A cervicogenic diagnosis is, ultimately, a diagnosis of exclusion. Before the cervical examination from Module 4 can carry decisive weight, peripheral and central vestibular causes must be ruled out — and "ruled out" here means actively probed, not merely deemed unlikely. This module covers the four investigations that do most of the rule-out: positional testing (Dix-Hallpike and the supine roll), videonystagmography, the video head impulse test, and computerised dynamic posturography.
The short version
A patient with dizziness and neck pain has not yet earned a cervical diagnosis. The neck might be coincidental. Before settling on cervicogenic dizziness, four sets of tests are performed to look directly at the inner ear and the central balance pathways:
Positional testing — a quick set of head-position manoeuvres to look for the most common inner-ear condition, BPPV (loose crystals).
Videonystagmography (VNG) — goggles that track the eyes during a series of standard tasks to assess the inner ear and the brain pathways that move the eyes.
Video Head Impulse Test (vHIT) — a quick head jerk while the goggles record whether the eyes can stay locked on a target. Sensitive to inner-ear hypofunction.
Posturography — standing balance measured on a force plate under combinations of eyes-open / eyes-closed and stable / unstable surfaces.
If all four are normal in a patient who has clear cervical findings and a history that fits, cervicogenic dizziness becomes a reasonable working diagnosis.
vHIT — Video Head Impulse Test
A brief, unpredictable head impulse provokes the horizontal-canal VOR. Healthy eyes move in the opposite direction with equal speed, keeping gaze on target. When VOR is impaired, the eyes lag — and catch-up saccades (covert during the movement, overt afterwards) bring gaze back to the target.
Right horizontal canal· impulse
gain = 0.45
Head velocity Eye velocity Catch-up saccades
Interpretation
Abnormal — canal hypofunction
Catch-up saccades present
Scenarios
Figure 5.1 — Interactive vHIT. The teal head-velocity pulse and the rust eye-velocity response should mirror each other in a healthy VOR (gain near 1.0). As gain drops below 0.7, covert saccades appear during the head movement and overt saccades appear immediately after — the visual signature of peripheral vestibular hypofunction. The cerebellar preset preserves gain but adds saccadic ripple, illustrating why both gain and saccade pattern matter to the diagnosis.
One sentence to remember. The vestibular workup does not find cervicogenic dizziness — it makes a cervicogenic diagnosis permissible by ruling out the alternatives.
The exclusion framework
Every test below is being used in this module for a specific rule-out purpose. The diagnostic value of a normal result is high only when the test addresses a candidate cause that you actually entertained. The framework I use:
Positional testing rules out canalithiasis (BPPV). It is fast, cheap, and decisive — and BPPV is the single most over-attributed-to-the-neck cause of position-evoked dizziness.
vHIT rules out peripheral semicircular canal hypofunction with a high-frequency stimulus.27 It is the most efficient way to identify an uncompensated vestibular neuritis or a bilateral vestibular loss masquerading as a balance problem.
VNG (saccades, pursuit, optokinetic, calorics) rules out central oculomotor pathology and probes low-frequency canal function. Smooth pursuit and saccade abnormalities are the typical clue to a brainstem or cerebellar lesion mimicking peripheral disease.
Posturography (SOT) probes how the patientuses their three sensory channels. It does not localise pathology, but the pattern of which conditions provoke sway tells you whether the patient has been functionally reweighting toward visual dependence — a finding that recurs in both vestibular and post-cervical chronic populations.
Positional testing — Dix-Hallpike and supine roll
The Dix-Hallpike manoeuvre tests for posterior canal BPPV — the commonest variant. The supine head-roll test (Pagnini-McClure) tests for horizontal canal BPPV. Each takes under a minute. The signature of BPPV — paroxysmal, position-triggered nystagmus with a 5–15 second latency, geotropic or apogeotropic depending on canal, and fatigable on repetition — is unlike anything a cervical examination produces, but the symptom report from the patient can sound identical.
Order matters. Always perform positional testing before any sustained cervical provocation. A missed BPPV that the examiner then attributes to cervical pathology is the most common diagnostic error in this space, and a horizontal-canal BPPV in particular can also be provoked by trunk rotation — falsely positive cervical signs.
Videonystagmography
VNG bundles four standard subtests under one set of goggles. Each subtest probes a different question:
Figure 5.3 — The four standard VNG subtests. Saccades and smooth pursuit assess oculomotor pathways and central integrators. Optokinetic nystagmus probes the visual-vestibular interaction. Bithermal caloric irrigation remains the low-frequency probe of horizontal-canal function and the traditional anchor of the vestibular workup. Jongkees' asymmetry formula quantifies unilateral weakness.
Saccades — latency, accuracy, and peak velocity of voluntary eye jumps to a target. Abnormalities point centrally — to brainstem, cerebellum, or basal ganglia disease.
Smooth pursuit — the same circuit the SPNT test of Module 4 builds on. In this module, smooth pursuit is measured in neutral only; an abnormal pursuit gain in neutral is a central sign and removes cervicogenic dizziness from the differential.
Optokinetic nystagmus — the response to a moving field. Tests visual-vestibular interaction; asymmetries suggest central pathways.
Bithermal caloric irrigation — warm and cool water (or air) delivered to each ear, evoking horizontal-canal VOR through endolymph convection. Jongkees' formula quantifies the percent asymmetry; values above ~25% indicate unilateral weakness.30
Video Head Impulse Test
The vHIT — introduced by MacDougall et al as a clinical-grade substitute for the scleral search coil27 and extended to the vertical canals shortly after28 — is the highest-yield single test for peripheral vestibular hypofunction in clinic. A brief, unpredictable head impulse at 150–200°/s peak velocity provokes the horizontal-canal VOR; the ratio of peak eye velocity to peak head velocity is the VOR gain.
vHIT — Video Head Impulse Test
A brief, unpredictable head impulse provokes the horizontal-canal VOR. Healthy eyes move in the opposite direction with equal speed, keeping gaze on target. When VOR is impaired, the eyes lag — and catch-up saccades (covert during the movement, overt afterwards) bring gaze back to the target.
Right horizontal canal· impulse
gain = 0.45
Head velocity Eye velocity Catch-up saccades
Interpretation
Abnormal — canal hypofunction
Catch-up saccades present
Scenarios
Figure 5.1 — Interactive vHIT. The teal head-velocity pulse and the rust eye-velocity response should mirror each other in a healthy VOR (gain near 1.0). As gain drops below 0.7, covert saccades appear during the head movement and overt saccades appear immediately after — the visual signature of peripheral vestibular hypofunction. The cerebellar preset preserves gain but adds saccadic ripple, illustrating why both gain and saccade pattern matter to the diagnosis.
Two pieces of information come from each impulse and both matter:
VOR gain — values ≥ 0.8 are normal; gain ≤ 0.7 on multiple impulses is pathological; the 0.7–0.8 band is borderline.29
Corrective saccades — when gain drops, the eye lags during the impulse and catches up afterwards. Saccades during the head movement are covert (invisible at the bedside); saccades after the impulse are overt (visible). vHIT detects both; the unaided eye usually misses covert saccades, which is the headline advantage of the video method over the classic head impulse manoeuvre.
The vHIT also has one specific high-stakes use: in acute vestibular syndrome, a normal head impulse test argues strongly for a central lesion (cerebellar stroke) over vestibular neuritis, despite a clinical picture that can otherwise look identical.32 A patient with acute spinning vertigo and a normal vHIT belongs in imaging, not a vestibular clinic.
Computerised Dynamic Posturography (SOT)
The Sensory Organization Test was originally described by Nashner et al31 and remains the best-established functional assessment of how a patient integrates the three balance afferents. The patient stands on a force plate that can sway with their centre of pressure (sway-referenced); the visual surround can do the same. Six conditions vary which channels are reliable:
Sensory Organization Test — six conditions
The SOT manipulates visual and somatosensory feedback to isolate the vestibular contribution to standing balance. The diagnostic value lies in the pattern across conditions — no single condition localises pathology, but the combination of which conditions provoke sway is informative.
1Eyes open, fixed
Eyes open, fixed platform, fixed visual surround. All three sensory channels available.
Equilibrium scores within age-matched normative limits across all six conditions.
Figure 5.2 — Interactive SOT matrix. Click a condition to see which sensory channels remain reliable; cycle through the pattern presets to see which conditions light up red for each clinical picture. The vestibular pattern — abnormal in conditions 5 and 6 only — is the classic peripheral-loss signature; the visual-preference pattern is more typical of PPPD and visually-induced dizziness, in which the cervicogenic patient may end up after months of central reweighting.
The diagnostic value of the SOT lies in pattern recognition, not localisation:
The vestibular pattern (5+6 abnormal) is the signature of an uncompensated peripheral or bilateral vestibular loss — these are the only two conditions in which the patient must rely on vestibular input alone.
The visual-preference pattern (3+6 abnormal) is seen in PPPD, visually-induced dizziness, and chronic cervicogenic patients who have reweighted toward visual cues (Module 3).
Composite scores are useful for tracking response to vestibular rehabilitation but not for diagnosis.
Reading the workup as a whole
The "clean four" supports a cervical diagnosis
The strongest positive presentation for cervicogenic dizziness combines:
Normal Dix-Hallpike and supine roll bilaterally.
Normal vHIT gain on both sides with no corrective saccades.
Normal VNG — preserved smooth pursuit in neutral, accurate saccades, symmetric calorics under 25% asymmetry.
SOT either normal or showing a visual-preference pattern (consistent with central reweighting) but not the vestibular pattern.
Then, an abnormal SPNT and abnormal JPE from Module 4 in a patient with clear cervical findings.
When all of these line up, the cervical diagnosis is defensible. Document each one explicitly.
vHIT divergence from calorics is informative, not contradictory
vHIT measures the high-frequency VOR; calorics measure the low-frequency VOR. These two probes can disagree, and the disagreement itself carries information. The classic patterns:
Both abnormal — a peripheral lesion involving the canal across frequencies. Vestibular neuritis or labyrinthitis.
Caloric abnormal, vHIT normal — often early Ménière's, where low-frequency canal function is the first to falter; or a compensated chronic loss in which the high-frequency VOR has recovered through plasticity while caloric weakness persists.29
vHIT abnormal, caloric normal — much less common; consider aminoglycoside vestibulotoxicity or superior-vestibular-nerve neuritis with sparing of the posterior canal.
HINTS and the acute vestibular syndrome
In a patient with continuous acute vertigo, the head impulse, nystagmus, and test-of-skew (HINTS) battery outperforms early MRI for ruling in a posterior-circulation stroke.32 A normal head impulse test in the setting of acute spontaneous vertigo, with direction-changing nystagmus or skew deviation, should escalate to neuroimaging within hours. Cervicogenic dizziness does not typically present acutely with continuous vertigo — but if it appears to, HINTS overrides it.
What "normal" cannot tell you
A clean workup makes peripheral and central pathology unlikely but does not rule out:
Vestibular migraine — the most common mimicker of cervicogenic dizziness, often with completely normal interictal vestibular testing. The Bárány committee specifically flagged this as the highest-yield alternative diagnosis to consider.22
Persistent postural-perceptual dizziness (PPPD) — a functional vestibular disorder that overlaps clinically with chronic cervicogenic dizziness, and may co-exist.
Rotational vertebral artery syndrome — requires dynamic vascular imaging, not the standard workup.
What to order, in what order, for the dizzy patient with neck pain
Dix-Hallpike and supine roll at the bedside, every time, before anything else.
vHIT and VNG in the same visit if available; otherwise vHIT first (faster and more sensitive to recent neuritis).
Posturography (SOT) when the picture is ambiguous or when you want to track response to rehabilitation.
Audiometry as a screen for asymmetric sensorineural hearing loss — a vestibular schwannoma can present with imbalance and neck-attributed symptoms.
Dynamic Doppler or MRA only when history specifically suggests RVAS (Module 6).
The clinical synthesis. The vestibular workup is the rate-limiting step for a defensible cervicogenic diagnosis. Treat it as the entry pass — only when peripheral and central pathology have been actively probed and excluded does the Module 4 cervical examination earn the diagnostic weight it was designed to carry.