Accuracy of the bedside head impulse test in detecting vestibular hypofunction.
OBJECTIVE
To determine the accuracy of the bedside head impulse test (bHIT) by direct comparison with results from the quantitative head impulse test (qHIT) in the same subjects, and to investigate whether bHIT sensitivity and specificity changes with neuro-otological training.


METHODS
Video clips of horizontal bHIT to both sides were produced in patients with unilateral and bilateral peripheral vestibular deficits (n = 15) and in healthy subjects (n = 9). For qHIT, eye and head movements were recorded with scleral search coils on the right eye and the forehead. Clinicians (neurologists or otolaryngologists) with at least 6 months of neuro-otological training ("experts": n = 12) or without this training ("non-experts": n = 45) assessed video clips for ocular motor signs of vestibular deficits on either side or of normal vestibular function.


RESULTS
On average, bHIT sensitivity was significantly (t test: p<0.05) lower for experts than for non-experts (63% vs 72%), while bHIT specificity was significantly higher for experts than non-experts (78% vs 64%). This outcome was a consequence of the experts' tendency to accept bHIT with corresponding borderline qHIT values as still being normal. Fitted curves revealed that at the lower normal limit of qHIT, 20% of bHIT were rated as deficient by the experts and 37% by the non-experts.


CONCLUSIONS
When qHIT is used as a reference, bHIT sensitivity is adequate and therefore clinically useful in the hands of both neuro-otological experts and non-experts. We advise performing quantitative head impulse testing with search coils or high speed video methods when bHIT is not conclusive.
Jorns-Häderli
M
M
Neurology Department, Zurich University Hospital, Frauenklinikstrasse 26, CH-8091 Zurich, Switzerland.
Straumann
D
D
Palla
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002150:Caloric Tests; D053483:Eye Movement Measurements; D019416:Head Movements; D006801:Humans; D008875:Middle Aged; D019095:Point-of-Care Systems; D012027:Reflex, Vestibulo-Ocular; D012680:Sensitivity and Specificity; D015837:Vestibular Diseases / Q000175:diagnosis*; D014724:Vestibular Function Tests / Q000295:instrumentation / Q000379:methods*; D014741:Video Recording