A new, hot therapy is being promoted for a range of problems, especially among chiropractors. It’s called near-infrared laser therapy (NILT), and its enthusiastic practitioners say the noninvasive, benign-sounding treatment is good for victims of strokes and head injuries hoping to recover their motor function.
But as reported on MedPageToday.com, the evidence supporting such claims is “extremely scant.”
There are some animal experiments, some in vitro data and a few “isolated case reports” involving humans. But the two largest clinical trials of the procedure, which involved patients who had suffered ischemic stroke, failed. And the sponsor of those trials has declared bankruptcy.
The technology sounds promising: Studies have shown that electromagnetic radiation in the near-infrared – that’s the wavelength just beyond the limit of human vision – can affect cell and organism biology. Some, but not all of the changes it caused, explains MedPageToday, can be attributed to the heat generated by absorption of near-infrared radiation.
These effects include increased ATP synthesis in mitochondria, which, essentially, is the provision of energy to cells, sometimes called “energy currency.” The process is relevant especially to the central nervous system because insults to brain neurons, such as those resulting from stroke, can impair energy metabolism. So raising the cells’ energy levels, the thinking goes, might keep them functioning.
According to MedPageToday, a NILT device designed for a study on rabbits that delivered moderate doses of radiation proved to be safe and effective, in terms of preserving motor function, when they were administered up to about six hours after the onset of a stroke. That’s a longer period than the window for which thrombolytic drugs (which dissolve blood clots) generally are considered effective after someone’s had a stroke.
Several studies sponsored by a company called PhotoThera followed, including a series of randomized clinical trials. One involved patients recruited within 24 hours of the onset of an acute ischemic stroke. Twice as many patients were assigned to NILT as those given the sham treatment.
At 90 days after treatment, functional measures were significantly better in the NILT group, so another trial with a similar design was initiated. But it missed its primary endpoint of improvement; slightly more than 1 in 3 NILT patients achieved favorable outcomes, but so did slightly less than 1 in 3 controls. (An endpoint is the measure the researchers consider a successful outcome of the therapy undergoing trial – for example, a statistically significant improvement in overall survival.)
PhotoThera raised money for another trial, which began in late 2010 and was to be completed two years later. But no results were ever released, and the trial supposedly was shut down in October 2012, as MedPageToday reports, “for futility.” Last year, PhotoThera filed for bankruptcy.
The problem might have been that stroke indication wasn’t a good choice as the first application for NILT because the radiation must penetrate too deeply. In the rabbit studies, the radiation reached the entire brain, but human skulls are thicker, and their larger brains prevent the radiation from reaching beyond the outer layers, or not deep enough to affect motor function reliably.
NILT studies to help preserve or restore cognitive function in patients with traumatic brain injury are underway, and have been promising for improvements in cognition. And encouraging results have been reported with respect to Alzheimer’s disease, Parkinson’s disease and some other neurological conditions. But this science is young.
Devices for delivering NILT are FDA-approved for musculoskeletal pain, but the treatment might be simply as a heat source. That’s why they’re popular in physiotherapy clinics and chiropractic offices, which see lots of patients for treatment of pain.
Beware of practitioners who promote the technology for nonpain treatments. There’s no solid evidence it works, it’s costly and any intervention has the possibility to cause harm, although this nonionized radiation does not carry the potential harm of overdose injuries that ionized radiation, such as that imparted by X-rays, does.
If your health-care provider suggests NILT to treat your pain, ask, instead, for a hot pack.