[An analysis of the results of video head impulse test in benign paroxysmal vertigo of childhood].

Objective:This study was to analyze the results of video head impulse test (vHIT) of benign paroxysmal vertigo of childhood (BPVC) in order to determine the potential value of vHIT in the diagnosis and treatment for BPVC and to discuss its possible pathogenesis of BPVC. Method:Thirty-six children with BPVC were enrolled. No hearing loss and skull abnormality were found in these children as assessed by pure tone audiometry, acoustic impedance, CT or MRI scan. The vHIT was carried out, and main outcome measures were the gain of vestibulo-ocular reflex, gain asymmetry, and refixation saccades. Eleven healthy children were selected as normal control who came to our hospital for doing a routine checkup and have no history of dizziness. The differences of vHIT results between these two groups were analyzed. Result:①The vHIT results in control group were normal. In all BPVC subjects, abnormalities were detected in 9 patients (25.0%),including vHIT gains decline in 3 patients, abnormal symmetry in 4 patients, and abnormal isolated overt saccades in 2 patients.②The average saccadic gain in different canals of BPVC group was 1.03±0.14, 1.01±0.15, 1.13±0.31, 1.18±0.36, 1.21±0.33, 1.14±0.30 in left horizontal, right horizontal, left anterior, right posterior, right anterior, left posterior canal, respectively; while in normal group, it was 1.14±0.15, 1.18±0.09, 1.16±0.30, 1.18±0.40, 1.34±0.26, 1.30±0.20, respectively. Significant statistical difference was found only in horizontal canals between these two groups (P<0.05). ③Asymmetry of the three pairs of conjugated semicircular canals was 0.04±0.07 (horizontal canal), 0.06±0.04 (left anterior and right posterior canal), 0.06±0.04 (right anterior and left posterior canal) in BPVC group, respectively; while in control group, it was 0.02±0.02, 0.04±0.03, 0.04±0.04,respectively. There was no statistical difference between the two groups (P>0.05). Conclusion:A certain proportion of abnormal peripheral vestibule function in children with BPVC was found. vHIT is a "child friendly," relatively easytouse, and simple tool to evaluate each of the 6 semicircular canals, which may offer some potential clinical information for assessing the vestibule dysfunction for BPVC.