Probabilities of Isolated and Co-Occurring Vestibular Disorder Symptom Clusters Identified Using the Dizziness Symptom Profile.

OBJECTIVES: Dizziness is among the most common reasons people seek medical care. There are data indicating patients with dizziness, unsteadiness, or vertigo may have multiple underlying vestibular disorders simultaneously contributing to the overall symptoms. Greater awareness of the probability that a patient will present with symptoms of co-occurring vestibular disorders has the potential to improve assessment and management, which could reduce healthcare costs and improve patient quality of life. The purpose of the current investigation was to determine the probabilities that a patient presenting to a clinic for vestibular function testing has symptoms of an isolated vestibular disorder or co-occurring vestibular disorders. DESIGN: All patients who are seen for vestibular function testing in our center complete the dizziness symptom profile, a validated self-report measure, before evaluation with the clinician. For this retrospective study, patient scores on the dizziness symptom profile, patient age, and patient gender were extracted from the medical record. The dizziness symptom profile includes symptom clusters specific to six disorders that cause vestibular symptoms, specifically: benign paroxysmal positional vertigo, vestibular migraine, vestibular neuritis, superior canal dehiscence, Meniere disease, and persistent postural perceptual dizziness. For the present study, data were collected from 617 participants (mean age = 56 years, 376 women, and 241 men) presenting with complaints of vertigo, dizziness, or imbalance. Patients were evaluated in a tertiary care dizziness specialty clinic from October 2020 to October 2021. Self-report data were analyzed using a Bayesian framework to determine the probabilities of reporting symptom clusters specific to an isolated disorder and co-occurring vestibular disorders. RESULTS: There was a 42% probability of a participant reporting symptoms that were not consistent with any of the six vestibular disorders represented in the dizziness symptom profile. Participants were nearly as likely to report symptom clusters of co-occurring disorders (28%) as they were to report symptom clusters of an isolated disorder (30%). When in isolation, participants were most likely to report symptom clusters consistent with benign paroxysmal positional vertigo and vestibular migraine, with estimated probabilities of 12% and 10%, respectively. The combination of co-occurring disorders with the highest probability was benign paroxysmal positional vertigo + vestibular migraine (~5%). Probabilities decreased as number of symptom clusters on the dizziness symptom profile increased. The probability of endorsing vestibular migraine increased with the number of symptom clusters reported. CONCLUSIONS: Many patients reported symptoms of more than one vestibular disorder, suggesting their symptoms were not sufficiently captured by the symptom clusters used to summarize any single vestibular disorder covered by the dizziness symptom profile. Our results indicate that probability of symptom clusters indicated by the dizziness symptom profile is comparable to prior published work on the prevalence of vestibular disorders. These findings support use of this tool by clinicians to assist with identification of symptom clusters consistent with isolated and co-occurring vestibular disorders.

Predictive properties of the video head impulse test: measures of caloric symmetry and self-report dizziness handicap.

OBJECTIVES: The purpose of this investigation was to determine whether a predictable relationship existed between self-reported dizziness handicap and video Head Impulse Test (vHIT) results in a large sample of patients reporting to a dizziness clinic. Secondary objectives included describing the characteristics of the vHIT ipsilesional and contralesional vestibulo-ocular reflex slow-phase velocity in patients with varying levels of canal paresis. Finally, the authors calculated the sensitivity and specificity of the vHIT for detecting horizontal semicircular canal impairment using the caloric test as the "gold standard." DESIGN: Participants were 115 adults presenting to a tertiary medical care center with symptoms of dizziness. Participants were administered a measure of self-report dizziness handicap (i.e., Dizziness Handicap Inventory) and underwent caloric testing and vHIT at the same appointment. RESULTS: Results showed that (1) there were no significant group differences (i.e., vHIT normal versus vHIT abnormal) in the Dizziness Handicap Inventory total score, (2) both ipsilesional and contralateral velocity gain decreased with increases in caloric paresis, and (3) a caloric asymmetry of 39.5% was determined to be the cutoff that maximized discrimination of vHIT outcome. CONCLUSIONS: The level of self-reported dizziness handicap is not predicted by the outcome of the vHIT, which is consistent with the majority of published reports describing the poor relationship between quantitative tests of vestibular function and dizziness handicap. Further, the study findings have demonstrated that vHIT and caloric data are not redundant, and each test provides unique information regarding the functional integrity of the horizontal semicircular canal at different points on the frequency spectrum. The vHIT does offer some advantages over caloric testing, but at the expense of sensitivity. The vHIT can be completed in less time, is not noxious to the patient, and requires very little laboratory space. However, the study data show that a caloric asymmetry of 39.5% is required to optimize discrimination between an abnormal and normal vHIT. It is the authors' contention that the vHIT is a complementary test to the balance function examination and should viewed as such rather than as a replacement for caloric testing.