Although initially used for treatments such as wound healing and pain relief, the uses of Laser Therapy have now broadened to address more severe items such as brain disorders and injury. Recently, Low-Level Laser Therapy (LLLT) has become a mainstream treatment modality in the treatment of stroke and traumatic brain injuries. This is partly because several animal and human clinical trials have shown the efficacy of LLLT for conditions related to neurology. A detailed look into the mechanism of action of Laser Therapy, as backed by research, elucidates its relevance in neurorehabilitation.
How Does Laser Therapy Work?
Photobiomodulation (PBM) or LLLT uses Laser light around the wavelength of 632 to 1064nm. It works by energizing the chromophores, which stimulate a biological response.[1] As a result, laser irradiation upregulates cellular respiration, which leads to a series of chemical reactions that enhance the production of adenosine triphosphate (ATP), cytokines, and growth factors, accelerating healing and tissue repair.[2] LLLT has also been shown to promote the production of proteins and stimulate cellular proliferation.[3] [4]
Lasers are getting popular because they are non-surgical, non-pharmacological, non-invasive, and painless. Photobiomodulation is cleared by the U.S. Food and Drug Administration (FDA) for several uses. It is also considered safe and side-effect free.[5] There have been a number of trials to study its safety and efficacy, and research has largely reported positive results.[6]
Neurorehabilitation and Transcranial Laser Therapy
Laser Therapy is being used to address neuropathologies through a treatment modality called transcranial Laser Therapy. In this treatment, laser radiation penetrates the skull and aids in healing damaged neurological tissues. Transcranial LLLT has been proven to increase cellular proliferation and angiogenesis, resulting in increased neurological, cognitive, and motor function.[7] Transcranial Laser Therapy finds relevance in the treatment of stroke, and traumatic brain injury as research shows that LLLT could activate brain repair pathways.[8]
Transcranial LLLT and Stroke
Since LLLT has been shown to increase cellular proliferation, several animal trials have been done to assess its efficacy in the treatment of stroke. These effects are in part due to Laser irradiation’s ability to elevate the numbers of neuronal cells and induction of neurogenesis.[9] One study aimed to investigate the effectiveness of transcranial LLLT in rats that had acute strokes at different locations in the brain.[10] The treatment lasted for around 28 days, and the results showed that Laser-treated subjects demonstrated significant improvement in neurological function.
Another similar animal trial showed that when initiated 24 hours after acute stroke, Laser Therapy reduced the neurological deficit, possibly due to the induction of neurogenesis.[11] Research has also shown that LLLT may be an effective treatment modality to reduce behavioral function post-stroke.[12] In this case, it serves as a neuroprotective method with significant clinical outcomes. Human trials have also shown similar results. One study investigated the effects of transcranial LLLT on patients with acute stroke. All patients showed significant improvement, regardless of the stroke’s location.[13] Patients with chronic stroke and paralysis have also shown improvements after receiving Laser Acupuncture.[14]
Transcranial LLLT and Traumatic Brain Injury (TBI)
TBI is responsible for around 80,000 cases of permanent disability in the US, with 1.4 million new cases every year.[15] LLLT has been found to be effective in the treatment of chronic and acute TBI due to various mechanisms, including ATP increase, angiogenesis, and neurogenesis.[16] It has beneficial effects for the treatment of TBI as LLLT has been shown to improve mitochondrial function, stimulate signaling pathways, and inhibit neural apoptosis.[17]
One study done on rats with cryogenic brain injury reported that transcranial Laser Therapy has positive effects on both local and systemic immunomodulation and could prevent cell death post-TBI.[18] Similar results were shown in human trials. A study reported that a series of transcranial Laser Therapy sessions resulted in improved cognition in two humans with chronic TBI.[19]
Conclusion
The success of LLLT lies not only in its efficacy but also in its non-invasive, nonpharmacological nature. Laser Therapy is an FDA-cleared modality with little to no side effects. The medical community is increasingly turning towards Laser Therapy as both surgery and medication pose risks, discomfort, and dependence and also because LLLT’s benefits for neurorehabilitation are well-documented.
Want to get your hands on FDA-cleared Laser Devices? Berman Partners’ Therapeutic Lasers are customizable and user-friendly. With these devices, you can alter the hertz levels and choose the setting most suitable to you. You can also check out our laser acupuncture tip and a light guide. For more information, contact us, and we would be happy to help.
References
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[2] Greco M, Guida G, Perlino E, Marra E, Quagliariello E. Increase in RNA and protein synthesis by mitochondria irradiated with helium-neon laser. Biochem Biophys Res Commun. 1989 Sep 29;163(3):1428-34. doi: 10.1016/0006-291x(89)91138-8. PMID: 2476986.
[3] Baxter, C. David, and Geaorge W. Waylonis, “Therapeutic Lasers: Theory and Practice.” American Journal of Physical Medicine & Rehabilitation 74.4 (1995): 327
[4] Zhang Y, Song S, Fong CC, Tsang CH, Yang Z, Yang M. cDNA microarray analysis of gene expression profiles in human fibroblast cells irradiated with red light. J Invest Dermatol. 2003 May;120(5):849-57. doi: 10.1046/j.1523-1747.2003.12133.x. PMID: 12713592.
[5] Khalkhal E, Razzaghi M, Rostami-Nejad M, Rezaei-Tavirani M, Heidari Beigvand H, Rezaei Tavirani M. Evaluation of Laser Effects on the Human Body After Laser Therapy. J Lasers Med Sci. 2020 Winter;11(1):91-97. doi: 10.15171/jlms.2020.15. Epub 2020 Jan 18. PMID: 32099633; PMCID: PMC7008747.
[6] Chung H, Dai T, Sharma SK, Huang YY, Carroll JD, Hamblin MR. The nuts and bolts of low-level laser (light) therapy. Ann Biomed Eng. 2012 Feb;40(2):516-33. doi: 10.1007/s10439-011-0454-7. Epub 2011 Nov 2. PMID: 22045511; PMCID: PMC3288797.
[7] Xuan W, Vatansever F, Huang L, Wu Q, Xuan Y, Dai T, Ando T, Xu T, Huang YY, Hamblin MR. Transcranial low-level laser therapy improves neurological performance in traumatic brain injury in mice: effect of treatment repetition regimen. PLoS One. 2013;8(1):e53454. doi: 10.1371/journal.pone.0053454. Epub 2013 Jan 7. PMID: 23308226; PMCID: PMC3538543.
[8] Thunshelle C, Hamblin MR. Transcranial Low-Level Laser (Light) Therapy for Brain Injury. Photomed Laser Surg. 2016 Dec;34(12):587-598. doi: 10.1089/pho.2015.4051. PMID: 28001759; PMCID: PMC5180077.
[9] Lampl Y. Laser treatment for stroke. Expert Rev Neurother. 2007 Aug;7(8):961-5. doi: 10.1586/14737175.7.8.961. PMID: 17678491.
[10] Detaboada L, Ilic S, Leichliter-Martha S, Oron U, Oron A, Streeter J. Transcranial application of low-energy laser irradiation improves neurological deficits in rats following acute stroke. Lasers Surg Med. 2006 Jan;38(1):70-3. doi: 10.1002/lsm.20256. PMID: 16444697.
[11] Oron A, Oron U, Chen J, Eilam A, Zhang C, Sadeh M, Lampl Y, Streeter J, DeTaboada L, Chopp M. Low-level laser therapy applied transcranially to rats after induction of stroke significantly reduces long-term neurological deficits. Stroke. 2006 Oct;37(10):2620-4. doi: 10.1161/01.STR.0000242775.14642.b8. Epub 2006 Aug 31. PMID: 16946145.
[12] Lapchak PA, Salgado KF, Chao CH, Zivin JA. Transcranial near-infrared light therapy improves motor function following embolic strokes in rabbits: an extended therapeutic window study using continuous and pulse frequency delivery modes. Neuroscience. 2007 Sep 21;148(4):907-14. doi: 10.1016/j.neuroscience.2007.07.002. Epub 2007 Jul 12. PMID: 17693028.
[13] Zivin JA, Albers GW, Bornstein N, Chippendale T, Dahlof B, Devlin T, Fisher M, Hacke W, Holt W, Ilic S, Kasner S, Lew R, Nash M, Perez J, Rymer M, Schellinger P, Schneider D, Schwab S, Veltkamp R, Walker M, Streeter J; NeuroThera Effectiveness and Safety Trial-2 Investigators. Effectiveness and safety of transcranial laser therapy for acute ischemic stroke. Stroke. 2009 Apr;40(4):1359-64. doi: 10.1161/STROKEAHA.109.547547. Epub 2009 Feb 20. PMID: 19233936.
[14] Naeser MA, Stiassny-Eder D, Galler V, Hobbs J, Bachman D, Lannin L. Laser acupuncture in the treatment of paralysis in stroke patients: a CT scan lesion site study. Am J Acupuncture. 1995. [November 30, 2010]. pp. 13–28.
[15] Thurman DJ, Alverson C, Dunn KA, Guerrero J, Sniezek JE. Traumatic brain injury in the United States: A public health perspective. J Head Trauma Rehabil. 1999 Dec;14(6):602-15. doi: 10.1097/00001199-199912000-00009. PMID: 10671706.
[16] Lapchak PA, De Taboada L. Transcranial near infrared laser treatment (NILT) increases cortical adenosine-5′-triphosphate (ATP) content following embolic strokes in rabbits. Brain Res. 2010 Jan 8;1306:100-5. doi: 10.1016/j.brainres.2009.10.022. Epub 2009 Oct 23. Erratum in: Brain Res. 2010 Mar 19;1321:182. PMID: 19837048.
[17] Wu Q, Xuan W, Ando T, Xu T, Huang L, Huang YY, Dai T, Dhital S, Sharma SK, Whalen MJ, Hamblin MR. Low-level laser therapy for closed-head traumatic brain injury in mice: effect of different wavelengths. Lasers Surg Med. 2012 Mar;44(3):218-26. doi: 10.1002/lsm.22003. Epub 2012 Jan 24. PMID: 22275301; PMCID: PMC3397203.
[18] Moreira MS, Velasco IT, Ferreira LS, Ariga SK, Barbeiro DF, Meneguzzo DT, Abatepaulo F, Marques MM. Effect of phototherapy with low intensity laser on local and systemic immunomodulation following focal brain damage in rat. J Photochem Photobiol B. 2009 Dec 2;97(3):145-51. doi: 10.1016/j.jphotobiol.2009.09.002. Epub 2009 Sep 11. PMID: 19800810.
[19] Naeser MA, Saltmarche A, Krengel MH, Hamblin MR, Knight JA. Improved cognitive function after transcranial, light-emitting diode treatments in chronic, traumatic brain injury: two case reports. Photomed Laser Surg. 2011 May;29(5):351-8. doi: 10.1089/pho.2010.2814. Epub 2010 Dec 23. PMID: 21182447; PMCID: PMC3104287.
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