title: Prevalence of post-headshake nystagmus in patients with caloric deficits and vertigo.
abstract: Post-headshake nystagmus (PHN) has recently been described as a clinically useful physical sign implying uncompensated asymmetric input from the vestibular end organs. A rapid 20-second headshake and sudden stop produces a jerk nystagmus of 5- to 20-second duration in certain individuals with symptoms suggestive of a peripheral vestibulopathy. This retrospective review of 214 patient evaluations was undertaken to study the associations between post-headshake nystagmus, caloric deficits after bithermal binaural irrigation, and the presence of vertigo. Both clinical observation of the nystagmus with eyes open (PHN-OBS) and routine EOG recording with eyes closed (PHN-EOG) were used. In patients with unilateral caloric deficits, 42% (18 of 43) had PHN-EOG, compared with 18% (3 of 17) in patients with bilateral dysfunction and 15% (23 of 154) in patients with normal calorics (p less than 0.001). In similar fashion, 26% (32 of 124) of patients with vertigo (recent or past) had PHN-EOG compared to 13% (12 of 90) of patients without vertigo (p less than 0.03). Finally, of 110 cases with both PHN-EOG and PHN-OBS performed, 45% (9 of 20) with PHN-EOG also had PHN-OBS, as opposed to only 4% (4 of 90) without PHN-EOG displaying PHN-OBS (p less than 0.0001). We conclude that the prevalence of post-headshake nystagmus is increased in patients with either a unilateral caloric deficit or a history of true vertigo, and is best detected in the absence of vision.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO.
authors.forename: J A
authors.initials: JA
authors.lastname: Goebel
authors.forename: P
authors.initials: P
authors.lastname: Garcia
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002150:Caloric Tests; D002648:Child; D004585:Electrooculography; D006801:Humans; D008875:Middle Aged; D009760:Nystagmus, Physiologic / Q000502:physiology; D012189:Retrospective Studies; D014717:Vertigo / Q000175:diagnosis* / Q000503:physiopathology; D015837:Vestibular Diseases / Q000175:diagnosis* / Q000503:physiopathology; D014724:Vestibular Function Tests / Q000379:methods*