Diagnosing and localizing the acute vestibular syndrome - Beyond the HINTS exam.

When assessing the acutely dizzy patient, the HINTS 'Plus' (Head Impulse, Nystagmus, Test of Skew, 'Plus' a bedside assessment of auditory function) exam is a crucial component of the bedside exam. However, there are additional ocular motor findings that can help the clinician distinguish peripheral from central etiologies and enable accurate localization, especially when the patient has acute dizziness, vertigo and/or imbalance but without spontaneous nystagmus. We will review the literature on these findings which are 'beyond HINTS' and include saccades/ocular lateropulsion, smooth pursuit, and provocative maneuvers including head-shaking and positional testing (not part of the HINTS exam). Additionally, we will expound on the localizing value of nystagmus, ocular alignment and the ocular tilt reaction (parts of the HINTS exam). The paper has been organized neuroanatomically, based on brainstem and cerebellar structures that have been reported to cause the acute vestibular syndrome.