Trigeminal Nerve & its Autonomic Considerations
A study in 2015 discussed the link of trigeminal neuralgia (TN) with dysfunction of the autonomic nervous system. 1
Method: 12 patients with classical TN and 12 healthy control patients. Patients are asked to submerge right arm for 5 into 10*C water to trigger pain. Patients rated their pain every 30 seconds on a 0-100 scale. Electrocardiograms were taken before and during experimental pain test. Heart rate was also analyzed in frequency domain, differentiating low frequency components ( HR fluctuations in the LF range reflect baroreflex-mediated sympathetic activity associated with Mayer waves of blood pressure) and high frequency components (HRV in the HF range is generated by respiratory sinus arrhythmia and
constitutes a sensitive measure of cardiac vagal parasympathetic activity).
Result: No difference in pain perception or heart rate between TN group and control group. No one in TN group experienced facial pain. All patients experienced an increase in low frequency oscillations (increased sympathetic activity) and decrease in high frequency (decrease in parasympathetic activity), but the changes were more pronounced in the TN group.
Conclusions: “Results indicate that TN patients and healthy controls have comparable
autonomic cardiac responses at rest, but that in response to a tonic experimental pain challenge, TN patients show greater sympathetic arousal and parasympathetic withdrawal than healthy controls.” “The exact reason for the negative association between sympathetic reactivity and the number of pain paroxysms experienced by TN patients remains unclear and surely merits future attention.”
The Vagus nerve has clear parasympathetic connections, but the jury is still out on the trigeminal nerve. However, one thing noticed frequently in chiropractic practices is how the temporomandibular joint (TMJ), when not functioning, will usually be associated with increased tension in that person, whether they are a child or an adult 2. Reducing the alignment issues in the TMJ often reduces that person’s stress as well.
References
1. Léonard, G., Chalaye, P., Goffaux, P., Mathieu, D., Gaumond, I., & Marchand, S. (2015). Altered
Autonomic Nervous System Reactivity to Pain in Trigeminal Neuralgia. Canadian Journal of
Neurological Sciences / Journal Canadien Des Sciences Neurologiques, 42(2), 125-131.
doi:10.1017/cjn.2015.10
2. Santos, E. et al. (2022). Association between temporomandibular disorders and anxiety: A systematic review. Frontiers in Psychiatry. https://www.frontiersin.org/journals/psychiatry/articles/10.3389/fpsyt.2022.990430/full