Pathophysiology

The short version

The brain uses three sets of signals to know where the head is in space: the inner ear, the eyes, and the neck. In a healthy person, all three agree. When the neck is painful or stiff, the neck signal can become unreliable — and the brain finds itself receiving three different stories about the same head.

That mismatch is uncomfortable. The brain tries to reconcile it, and the attempt produces the symptom we call dizziness. It is the same kind of process that makes people queasy in a car: the eyes see a still cabin while the inner ear feels motion, and the brain struggles with the disagreement.

A second mechanism is mechanical: when the neck rotates far to one side, the artery that runs through the neck bones to the brainstem can be pinched. This is rare, but it is the reason examiners are cautious about sustained head turning in older patients.

A short history of the idea

Cervical vertigo was first described by Ryan and Cope in 1955 in a Lancet paper that argued for a cervical contribution to positional dizziness through disordered proprioception.²⁶ Brandt and Bronstein, half a century later, reframed the syndrome and emphasised that no single mechanism could account for all presentations — they proposed considering several distinct aetiologies under one clinical umbrella.²³ Most recently, the Bárány Society's 2022 position statement concluded that the evidence supporting a mechanistic link between neck pathology and an illusory sensation of self-motion remains lacking, and recommended the term "cervical dizziness" over "cervicogenic" to reflect that mechanistic uncertainty.²²

The clinical reality has not waited for the controversy to resolve. Patients with co-existing neck pain and dizziness present frequently, the manual-therapy and physiotherapy literatures have documented characteristic sensorimotor disturbances, and trials of cervical-directed treatment show benefit. The four mechanisms below are the proposed substrates — knowing them lets you reason about each patient rather than reaching for a single label.

Mechanism 1 — Proprioceptive mismatch

The dominant model. The brain integrates three afferent streams to localise the head: the vestibular labyrinth, the visual system, and the cervical proprioceptors. In the healthy state, all three deliver congruent information. When cervical input is altered — by pain, by inflammation, by altered muscle spindle gain, by trauma — the cervical stream drifts in amplitude and in phase, and the integration that previously produced a coherent percept now produces an internally inconsistent one.^5,4,1

The mismatch hypothesis makes several testable predictions:

• Provoking the cervical channel alone should reproduce symptoms (the basis of the Cervical Torsion Test, Module 4).
• Quieting the cervical channel — by cervical anaesthetic injection, by manual therapy, by collar immobilisation — should reduce symptoms.
• Patients should show measurable proprioceptive errors (the basis of Joint Position Error testing).
• Pursuit gain should drop in torsion (the basis of SPNT).

All four predictions have empirical support, although none of the individual tests has high enough specificity to serve as a gold standard — which is precisely why the Bárány Society reserved judgment.

Mechanism 2 — The vestibulo-sympathetic loop

The proprioceptive-mismatch model explains the perceptual symptom — the spinning, the unsteadiness, the visual disturbance. It does not, on its own, explain why cervicogenic dizziness so often arrives with autonomic features: nausea, vomiting, palpitations, pallor, and a global feeling of being unwell. Those arrive through a second anatomical channel.

The vestibular nuclei project to the reticular formation and the parabrachial nucleus, both of which project in turn to the sympathetic preganglionic neurons in the intermediolateral cell column of the thoracic spinal cord. When the convergence at the vestibular nuclei is in disarray — for any reason, including cervicogenic mismatch — the autonomic output downstream becomes turbulent.⁵ This is the same loop that generates motion sickness and the autonomic features of vestibular migraine; it is not specific to cervical disease but is engaged by it.

Two further details give this loop clinical relevance:

• Sympathetic efferents directly innervate intrafusal muscle fibres, and experimental sympathetic outflow can itself modulate cervical muscle spindle firing.⁸ A patient in pain and autonomically aroused can therefore feed their own cervical-input disturbance — a small positive feedback loop that may explain chronicity.
• The older Barré-Liéou framing — that the syndrome is driven primarily by sympathetic outflow from the cervical chain — has not survived modern scrutiny.⁵ Sympathetic features are now best understood as downstream of the sensorimotor mismatch, not its cause.

Mechanism 3 — Rotational vertebral artery compromise

A small but important fraction of position-provoked dizziness arises from mechanical compromise of the vertebral artery during head rotation. The dominant artery passes through the C6 to C1 transverse foramina before piercing the dura, and the V3 segment between the C2 transverse foramen and the dural entry point is fixed at both ends — making it the most mechanically vulnerable segment to rotation. Sustained end-range rotation can compress the dominant vertebral artery against an osteophyte, a fibrous band, or a contralateral hypermobile atlas, producing transient vertebrobasilar insufficiency.²⁴

This is Rotational Vertebral Artery Syndrome (RVAS), historically also called Bow Hunter syndrome after a published case of a patient who developed lateral medullary infarction while holding the archer's stance.²⁴ The syndrome is rare in the published literature, but it is the one mechanism on this list that can cause a stroke, and so it deserves disproportionate vigilance.

Clinically suggestive features:

• Symptoms reliably triggered by sustained end-range rotation, not by gentle movement.
• Symptoms include brainstem features — diplopia, dysarthria, drop attacks, presyncope — rather than purely cervical proprioceptive complaints.
• Often a setting of cervical degenerative change, atlantoaxial instability, or aberrant arterial anatomy.

Pre-screening before sustained provocation manoeuvres is essential. The imaging workup — dynamic Doppler and MRA — is covered in Module 6.

Mechanism 4 — Whiplash and central sensitisation

Whiplash-associated disorder (WAD) is the best-studied model of cervicogenic dizziness, partly because the onset is acute and dated, and partly because the population is large.³ Persistent post-whiplash patients show a characteristic four-domain sensorimotor deficit (joint position error, postural stability, smooth pursuit, eye-head coordination), and those with persistent dizziness show consistently larger errors than those without.²

What WAD makes plausible is that the cervical contribution to dizziness can outlast the original injury through central reorganisation. Repeated mismatch between cervical and vestibular streams over weeks and months appears to drive a maladaptive sensory reweighting in which the brain comes to rely more heavily on visual input and less on proprioception — explaining the visual dependence often observed in chronic cervicogenic patients and the symptomatic overlap with persistent postural-perceptual dizziness (PPPD). Some of the symptom persistence after WAD therefore reflects neural plasticity, not ongoing tissue injury.²⁵

The Bárány position and clinical practice

The 2022 Bárány Society position statement deserves direct engagement rather than a footnote.²² The committee — including Bisdorff, Bronstein, Cullen, Magnusson, Strupp, and others — reviewed the evidence and concluded that no published study has demonstrated a mechanistic link between cervical pathology and an illusory sensation of self-motion that meets contemporary methodological standards. They preferred the term "cervical dizziness" over "cervicogenic", on the grounds that the latter implies a mechanistic understanding that the evidence does not yet support.

Two things follow from this for the practising clinician:

• The label is provisional. When you record a diagnosis of cervicogenic dizziness, you are making a working inference, not stating an established mechanism. Document the differential you have excluded and the cervical findings that supported the inference.
• Vestibular migraine is the elephant in the room. The Bárány committee specifically noted that vestibular migraine is by far the commonest cause of co-existing neck pain and vestibular symptoms — and is, importantly, treatable on its own terms. A patient with neck pain and episodic spinning should be screened for vestibular migraine before settling on a cervical diagnosis.

How the mechanisms combine in real patients

The four mechanisms are not mutually exclusive. A typical chronic patient may carry contributions from several at once:

1. Baseline cervical degeneration or post-whiplash injury produces persistent proprioceptive mismatch.
2. The mismatch engages the vestibulo-sympathetic loop, producing the autonomic surround.
3. Over months, central reweighting shifts the patient toward visual dependence — they become symptomatic in supermarkets, on staircases, in busy patterns — and the symptom set drifts toward something that looks more like PPPD than mechanical dizziness.
4. In some patients, sustained end-range rotation additionally provokes vertebrobasilar symptoms that are mechanistically separate.

The clinical reasoning is to identify which of these is loudest in this patient. The cervical examination (Module 4) interrogates mechanism 1. The autonomic history identifies mechanism 2. The history of position-triggered brainstem features identifies mechanism 3. The chronicity, visual dependence, and avoidance behaviour identify mechanism 4.

Implications for treatment

Treatment should target the dominant mechanism:

• Mechanism 1 — manual therapy, cervical proprioceptive retraining, joint position retraining.¹¹
• Mechanism 2 — symptomatic antiemetic cover during flare-ups, avoidance of habit-forming vestibular suppressants.⁵
• Mechanism 3 — avoidance of provocative postures, imaging, sometimes surgical decompression.²⁴
• Mechanism 4 — vestibular rehabilitation tailored to reweight sensory inputs back toward proprioception, cognitive-behavioural elements where avoidance is prominent.³

A patient who is given manual therapy alone when the dominant mechanism is central reweighting will not improve. A patient who is given habituation exercises alone when the dominant mechanism is unrecognised RVAS will be put at risk. Module 8 develops the treatment pathway in detail.