Comparison between bipolar and tetrapolar of the interferential current in nociceptive threshold, accommodation and pleasantness in healthy individuals

Abstract

The study compared the effects between bipolar (BI) and tetrapolar (TT) forms of the interferential current (IC), on intensity and pain threshold to cold and pressure, accommodation and pleasantness of the current in healthy subjects. For this, a random, double-blind crossover study with 24 healthy subjects, of both genders, who were equally distributed in two groups, was conducted. The first evaluated item was the pain threshold to cold. The volunteers immersed the dominant foot in iced water (5°C) for 30 s, and recorded the pain threshold to cold. At the end, they graded the pain intensity by a visual analog scale (VAS). Soon after the pain threshold to pressure was evaluated with the use of a pressure algometer between the first and second metatarsal and L3 spinous process. Then the volunteers were submitted to the application of the IC, with the following parameters: 4000 Hz base frequency, amplitude modulated frequency (AMF) 50 Hz, for 20 min. Volunteers were re-evaluated straight away, 20 and 60 min after the IC usage. The last part of the analysis consisted of, after application of BI and TT, knowing which was the most enjoyable. The results revealed that in the evaluation of the pain threshold to pressure on the metatarsal, there was significant difference when comparing all evaluations of BI with only the last of TT; there was also difference on the accommodation threshold. We concluded that the IC usage, on nerve roots L4 and S3, on the proposed parameters, produced a higher accommodation threshold in the TT form, and it was more effective than BI on the metatarsal. However, the pain threshold to pressure (on the spine), to cold and its intensity did not suffer any change.

Key words::

• Electric stimulation therapy
• pain measurement
• physical therapy modalities

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.