Sa. Harvey et al., RELATIONSHIP OF THE HEAD IMPULSE TEST AND HEAD-SHAKE NYSTAGMUS IN REFERENCE TO CALORIC TESTING, The American journal of otology, 18(2), 1997, pp. 207-213
Objective: The objective of this study was to determine the usefulness
of the head impulse test (HIT) and head-shake nystagmus (HSN), two ea
sily performed office maneuvers, in the evaluation of the dizzy patien
t 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 evalua
tion of dizziness and ranged in age from 13 to 87 years (mean 52.1). I
ntervention: The intervention was HIT and HSN evaluation followed by b
ithermal binaural air caloric irrigations. Main Outcome Measures: The
main outcome measures were sensitivity, specificity, and predictive va
lues of HIT and HSN evaluation (individually and in combination) in re
lation to caloric results. Results: Sensitivity of the tests was equal
ly low (35%), whereas specificity was high (HIT 95%, HSN 92%). The pos
itive predictive value for the two tests in combination (80%) was grea
ter than for each individually (HIT 64%, HSN 50%). Negative predictive
values remained stable when considering each test individually (HIT 8
6%, HSN 86%) or in combination (88%). Conclusions: The low sensitivity
renders both tests inadequate as a screening tool for peripheral vest
ibular disease based on caloric results. However, when HIT and HSN res
ults are both abnormal, there is a high likelihood of a significant ca
loric deficit.