Significant improvements in cognitive performance post-transcranial, red/near-infrared light-emitting diode treatments in chronic, mild traumatic brain injury: open-protocol study

Abstract

This pilot, open-protocol study examined whether scalp application of red and near-infrared (NIR) light-emitting diodes (LED) could improve cognition in patients with chronic, mild traumatic brain injury (mTBI). Application of red/NIR light improves mitochondrial function (especially in hypoxic/compromised cells) promoting increased adenosine triphosphate (ATP) important for cellular metabolism. Nitric oxide is released locally, increasing regional cerebral blood flow. LED therapy is noninvasive, painless, and non-thermal (cleared by the United States Food and Drug Administration [FDA], an insignificant risk device). Eleven chronic, mTBI participants (26-62 years of age, 6 males) with nonpenetrating brain injury and persistent cognitive dysfunction were treated for 18 outpatient sessions (Monday, Wednesday, Friday, for 6 weeks), starting at 10 months to 8 years post- mTBI (motor vehicle accident [MVA] or sports-related; and one participant, improvised explosive device [IED] blast injury). Four had a history of multiple concussions. Each LED cluster head (5.35 cm diameter, 500 mW, 22.2 mW/cm(2)) was applied for 10 min to each of 11 scalp placements (13 J/cm(2)). LEDs were placed on the midline from front-to-back hairline; and bilaterally on frontal, parietal, and temporal areas. Neuropsychological testing was performed pre-LED, and at 1 week, and 1 and 2 months after the 18th treatment. A significant linear trend was observed for the effect of LED treatment over time for the Stroop test for Executive Function, Trial 3 inhibition (p=0.004); Stroop, Trial 4 inhibition switching (p=0.003); California Verbal Learning Test (CVLT)-II, Total Trials 1-5 (p=0.003); and CVLT-II, Long Delay Free Recall (p=0.006). Participants reported improved sleep, and fewer post-traumatic stress disorder (PTSD) symptoms, if present. Participants and family reported better ability to perform social, interpersonal, and occupational functions. These open-protocol data suggest that placebo-controlled studies are warranted.

Keywords: executive function; mTBI; photobiomodulation; treatment for mTBI.

Figures

FIG. 1.

(a) Sample light-emitting diode (LED) cluster head, showing the side that was applied to the skin. The “X” shows location of the nine red diodes embedded within the LED cluster head. The 52 near-infrared (NIR) diodes surrounding the “X” are not visible to the eye. Each red/NIR LED cluster head had a 5.35 cm diameter, and the total power output was 500 mW. (b) View of subject being treated, and example of three LED placement areas on the head from Set A (first, second, and third LED placements described in Table 2). During each treatment, six LED cluster heads were used simultaneously (13 J/cm2, 10 min per LED placement). Immediately after treatment using the Set A LED placements, the LED cluster heads were moved to other placements on the scalp (Set B) for 10 min. The LED cluster heads were held in place with a soft, nylon cap. The total treatment time per visit was 20 min; it was painless, noninvasive, and non-thermal.

FIG. 2.

Graphs showing a significant linear trend over time for the effect of LED treatments on specific neuropsychological tests. (A) Stroop Test for Executive Function, Trial 3 inhibition (p=0.004); (B) Stroop, Trial 4 inhibition switching (p=0.003); (C) California Verbal Learning Test (CVLT)-II, Total Trials 1–5 (p=0.003); and (D) CVLT-II, Long Delay Free Recall (p=0.006).