TRANSCRANIAL photobiomodulation (tPBM)

Can you think of ways that we get therapy from light sources? Hint: One natural source also provides us with our Vitamin D and helps us grow!

Similarly, Transcranial Photobiomodulation (tPBM) involves administering low-level light therapy to the brain to promote positive change in the cells. It is used to treat symptoms of traumatic brain injuries (TBI). It has also shown to help with;

1. Depression
2. PTSD
3. Insomnia
4. Headaches
5. Dementia, and others.

Furthermore, it has been shown to;

1. Improve sleep quality
2. Improve cognitive functioning, including memory and learning ability
3. Improve mental performance in sports
4. Improve blood flow / lower blood pressure
5. Improve functional connectivity in brain tissue amongst patients suffering from TBI
6. Increase energy levels (through ATP production)
7. Increase oxygenation/oxygen consumption in cells
8. Reduce inflammation

In a nutshell, certain frequencies of low-level light (600nm to 1100nm) are applied transcranially (“across the cranium”) to different regions of the skull through light-emitting diode (LED) devices. Light bypasses the skull, which can then be harnessed by the local cells in the tissue. In turn, cells metabolize the frequencies of light and produce ATP, amongst other cellular metabolites.

Near-infrared LED can transmit low-level light therapy through a variety of modalities. For example, some devices may come in the form of caps that are placed over the head, some may be hand-held devices that emit concentrated low-level light, and some devices transmit near-infrared light intranasally. Sometimes, therapy can include the use of multiple modalities.

Typically, treatment is administered 2-3x a week for 30-40 minutes. The length of treatment is dependent on many factors, such as the number of modalities involved, the severity of trauma, and patient compliance. Further, performance measures are often taken pre- and post-treatment to measure the efficacy of the treatment intervention.

Near-infrared LED therapy is a non-invasive, pain-free and safe technique that has been used in managing mTBI, psychiatric disorders, chronic pain, inflammation, and physical therapy.

With that said, there are certain guidelines for the use of tPBM. These guidelines include but are not limited to;

1. Consulting a physician/practitioner licensed in administering low-level light therapy prior to beginning your treatment.
2. Do not shine the light on; cancerous tumors, warts, tattoos, skin sites that have corticosteroids/Botox applied, or topical coloured substances on the skin (i.e. iodine)
3. Do not apply to surgical sites of repair, as sometimes, scar tissue is desirable and the use of tPBM could inhibit the formation/production of scar tissue

There are various theories in regards to how tPBM can help. Here are some possible mechanisms of change in tPBM

1. ATP production – Cytochrome c oxidase, the last complex of the electron transport chain in mitochondria absorbs light in wavelengths of red and near-infrared (NIR), and in turn, harnesses the light energy to produce more ATP
2. Improved Sleep – studies suggest that patients who undergo 2 weeks of transcranial LED treatment see increased levels of serum melatonin (a hormone involved in regulating our circadian rhythm, or our body’s biological clock). Melatonin is also responsible for inducing sleep.
3. Improvements in blood flow / lowering blood pressure – tPBM has been shown to promote vasodilation after 3 months of LED treatment by releasing nitric oxide (NO). Nitric oxide, a vasodilator, helps improve blood flow by relaxing the inner walls of our blood vessels, effectively lowering blood pressure and widening the blood vessels, allowing for easy passage of blood.
4. Improvements in cognitive function: altering the activity of the Default Mode Network – tPBM has been shown to improve the functional connectivity in the brain, ultimately minimizing the activity of the DMN. To better understand this, we should consider the role of the default mode network (DMN) and its implications in mTBI.

Have you ever been so absorbed in a task that you lose your sense of time? A state of effortless concentration where you are so involved in a certain activity? Then you’ve likely experienced ‘flow’, a state of effortless concentration that tends to trigger when we’re challenged with a difficult task.

Think of the ‘default mode network’ as the opposite to the ‘flow’ state, as though it is the ‘autopilot’ version of your mind.

The DMN is not a single part of the brain – rather, it involves multiple subsystems in the brain that are responsible for brain activity when the mind isn’t actively engaged in a task (for example, when we are daydreaming, self-reflecting, ruminating, our sense of time and sense of self, spatial navigation, moral reasoning, interpreting emotions, or consolidating information from our environment). It is also negatively correlated with attentional abilities (thus, as the default mode network activity increases, attentional task performance decreases).

Concussions, psychiatric disorders (such as alzheimer’s, addiction, dementia, PTSD), or other forms of mild traumatic brain injuries, often yield neurocognitive impairments that alter the activity of the default mode network. For example, studies reflect that patients who sustain concussions often suffer from increased activity of the DMN. Naturally, this can surface as deficits in attention, memory, goal-oriented behaviour, or expressive ability. Activity in the DMN has also been positively correlated with unhappiness.

Fundamentally, tPBM has been shown to improve the cognitive functionality of the DMN by upregulating desirable metabolic activity in various regions of the DMN, alongside the possible mechanisms of change mentioned above.

• Other modalities that have been investigated and shown to improve the cognitive functionality of the DMN include: sleep, aerobic exercise, mindfulness-based meditation, psychotherapy, and therapeutic activities.

To better illustrate the use of tPBM in mTBI, consider the following case studies

1. Study 1 – mTBI patients with persistent cognitive dysfunction (Naessar et. al, 2014).
   • 11 chronic mTBI patients, sustained through motor vehicle accidents, sport-related injuries, and military casualties, were given LED treatment for 6 months, yielding improvements in executive functioning and verbal learning. Further, patients reported clear improvements in social, interpersonal and occupational function.
2. Study 2 – Athletes looking to improve sleep quality (Zhao et. al., 2012).
   • 20 female basketball players (10 subjects were given LED therapy and 10 were placed in a control group) underwent 30 minutes of NIR therapy every night for 2 weeks, yielding objective/subjective improvements to sleep quality following treatment
3. Study 3 – Investigating Cognition in patients suffering from Dementia (Saltmarche et. al. 2017)
   • 5 patients with mild to moderate impairment went through 12 weeks of daily tPBM therapy targeting the default mode network (DMN). Patients were assessed with standardized tests and demonstrated significant improvement in social function (fewer angry outbursts, less anxiety)

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2. David J. Sharp, Christian F. Beckmann, Richard Greenwood, Kirsi M. Kinnunen, Valerie Bonnelle, Xavier De Boissezon, Jane H. Powell, Serena J. Counsell, Maneesh C. Patel, Robert Leech, Default mode network functional and structural connectivity after traumatic brain injury, Brain, Volume 134, Issue 8, August 2011, Pages 2233–2247, https://doi.org/10.1093/brain/awr175
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5. Naesar, M. A. et. al. (2014). Significant Improvements in Cognitive Performance Post-Transcranial, Near-Infrared LED Treatments in Chronic, Mild Traumatic Brain Injury: Open-Protocol Study. Journal of Neurotrauma. (31) p1008-1017. DOI: 10.1089/neu.2013.3244
6. Naesar, M. A. et. al. (2016). Transcranial Red/Near-Infrared Light-Emitting Diode Therapy to Improve Cognition in Chronic Traumatic Brain Injury. Photomedicine & Laser Surgery. 34(12). p610-626. DOI: 10.1089/pho.2015.4037
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8. Saltmarche, A. E., Naesar, M. A. et. al. (2017). Significant Improvements in Cognition in Mild to Moderately Severe Dementia Cases Treated with Transcranial Plus Intranasal Photobiomodulation: Case Series Report. Photomedicine and Laser Surgery. 35(8). P432-441. DOI: 10.1089/pho.2016.4227