Beneficial neurocognitive effects of transcranial laser in older adults

• Published in: Lasers in medical science Vol. 32; no. 5; pp. 1153 - 1162
• Main Authors: Vargas, Enrique, Barrett, Douglas W., Saucedo, Celeste L., Huang, Li-Da, Abraham, Jacob A., Tanaka, Hirofumi, Haley, Andreana P., Gonzalez-Lima, F.
• Format: Journal Article
• Language: English
• Published: London Springer London 01.07.2017; Springer Nature B.V
• Subjects: Adults; Age; Aged; Aged, 80 and over; Aging; Attention task; Blood; Brain; Brain - physiology; Brain - radiation effects; Brain mapping; Carotid arteries; Carotid artery; Carotid Intima-Media Thickness; Clinical trials; Cognition; Cognition - radiation effects; Cognitive ability; Cognitive tasks; Correlation analysis; Dentistry; EEG; Electroencephalography; Female; Functional anatomy; Functional magnetic resonance imaging; Head injuries; Humans; Infrared lasers; Injuries; Lasers; Light therapy; Magnetic Resonance Imaging; Male; Media; Medical research; Medicine; Medicine & Public Health; Memory; Middle Aged; Neuroimaging; Older people; Optical Devices; Optics; Original Article; Oxygen; Oxygen - blood; Photonics; Pilot Projects; Prefrontal cortex; Prefrontal Cortex - physiology; Psychomotor performance; Quantum Optics; Reaction time; Reaction time task; Resonance; Rest; Risk; Side effects; Stimulation; Task Performance and Analysis; Traumatic brain injury; Ultrasound; Veins & arteries; Vigilance; Young adults; fMRI; Brain photobiomodulation; Infrared laser; Memory; EEG; Attention
• ISSN: 0268-8921; 1435-604X
• DOI: 10.1007/s10103-017-2221-y

Transcranial infrared laser stimulation (TILS) at 1064 nm, 250 mW/cm 2 has been proven safe and effective for increasing neurocognitive functions in young adults in controlled studies using photobiomodulation of the right prefrontal cortex. The objective of this pilot study was to determine whether there is any effect from TILS on neurocognitive function in older adults with subjective memory complaint at risk for cognitive decline (e.g., increased carotid artery intima-media thickness or mild traumatic brain injury). We investigated the cognitive effects of TILS in older adults (ages 49–90, n  = 12) using prefrontal cortex measures of attention (psychomotor vigilance task (PVT)) and memory (delayed match to sample (DMS)), carotid artery intima-media thickness (measured by ultrasound), and evaluated the potential neural mechanisms mediating the cognitive effects of TILS using exploratory brain studies of electroencephalography (EEG, n  = 6) and functional magnetic resonance imaging (fMRI, n  = 6). Cognitive performance, age, and carotid artery intima-media thickness were highly correlated, but all participants improved in all cognitive measures after TILS treatments. Baseline vs. chronic (five weekly sessions, 8 min each) comparisons of mean cognitive scores all showed improvements, significant for PVT reaction time ( p  < 0.001), PVT lapses ( p  < 0.001), and DMS correct responses ( p  < 0.05). The neural studies also showed for the first time that TILS increases resting-state EEG alpha, beta, and gamma power and promotes more efficient prefrontal blood-oxygen-level-dependent (BOLD)-fMRI response. Importantly, no adverse effects were found. These preliminary findings support the use of TILS for larger randomized clinical trials with this non-invasive approach to augment neurocognitive function in older people to combat aging-related and vascular disease-related cognitive decline.