Transcranial low-level light therapy (LLLT) appears to be safe when administered in the acute phase of traumatic brain injury (TBI), new research has shown.
The US study, published in JAMA Network Open, comprised 68 patients with an acute, non-penetrating moderate TBI randomised to either LLLT or sham therapy commenced within 72 hours of their injury.
Low-level light therapy was delivered in three, 20-minute therapy sessions via a custom-built helmet outfitted with 18 clusters of 20 NIR light-emitting diodes. Sham therapy was delivered using the same helmet with the fans on but the light-emitting diodes turned off.
While only 19 patients in the active arm and 24 controls completed the study with follow-up MRI scans, there were no adverse events associated with use of the helmet in either group.
“The helmet application was feasible even in patients with subgaleal hemorrhage, soft tissue swelling, and small dressings applied to portions of the head,” the study reported.
The study also noted a non-significant reduction in patient-reported symptoms of headache, dizziness, and nausea/vomiting in the light therapy group compared to the controls.
However there was some indication that light therapy does affect the brain, supporting the previous beneficial effects seen in preclinical studies.
“In the late subacute stage, there were statistically significant differences in the magnetic resonance imaging–derived diffusion parameters of the white matter tracts between the sham- and light-treated groups, demonstrating neuroreactivity of LLLT.”
“Our results provide what is, to our knowledge, the first direct evidence that trans-cranial LLLT targets and engages neural substrates that play an integral role in the pathophysiologic effects of moderate TBI.”
The authors said their findings support the premise that light therapy was likely to affect myelin repair pathways.
“Since the degree of damage to the axons and surrounding myelin is a function of the severity of the neurotrauma, our observations should not be generalized to mild or severe TBI,” they said.
An Invited Commentary, also published in JAMA Network Open, said it was certainly justifiable to pursue further investigation of LLLT.
“Larger multicenter trials with longer follow-up periods are the next step and should be pursued.”
However, ”… given the complexity and variability of TBI-related disabilities, it is unlikely that LLLT will assume an isolated role in the secondary prevention of physical, cognitive, and emotional repercussions of TBI.”
“Individually tailored multidisciplinary rehabilitation programs will probably continue to be the standard of care after moderate and severe TBI.”
“Moreover, pursuing gains in TBI treatment should accompany continuing investment in primary prevention strategies. Preventing trauma from falls, road accidents, terrorism, violence, and crime has the highest potential to achieve worldwide reduction of TBI-related disabilities.”