5Reading the Dizzy History and the Five-Minute Screen
History is the first vestibular test. Separating true vertigo from non-vestibular dizziness, then reading the timing and triggers of episodes, localizes the cause before any machine is switched on. A focused bedside screen — Frenzel lenses, head thrust, tandem Romberg, dynamic visual acuity — plus a review of the planning scan can flag asymmetry in under five minutes.
FVertigo versus other dizziness
Vertigo is an illusory sense of movement, typically rotary and rarely translational; it must be separated from light-headedness, orthostatic symptoms, anxiety and nausea without movement Unilateral oscillopsia on rapid head turns, plus monaural hearing fluctuation, fullness and tinnitus and tragal-compression vertigo, point to asymmetric vestibular function History is the first vestibular test and frames every subsequent quantitative study.[1995][2004]
TEpisode duration as a diagnostic axis
Very brief episodes (<10 s) triggered by Valsalva or loud sound suggest superior canal dehiscence Episodes of ~15-30 s on head reorientation suggest BPPV Spontaneous 20-min to 2-hr spells with fluctuating hearing, tinnitus and fullness suggest Meniere disease Episodes of minutes to days suggest migraine, while a single day-long episode with slow compensation suggests vestibular neuritis, schwannoma or trauma.[1995][2004]
TThe five-minute bedside screen
A screening exam can be completed in under five minutes using Frenzel lenses for spontaneous, gaze-evoked and post-head-shaking nystagmus, plus head thrust (~15° quick passive rotations) for each canal Tandem head-shake Romberg elicits a fall in ~50% of patients with unilateral hypofunction and ~90% of those with caloric-defined bilateral hypofunction A Snellen drop of more than ~three lines between head-still and 2-Hz head shaking (dynamic visual acuity) suggests bilateral hypofunction.[1988][1982]
TReviewing the planning scan
The pre-op CT/MRI obtained for surgical planning should be reviewed for labyrinthine dysplasia, ossification, superior canal dehiscence, and prior labyrinthine violation from surgery, trauma or cholesteatoma Enlarged vestibular aqueduct is a risk factor for post-cochleostomy vertigo via a persistent perilymphatic fistula Anatomic review complements the bedside screen before any quantitative testing.[2004]
Which etiology does this symptom-timing pattern most suggest?
A fall on the tandem head-shake Romberg is seen in roughly what proportion of patients with caloric-defined bilateral vestibular hypofunction?
Brief vertigo (<10 s) triggered by Valsalva or loud sound most suggests: