Effects of 8-weeks acupuncture on eyes-closed resting state natural EEG frequency components in endometriosis:...

The aim of this study was to examine changes in resting electroencephalography (EEG) activity associated with an 8-week acupuncture intervention for women with endometriosis and chronic pelvic pain.

Eighteen women aged 18-45 years with laparoscopic diagnosis of endometriosis completed this study. The treatment group (n = 13) received 16 acupuncture sessions over eight weeks, administered in 45-min sessions twice weekly. Self-reported daily pain ratings and eyes-closed resting state EEG were obtained pre- and post-intervention (T1, T2). The control group was insufficient and omitted. Frequency principal components analysis (fPCA) was used to decompose EEG data for each timepoint.

Four fPCA component pairs showed suitable correspondence between T1 and T2: Alpha-II (9 Hz), alpha-III/IV (~10-11 Hz), beta-I (19 Hz), and beta-II (~26 Hz). From T1 to T2, global alpha-II amplitude increased, peak alpha-III/IV frequency increased and amplitude decreased, whilst beta-I amplitude decreased. The relative alpha-III/IV amplitude reduction was associated with the relative reduction in pain severity scores.

Changes in alpha-III/IV peak frequency and amplitude, and the relationship with chronic pelvic pain suggest that ~10-11.5 Hz alpha may index pain severity in women with endometriosis. However, the potential acupuncture-related modulation of alpha could not be determined due to the lack of a suitable control group.

Resting state EEG may be a viable tool to further characterise changes in chronic pain states in a clinical setting and provide objective quantification of responsivity to treatment. Further research with an appropriate control group is recommended to test this.