Objectives: To compare the immediate analgesic effects of 2 kHz or 4 kHz interferential current (IFC) with different amplitude-modulated frequencies (AMFs) (2 Hz or 100 Hz) on chronic low back pain (CLBP).
Design: Three-arm double-blinded randomized controlled trial.
Setting: Primary care.
Participants: 175 patients (19 to 60 years of age, 105 female) with CLBP.
Interventions: One session of IFC: Interferential group (GI): GI2 kHz/100 Hz, GI2 kHz/2 Hz, GI4 kHz/100 Hz, GI4 kHz/2 Hz, or placebo.
Main outcomes measures: Pain intensity by numerical rating scale of pain (NRS), McGill Pain Questionnaire (MPQ), and algometry.
Results: There was a significant difference in NRS scores (P < 0.05) in the GI2 kHz/2 Hz, GI4 kHz/2 Hz, and GI4 kHz/100 Hz groups compared with those of the placebo group (PG), and a significant difference in MPQ scores in the GI4 kHz/2 Hz and GI4 kHz/100 Hz groups compared with those of the PG. In algometry, only the GI4 kHz/100 Hz group showed a significant difference (by 2 points in the lumbar region) compared with the PG. Of the carrier frequencies, an IFC of 4 kHz showed more effective results, although no significant difference was noted between the AMFs.
Conclusion: An IFC with a carrier frequency of 4 kHz and an AMF of 100 Hz provide immediate analgesic effects in individuals with CLBP.
Clinical trial registration number: RBR-59YGRB.
Keywords: low back pain; pain measurement; transcutaneous electrical nerve stimulation.
© 2020 World Institute of Pain.