The clinical utility of search coil horizontal vestibulo-ocular reflex testing.
CONCLUSIONS
Testing of the horizontal vestibulo-ocular reflex (VOR) with head rotations (including head impulses) using the magnetic scleral search coil technique (SCT HHI) provides valuable additional diagnostic information in patients with persistent dizziness, oscillopsia or imbalance. It identifies high and low frequency/acceleration vestibular abnormalities that are frequently missed using other methods.


OBJECTIVE
To evaluate the diagnostic utility of SCT measurement of the horizontal VOR in the multidisciplinary neurotology clinic of a tertiary referral centre.


METHODS
The records of 127 consecutive patients referred for persistent dizziness, oscillopsia, imbalance, or with clinical findings suggestive of high frequency/acceleration vestibular dysfunction were reviewed. All had been tested with clinical head impulses, bithermal calorics and vestibular-evoked myogenic potentials. VOR gain (peak eye velocity/peak head velocity) had been measured both in response to sinusoidal oscillations in a rotating chair (0.1-11 Hz) and to manually delivered horizontal head rotations (peak head velocities 50-500 degrees/s) using SCT.


RESULTS
Agreement between the different test modalities of horizontal semicircular canal function was moderate. Relative to SCT HHI, clinical HHI showed the highest sensitivity and the lowest specificity (both 70%). SCT HHI appeared to have the greatest diagnostic yield, when compared with calorics and SCT ROT (23% of all abnormalities shown were detected only by SCT HHI) and also allowed detection of significant asymmetries in patients with bilateral vestibular dysfunction.
Kessler
Paul
P
Otoneurology Laboratory, University Health Network, University of Toronto, Toronto, Ontario, Canada.
Zarandy
Masoud Motasaddi
MM
Hajioff
Daniel
D
Tomlinson
David
D
Ranalli
Paul
P
Rutka
John
J
D000054:Acceleration; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002150:Caloric Tests; D003937:Diagnosis, Differential; D004244:Dizziness / Q000209:etiology*; D004574:Electromagnetic Fields; D004584:Electronystagmography; D004867:Equipment Design; D005260:Female; D019416:Head Movements / Q000502:physiology; D006801:Humans; D007699:Kinesthesis; D008297:Male; D008875:Middle Aged; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D012189:Retrospective Studies; D012399:Rotation; D012665:Semicircular Canals / Q000503:physiopathology; D054776:Semicircular Ducts / Q000503:physiopathology; D014717:Vertigo / Q000209:etiology*; D015837:Vestibular Diseases / Q000175:diagnosis* / Q000503:physiopathology; D014724:Vestibular Function Tests / Q000295:instrumentation*; D014725:Vestibular Nerve / Q000503:physiopathology; D020338:Vestibular Neuronitis / Q000175:diagnosis / Q000503:physiopathology