Immediate Effects of the Combination of Interferential Therapy Parameters on Chronic Low Back Pain: A Randomized Controlled Trial.

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.