Nighttime Jaw Clenching Linked to Migraine-Related Disability

Aim

To evaluate the nocioceptive information of habitual nocturnal jaw clenching that acts as a contributing factor in the pathogenesis of migraine.

Background

Habitual nocturnal jaw clenching has been implicated as a trigger, particularly in those whose headaches are present upon awakening or shortly after. Nocturnal EMG studies of patients diagnosed with migraine show nearly double the temporal twitch EMG levels and twice the bite force of matched asymptomatic controls, leading to speculation that parafunctional twitch activity may have some role in the pathogenesis of headache.

The NTI (Nociceptive Trigeminal Inhibition) Oral Device is a dental splint designed to reduce the intensity of nocturnal jaw clenching and is FDA approved for the prevention of medically diagnosed migraine pain based on open studies. There are no previous placebo-controlled trials to evaluate the effectiveness of the NTI splint in preventing migraine. This is the first placebo-controlled crossover study to evaluate the efficacy of the NTI splint in patients with chronic migraine.

Methods

A single-blind, placebo-controlled crossover study was conducted with IRB supervision to evaluate the efficacy of the NTI splint compared to placebo using the change in HIT-6 score as the outcome measure.

NTI device. 1) Initial closing. 2) Lower device 3) Protruding position. 4) retrusive position. The device must be modified to ensure contact of the incisive edge at the ends of each position 

Results

68% of patients with chronic refractory migraine using the NTI, as measured by sequential HIT 6 scores, had at least one category improvement (severe to substantial, or substantial to some, or some to none) in compared to 12% when using a placebo device. 36% of subjects using the NTI device reported a two-category improvement in their HIT-6 score, compared to 0% when using placebo.

Comparison of the Effect of NTI Versus Placebo on the Degree of Negative Impact of Chronic Migraine in Individual Subjects

Conclusion

The improvement in HIT-6 scores produced by the NTI device suggests that patients with chronic migraine may have severe jaw clenching at night as a contributing factor to their headache-related disability. An NTI device is a method of evaluating whether jaw clenching is a contributing factor to an ongoing migraine.

Comments

For 30 days, migraineurs were randomly assigned to an FDA-approved dental device to help clench their jaw or a placebo device.

Findings from a randomized controlled trial suggest that intense jaw clenching at night may be a contributing factor to headache-related disability among patients with chronic migraine. The results were published in BMC Neurology and also confirm that an oral nociceptive trigeminal inhibition (NTI) device is a method to evaluate whether jaw clenching contributes to ongoing migraine.

Chronic migraineurs may be refractory to multiple preventive medications, while others may be reluctant to use pharmacotherapeutic treatments due to their systemic side effects, the researchers explained.

Although the exact underlying pathology of migraine is unknown, the condition is thought to involve hyperactivity in the trigemino-occipital-cervical nerve complex.

Previous research has implicated habitual nighttime jaw clenching as a potential migraine trigger, especially among those who have headaches upon waking or shortly after.

To help address his condition, the NTI was developed to minimize the intensity of the squeezes and subsequent afferent nociceptive activity. “The NTI is a semi-customized intraoral mouthpiece approved by the FDA in 2001 for the prophylactic treatment of medically diagnosed migraine pain by reducing muscle activity innervated by the trigeminal nerve,” the authors wrote.

In an effort to evaluate the effectiveness of the NTI splint in improving disability, researchers conducted a single-blind study among 25 chronic migraineurs presenting to a headache center.

All participants were referred to a dental practice to be considered for the study and were treated with a placebo device and an NTI device, however, “participants did not know which device was FDA approved, while practitioners were familiar with the NTI. ”

At baseline, patients completed a Headache Impact Test (HIT-6) questionnaire. After being randomized to 30 days of NTI splint use or placebo splint use, patients completed another HIT-6 questionnaire and switched to the alternative device. They then completed a final questionnaire after the second 30-day use period.

Of the 25 participants, 19 completed the full trial and the patients’ baseline average HIT-6 score was 4 or "severe impact, disabling pain."

The analyzes revealed:

• 68% (17 of 25) of patients using the NTI as measured by sequential HIT 6 scores had at least 1 category improvement (severe to substantial, or substantial to somewhat, or somewhat to none) compared with 12% (3 of 25) when using a placebo device:
   
• 36% (9 of 25) of patients using the NTI device reported a 2-category improvement in their HIT-6 score, compared to 0% when using placebo.
   
• No patients reported adverse events.
   
• A Fisher test revealed (P = .00125) that there is a statistically significant difference between the improvement of NTI and Placebo.

“Decreasing peripheral sensitization with modalities such as the NTI splint protocol that reduces chronic nociceptive input may help decrease central sensitization, which is a hallmark of chronic migraine,” the authors wrote.

Although approved more than 2 decades ago, NTI has not become a commonly used adjunctive preventive treatment for migraine, possibly due to patients’ negative experiences with traditional dental splints or lack of awareness among providers.

“The production of nociceptive information by the teeth, bones, [temporomandibular joints] and muscles affected by the trigeminal sensory nucleus produced by nocturnal clenching of the jaw should be considered as a possible cofactor in the perpetuation and confusion of chronic migraine,” the researchers concluded.