Vestibulological differential diagnostic criteria of Meniere’s disease and vestibular migraine

Abstract. Objective. Тo identify and systematize specific features of vestibular function in patients suffering from Meniere’s disease (MD) and vestibular migraine (VM) by means of comprehensive vestibular examination. Materials and methods. 100 patients with verified MD and 50 patients with VM were comprehensively examined in the interictal period. All patients underwent assessment of spontaneous and positional vestibular symptoms, oculomotor tests using videonystagmography, function of the semicircular canals (vHIT (video head impulse test), caloric tests), otolith function (registration of cervical and ocular vestibular evoked myogenic potentials: cVEMP, oVEMP). Results. Spontaneous nystagmus: obvious not detected, hidden horizontal (toward the healthy labyrinth) detected in 28% in MD, hidden vertical (upward-beating) in 24% in VM. Head-shaking test was positive in 64% in MD, negative in 88% in VM. The caloric test in MD registered clinically significant hypofunction of the affected labyrinth in 94% at stage II and in 26% at stage I of MD, in other cases subclinical hypofunction was observed. In VM, caloric reactions were symmetrical and pronounced in 92%. The results of vHIT and oculomotor tests were normal in patients of both groups. However, optokinetic stimulation provoked headache or dizziness in 56% in VM. Positional tests revealed signs of BPPV (benign paroxysmal positional vertigo) in 18% with MD and in 6% with VM. Besides, the VM group showed positional nystagmus, atypical for BPPV in 54%. VEMP recorded bilaterally symmetrical responses in VM, with a maximum amplitude of response at a frequency of 500 Hz, while in MD there was an asymmetry of amplitudes due to hypofunction on the affected side in 62%, at least in one of the VEMP classes, as well as a shift in the maximum response amplitude from a frequency of 500 Hz to 1,000 and 1,500 Hz in 64%. Conclusion. In complex differential diagnostic situations, it is necessary to consider the following characteristic features of the vestibular function in MD patients: a positive head shake test, dissociation of normal vHIT results, and hyporeflexia (including subclinical) of the diseased ear according to the caloric test. In the case of VM, latent spontaneous vertical nystagmus, positional nystagmus that does not meet the criteria for BPPV, symmetrical vestibular function according to caloric, video impulse tests and VEMP, poor tolerance of exercise tests are of great importance.