Understanding the mechanisms that support healthy brain aging is a growing priority in the scientific and clinical community. Among the various non-invasive strategies being explored, transcranial photobiomodulation has gained attention for its potential to improve cerebral perfusion. A study published in Lasers in Medical Science evaluated the effects of transcranial LED therapy (TCLT) on cerebral blood flow in elderly women, providing new insights into its potential hemodynamic benefits.
A Closer Look at the Intervention
In this study, healthy, independent elderly women received transcranial LED therapy using a 627-nm wavelength. The intervention parameters were carefully selected to ensure both safety and effectiveness. The LED device operated at 0.2 W, with a power density of 70 mW/cm² and an energy density of 10 J/cm². The light was applied for 30 seconds at each of four frontal and parietal points, totaling 120 seconds per session. Each participant underwent two sessions per week for four weeks—adding up to 14 sessions in total.
The procedure was carried out with standardized protocols: participants remained seated with head support, their eyes were protected, and the LED probe was applied directly to the skin. All sessions were conducted by a trained therapist and scheduled consistently at the same time of day to maintain methodological uniformity.
Key Results: Enhanced Cerebral Hemodynamics
The findings showed that TCLT induced significant changes in blood flow velocity, particularly in the left middle cerebral artery (MCA) and basilar artery (BA). The increases were more pronounced in diastolic velocity than systolic velocity. Importantly, the resistance index (RI)—a marker of vascular resistance—was notably reduced, especially in the left MCA.
Interestingly, no significant changes were observed in the right MCA. The authors noted that all participants were right-handed, suggesting that the dominant hemisphere (typically the left in right-handed individuals) might have a greater physiological response to the intervention.
The results suggest that the observed increases in blood velocity were not due to changes in systemic blood pressure, which remained stable, but rather to localized improvements in cerebral blood volume. These changes reflect improved vascular elasticity and reduced resistance in the cerebral arteries, both of which are favorable indicators of cerebral health.
Conclusions: A Potential Pathway for Non-Invasive Brain Support
The authors concluded that transcranial LED therapy could influence vasomotor behavior and cerebral blood flow in elderly women. The light used in TCLT is capable of penetrating the bone and blood-brain barriers, enabling its non-invasive action on cortical structures. By enhancing perfusion in critical brain regions, particularly in the dominant hemisphere, TCLT may offer supportive benefits for maintaining or improving cerebral function in aging populations.
While the results are promising, it’s important to note that the study had limitations, including a small sample size and the absence of a control group. These factors call for cautious interpretation and further research to confirm the findings and explore applications in populations with neurological disorders.
Still, this study adds to the growing body of evidence supporting photobiomodulation as a safe and accessible tool to promote brain health in aging individuals.
Reference: Salgado AS, Zângaro RA, Parreira RB, Kerppers II. The effects of transcranial LED therapy (TCLT) on cerebral blood flow in the elderly women. Lasers Med Sci. 2015; 30(1):339-46. doi: 10.1007/s10103-014-1669-2.