Effects of acupressure, manual acupuncture and Laserneedle® acupuncture on EEG bispectral index and spectral edge frequency in healthy volunteers
Background and objective: The main purpose of this study was to investigate the effects of sensory (acupressure and acupuncture) and optical stimulation (Laserneedle® acupuncture) on electroencephalographic bispectral index, spectral edge frequency and a verbal sedation score.
Methods: Twenty-five healthy volunteers (mean age ± SD: 25.5 ± 4.0 yr) were investigated during the awake state. The acupuncture point Yintang and a placebo control point were stimulated. The study was performed as a randomized, controlled and partly blinded cross-over trial.
Results: Bispectral index and spectral edge frequency values both decreased significantly (P < 0.001) during acupressure on Yintang to values of 62.9 (minimum 35) ± 13.9 bispectral index and to 13.3 (minimum 2.9) ± 8.1 Hz (spectral edge frequency right) and 13.8 (minimum 2.7) ± 7.3 Hz (spectral edge frequency left), respectively. Bispectral index was also significantly (P < 0.05) affected by Laserneedle® acupuncture and acupressure on the control point but the changes were not clinically relevant, 95.4 ± 4 and 94.2 ± 4.8, respectively. All interventions significantly (Yintang: P < 0.001; control point: P < 0.012) reduced verbal sedation score.
Conclusions: The study highlights the electroencephalographic similarities of acupressure induced sedation and general anaesthesia as assessed by bispectral index and spectral edge frequency.(Accepted August 2003)
Key Words: ACUPRESSURE; ACUPUNCTURE; ELECTROENCEPHALOGRAPHY, bispectral index, spectral edge frequency.
c1 Correspondence to: Gerhard Litscher, Department of Biomedical Engineering and Research in Anesthesia and Intensive Care, University of Graz, Auenbruggerplatz 29, A-8036 Graz, Austria. E-mail: firstname.lastname@example.org; Tel: +43 316 385 3907/83907; Fax: +43 316 385 3908