Light therapy, also known as photobiomodulation or infrared/red light therapy, is gaining considerable attention from the health and medical industries as an effective, natural, and non-invasive treatment option for a range of brain conditions (1, 2). More and more research is being published supporting its potential use as an adjunct therapy for Parkinson's, dementia, traumatic brain injury, mental health disorders, ADHD, and more (1, 2). There's also a growing body of literature supporting its use for enhancing cognitive performance in everyday people (3).
So how do light therapy helmets work?
We all know intuitively that light has effects on our bodies. It can cause us to change colour from being in the sun, produce vitamin D, regulate our sleep, and improve our mood. Just like plants, humans also need light to survive. However, we can also harness specific wavelengths of red and infrared light in the form of a helmet treatment for our brain. So, what happens when we actually shine lights on the brain?
1) Stimulates mitochondria to energise cells.
The mitochondria within the cell is our body's "engine house”: it's where we create energy that our body uses to heal, repair, and function normally. This energy is known as ATP. When we're stressed or unwell, or simply as an effect of ageing, these mitochondria stop working so well. This is called mitochondrial dysfunction or insufficiency, and has been associated with many chronic conditions including Parkinson’s, Alzheimer’s, metabolic conditions, cardiovascular diseases and chronic pain (4).
Light therapy stimulates the mitochondria to produce more energy (2). This extra energy can then be used by the cells for growth, repair and regulating healthy cellular activities. This natural approach to boost mitochondrial function, which can be done at home, is particularly useful when it comes to supporting brain health. The brain is the most energy-demanding organ in the body, constituting 2% of body weight, yet consuming 20% of our energy supplies (5). For this reason, it has a lot of mitochondria, to help produce the energy that it needs. The sheer quantity of mitochondria in the brain makes it a particularly useful organ to target with light therapy.
2) Reduces inflammation and oxidative stress.
Light therapy is both anti-inflammatory and anti-oxidating, which is very important for brain health (2, 6, 7). Neuroinflammation, which is inflammation of the brain, has been linked with a variety of brain conditions, including Parkinson’s, Alzheimer’s, mental health issues, brain fog and memory problems (2, 6, 7). Light therapy triggers both anti-inflammatory and anti-oxidating cascades, which can accelerate healing and repair in both acute and chronic conditions (2, 6, 7).
3) Improves circulation of oxygenated blood.
Light therapy causes the dissociation of nitric oxide, which helps to regulate and improve blood flow to the brain. This helps get fresh nutrients to the brain, as well as remove toxins, which build up either due to illness, or naturally over the course of a day (in fact, one of the vital roles sleep plays is to remove these daily toxins from the brain while we are sleeping) (8).
A properly functioning circulatory system is critical to ensuring brain health. The brain, our 'hungriest' organ, cannot store energy, like other organs such as the liver. Instead, it depends on constantly being fed energy and oxygen via the bloodstream. Light therapy is a natural way to enhance the supply of both energy (ATP) and oxygen to the brain, so that it can work more effectively.
4) Modulates natural brainwaves.
Research suggests that light therapy can also help modulate our natural brainwave patterns (2). Our brain naturally produces electrical impulses, known as brainwaves, which help the nerves to function and communicate with one another. The 5 brainwaves are: gamma, beta, alpha, theta, delta. Each one is associated with a different state of mind. For example, alpha (8-12 Hz) is the primary kind of brainwave pattern when we're in a calm, relaxed state. 40+ Hz, on the other hand, is the frequency of gamma waves, which are particularly important for focus, alertness, and movement control (9).
Gamma brainwaves are the fastest of our 5 natural brainwaves. They are active when we are most alert and focused, and are critical for memory, learning, and concentration. Gamma brainwaves affected in a number of conditions, including Parkinson’s (9). In fact, providing electrical impulses to modulate brainwave patterns is one way Deep Brain Stimulation (DBS) surgery is believed to help Parkinson's disease. Although DBS typically uses a higher frequency than light therapy (60-200 Hz, as opposed to 40 Hz with light therapy), they all work within the frequency of gamma. It may be that light therapy may offer a natural, non-invasive, cost-friendly treatment to also help modulate brainwave patterns, that doesn't require surgery or specialist referral.
How much light penetrates through to the brain?
It's important to state that a large part of the light that is emitted by a helmet is absorbed by the cells in the skin, fascia, blood, nerves, skull and other vessels more superficial to the brain than the brain itself (10). Only a small percentage penetrates through the skull to the brain.
Infrared light, which we cannot see, has been shown to be able to penetrate through the skull to stimulate brain tissue (1, 2). 810 nm is the wavelength that's been shown to be most appropriate for directly treating the brain (1, 2, 10). Red light, on the other hand, does not penetrate through the skull (1, 2, 10).
Nevertheless, it's very unlikely that the light is able to directly penetrate to really deep structures, such as the substantia nigra, which sits in the very centre of our skull, in a very deep part of the brain. And yet, we know from numerous clinical trials that light therapy may still be effective for a range of brain conditions that involve the substantia nigra, and other deep brain structures (1, 2, 3).
Brain imaging studies demonstrate that light therapy can activate whole brain networks, even though only a small part of the brain is directly stimulated by the light (1, 2, 3). Most likely, the light initiates a reaction that triggers a whole bunch of downstream cell-to-cell effects, sort of like a domino reaction. This is quite typical for how the brain works: it operates in networks, rather than isolated parts, that involve multiple areas of the brain talking to one another and coordinating a response between them. A lot of conditions are due to faulty communication between these networks (1, 2, 3). In Parkinson's disease, this typically includes the Default Mode Network and Salience Network (1, 2, 3).
In Parkinson's disease, we know that the brainstem and the cerebellum are also affected by the disease process (11, 12). Both these areas are critically important for movement and autonomic control, and, as some research is suggesting, first, before then traveling to the deep parts of the brain such as the substantia nigra (13).
In fact, people with Parkinson's may have alpha-synucleins existing in these areas for up to 10-15 years before it travels to the substantia nigra and they develop the classic Parkinson's symptoms of slowness, stiffness and tremor (13). These areas are much more superficial than the substantia nigra, which is really deep in the brain. Therefore, it may be that these areas are also more responsive to light therapy, while still being able to communicate with, and thus elicit a response from, deeper parts of the brain.
Another possibility for how light therapy may still be affecting these deeper brain structures is by affecting circulating cells in the bloodstream and lymphatics. This is, in fact, one argument for using red light, even though it doesn't penetrate through the skull. While red light does not penetrate as deeply as infrared light, it may still have positive effects on these circulating mitochondria and improving cerebral blood flow, which may still improve function in deeper structures via the bloodstream (1-3).
Of course, there are other ways we can also affect dopamine in the brain. A major example is by targeting the gut and the gut microbiome. For a discussion why we treat the gut for Parkinson's, please read our other post here.
Choosing a helmet:
It's important to understand that not all light therapy devices are made equal. There are three main factors that impact the quality of light therapy you are receiving such as diode placement, wavelength, and frequency. These factors are all really important to ensure that the helmet you're using is having the desired effect, so let's talk a little more about each of these features.
1. Diode placement
Perhaps one of the most important features of any light therapy helmet is what parts of the brain it shines the light on. Diodes are the parts where the light comes out of. They can either be like small light bulbs (LEDs), or a laser. In helmets, we use LEDs, and typically they'll be placed to shine the light over specific areas of the brain.
Different parts of the brain control different aspects of our health. For example, the front part of our brain is particularly important for cognitive functions and social interaction, whereas the sides are important for emotional control and memory, and the back part of our brain is famous for vision. At the back of the brain we also have the "little brain", the cerebellum, as well as the brainstem. These structures are particularly important for movement control and autonomic functions such as regulating sleep, digestion, breathing and heart rate.
It makes sense that where you shine the lights will have different effects. If you're unsure which helmet might be right for you, you can always reach out to our Clinical Support team. They're a team of international clinicians who're highly skilled in using light therapy, and can determine what type of helmet may be best for you. You can email your questions through to our team at info@symbyxbiome.com.
2. Wavelength
Wavelength is another important factor that you should always consider when you're looking at a light therapy device, regardless of whether that is a helmet or a handheld laser.
Wavelength refers to the kind of light that is used. Different wavelengths produce different colours: for example, blue light has a wavelength between 450-495 nanometres (nm), while red light therapy has a wavelength around 600-700 nm. This means that red light wavelengths are longer than blue light, which is why they look red, as opposed to blue. Infrared light has wavelengths even longer: between 750- 1000000 nm (which is 1 millimetre). Infrared light is invisible to the human eye.
Typically, when we talk about light therapy, we're talking about using red or infrared light, as these are the wavelengths that have most been shown to work on our cells. They're also at the opposite end of the spectrum to harmful UV light.
There are important differences between red light and infrared light when we shine it on our brain. Infrared light, which we cannot see, has been shown to be able to penetrate through the skull to stimulate brain tissue (1, 2). 810 nm is the wavelength that's been shown to be most appropriate for directly treating the brain (1, 2, 10).
Red light, on the other hand, does not penetrate through the skull (1, 2, 10). Therefore, if you're looking to treat the brain, make sure you get a device that uses infrared light. Or, even better, get a helmet that uses both infrared and red light. This is because red light may still help to stimulate circulating mitochondria within the vascular and lymphatic systems, to bring fresh nutrients and remove toxins from the brain (1-3). Typically, the device should run through red light first, followed by infrared light.
For more of a discussion on red vs infrared light, please see our other blog post here.
3. Frequency
As discussed already, light therapy has been shown to be able to modulate brainwaves (2). This is why the frequency (Hz) of a device is really important. If someone has issues with cognition or alertness, or has a neurodegenerative condition, such as Parkinson's, research suggests that their gamma waves (40+ Hz) may be aberrant (9). Therefore, they may wish to look for a device that pulses at 40 Hz.
Still have questions?
Our international Clinical Support team are happy to answer any clinical or technical questions you may still have about light therapy. Please email your questions through to us at info@symbyxbiome.com.
We hope you found this blog post useful and informative!
References:
1) Salehpour F, Mahmoudi J, Kamari F, Sadigh-Eteghad S, Rasta SH, Hamblin MR. Brain Photobiomodulation Therapy: a Narrative Review. Mol Neurobiol. 2018 Aug;55(8):6601-6636.
2) Salehpour F, Sadigh-Eteghad S, Mahmoudi J, Kamari F, Cassano P, Hamblin MR (2023). Photobiomodulation for the Brain: Photobiomodulation Therapy in Neurology and Neuropsychiatry. Springer Charm. https://doi.org/10.1007/978-3-031-36231-6.
3) Salehpour F, Majdi A, Pazhuhi M, Ghasemi F, Khademi M, Pashazadeh F, Hamblin MR, Cassano P. Transcranial Photobiomodulation Improves Cognitive Performance in Young Healthy Adults: A Systematic Review and Meta-Analysis. Photobiomodul Photomed Laser Surg. 2019 Oct;37(10):635-643.
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5) Mergenthaler P, Lindauer U, Dienel GA, Meisel A. Sugar for the brain: the role of glucose in physiological and pathological brain function. Trends Neurosci. 2013 Oct;36(10):587-97. doi: 10.1016/j.tins.2013.07.001. Epub 2013 Aug 20. PMID: 23968694; PMCID: PMC3900881.
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8) Reddy OC, van der Werf YD. The Sleeping Brain: Harnessing the Power of the Glymphatic System through Lifestyle Choices. Brain Sci. 2020 Nov 17;10(11):868. doi: 10.3390/brainsci10110868. PMID: 33212927; PMCID: PMC7698404.
9) Guan Ao , Wang Shaoshuang , Huang Ailing , Qiu Chenyue , Li Yansong , Li Xuying , Wang Jinfei , Wang Qiang , Deng Bin. The role of gamma oscillations in central nervous system diseases: Mechanism and treatment. Frontiers in Cellular Neuroscience. 2022; 16.
10) Henderson T. Can infrared light really be doing what we claim it is doing? Infrared light penetration principles, practices, and limitations. Frontiers in Neurology. 2024; 15. 10.3389/fneur.2024.1398894.
11) Wu T, Hallett M. The cerebellum in Parkinson's disease. Brain. 2013 Mar;136(Pt 3):696-709. doi: 10.1093/brain/aws360. Epub 2013 Feb 11. PMID: 23404337; PMCID: PMC7273201.
12) Seidel K, Mahlke J, Siswanto S, Krüger R, Heinsen H, Auburger G, Bouzrou M, Grinberg LT, Wicht H, Korf HW, den Dunnen W, Rüb U. The brainstem pathologies of Parkinson's disease and dementia with Lewy bodies. Brain Pathol. 2015 Mar;25(2):121-35. doi: 10.1111/bpa.12168. Epub 2014 Sep 12. PMID: 24995389; PMCID: PMC4397912.
13) Calabresi, P., Mechelli, A., Natale, G. et al. Alpha-synuclein in Parkinson’s disease and other synucleinopathies: from overt neurodegeneration back to early synaptic dysfunction. Cell Death Dis 14, 176 (2023). https://doi.org/10.1038/s41419-023-05672-9
