Trigeminal nerve stimulation may have protective effects after severe traumatic brain injury.
Traumatic brain injury (TBI) is a leading cause of morbidity and mortality worldwide. One-third of all injury-related deaths are caused by TBI, and those who do survive are often left with permanent disability. Although recent research has improved clinicians’ understanding of the mechanisms and treatment of TBI, currently there are no medications that significantly improve patient outcomes. People who sustain TBI typically rely on therapeutic strategies to improve their recovery outcomes, so clinicians are investigating new treatment programs.
These therapeutic strategies usually focus on treating secondary TBI, which may have reversible effects. Unlike primary TBI (which is classified as damage that occurs immediately at the time of injury and cannot be reversed), secondary TBI occurs in the post-injury period as the brain struggles with structural damage. Secondary TBI often occurs when cerebral blood flow decreases, depriving brain cells of energy and causing neuron death. Stimulating blood flow after a head injury may then prevent secondary TBI and decrease the likelihood of brain cell death.
A group of researchers in New York investigated the relationship between stimulating blood flow and decrease in secondary TBI. They hypothesized that stimulating the trigeminal nerve – the brain’s largest nerve system – can increase blood flow to injured areas and allow blood to flow through the brain more easily. Using an animal model, the researchers applied trigeminal nerve stimulation to one group with TBI and did not apply the same treatment to another TBI control group. They found that:
- Those who were treated with trigeminal nerve stimulation (TNS) had increased cerebral blood flow.
- TNS increased participants’ blood pressure, allowing blood to reach injured areas of the brain more quickly.
- The TNS-treatment group experienced less brain swelling and showed a slight reduction in structural damage to the brain.
Currently, clinicians rely primarily on therapeutic interventions to increase positive outcomes after TBI. Because TNS increases blood flow to injured areas of the brain after TBI, the TNS method is a promising strategy for reducing the cell death and other negative outcomes associated with secondary TBI.
Chiluwal A, Narayan RK, Chaung W, et al. Neuroprotective effects of trigeminal nerve stimulation after severe traumatic brain injury. Scientific Reports. (July 2017).