The site of lesion in “vestibular neuritis”: Study by galvanic VEMP

Vestibular neuritis (VN) is characterized by isolated vertigo without other neurologic signs or symptoms.1 Patients show unilateral peripheral vestibular dysfunction mainly in the superior vestibular nerve region,2 although some patients also have dysfunction in the inferior vestibular nerve region.1,3⇓ Although VN supposedly involves the vestibular nerve, insufficient evidence is available concerning the VN lesion site. It is known that some patients with VN have benign paroxysmal positional vertigo (BPPV) following severe vertigo attacks.1 These patients would be expected to have some lesions in the labyrinth because BPPV is caused by floating debris in the semicircular canal.4 Recently, it was reported that short-duration galvanic stimulation could evoke vestibulocollic reflexes in the sternocleidomastoid muscle (SCM)5-7⇓⇓ (galvanic vestibular evoked myogenic potentials [VEMP]). It has also been reported that these reflexes are useful for differentiating labyrinthine lesions from nerve lesions in patients with an absence of VEMP by click (click VEMP).6 We postulated that galvanic VEMP could indicate the site …