Vestibular autorotation testing in patients with benign paroxysmal positional vertigo PETER BELAFSKY, MD, PhD, GERARD GIANOLI, MD, JAMES SOILEAU, MD, DAVID MOORE, MD, and SHERI DAVIDOWITZ, MD,

New Orleans, Louisiana

OBJECTIVES: The current gold standard for diagnosis of benign paroxysmal positional vertigo (BPPV) is the Dix-Hallpike maneuver. However, because of fatigability, the Dix-Hallpike is often falsely normal. The objective of this study was to evaluate the utility of vestibular autorotation testing in the diagnosis of BPPV. METHODS: The charts of 210 patients at a tertiary referral center for vertiginous disorders were reviewed. All patients underwent clinical evaluation, Dix-Hallpike testing, audiometry, electronystagmography, and vestibular autorotation testing. The vestibular autorotation results of patients with BPPV were compared with the findings in patients with non-BPPV vestibular disorders. The sensitivity and specificity of vestibular autorotation testing in diagnosing BPPV were calculated. RESULTS: Ninety-one patients (42.9%) had BPPV, 76 patients (36.2%) had vertigo of uncertain cause, 28 (13.3%) had unilateral vestibular hypofunction, 9 patients (4.3%) had Meniere’s disease, and 2 patients (1.0%) had perilymphatic fistula. Patients with BPPV were 3.32 times more likely to have a normal horizontal gain (95% CI = 1.54-7.19). A normal horizontal gain is 85% sensitive but only 36% specific for BPPV. Patients with BPPV were 1.9 times more likely to have vertical phase lead (95% CI = 0.953.93). Patients with BPPV were 2.20 times more likely to have both normal horizontal gain and vertical phase lead (95% CI = 1.03-4.69) The sensitivity of the combination of normal horizontal gain and vertical phase lead on vestibular autorotation testing is 87% specific but only 25% sensitive in the diagnosis of BPPV. CONCLUSION: A normal horizontal gain or vertical phase lead on vestibular autorotation testing in a vertiginous patient is suggestive of but not exclusive From the Department of Otolaryngology–Head and Neck Surgery, Tulane University. Reprint requests: Gerard J. Gianoli, MD, Department of Otolaryngology–Head and Neck Surgery, Tulane University Medical School, 1430 Tulane Ave, SL-59, New Orleans, LA 70112-2699. Copyright © 2000 by the American Academy of Otolaryngology– Head and Neck Surgery Foundation, Inc. 0194-5998/2000/$12.00 + 0 23/1/99973

to a diagnosis of BPPV. The combination of a normal horizontal gain and vertical phase lead on vestibular autorotation testing is highly suggestive of the diagnosis of BPPV. Adjuvant use of these parameters in vestibular autorotation testing may prove to be helpful in the diagnosis of BPPV. (Otolaryngol Head Neck Surg 2000;122:163-7.)

Benign paroxysmal positional vertigo (BPPV) is a

potentially debilitating but easily treatable disorder. It is responsible for up to 25% of all cases of vertigo and is the principal cause of vertigo in the elderly.1-3 First described by Barany4 in 1921, the disorder is characterized by vertigo and nystagmus that are precipitated by head tilt toward the affected ear. Classically, the rotary nystagmus beats toward the affected ear, begins after a several-second latency, has a duration of less than 1 minute, and is fatigable with repetitious head tilts. Although most patients with BPPV will experience the classic symptoms, atypical presentations are frequently encountered. These symptoms can occur in the normal, head upright position and may be difficult to differentiate from other peripheral or central vestibular disorders. The cause of BPPV has been ascribed to the accumulation of dense particles in dependent portions of the semicircular canals. These particles, or otoconia, move with gravitational and positional forces and stimulate the cupula, resulting in the transmission of aberrant signals to the central nervous system.5 The gold standard of diagnosing BPPV is the DixHallpike test.6 The maneuver is performed by rapidly placing the patient in the lateral supine position with the head hanging below the level of the horizontal plane. The result is considered positive if the position elicits rotary nystagmus and vertigo that last for less than 1 minute, are fatigable, and are associated with a severalsecond latency. The peripheral abnormality in BPPV and its relationship to certain head movements suggest that the vestibular-ocular reflex (VOR) may assist in the diagnosis of BPPV. The VOR functions to maintain the image of a distant object on the retina during head rotation, such as occurs during locomotion or other activities of daily life. To accomplish this aim, the VOR gen163

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Table 1. Distribution of cohort diagnoses (N = 210) Diagnosis

n (%)

BPPV Dysequilibrium of unknown cause Unilateral vestibular hypofunction Bilateral vestibular hypofunction Meniere’s disease Perilymphatic fistula

91 (42.9) 76 (36.2) 28 (13.3) 9 (4.3) 4 (1.4) 2 (1)

Table 2. Association between age, race, sex, and BPPV (N = 210)

Mean age (y) Sex Male Female Race White Nonwhite *Non-BPPV

BPPV

Control*

P value

60.5 ± 14.1

53.7 ± 18.28

0.05

85 6

105 14

>0.05

vertiginous patients.

erates compensatory eye movements equal in velocity and opposite in direction to the motions of the head. Traditionally, the VOR is evaluated by caloric testing. Calorics, however, are limited in that they test only the horizontal semicircular canals in a nonphysiologic frequency (