Table 3.
Summary of Prevalence of Abnormal Clinical Findings in the Affected Patients
| CLINICAL FINDING (Affected Patients) | Number Tested (N) | Abnormal (Percentage) | Prevalence 99% Confidence Interval |
|---|---|---|---|
| Subjective visual vertical (SVV) | 25 | 22 (88%) | 65–98% |
| Antisaccade test (abnormal error rate) | 25 | 13 (52%) | 31–73% |
| Standard audiometry | 25 | 2 (8%) | 0–31% |
| Central vestibular findings | 25 | 9 (36%) | 18–59% |
| Chair impulse test (HVOR) | 12 | 10 (83%) | 48–98% |
| Cervical vestibular evoked myogenic potential (VEMP) | 12 | 8 (67%) | 34–89% |
| Ocular VEMP | 12 | 8 (67%) | 34–89% |
| At least one VEMP | 12 | 11 (92%) | 56–>99% |
SVV—greater than or equal to 3.2 degrees deviation (lower fifth percentile of normative data from 300 subjects).
Antisaccade—error rate (moving in the wrong direction) greater than or equal to 43% (lower fifth percentile of normative data from 300 subjects).
Standard Audiometry Battery—audiogram, word identification, speech recognition test, tympanometry, reflexes.
Central Vestibular Findings—abnormality on any central vestibular test.
Chair Impulse Test—HVOR gain less than 0.80 at 100 degrees/sec impulse.
Cervical VEMP—abnormal if amplitude less than 100 microvolts and/or greater than 35% amplitude asymmetry between sides.
Ocular VEMP—abnormal if amplitude less than 3 microvolts and/or greater than 35% amplitude asymmetry between sides abnormal if amplitude typically less than 5 microvolts.