Peripheral neuropathy is one of the most common chronic diseases and a leading cause of adult disability in the U.S. Diabetic neuropathy represents over a third of all neuropathies, making diabetes the leading cause of peripheral neuropathy, affecting about 15-18 million Americans.~Living with neuropathy can cause tremendous frustration and social isolation. The daily chronic pain impacts day-to-day functionality resulting in physical and psychological problems including impaired concentration, anxiety, depression, a decline in cognitive abilities, and sleep difficulties which in turn can lead to irritability and increased pain sensitivity. Additionally, the economic burden from medical costs and workplace productivity losses are high and on the rise as the incidence of peripheral neuropathy increases.~Peripheral neuropathy describes damage to the peripheral nervous system that interferes with vital nerve connections, distorting and sometimes interrupting messages between the brain and the rest of the body. Diabetic peripheral neuropathy is a chronic acquired form of nerve damage that can occur in individuals with diabetes wherein the primary cause is damage to nerve fibers and blood vessels from prolonged exposure to high blood sugar (glucose). While the precise mechanism for this damage remains unclear, a combination of factors likely plays a role, including the complex interaction between nerves and blood vessels. High blood glucose interferes with the ability of the nerves to transmit signals and weakens the walls of the small blood vessels (capillaries) that supply the nerves with oxygen and nutrients.~The primary and most debilitating symptom of diabetic peripheral neuropathy is a sensation of tingling, prickling, buzzing, pinching, burning, and/or sharp jabbing stabbing pain in the feet. Nerve pain from diabetic peripheral neuropathy can be severe, constant, and difficult to treat. Current therapies include an array of over-the-counter and prescription medications or alternative treatment options such as injections or patches of local anesthetics; surgical destruction of nerves; implantation of a device to relieve pain; transcutaneous electrotherapy (TENS); hand or foot braces and orthopedic shoes.~Low Level Laser Therapy (LLLT) communicates information to the receptors on the membrane of the cell and mitochondrion (the enzymatic engine of the cell). This energetic information reaches the cell's DNA, which directly controls cell function. When the cells receive better information, they work better, as do the tissues they comprise, like bones, cartilage, tendons, ligaments, etc. In this way, LLLT promotes the healing and regeneration of damaged tissues, having both local effects on tissue function and also systemic effects carried throughout the body by the blood and acupuncture meridians.~The key basic physiological effects of low level laser light include increased cell membrane polarization and permeability; Adenosine-5-triphosphate (ATP) production and respiratory chain activity; enzyme activity; collagen and epithelial production; capillary formation; macrophage (immune) activity; analgesic effects due to elevated endorphin production, electrolytic nerve blockage, and improved blood and lymph flow; anti-inflammatory effect due to improved circulation and accelerated tissue regeneration; and increased production of antioxidants. Of additional benefit is that light energy from low level lasers will only be absorbed by cells and tissues that are not functioning normally and has no effect on healthy cells.~Therefore, low level laser therapy has the potential benefit of providing an effective means of reducing low back pain that is simple, quick, non-invasive and side-effect free.
The purpose of this study is to determine whether low level laser therapy is effective in the reduction of foot pain associated with diabetic peripheral neuropathy.