Comparison of interferential current accommodation and comfort using three different base frequencies

sensation of paresthesia, which naturally decreases with the therapy time course due to accommodation (7). The accommodation phenomenon occurs after a decrease in the number of nerve depolarization and is related to the repetitive and prolonged stimulation. Therefore, to maintain a constant stimulation, usually an increase in current intensity is required always when the patient reports a reduction related to the current perception (8). The addition of other frequencies ( Δ f) with different slopes has been used as a strategy to avoid the IC accommodation. However, some studies reported that when a 4 kHz base frequency is used, the Δ f strategy is not effective to reduce the accommodation phenomenon (9,10). Indeed, we found only few studies, with contradictory results, establishing which IC base frequencies could avoid current accommodation and which parameters are supposed to be more comfortable during treatment with IC. Therefore, the aim of this study was to assess the required time for the first and the total number of accommodations throughout a 20-minute IC stimulation session and investigate which base frequency (2, 4 or 8 khz) has the best comfort perception during electrical stimulation. Abstract Introduction: The Interferential Current (IC) is widely used by physiotherapists to promote analgesia; however, the stimulus decrease during treatment due to accommodation. It is not clear which current parameters are better to induce less accommodations, therefore, aim of the study was to evaluate the time (seconds) of the first and the total number of current accommodations over a 20- minute treatment with currents of 2kHz, 4kHz and 8kHz and which of the base frequencies are more comfortable during the electrical stimulation. Materials and Methods: 22 subjects were divided into 3 subgroups, which underwent a 20-minute stimulation protocol with all three base currents at different moments. The stimulation was above the sensory threshold and the subjects indicated the time of the first accommodation, how often it occurred, and on the last day reported which frequency was the most comfortable. Results: No differences regarding the accommodation time and base frequency (p>0.05) could be found, however, the 8 kHz current was preferred for almost 82% of the sample (p<0.05). Conclusion: There was no difference in time and number of accommodations among the currents, but the 8 KHz base frequency was the most comfortable used in this protocol.