title: Effect of transcutaneous electrical nerve stimulation on primary dysmenorrhea.
abstract: Objectives. Dysmenorrhea is a disturbing problem among women of childbearing age. The purpose of this study is to investigate the effect of high-frequency transcutaneous electrical nerve stimulation (TENS) on primary dysmenorrhea and to compare the placebo effect by sham TENS in a randomized controlled study. Materials and Methods. Twenty-two women participated in the two-month experiment by using TENS or sham TENS in a random order for their dysmenorrhea. Outcome measures included self-reported pain intensity, symptom and function questionnaire related to dysmenorrhea, quality of life, satisfaction after TENS application, and other pain management agents adapted by the participants. Two-way repeated measures analysis of variance (two-way ANOVA) was conducted to compare pain intensity between pre-post values and groups (TENS vs. placebo). One-way repeated measures analysis of variance (one-way ANOVA) was conducted to compare scores from questionnaire of symptoms and quality of life at baseline, and after placebo or TENS stimulation. Results. Pain intensity in TENS is significantly decreased than in the placebo group (p= 0.018). The decrease of pain intensity after TENS and placebo TENS were both significant, with p < 0.00005 and p < 0.00005 respectively. Furthermore, TENS significantly changed the degree of autonomic symptoms (p= 0.048); but not after placebo TENS. Conclusion. This result supports that women in our country who suffer from primary dysmenorrhea could benefit by using TENS, which is consistent with the previous studies. In addition to pain-relieving effects, relief of the autonomic symptoms associated with dysmenorrhea also indicated that the mechanism of TENS might be different from the placebo effect of the sham TENS stimulation. These findings indicate the immediate effects of TENS in women with primary dysmenorrheal.
authors.affiliation: Graduate Institute and School of Physical Therapy, College of Medicine, National Taiwan University, Taiwan;              Department of Physical Medicine and Rehabilitation, National Taiwan University Hospital, Taiwan;              Center of Physical Therapy, National Taiwan University Hospital, Taiwan; and              Department of Obstetric and Gynecology, Department and Graduate institute of Forensic Medicine, College of Medicine, National Taiwan University, Taiwan.
authors.forename: Shwu-Fen
authors.initials: SF
authors.lastname: Wang
authors.forename: Jo-Ping
authors.initials: JP
authors.lastname: Lee
authors.forename: Hsiao-Lin
authors.initials: HL
authors.lastname: Hwa