Relationship of the Head Impulse Test and Head-Shake Nystagmus in Reference to Caloric Testing.
Harvey, Steven A. *; Wood, Douglas J. +; Feroah, Thom R. +
[Miscellaneous] American Journal of Otology. 18(2):207-213, March 1997.

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Objective: The objective of this study was to determine the usefulness of the head impulse test (HIT) and head-shake nystagmus (HSN), two easily performed office maneuvers, in the evaluation of the dizzy patient with reference to caloric irrigation results.

Objective and Setting: This was a prospective double-blind trial conducted at an outpatient academic tertiary referral center.

Patients: The study population was composed of 105 patients (35 male, 70 female) who presented for evaluation of dizziness and ranged in age from 13 to 87 years (mean 52.1).

Intervention: The intervention was HIT and HSN evaluation followed by bithermal binaural air caloric irrigations.

Main Outcome Measures: The main outcome measures were sensitivity, specificity, and predictive values of HIT and HSN evaluation (individually and in combination) in relation to caloric results.

Results: Sensitivity of the tests was equally low (35%), whereas specificity was high (HIT 95%, HSN 92%). The positive predictive value for the two tests in combination (80%) was greater than for each individually (HIT 64%, HSN 50%). Negative predictive values remained stable when considering each test individually (HIT 86%, HSN 86%) or in combination (88%).

Conclusions: The low sensitivity renders both tests inadequate as a screening tool for peripheral vestibular disease based on caloric results. However, when HIT and HSN results are both abnormal, there is a high likelihood of a significant caloric deficit.

(C) 1997, The American Journal of Otology, Inc.