Transcranial Photobiomodulation Promotes Neurological Resilience in Current Collegiate American Football Players Exposed to Repetitive Head Acceleration Events
Abstract
Repetitive head acceleration events (RHAE) are common in contact sports and associated with neuroinflammation, axonal injury, and long-term neurological impairments, including increased risk for chronic traumatic encephalopathy. Current strategies for addressing RHAE focus on post-injury care rather than proactive neuroprotection, leaving athletes vulnerable to cumulative neurotrauma. Transcranial photobiomodulation (PBM) has shown promise in reducing neuroinflammation and promoting neuroprotection in traumatic brain injury; however, its potential to mitigate the structural brain changes associated with RHAE in actively competing athletes has not been investigated. The aim of this study was to investigate whether PBM mitigates RHAE-related neuroinflammatory and microstructural changes in collegiate American football players over a single National Collegiate Athletic Association Division I season. We hypothesized that restricted diffusion imaging (RDI) and quantitative anisotropy (QA), diffusion magnetic resonance imaging markers of neuroinflammation and axonal remodeling, respectively, would increase in the Sham PBM group due to RHAE exposure but remain stable in the Active PBM group, indicating neurological resilience. Twenty-six collegiate football players were randomly assigned to Active (n = 13) or Sham (n = 13) PBM groups. PBM (810 nm) was self-administered 3 days a week under supervision in the athletic training room with a transcranial plus intranasal device throughout the preseason practice period and regular season (16 weeks). Diffusion MRI data were collected pre- and postseason, and correlational tractography was used to assess the effects of PBM on longitudinal changes in RDI and QA. Moderation analyses examined time × group interactions, with post hoc analyses exploring within- and between-group differences in RDI and QA cross-sectionally and longitudinally. Correlational tractography revealed significant main effects and interactions of time and group, with widespread increases in RDI and QA observed in the Sham PBM group over the season, consistent with neuroinflammation and axonal remodeling. In contrast, the Active PBM group showed relative stability in RDI and QA over time, with significant reductions observed in some areas. These findings suggest that PBM may mitigate ongoing neuroinflammation and facilitate the recovery processes. This study provides the first evidence suggesting that transcranial PBM reduces neuroinflammatory and axonal injury markers in American collegiate football players over a single season. PBM may serve as a noninvasive and accessible intervention for mitigating the cumulative neurological effects of RHAE exposure, offering a neuroprotective strategy for athletes participating in collision and contact sports. Future research should examine the long-term benefits of PBM across multiple seasons and its impact on functional outcomes to further establish the role of PBM in athlete brain health and wellness.
A Proof-of-Concept Study Investigating the Effects of Transcranial Plus Intranasal Photobiomodulation on Cognitive Function after Repetitive Head Acceleration Events
Abstract
Objective: Investigate the effects of transcranial plus intranasal photobiomodulation (PBM) treatment on cognitive function, using an 810 nm light emitting diode headset and intranasal applicator every other day for 8–10 weeks.
Background Data: An effective gold standard for the rehabilitation of repetitive head acceleration events (RHAEs) does not yet exist.
Methods: Forty-four participants with a history of RHAEs completed a battery of cognitive tests before and after PBM treatment. Data were analyzed at the group level (paired samples t-tests, controlling for multiple comparisons) and on the individual-person level (reliable change indices).
Results: On a group level, participants demonstrated statistically significant improvements with moderate-to-large effect sizes in fluid cognition, verbal learning and memory, attention and working memory, and aspects of executive function following PBM treatment. Specific improvements were observed in verbal learning/encoding and delayed recall, sustained attention, errors of omission and commission, working memory, inhibition, and cognitive switching. On the individual level, 0–36% of participants showed reliable improvement across cognitive measures, depending on the subtest; changes were greatest on measures of attention and memory.
Conclusions: Results suggest that PBM treatment may be a promising intervention for improving cognitive function in individuals with a history of RHAEs. Observed improvements in cognitive function following PBM treatment may have important implications for the prevention and treatment of cognitive impairments associated with RHAEs. Further studies with more robust research designs that utilize clinical trial methodologies are needed to confirm and extend these findings.
PBM or LED Therapy for TBI
Abstract
Light emitting diode (LED) therapy: is a non-invasive treatment modality that can be used in the office setting and at home (when indicated). LED is a painless, non-thermal photobiomodulation (PBM) treatment that directly targets the cellular functioning of injured brain cells.
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Can Transcranial Photobiomodulation Improve Cognitive Function in TBI Patients?
Abstract
Introduction: Transcranial photobiomodulation (tPBM) is a non-invasive neuromodulation technology which has become a promising therapy for treating many brain diseases. Although it has been confirmed in studies targeting neurological diseases including Alzheimer’s and Parkinson’s that tPBM can improve cognitive function, the effectiveness of interventions targeting TBI patients remains to be determined. This systematic review examines the cognitive outcomes of clinical trials concerning tPBM in the treatment of traumatic brain injury (TBI).
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The Effect of Intranasal Plus Transcranial Photobiomodulation on Neuromuscular Control in Individuals with Repetitive Head Acceleration Events
Introduction
Approximately 3.8 million sport- and recreation-related concussions occur annually in the United States. The effects of concussion, including persistent long-term issues with concentration and physical skills is a growing concern. Equally concerning are the effects of repetitive head impacts (RHIs), also known as repetitive head acceleration events (RHAEs). RHAE has the same meaning as RHI; however, it is emerging as a preferred term because it inherently indicates that the brain is experiencing translational and/or rotational movement because of external forces regardless of the source (blast or mechanical blow) or location (head or body) of the impact forces. Although RHAE may include concussions or mild traumatic brain injury (mTBI), most do not result in any acute detectable clinical symptoms. However, the cumulative effect of RHAE, like concussion or mTBI, could progress to traumatic encephalopathy syndrome (TES), a clinical disorder associated with chronic traumatic encephalopathy (CTE). An athlete may experience over 100 RHAEs per season. Although the athlete may be asymptomatic, RHAEs result in microstructural and functional changes in the brain similar to that seen in concussion or mTBI, leading to altered motor unit recruitment strategies, increased acute corticomotor inhibition, and other neuromuscular impairments, such as reduced dynamic balance or reaction time, in the long-term.
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Effects of Low-Level Light Therapy on Resting-State Connectivity Following Moderate Traumatic Brain Injury: Secondary Analyses of a Double-Blinded Placebo-Controlled Study
Abstract
Patients with moderate traumatic brain injury who were administered low-level light therapy within 72 hours after injury showed increased resting-state brain connectivity as measured with functional MRI during the acute to subacute recovery phases compared with sham-treated patients.
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Effects of Low-Level Light Therapy on Resting-State Connectivity Following Moderate Traumatic Brain Injury: Secondary Analyses of a Double-blinded Placebo-controlled Study
Abstract
Background Low-level light therapy (LLLT) has been shown to modulate recovery in patients with traumatic brain injury (TBI). However, the impact of LLLT on the functional connectivity of the brain when at rest has not been well studied. Purpose To use functional MRI to assess the effect of LLLT on whole-brain resting-state functional connectivity (RSFC) in patients with moderate TBI at acute (within 1 week), subacute (2-3 weeks), and late-subacute (3 months) recovery phases. Materials and Methods This is a secondary analysis of a prospective single-site double-blinded sham-controlled study conducted in patients presenting to the emergency department with moderate TBI from November 2015 to July 2019. Participants were randomized for LLLT and sham treatment. The primary outcome of the study was to assess structural connectivity, and RSFC was collected as the secondary outcome. MRI was used to measure RSFC in 82 brain regions in participants during the three recovery phases. Healthy individuals who did not receive treatment were imaged at a single time point to provide control values. The Pearson correlation coefficient was estimated to assess the connectivity strength for each brain region pair, and estimates of the differences in Fisher z-transformed correlation coefficients (hereafter, z differences) were compared between recovery phases and treatment groups using a linear mixed-effects regression model. These analyses were repeated for all brain region pairs. False discovery rate (FDR)-adjusted P values were computed to account for multiple comparisons. Quantile mixed-effects models were constructed to quantify the association between the Rivermead Postconcussion Symptoms.
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Photobiomodulation combination therapy as a new insight in neurological disorders: a comprehensive systematic review
Abstract
Preclinical and clinical studies have indicated that combining photobiomodulation (PBM) therapy with other therapeutic approaches may influence the treatment process in a variety of disorders. The purpose of this systematic review was to determine whether PBM-combined therapy provides additional benefits over monotherapies in neurologic and neuropsychiatric disorders. In addition, the review describes the most commonly used methods and PBM parameters in these conjunctional approaches.
To accomplish this, a systematic search was conducted in Google Scholar, PubMed, and Scopus databases through January 2024. 95 potentially eligible articles on PBM-combined treatment strategies for neurological and neuropsychological disorders were identified, including 29 preclinical studies and 66 clinical trials.
According to the findings, seven major categories of studies were identified based on disease type: neuropsychiatric diseases, neurodegenerative diseases, ischemia, nerve injury, pain, paresis, and neuropathy. These studies looked at the effects of laser therapy in combination with other therapies like pharmacotherapies, physical therapies, exercises, stem cells, and experimental materials on neurological disorders in both animal models and humans. The findings suggested that most combination therapies could produce synergistic effects, leading to better outcomes for treating neurologic and psychiatric disorders and relieving symptoms.
These findings indicate that the combination of PBM may be a useful adjunct to conventional and experimental treatments for a variety of neurological and psychological disorders.
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Traumatic Brain Injury Recovery with Photobiomodulation: Cellular Mechanisms, Clinical Evidence, and Future Potential
Abstract
Traumatic Brain Injury (TBI) remains a significant global health challenge, lacking effective pharmacological treatments. This shortcoming is attributed to TBI’s heterogeneous and complex pathophysiology, which includes axonal damage, mitochondrial dysfunction, oxidative stress, and persistent neuroinflammation. The objective of this study is to analyze transcranial photobiomodulation (PBM), which employs specific red to near-infrared light wavelengths to modulate brain functions, as a promising therapy to address TBI’s complex pathophysiology in a single intervention. This study reviews the feasibility of this therapy, firstly by synthesizing PBM’s cellular mechanisms with each identified TBI’s pathophysiological aspect. The outcomes in human clinical studies are then reviewed. The findings support PBM’s potential for treating TBI, notwithstanding variations in parameters such as wavelength, power density, dose, light source positioning, and pulse frequencies. Emerging data indicate that each of these parameters plays a role in the outcomes. Additionally, new research into PBM’s effects on the electrical properties and polymerization dynamics of neuronal microstructures, like microtubules and tubulins, provides insights for future parameter optimization. In summary, transcranial PBM represents a multifaceted therapeutic intervention for TBI with vast potential which may be fulfilled by optimizing the parameters. Future research should investigate optimizing these parameters, which is possible by incorporating artificial intelligence.