Quantitative Eye Movement Measurements in Patients with Acute Vestibular Syndrome

BACKGROUND: A chief complaint of acute vertigo/dizziness is related to about 2.1-7.1% of all emergency department (ED) visits. About 25% of all patients with acute prolonged vertigo meeting diagnostic criteria of AVS (acute vestibular syndrome) suffer from a vertebrobasilar stroke and about 35% of these patients are initially missed. Differentiating dangerous central from more benign peripheral causes of AVS is essential. Subtle oculomotor paradigms such as HINTS (Head-Impulse, Nystagmus, Test-of-Skew) have been shown to detect central causes with high diagnostic accuracy, however, require sufficient training. Thus, identifying other bedside tests that can be reliably performed by frontline providers is essential to reduce misdiagnosis. WORKING HYPOTHESIS: By using additional oculomotor (saccades, pursuit) and pupillomotor parameters at the bedside or quantitatively, the diagnostic accuracy for distinguishing peripheral from central AVS causes can be further improved, especially in the setting when expertise for applying more sophisticated algorithms (HINTS(+), STANDING) is lacking. AIM 1: Detecting changes in oculomotor and pupillomotor responses in acutely dizzy patients and characterizing the spectrum of abnormalities in peripheral and central AVS. AIM 2: Comparing different composite oculomotor-/pupillomotor scores to identify those scores with the highest diagnostic accuracy at the bedside and quantitatively. AIM 3: Comparing the diagnostic accuracy of bedside and quantitative oculomotor and pupillomotor testing in AVS- identifying potential limitations of bedside testing. METHODS: To assess oculomotor and pupillomotor responses in patients with peripheral or central AVS and healthy controls (25 participants each) at the bedside and quantitatively by use of a Pioneer research eye tracker (PRET) system and to compare the diagnostic accuracy of individual and composite responses. EXPECTED VALUE OF THE PROJECT: The proposed project will shed more light on the value of different examination techniques in AVS for distinguishing peripheral from central causes. This is achieved by investigating oculomotor and pupillomotor parameters obtained at the bedside and quantitatively in the acute stage and at follow-up. The insights gained will likely have a direct impact on diagnostic accuracy and thus on future strategies how to evaluate acutely dizzy patients in the ED. Eventually, this may reduce the rate of misdiagnosis and may improve patients' outcome.