History-based diagnostic algorithms

HINTS is a quick three-step eye examination for someone with sudden, continuous vertigo. Surprisingly, it can spot a stroke better than an early scan. The steps are the head-impulse test, looking at the nystagmus, and a test for vertical eye misalignment.

In the acute vestibular syndrome, HINTS — head impulse, nystagmus, test of skew — distinguishes peripheral from central causes and is more sensitive than early MRI-DWI for stroke when performed by trained examiners.1,3 Adding a bedside hearing check (HINTS Plus) catches AICA infarcts that mimic peripheral disease, and HINTS outperforms risk scores such as ABCD².2

The counter-intuitive core is the “INFARCT” rule: Impulse Normal, FAst-phase alternating (direction-changing), or Refixation on Cover Test each indicate a central lesion. HINTS only applies to a true AVS — continuous vertigo with spontaneous nystagmus — and is invalid for episodic or positional presentations, which is why the history must establish the syndrome first.

SO STONED is a memory aid that makes sure you ask about every important part of the history. Each letter is a question to cover — tap the cards to reveal them.

The SO STONED mnemonic organises outpatient vertigo evaluation: Symptoms, Onset, Speed, Triggers, Otological, Neurological, Evolution, Duration.4 It gives generalists, ENT, and neurology a shared language for the history.

These algorithms are cognitive scaffolds, not substitutes for clinical reasoning. Used judiciously they improve early diagnosis of vestibular migraine, BPPV, and PPPD and reduce misdiagnosis — particularly valuable in acute-care, older, and vascular-risk populations.