Why HINTS matters here

Posterior circulation strokes are commonly misdiagnosed as peripheral vertigo in emergency departments. The bedside HINTS protocol, when performed by trained clinicians, has been reported to be more sensitive than diffusion-weighted MRI in the first 24–48 hours of symptoms — DWI can be falsely negative in small brainstem and cerebellar infarcts during this window^3,9,4.

The INFARCT mnemonic

Impulse Normal, Fast-phase Alternating, Refixation on Cover Test. Any one of these in a patient with acute vestibular syndrome is a central red flag³.

HINTS signature — central pattern

Head Impulse: normal (no corrective saccade)
Nystagmus: direction-changing on lateral gaze, or pure vertical, or pure torsional
Skew: present — vertical refixation on cover-uncover

Trainee

Territory-specific features

PICA territory (lateral medullary / Wallenberg). Ipsilateral Horner syndrome, ipsilateral facial sensory loss, contralateral body sensory loss, dysphagia, hoarseness, ipsilateral limb ataxia. Central HINTS pattern plus brainstem signs.
AICA territory. Can mimic peripheral vestibulopathy when the labyrinthine artery is involved — peripheral HINTS plus acute sensorineural hearing loss. Facial weakness, ipsilateral deafness, cerebellar ataxia^1,10.
Cerebellar (non-AICA/PICA). Isolated vertigo and ataxia are possible. Skew may be absent; reliance on impulse and nystagmus components is critical⁹.

Clinician

HINTS vs neuroimaging — operational reality

Early MRI DWI sensitivity for posterior circulation stroke is approximately 80% in the first 24–48 hours, with reported sensitivity as low as ~50% for small infarcts. A negative DWI does not exclude posterior stroke in this window³. Conversely, the operator-dependent sensitivity of HINTS in non-subspecialty hands is much lower than in the validation studies. The practical message: HINTS by a trained examiner with HINTS-plus audiometric assessment, followed by appropriately timed MRI, is the current best-evidence approach^10,4.