An in-depth study of long-term users of transcutaneous electrical nerve stimulation (TENS). Implications for clinical use of TENS.

This in-depth study examines the relationships between patient, stimulator and outcome variables in a large number of chronic pain patients utilising TENS on a long-term basis. 179 patients completed a TENS questionnaire designed to record age, sex, cause and site of pain and TENS treatment regime. Of these 179 patients, 107 attended our research unit for assessment of the electrical characteristics of TENS during self-administered treatment. Although a remarkable lack of correlation between patient, stimulator and outcome variables was found to exist, the analysis revealed much information of importance: 47% of patients found TENS reduced their pain by more than half; TENS analgesia was rapid both in onset (less than 0.5 h in 75% patients) and in offset (less than 0.5 h in 51% patients); one-third of patients utilised TENS for over 61 h/week; pulse frequencies between 1 and 70 Hz were utilised by 75% of patients; 44% of patients benefitted from burst mode stimulation. The clinical implications of these findings are discussed.