Abstract
Success or failure of EEG feedback training for alpha enhancement can depend on how alpha activity is quantified and fed back. Alpha-enhancement failures usually employ a percent time(%) technique; successes typically use amplitude integration(ε). To dramatize the differences between percent and integration techniques, we derived both measures simultaneously from left occipital(O 1 ) and left central(C 3 ) sites for 16 male subjects who were given 5.6 hours of integrated alpha feedback from the midline occipital(Oz ) site. At both the O 1 and C 3 sites the integrated and percent measures were not equivalent and not linearly related. Statistically significant differences in the(integrated, percent) correlation coefficients(z-transformed) were observed under the different recording conditions: alpha enhancement, alpha enhancement, alpha suppression, and baselines. Theoretical discussion of integration and percent techniques is given and the adoption of amplitude integration measures and feedback stimuli is strongly advocated.
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This study was supported by the following grants and contracts: National Institute of Mental Health (NIMH) Predoctoral Fellowship #1 F01 MH51704-01, NIMH General Research Support Grant #LPNI 185, and a Langley Porter Neuropsychiatric Institute Postdoctoral Fellowship (Interdisciplinary Training Program, NIMH #7082) to James V. Hardt, and by NIMH Research Scientist Development Award 2K02 MH38897, NIMH Research Grant #1 R01 MH24820, Office of Naval Research (ARPA) Contract N00014-70-C-0350, and Instruction and Research Funds, Computer Center Accounts (UCSF) #1431 and #1437 to Joe Kamiya.
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Hardt, J.V., Kamiya, J. Conflicting results in EEG alpha feedback studies. Biofeedback and Self-Regulation 1, 63–75 (1976). https://doi.org/10.1007/BF00998691
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DOI: https://doi.org/10.1007/BF00998691