Blinding Techniques for Laser Therapy

Evid Based Complement Alternat Med. 2008 Dec;5(4):383-9. Epub 2007 Sep 13.

Blinding techniques in randomized controlled trials of laser therapy:

Relf I, Chow R, Pirotta M.

Department of General Practice, University of Melbourne, 200 Berkeley Street Carlton 3053, Victoria, Australia. i.relf@unimelb.edu.au.

Low-level laser therapy has evidence accumulating about its effectiveness in a variety of medical conditions. We reviewed 51 double blind randomized controlled trials (RCTs) of laser treatment. Analysis revealed 58% of trials showed benefit of laser over placebo. However, less than 5% of the trials had addressed beam disguise or allocation concealment in the laser machines used. Many of the trials used blinding methods that rely on staff cooperation and are therefore open to interference or bias. This indicates significant deficiencies in laser trial methodology. We report the development and preliminary testing of a novel laser machine that can blind both patient and operator to treatment allocation without staff participation. The new laser machine combines sealed preset and non-bypassable randomization codes, decoy lights and sound, and a conical perspex tip to overcome laser diode glow detection.

Acupunct Med. 2005 Sep;23(3):103-11.

Laser acupuncture for mild to moderate depression in a primary care setting–a randomised controlled trial.

Quah-Smith JI, Tang WM, Russell J.

Monash University, Victoria, Australia. jiqs@tpq.com.au

OBJECTIVE: Depression is a major public health problem. There is some evidence supporting the effectiveness of needle acupuncture in its treatment. Laser stimulation, regarded here as a modality of acupuncture, is non-invasive and therefore free of infection risk; and it is acceptable to patients with needle phobia. The technique is relatively easily learned by community-based general practitioners. It is also amenable to sham control and therefore double-blinding in clinical trials. A double-blind randomised controlled trial was conducted to test the efficacy of low level laser acupuncture in mild to moderate depression. METHODS: Thirty patients with depression were randomised to receive either active or inactive laser treatment. The laser unit could be switched to one of two settings. One switch position delivered active laser acupuncture and the other was inactive (sham). In the active mode, 0.5J was delivered to each of six to eight individually tailored acupuncture sites per visit. All patients were treated twice weekly for four weeks then weekly for a further four weeks. The patients and the acupuncturist were both blinded to conditions. Outcome was assessed using the Beck Depression Inventory at baseline, weeks four and eight during treatment, and at 4 and 12 weeks following the treatment. RESULTS: At the end of the treatment period, Beck Depression Inventory scores fell from baseline by 16.1 points in the intervention group and by 6.8 points in the sham control group (P<0.001). The difference showed only a trend four weeks later, but was again significant after 12 weeks (P=0.007). Laser acupuncture was well tolerated with transient fatigue as the most common adverse effect. CONCLUSION: Laser acupuncture may be worth further investigation as a treatment for mild to moderate depression in primary care.