Photobiomodulation for traumatic brain injury and stroke

Abstract

There is a notable lack of therapeutic alternatives for what is fast becoming a global epidemic of traumatic brain injury (TBI). Photobiomodulation (PBM) employs red or near-infrared (NIR) light (600-1100nm) to stimulate healing, protect tissue from dying, increase mitochondrial function, improve blood flow and tissue oxygenation. PBM can also act to reduce swelling, increase antioxidants, decrease inflammation, protect against apoptosis, and modulate microglial activation state. All these mechanisms of action strongly suggest that PBM delivered to the head should be beneficial in cases of both acute and chronic TBI. Most reports have used NIR light either from lasers or from light-emitting diodes (LEDs). Many studies in small animal models of acute TBI have found positive effects on neurological function, learning and memory, and reduced inflammation and cell death, in the brain. There is evidence that PBM can help the brain to repair itself by stimulating neurogenesis, upregulating BDNF synthesis, and encouraging synaptogenesis. In healthy human volunteers (including students and healthy elderly women) PBM has been shown to increase regional cerebral blood flow, tissue oxygenation and improve memory, mood and cognitive function. Clinical studies have been conducted in patients suffering from the chronic effects of TBI. There have been reports of improvements in executive function, working memory, and improved sleep. Functional magnetic resonance imaging has shown modulation of activation in intrinsic brain networks likely to be damaged in TBI (default mode network and salience network).

Transcranial Low-Level Laser Therapy for Depression and Alzheimer’s Disease

“…Low-level laser therapy (LLLT) was discovered 50 years ago and has been used to treat wounds, pain, inflammation and cancer [1]. LLLT applies low-powered red or near-infrared (NIR) laser light (1-500 mW of power levels and 600-1100 nm of wavelengths) to stimulate a biological response [1].…”

“…LLLT applies low-powered red or near-infrared (NIR) laser light (1-500 mW of power levels and 600-1100 nm of wavelengths) to stimulate a biological response [1]. These lasers generate a thermal effect without heating, sound, or vibration [1].…”

“…It belongs to class 3 of laser classification. Recently, researchers have shifted the focus of research to the application of LLLT on brain disorders [1][2][3]. During the past decade, LLLT has been widely used to study neurological and psychological diseases [3] such as depressionlike behaviors [4][5][6][7][8], Alzheimer's disease (AD) [9][10][11][12][13][14][15][16][17][18][19][20], Parkinson's disease [21], stroke [22,23] and traumatic brain injury (TBI) [24][25][26][27][28][29][30][31][32].…”

“…During the past decade, LLLT has been widely used to study neurological and psychological diseases [3] such as depressionlike behaviors [4][5][6][7][8], Alzheimer's disease (AD) [9][10][11][12][13][14][15][16][17][18][19][20], Parkinson's disease [21], stroke [22,23] and traumatic brain injury (TBI) [24][25][26][27][28][29][30][31][32]. Because red or NIR light can effectively penetrate into brain tissues [33,34], it can be noninvasive and play a beneficial role in increasing ATP biosynthesis and neurogenesis [1,2]. A number of excellent reviews have focused on LLLT for TBI [1][2][3]35], depression [36] and AD [35,37].…”

“…Because red or NIR light can effectively penetrate into brain tissues [33,34], it can be noninvasive and play a beneficial role in increasing ATP biosynthesis and neurogenesis [1,2]. A number of excellent reviews have focused on LLLT for TBI [1][2][3]35], depression [36] and AD [35,37].…”