Cerebral blood flow in the elderly: impact of photobiomodulation

The world’s population is aging at a faster pace than it has ever before. This demographic tendency is directly linked to lower fertility rates and a steep reduction in mortality, especially in the western world. The aging process is progressive and dynamic; and involves biochemical, morphological, and functional alterations that progressively modify the organism, making it more susceptible to the deleterious effects of intrinsic and extrinsic factors, and insults that will eventually culminate in death. After the sixth decade of life, one of the main alterations that occurs, is the degradation of the neurological system and the development of neurovascular diseases and cerebral vascular dysfunction due to decreased cerebral blood flow and abnormal brain metabolism; which consequently elevate the risk of dementia related diseases. Some studies have demonstrated the positive effects of photobiomodulation in the human brain. But in the elderly, research on cerebral circulation is very scarce. We observed through Doppler ultrasonography that transcranial low level light therapy with an LED device (light-emitting diode device—627 nm, 70 mW/cm2, 10 J/cm2, for a total of 2 minutes) applied to in the frontal and parietal encephalic regions in elderly individuals, twice a week for 4 weeks, increased blood flow velocity in the middle and basilar cerebral arteries. Likewise, there was a reduction in PI and RI in the three arteries analyzed. We suggest that PBM with transcranial LED irradiation could be used as a prophylactic therapy in the elderly population, who are commonly affected by vascular and cognitive alterations derived from the aging process.