Horizontal VOR function shows frequency dynamics in vestibular schwannoma.
The objective of this retrospective study was to investigate the horizontal vestibulo-ocular reflex (hVOR) pathway with caloric test (low-frequency hVOR) and video head impulse test (vHIT) (high-frequency hVOR) in patients with sporadic vestibular schwannoma (69 patients, 27-86 years, mean age 58.1 years) and to compare both test methods in terms of their sensitivity and specificity to detect a retrocochlear lesion. Test results with a unilateral weakness (UWCaloric) >25 % (caloric test) or a Mean-GainvHIT <0.79/asymmetry ratio of Gain (AR-GainvHIT) >8.5 % and accompanied refixation saccades (vHIT) were considered abnormal. The overall sensitivity of the caloric test was 72 %. The evaluation of AR-GainvHIT detected more abnormal cases than did Mean-GainvHIT (44 vs. 36 %). In up to 4 %, a normal caloric test result was related to an abnormal vHIT. There was only a moderate correlation of UWCaloric and AR-GainvHIT (r = 0.54, p < 0.05) with a linear regression line intercept/slope of 32.2/0.9 (p < 0.05). Receiver operating characteristics curve analysis exhibited at a UWCaloric of 50 % a vHIT sensitivity/specificity/positive predictive value/negative predictive value of 0.45/0.9/0.94/0.42. Vestibular testing at varying frequencies provides deeper insights into hVOR function and is helpful in detecting a cerebello-pontine lesion. Whereas caloric test yields a high sensitivity for nerve dysfunction, vHIT test reveals a remaining function of hVOR in the high-frequency range.
Department of Otorhinolaryngology, Head and Neck Surgery and Communication Disorders, HELIOS-Clinic Berlin-Buch, Schwanebecker Chaussee 50, 13125, Berlin, Germany, alexander.bloedow@helios-kliniken.de.
Alexander
A
Blödow
Julia
J
Blödow
Marc Boris
MB
Bloching
Ralf
R
Helbig
Leif Erik
LE
Walther
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002150:Caloric Tests; D005260:Female; D064087:Head Impulse Test; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D009464:Neuroma, Acoustic / Q000175:diagnosis* / Q000503:physiopathology*; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014741:Video Recording