Effects of Cranial Transcutaneous Electrical Nerve Stimulation in Normal Subjects at Rest and during Psychological Stress

Some effects of sub-threshold sine-wave transcutaneous electrical nerve stimulation (TENS), passed between earlobe electrodes at a constant alternating current (AC) frequency of 100 Hertz (Hz), were investigated in 90 normal subjects after 30 minutes of treatment, and after 3 minutes of standardized mental stress (mental arithmetic) which immediately followed the 30 minute treatment. In a double-blind protocol, five groups received 1) active TENS during treatment and active TENS during stress; 2) active TENS during treatment and placebo TENS during stress; 3) placebo TENS during treatment and placebo TENS during stress; 4) placebo TENS during treatment and active TENS during stress; and 5) no treatment during both treatment and stress. Results showed significant reductions in systolic blood pressure, pulse rate and anxiety, but not in diastolic blood pressure or peripheral vascular tension, after 30 minutes of active TENS as compared to no treatment. No placebo TENS effect was observed. No significant differences were observed between active TENS, placebo TENS and no treatment in physiological or psychological response to the stress procedure. Results are discussed in terms of the applicability of this technique to the management of stress.