HINTS Examination Should Be Performed in Clinic
The most critical bedside examination to perform is the HINTS (Head Impulse, Nystagmus, Test of Skew) examination, which when performed by a trained clinician can distinguish central from peripheral causes of vertigo with greater sensitivity than early MRI (100% vs 46%). 1
Why HINTS is Essential in This Case
This 27-year-old man presents with brief spontaneous vertigo episodes (episodic vestibular syndrome), not acute persistent vertigo. However, given the negative Dix-Hallpike test ruling out BPPV, the differential diagnosis must now include:
- Vestibular migraine (most common cause of episodic vertigo after BPPV)
- Transient ischemic attacks affecting the posterior circulation (25% of acute vestibular syndrome cases have cerebrovascular disease) 1
- Early vestibular neuritis (if episodes become persistent)
- Central causes (brainstem/cerebellar lesions, demyelinating disease)
The HINTS Examination Components
Perform these three tests sequentially:
Head Impulse Test: Rapidly rotate the patient's head horizontally while they fixate on your nose. A corrective saccade (catch-up movement) indicates peripheral vestibular dysfunction. Normal head impulse test suggests central pathology 2, 3
Nystagmus Assessment: Examine for spontaneous nystagmus with Frenzel glasses (to remove visual fixation). Direction-changing gaze-evoked nystagmus indicates central pathology. Unidirectional horizontal-torsional nystagmus suggests peripheral cause 1, 4
Test of Skew: Perform alternate cover test looking for vertical misalignment. Skew deviation indicates central pathology 2, 3
Critical Caveats
HINTS accuracy depends entirely on proper training. When performed by emergency physicians without specialized training, sensitivity drops to 83% with specificity of only 44%, compared to 96.7% sensitivity and 94.8% specificity when performed by trained neurologists 5. If you lack formal training in HINTS, do not rely on it alone 2.
Additional Bedside Tests to Perform
Beyond HINTS, perform these examinations:
Head-shaking nystagmus test: Shake the head horizontally 20 times with eyes closed, then observe for nystagmus. This can unmask subtle vestibular asymmetry 4
Finger rub test: Test high-frequency hearing bilaterally. Unilateral hearing loss suggests peripheral pathology 2
Gait assessment: Severe gait unsteadiness (inability to walk independently) in patients without nystagmus suggests central pathology 2
Hyperventilation test: 30 seconds of hyperventilation may provoke nystagmus in vestibular disorders 4
Positional testing beyond Dix-Hallpike: Perform supine head roll test (for horizontal canal BPPV) and straight head hanging test, as atypical BPPV variants exist 4
When HINTS Cannot Be Reliably Performed
If you lack training in HINTS or the patient has no nystagmus during examination, assess for:
- Vascular risk factors (hypertension, diabetes, smoking, age >50)
- Focal neurologic signs (dysarthria, diplopia, facial numbness, limb weakness)
- Severe gait instability requiring assistance to walk
- Symptoms of cerebral ischemia (headache, visual changes, sensory deficits) 2, 6
The presence of any concerning features warrants neuroimaging with MRI (not CT), as CT detects central pathology in <1% of patients with normal neurologic examination 1. However, even MRI has a false-negative rate up to 50% in the first 24-48 hours after stroke onset 3, 6.
The Bottom Line for This Patient
Given brief episodic vertigo with negative Dix-Hallpike, perform HINTS examination if trained, combined with head-shaking nystagmus test, finger rub test, and comprehensive gait assessment. Search specifically for symptoms suggesting vestibular migraine (photophobia, phonophobia, headache) or transient ischemic attack (other neurologic symptoms, vascular risk factors) 1, 2. The young age makes stroke less likely but does not exclude it, as 11% of patients with acute vertigo and no focal neurologic signs have acute infarct 1.