Effects of linear-polarized near-infrared light irradiation on chronic pain

ScientificWorldJournal. 2012;2012:567496. doi: 10.1100/2012/567496. Epub 2012 Apr 19.


In order to study the efficacy of linear-polarized near-infrared light irradiation (LPNIR) on relieving chronic pain in conjunction with nerve block (NB) or local block (LB), a 3-week prospective, randomized, double-blind, controlled study was conducted to evaluate the pre- and post-therapy pain intensity. Visual analogue scales (VASs) were measured in all patients before and 6 months after therapy visiting the pain clinic during the period of August 2007 to January 2008. A total of 52 patients with either shoulder periarthritis or myofascial pain syndrome or lateral epicondylitis were randomly assigned into two groups by drawing lots. Patients in Group I were treated with NB or LB plus LPNIR; Group II patients, for their part, were treated with the same procedures as in Group I, but not using LPNIR. In both groups, the pain intensity (VAS score) decreased significantly immediately after therapy as compared to therapy. There was a significant difference between the test and control groups immediately after therapy (P < 0.05), while no effect 6 months later. No side effects were observed. It is concluded that LPNIR is an effective and safe modality to treat various chronic pains, which has synergic effects with NB or LB.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Aged
  • Chronic Pain / therapy*
  • Combined Modality Therapy
  • Double-Blind Method
  • Female
  • Humans
  • Infrared Rays / therapeutic use*
  • Male
  • Middle Aged
  • Myofascial Pain Syndromes / therapy
  • Nerve Block / methods*
  • Pain Measurement
  • Periarthritis / complications
  • Prospective Studies
  • Shoulder Pain / etiology
  • Shoulder Pain / therapy
  • Tennis Elbow / therapy
  • Treatment Outcome