The use of photobiomodulation (PBM) for chiropractic applications is not a novelty. Red and near-infrared (NIR) light devices have been employed by many chiropractors for years. They are routinely used to help alleviate joint and muscle pain and strain, as well as tissue healing from an injury or trauma.
Transcranial photobiomodulation (tPBM) is a newer form of PBM that is gaining recognition from health and wellness practitioners, including the chiropractic community. Functional neurologists, in particular, are leading the way in employing tPBM.
In addition to applications for recovery from various musculoskeletal disorders relevant for chiropractic interventions, tPBM can be beneficial for injuries and conditions involving the brain. Numerous published studies provide evidence to support such benefits from tPBM, such as better brain perfusion and oxygenation1, cellular repair, and even synaptogenesis and neurogenesis2. These effects of tPBM are possible because of conversion of photonic energy of red or near-infrared light into chemical energy via biochemical processes.
The Biochemical Mechanism of Photobiomodulation
The fundamental mechanism presumed to underly photobiomodulation (PBM) is based on its effect on cytochrome c oxidase (CcO), the fourth unit of the mitochondrial respiratory chain. The absorption of photons by CcO causes nitric oxide photodissociation3. This event leads to an increase in electron transport activity and in adenosine triphosphate (ATP), the energy source of cells.
Coincidently, there is an increase in production of reactive oxygen species (ROS) by the mitochondria. ROS play an important role in facilitating communication among the cells, as well as support of immune response. The release of Ca2+, as versatile second messengers, also takes place. In turn, these processes lead to the activation of transcription factors and signaling mediators (i.e., NF-KB), producing long-lasting cellular effects4.
A study by Wang et al. (2017) revealed a new cellular mechanism using a longer wavelength near-infrared light. They reported activation of heat or light-sensitive calcium ion channels. This is important because, as crucial components of the nervous system, ion channels are necessary for the normal activity of neurons and glia.
The effect can be useful in managing pain and inflammation, including neural inflammation, and in increasing the speed of improvement, not just with various musculoskeletal injuries but also with brain-related issues. Thousands of published studies available on PubMed. gov provide support for the effectiveness of PBM and tPBM for many musculoskeletal and neurological conditions.
tPBM Promotes Unique Benefits for the Body and the Brain while Lacking Side Effects
Dr. M. Hamblin, associate professor at Harvard Medical School, notes in one of his research publications:
PBM has an almost complete lack of reported adverse effects, provided the parameters are understood, at least at a basic level. The remarkable range of medical benefits provided by PBM, has led some to suggest that it may be “too good to be true.” However, one of the most general benefits of PBM that has recently emerged is its pronounced anti-inflammatory effects. While the exact cellular signaling pathways responsible for this anti-inflammatory action are not yet completely understood, it is becoming clear that both local and systemic mechanisms are operating. The local reduction of edema and reductions in markers of oxidative stress and pro-inflammatory cytokines are well established. However, there also appears to be a systemic effect whereby light delivered to the body can positively benefit distant tissues and organs5.
Furthermore, in another research publication entitled “Photobiomodulation and the Brain: A New Paradigm,” authors state:
One of the most notable and potentially significant effects of (t)PBM in the brain is its ability to promote both synaptogenesis and neurogenesis. This is vitally important, as many brain conditions, including traumatic brain injury (TBI), neurodegenerative diseases, and mood disorders, can be traced, either partially or in full, to atrophy, cell death, and poor neuronal connections in certain regions of the brain. If (t)PBM possesses the ability to counter these effects by facilitating neural regeneration and rewiring, it could prove to be extremely promising as a novel method of treating such conditions.2
Since then, a number of studies focused on the use of tPBM to mitigate symptoms of TBI and neurodegenerative diseases have been published (e.g., 1, 6, 7).
Pulsed Transcranial Photobiomodulation
Pulsed transcranial photobiomodulation (PtPBM) is a newer from of PBM. It employs pulsed NIR stimulation at various frequencies. When targeted at the brain, PtPBM can modulate brain activity and response.
The most-studied PtPBM frequencies are 40 Hz and 10 Hz. The former falls within the brain’s gamma band oscillations and the latter within the alpha band.
A study published by Dr. Hamblin’s laboratory compared the effects of same-dose NIR light tPBM delivered with different pulse rates. Three tPBM parameters were compared. One with continuous wave light (no pulse), another with light pulsed at 10 Hz, and one with light pulsed at 100 Hz. All three tPBM options were delivered to mice with traumatic brain injuries (TBI)8. The study found that beneficial effects on cognitive function were statistically better with 10 Hz tPBM than they were with either continuous wave or 100 Hz.
Another animal study from MIT demonstrated that genetically engineered Alzheimer’s mice ended up with reduced amyloid beta after tPBM with NIR light pulsing at 40 Hz (gamma)8. Amyloid beta is the main component of the amyloid plaques found in brains affected by Alzheimer’s disease. Notably, the researchers did not see the same effect with other pulse frequencies.
Over the past five years, a number of studies analyzed the effects of pulsed tPBM on the brain1-10. Researchers noted that 40 Hz pulsed NIR tPBM using the Vielight Neuro Gamma altered brain activity, increasing the power of the higher oscillatory frequencies of alpha, beta, and gamma, and reducing the power of the slower frequencies of delta and theta in subjects in resting state. The stimulation impacted integration and segregation of brain networks10. A subsequent study by the same group demonstrated that 10 Hz also modulated neural oscillations in a frequency and location dependent manner10.
Summary
In summary, as discussed here, tPBM has the potential to address TBI, neurodegenerative diseases (such as dementia and Parkinson’s), mood disorders, and other brain conditions. Many tPBM devices are commercially available as low-risk general-wellness devices at affordable prices.
For references see page 51.
Dr. Loheswaran has over 15 years of research experience and knowledge in neuroscience, neurophysiology, brain stimulation and clinical research. She holds a MSc in Neuroscience from McMaster University and a PhD in Pharmacology from the University Toronto. She has extensive experience in clinical trial design, brain stimulation and EEG acquisition and analysis. As the Research Manager at Vielight Inc., Dr. Loheswaran oversees research activities focused on studying the neurophysiological mechanisms underlying the therapeutic effects of Vielight's technology, for more information visit vielight.com. Dr. Loheswaran can be contacted via email at [email protected].
References for "Chiropractic Photobiomodulation: Pathways and Applications" article:
1. Chao LL. Effects of Home Photobiomodulation Treatments on Cognitive and Behavioral Function, Cerebral Perfusion, and Resting-State Functional Connectivity in Patients with Dementia: A Pilot Trial Photobiomodul Photomed Laser Surg. 2019 Mar;37(3):133-141. doi: 10.1089photob.2018.4555. Epub 2019 Feb 13. PMID: 31050950.
2. Hennessy M, Hamblin MR Photobiomodulation and the brain: a new paradigm. J Opt. 2017 Jan;19(1):013003. doi: 10.1088 20408986/19/1/013003. Epub 2016 Dec 14. PMID: 28580093; PMCID: PMC5448311.
3. Lane, N. Power games. Nature 443, 901-903 (2006). https://doi. org/10.1038/44390la
4. de Freitas LF, Hamblin MR Proposed Mechanisms of photobiomodulation or Low-Level Light Therapy. IEEEJSel Top Quantum Electron. 2016 May-Jun;22(3):7000417. doi: 10.1109 JSTOE.2016.2561201. PMID: 28070154; PMCID: PMC5215870.
5. Michael R Hamblin. Mechanisms and applications of the anti-inflammatory effects of photobiomodulation [J]. AIMS Biophysics, 2017, 4(3): 337-361. doi: 10.3934/biophy.2017.3.337.
6. Martin PI, Chao L, Krengel MH, Ho MD, Yee M, Lew R, Knight J, Hamblin MR, Naeser MA. Transcranial Photobiomodulation to Improve Cognition in Gulf War Illness. Front Neurol. 2021 Jan 21:11:574386. doi: 10.3389ffieur.2020.574386. PMID: 33551948;
PMCID: PMC7859640.
7. Naeser MA, Ho MD, Martin PI, Hamblin MR Koo BB. Increased Functional Connectivity Within Intrinsic Neural Networks in Chronic Stroke Following Treatment with Red/Near-Infrared Transcranial Photobiomodulation: Case Series with Improved Naming in Aphasia. Photobiomodul Photomed Laser Surg. 2020 Feb;38(2): 115-131. doi: 10.1089photob.2019.4630. Epub 2019 Oct 17. PMID: 31621498.
8. Ando T, Xuan W, Xu T, Dai T, Sharma SK, Kharkwal GB, Huang YY, Wu O, Whalen MJ, Sato S, ObaraM, Hamblin MR. Comparison of therapeutic effects between pulsed and continuous wcn’e 810-nm wavelength laser irradiation for traumatic brain injury in mice. PLoS One. 2011;6(10):e26212. doi: 10.1371 journal.pone.0026212. Epub 2011 Oct 18. PMID: 22028832; PMCID: PMC3196530.
9. Iaccarino, H., Singer, A., Martorell, A. et al. Gamma frequency entrainment attenuates amyloid load and modifies microglia. Nature 540, 230-235 (2016). https://doi.org/10.1038/nalure...
10. Zomorrodi, Reza, et al. Modulation of Cortical Oscillations Using lOhz Near-infrared Transcranial and Intranasal Photobiomodulation: A Randomized Sham-controlled Crossover Study. Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation, 1 Nov. 2021, www.brainstimjrnl.com/article/... abstract.
