Rotatory recovery nystagmus: an important localizing sign in endolymphatic hydrops.

Localizing the ear responsible for vertigo attacks may be exceedingly difficult in patients with delayed endolymphatic hydrops, vestibular Ménière's disease or bilateral Ménière's disease. This has important clinical implications when planning operative treatment. We present a case of delayed endolymphatic hydrops to exemplify these difficulties and demonstrate the localizing value of recovery nystagmus. We stress the importance when possible of monitoring patients with endolymphatic hydrops for recovery nystagmus during acute vertigo attacks. Monitoring should include direct eye observation as pure rotatory nystagmus escapes detection on electronystagmography.