Effect of interferential current stimulation in management of hemiplegic shoulder pain.

Objective: To study the immediate effects of interferential current stimulation (IFC) on shoulder pain and pain-free passive range of motion (PROM) of the shoulder in people with hemiplegic shoulder pain (HSP).

Design: Double-blind, placebo-controlled clinical trial.

Setting: Institutional physical therapy clinic, neurologic rehabilitation center.

Participants: A population-based sample of people with HSP (N=30) was recruited.

Intervention: Participants were divided into 2 groups--an IFC group and a placebo group--by using a match-paired method (age, sex, and Brunnstrom motor recovery stage). In the IFC group, participants received IFC for 20 minutes with an amplitude-modulated frequency at 100 Hz in vector mode. The current intensity was increased until the participants felt a strong tingling sensation.

Main Outcome Measures: Pain intensity and pain-free PROM of the shoulder until the onset of pain were measured at baseline and immediately after treatment.

Results: Participants reported a greater reduction in pain during the most painful movement after treatment with IFC than with placebo (P<.05). The IFC group showed a greater improvement in posttreatment pain-free PROM than the placebo group in shoulder flexion (P<.01), abduction (P<.01), internal rotation (P<.01), and external rotation (P<.01).

Conclusions: This study provides evidence that IFC is effective for the relief of pain during movement and also increases the pain-free PROM of the shoulder in people with HSP.