Researchers tested 671 nm and 808 nm 1 mW/cm^2 laser photon delivery in a severed cadaver head. They compared sinus (transsphenoidal), oral, and head (transcranial) light delivery at both wavelengths. 808 delivered more energy than 671 to a 40 mm target inside the brain tissue. They found that sinus delivery delivered 20 times more photons than transcranial delivery. Comparing oral, sinus and head delivery, and comparing 671 nm to 808 nm delivered at the same power density, the 808 nm diode transferred the largest quantity of photons to the farthest parts of the brain.
A 2017 study in Photomedicine and Laser Surgery found improved dementia symptoms after 810 nm infrared transcranial and intranasal irradiation of five patients using Vielight 810 and Neuro LED devices. Patients received 10.65 J/cm2 from 14.2 mW/cm^2 or 24.6+13.8 J/cm^2 from 41+23 mW/cm^2. Treatment times for 25 or 20 minutes. The devices output 10 Hz pulsed wave. The study lasted 12 weeks. Vielight 810 is an intranasal device. The Neuro is transcranial and intranasal. Light reached “bilateral mesial prefrontal cortex, precuneus/posterior cingulate cortex, angular gyrus, and hippocampus.” Results included dementia improvement of sleep, fewer angry outburts, reduced anxiety and reduced wandering.
11 dementia patients received 1060 nm to 1080 nm infrared pulsed at 10 Hz LED treatment for 6 minutes a day for 28 days. They wore a brain helmet irradiating the brain from all directions. Researchers found improved executive functioning, recall, visual attention and task switching, as well as improved EEG amplitude.
89 Alzheimer’s patients received a range of wavelengths in the visible spectrum (25-1000 nm) for 20 to 40 minutes, with continuous or pulsed wave laser. Researchers inserted a fiber optic through a femoral artery catether to deliver light to the cerebral arteries. Analysis showed improved microcirculation, cognitive recovery and decreased dementia.