Abstract
We report a case of Costen's syndrome that showed chewing-induced nystagmus and vertigo. A 31-year-old woman visited our hospital complaining of chewing-induced vertigo 5 days after dental therapy. During chewing a stick of gum, she complained of vertigo and showed nystagmus beating to the right, the direction of which changed to the left thereafter. No spontaneous and positional nystagmus or any abnormalities in the neurological examination could, however, be found. The chewing-induced nystagmus and vertigo gradually disappeared within 2 weeks. Costen's syndrome is associated with various symptoms due to temporomandibular dysfunction. In the case, it is suggested that malinterdigitation after dental therapy caused temporomandibular dysfunction, resulting in the chewing-induced nystagmus, therefore, Costen's syndrome was diagnosed.
Eustachian tube hypothesis, Tensor tympani hypothesis and otomandibular ligament hypothesis that accounted for temporomandibular dysfunction-induced aural symptoms in patient with Costen's syndrome had been proposed, but recently were withdrew. On the other hand, it is reported that reciprocal connections between trigeminal and vestibular nuclei. The trigeminal somatosensory input associated with temporomandibular dysfunction after dental therapy may cause chewing-induced nystagmus via the trigemino-vestibular connection in the brainstem in the case.
