Heffernan, Michael. Comparative effects of microcurrent stimulation on EEG spectrum and correlation dimension. Integrative Physiological and Behavioral Science, 31(3):202-209, 1996.
Two mathematical derivatives of electroencephalogram (EEG), fast fourier transform (FFT), and non-linear, system dynamic measures of correlation dimension from chaos analysis, were used to assess the objective effects of Alpha-Stim earlobe (CES) versus Alpha-Stim mid-trapezius muscle stimulation on brain EEG. These measures were considered to be clinically relevant since low points in the FFT have been associated with attention deficit disorder, and declining correlation dimension has been associated with onset of epilepsy.
30 subjects from the author’s practice who completed informed consent were randomly assigned to 1 of 3 treatment groups: earlobe, trapezius, and a double-blind placebo control. 18 female and 12 male subjects between 40 and 70 years old (mean of 65), participated. Typical symptoms included head, neck, and shoulder pain of several years duration, with 75% having been diagnosed with some level of auto-immune disease, primarily of a rheumatoid type. All subjects also displayed symptoms of slow wound healing, fatigue, and periodic flare-ups of joint inflammation. After an initial 5 minute rest period, 10 minutes of Alpha-Stim treatment of 100 A at 0.5 Hz, or placebo, was given between 2, 2 minute EEG recordings. 4,000 data points were generated for each subject representing successive EEG amplitudes in the 2 minute EEG records. Results showed that trapezius stimulation proved more effective in producing significant declines in FFT spectral smoothing, with an average standard deviation (SD) in the FFT of 1.1, as compared to the CES group showing a SD of 2.9. Correlation dimension of both trapezius and CES groups increased significantly (P<.001) as compared to placebo, with the correlation dimension measures for earlobe being 5.7, trapezius 5.6, and placebo 3.7.
The author discusses the significance of using stimulation of body sites for promoting clinically beneficial effects in brain electrophysiology as evidenced by improved FFT and correlation dimension. Significant changes in FFT, represented as spectral smoothing, followed trapezius microcurrent stimulation, suggesting a clinical application to treat low amplitude FFT bands associated with anxiety disorders (5 - 12 Hz), and attention deficit disorder (12 - 14 Hz). As correlation dimension increases in EEG data, the eigenvectors transverse many more paths, avoiding a collapse into fixed point attractors and resultant pathologic brain electrical patterns. This study’s effects on raising return plot complexity, and correlation dimension, may only apply to microcurrent devices that have complex, or chaotic waveforms, such as the Alpha-Stim. Not all commercially available stimulators have such parameters. No side effects were reported.