Effects of Light Therapy on Vascular Function in Patients with Diabetic Peripheral Neuropathy

Abstract

Diminished vascular function has been reported to be common in patients with diabetic peripheral neuropathy (DPN) and acts as a major contributor to cardiovascular disease as well as lower limb complications. DPN is a consequence of diabetes-mediated impairment blood flow which leads to microvascular disturbances, which is best characterized as neuropathic pain. Foot pain due to DPN is one of the factors affecting walking ability. Infrared light therapy has been shown to be effective in reducing pain and increasing local circulation in a variety of painful conditions including neuropathy. This study aimed to determine the effects of infrared light therapy treatment on vascular function (i.e., microcirculation) and pain relief among patients with DPN. Nine patients (age: 74 ± 8.68 years) participated in this study. Infrared light therapy treatment was applied 3 times per week for 30 minutes per day, across 5 weeks. The light therapy intervention was performed using the Anodyne Therapy System (ATS). Before and after infrared light therapy treatment, vascular function [Digital Thermal Monitoring (DTM) of vascular reactivity] and pain assessment [Brief Pain Inventory-short form (BPI-SF) and short-form McGill Pain Questionnaire (SF-MPQ)] were evaluated. After the 5-week treatment, the vascular reactivity index (i.e., microvascular function) increased significantly by 25% from baseline (1.76 ± 0.13 to 2.20 ± 0.15, p < .05). In addition, the BPI-SF and SF-MPQ showed that pain decreased following light therapy. Our preliminary findings indicated that infrared light therapy promoted positive effects on microvascular function and pain relief in patients with DPN.