Comparative effectiveness of different stimulation modes in relieving pain. Part I. A pilot study.

In this pilot study, to assess the optimal stimulation parameters, 3 different forms of transcutaneous electrical nerve stimulation were performed in 27 patients. Conventional continuous stimulation with a constant frequency of 70 Hz, burst stimulation (90 msec trains of pulses with an internal frequency of 100 Hz repeated at 2 Hz, each train consisting of 10 pulses), and frequency-modulated stimulation (continuous pulses changed from 90 Hz to 55 Hz over 90 msec) were randomly delivered to the patients for half an hour in 3 separate sessions. The patients were blind to the modes of stimulation. This pilot study demonstrated that patients preferred modulated stimulation modes such as frequency modulation and burst rather than conventional constant mode.