Eye-ECG Approach to Emergencies : Diagnostic Performance of the HINTS Test

Overview

Vertigo integrated with acute vestibular syndrome (AVS) is a frequent reason for emergency visits. The French and international literature estimates between 2 to 4% of vertigo prevalence among reasons for coming to emergencies. International classifications define AVS as vertigo or acute dizziness (less than one month) and persistent, gait instability, nausea or vomiting, nystagmus or an intolerance to head movements. In emergency departments, the clinical approach of vertiginous patients is difficult because the "vertigo" term is sometimes used in by patients, or because they use the terms "uneasiness", "vertigo", or "dizziness" without distinction. These terms sometimes include various sensations of "sleeping head", "blurred vision", "instability", "pitch" etc. A first difficulty is therefore to clarify these terms and organize syndrome expressed by the patient. A rigorous interrogation is therefore essential and can be time-consuming. Another difficulty is to carry out an exhaustive clinical examination including the assessment of the general condition and hydration, an ENT examination and a neurological examination. However, at the end of these steps, the orientation central or peripheral etiology is not simple. In the last consensus conference of the Barany Society (2014) the classification of VAS into three types was not sufficient to distinguish "benign" vertigo from "risky" dizziness (related to a central cause).

The HINTS test (Head Impulse, Nystagmus, Test of Skew) is a clinical test composed of 3 oculomotor examinations: the search for high frequency vestibulo-ocular reflex during a passive impulse of the head (Head Impulse test), the detection of a spontaneous nystagmus and a vertical divergence. It has been developed to evaluate patients with AVS defined as vertigo or acute and persistent dizziness sometimes accompanied by nausea or vomiting, and/or gait instability, and/or nystagmus, and/or intolerance to head movements. This time saving is important, as a complete neurological examination usually takes between 10 and 15 minutes. The presence of at least one of the three items of central locator value is sufficient to diagnose a central cause of AVS, including normal early brain imaging. Some studies suggest that absence of these three criteria does not require an emergency neuroimaging examination and allows ambulatory management of the patient, in search of a peripheral cause of the ENT sphere. The STANDING clinical algorithm (SponTAneous, Nystagmus, Direction, head Impulse test, STANDING) was proposed by Vanni in 2015 for diagnosis of the AVS central causes in emergencies in a one-year prospective Italian monocentric study. The STANDING algorithm consists of clinical elements that can be evaluated in about 10 minutes at the patient's bedside: two oculomotor examinations (Head Impulse Test and detection of a nystagmus), detection of ataxia and practice of release maneuvers. Currently, the patient management with isolated AVS in the emergency room lacks an ideal diagnostic clinical test: efficient, non-invasive, inexpensive and painless. The investigators would like to know what diagnostic performance of the HINTS test (sensitivity and specificity) is when it is performed by emergency physicians on a population of patients with isolated AVS in emergency room. They can thus either be part of non-urgent outpatient care in the event of suspicion of a peripheral cause of the ENT sphere, or part of rapid and aggressive inpatient neurological care in the event of suspicion of a central cerebral cause.