 and O2-ear placements do not have differential effects on EEG alpha or on experiential state. [ABSTRACT FROM AUTHOR]