Diagnostic value of vestibulo-ocular reflex parameters in the detection and characterization of labyrinthine lesions.
OBJECTIVE
To evaluate the power of various parameters of the vestibulo-ocular reflex (VOR) in detecting unilateral peripheral vestibular dysfunction and in characterizing certain inner ear pathologies.


METHODS
Prospective study of consecutive ambulatory patients presenting with acute onset of peripheral vertigo and spontaneous nystagmus.


METHODS
Tertiary referral center.


METHODS
Seventy-four patients (40 females, 34 males) and 22 normal subjects (11 females, 11 males) were included in the study. Patients were classified in three main diagnoses: vestibular neuritis: 40; viral labyrinthitis: 22; Meniere's disease: 12.


METHODS
The VOR function was evaluated by standard caloric and impulse rotary tests (velocity step). A mathematical model of vestibular function was used to characterize the VOR response to rotational stimulation. The diagnostic value of the different VOR parameters was assessed by uni- and multivariable logistic regression.


RESULTS
In univariable analysis, caloric asymmetry emerged as the most powerful VOR parameter in identifying unilateral vestibular deficit, with a boundary limit set at 20%. In multivariable analysis, the combination of caloric asymmetry and rotational time constant asymmetry significantly improved the discriminatory power over caloric alone (p<0.0001) and produced a detection score with a correct classification of 92.4%. In discriminating labyrinthine diseases, different combinations of the VOR parameters were obtained for each diagnosis (p<0.003) supporting that the VOR characteristics differ between the three inner ear disorders. However, the clinical usefulness of these characteristics in separating the pathologies was limited.


CONCLUSIONS
We propose a powerful logistic model combining the indices of caloric and time constant asymmetries to detect a peripheral vestibular loss, with an accuracy of 92.4%. Based on vestibular data only, the discrimination between the different inner ear diseases is statistically possible, which supports different pathophysiologic changes in labyrinthine pathologies.
Maire
Raphaël
R
Clinic of Otolaryngology, Head & Neck Surgery, University Hospital Lausanne, Switzerland. raphael.maire@chuv.ch
van Melle
Guy
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007759:Labyrinth Diseases / Q000175:diagnosis* / Q000503:physiopathology; D007762:Labyrinthitis / Q000175:diagnosis / Q000503:physiopathology / Q000821:virology; D016015:Logistic Models; D008297:Male; D008575:Meniere Disease / Q000175:diagnosis / Q000503:physiopathology; D008875:Middle Aged; D015999:Multivariate Analysis; D009759:Nystagmus, Pathologic; D011446:Prospective Studies; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D014717:Vertigo; D014724:Vestibular Function Tests