The acute syndrome
HINTS in the ED
A normal head impulse, direction-changing nystagmus, or a vertical skew in the AVSpatient is more sensitive than early DWI-MRI for posterior-circulation stroke. When the examiner is trained, HINTS is the most powerful single instrument in the dizzy ED workup.
HINTS is three short bedside tests in sequence: Head Impulse, Nystagmus, Test of Skew. Each of them either supports a peripheral diagnosis (vestibular neuritis) or pushes the case toward central (posterior-circulation stroke).
The trick is that a normal HIT in the AVS patient is the most worrying finding of the three — the opposite of intuition. A normal VOR means the labyrinth and vestibular nerve are fine, so something more central is producing the vertigo.
The HINTS battery, validated by Kattah et al. in 2009, has >96% sensitivity and specificity for posterior-circulation stroke in AVS when performed by a trained examiner — better than early DWI-MRI in the first 24–48 hours.1 The decisive observation is the same as Newman-Toker's: a normal head impulse in AVS is a red flag for cerebellar/brainstem stroke.2
Tarnutzer's systematic review confirms that HINTS outperforms ABCD² and other vascular-risk-based instruments in AVS.3 The "HINTS family" — HINTS plus targeted hearing assessment ("HINTS-plus") — adds further sensitivity for AICAstrokes that mimic labyrinthitis.4
The HIT itself derives from Halmagyi and Curthoys's 1988 description of canal paresis: a rapid head thrust ~15° in the plane of the horizontal canal while the patient fixates a target.5 The catch-up saccade marks ipsilateral peripheral hypofunction.
Limits to know: HINTS is examiner-dependent (the saccade is brief), only valid in AVS (not in normal-between-attacks episodic vertigo), and requires spontaneous nystagmus to interpret skew reliably. Where the examiner is uncertain or the patient is uncooperative, video-augmented HIT (vHIT) is the natural fallback — it quantifies VOR gain and detects covert saccades.6,7
Interactive HINTS interpreter
Pick one option in each step; the verdict updates live with a colour-coded call (peripheral / central / indeterminate) and the matching INFARCT cue.
Pick one option in each step to see the verdict.
Calibrating the examiner
HINTS is examiner-dependent. The decisive movement (HIT catch-up saccade) is brief, easy to miss, and harder to elicit in the agitated patient. Train HINTS with video review, and pair it with vHIT in the established clinic. A central HINTS pattern is reliable only when the examiner has interpreted ≥20 prior cases under supervision.