Correlations between the blink reflex and magnetic resonance imaging in patients with trigeminal neuralgia.

Background: Trigeminal neuralgia is a disease characterized by severe facial pain that significantly reduces patients quality of life. Trigeminal neuralgia is subcategorized as idiopathic, classic or secondary. Magnetic resonance imaging is the basis for classification, but neurophysiological tests are also used. Magnetic resonance imaging provides neuroanatomical information and neurophysiological testing provides physiological information about the trigeminal nerve.

Methods: Thirty volunteer patients who were diagnosed with trigeminal neuralgia according to the ICHD-3 diagnostic criteria and met the exclusion and inclusion criteria were included. Blink reflex testing was performed after posterior fossa magnetic resonance imaging. Magnetic resonance imaging was evaluated blindly to avoid bias by one radiologist experienced in neuroradiology.

Results: The blink reflex was determined to be abnormal in 26.7% (n = 8) and normal in 73.3% (n = 22) of the patients included in the study. Magnetic resonance imaging revealed no contact with the trigeminal nerve in 53.3% (n = 16) of the patients, whereas 46.7% (n = 14) of the patients had contact with nerves in the cisternal segment. The blink reflex has sensitivity 42.9% and specificity 87.5%, accuracy value of 66.7%, positive predictive value of 75% and negative predictive value of 63.6% with respect to symptomatic mechanic contact.

Conclusion: The blink reflex is a neurophysiologic test that is well tolerated by patients, cost-effective and highly specific in the context of nerve contact in patients with trigeminal neuralgia. The blink reflex is particularly important in the follow-up and evaluation of trigeminal neuralgia patients for whom magnetic resonance imaging is contraindicated.