Studies show that vestibulo-ocular reflexes can use qualitatively different processing mechanisms than vestibular perception. Given this, it is not surprising that vestibular symptoms correlate poorly with reflexive measures. Yet, quantitative clinical assays of motion-evoked perception are seldom, if ever, performed. Instead, clinicians primarily assay vestibular perception via patient histories, which may help explain why the underlying cause of perceptual symptoms often goes undiagnosed. It has been reported that roughly 30% of patients reporting symptoms of dizziness or disorientation receive an uncertain diagnosis and/or a diagnosis that is unconfirmed by measurements or signs. We reason that quantitative perceptual tests can contribute to our ability to diagnose patients. More specificall, because of high sensitivity and specificity, perceptual thresholds provide a common way to evaluate sensory function clinically (e.g., audiogram), so measuring vestibular thresholds may provide a new diagnostic toolkit that will help diagnose both central (e.g., vestibular migraine) and peripheral (e.g., Meniere's disease) vestibular dysfunction using a single common methodology. In fact, vestibular thresholds mimic the audiogram test of hearing; this takes advantage of clinician experience with audiograms and helps make vestibular threshold interpretation straightforward. We have previously reported measureable threshold differences among various patient classes and normal subjects. These results suggest that thresholds provide graded quantitative measurements that can help confirm a diagnosis (perhaps obviating the need for additional rule- out testing) or guide new and/or more refined diagnoses. Furthermore, we have developed automated procedures that reduce test times dramatically. These advances, alongside data analysis improvements, allow us to measure perceptual thresholds across a broad range of conditions in less than 2 hours. We propose to recruit qualifying MEE patients suffering episodic vestibular symptoms to participate in threshold testing, alongside other standard clinical measures like the VOR We specifically propose to evaluate the diagnostic power of threshold testing and existing clinical tests quantitatively - bot individually and when combined - using standard statistical approaches. To provide normative data that is both age and gender-matched, we also propose to measure thresholds in healthy normal subjects between the ages of 18-80.
Recurrent episodes of vertigo are caused by numerous disorders, including vestibular migraine and Meniere's disease that together affect more than 1% of the population. The underlying cause can be difficult to diagnose, since similar symptoms are often reported despite very different pathophysiology and since standard tests are often normal or non-specific. The goal of this proposal is to quantify the extent that perceptual thresholds can improve the diagnosis of patients suffering recurrent vestibular symptoms.
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|Bermúdez Rey, María Carolina; Clark, Torin K; Merfeld, Daniel M (2017) Balance Screening of Vestibular Function in Subjects Aged 4 Years and Older: A Living Laboratory Experience. Front Neurol 8:631|
|Lim, Koeun; Karmali, Faisal; Nicoucar, Keyvan et al. (2017) Perceptual precision of passive body tilt is consistent with statistically optimal cue integration. J Neurophysiol 117:2037-2052|
|Bermúdez Rey, María Carolina; Clark, Torin K; Wang, Wei et al. (2016) Vestibular Perceptual Thresholds Increase above the Age of 40. Front Neurol 7:162|