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M. J. Schroeder, , a, b and R. E. Barrb, c

a Department of Electrical and Computer Engineering, North Dakota State University, Fargo, ND 58105, USA

b Biomedical Engineering Program, The University of Texas at Austin, Austin, TX 78712, USA

c Mechanical Engineering Department, The University of Texas at Austin, Austin, TX 78712, USA

Accepted 3 August 2001 Available online 25 October 2001.

Abstract
Objective: Normal individuals were used to quantitate electroencephalographic (EEG) changes during concurrent administration of 0.5 and 100 Hz cranial electrotherapy stimulation (CES).

Methods: Twelve normal, right-handed males were used in a randomized, double-blind crossover design study. A 3 amplifier system incorporating noise-cancellation was used to collect one channel of EEG (O1-Cz configuration) for 30 min. Either 0.5, 100 Hz, or sham CES treatment was administered for 20 min of each session. Statistical analyses were applied to time- and frequency-domain EEG variables.

Results: Relative to sham control, 0.5 and 100 Hz CES caused the alpha band mean frequency to shift downward. Additionally, 100 Hz CES also caused a decrease of the alpha band median frequency and beta band power fraction.

Conclusions: Both 0.5 and 100 Hz CES provide frequency distribution shifts that suggest beneficial changes in mental state. However, compared to 0.5 Hz CES, 100 Hz CES effected a greater overall change. It is suggested that similar tests be performed on individuals with various behavioral and neurological disorders to determine if comparable EEG changes can be realized and correlated with beneficial effects of CES therapy.