Vertigo and Dizziness
Cervical Vertigo
Cervical Vertigo, also known as cervicogenic vertigo or cervicogenic dizziness is a controversial entity. There is evidence that it is a distinct disorder but there is no agreed upon pathophysiology, reliable test, or diagnostic criteria. Reliable and well established tests support an alternative diagnosis in almost all patients with vertigo. [1] In centres with advanced capabilities for assessing vertigo, cervical vertigo probably makes up about 1% of all cases. However, in settings of whiplash, post-traumatic dizziness is very common.
All clinical studies on the condition have three major weak points: inability to confirm the diagnosis, no specific laboratory test, and unexplained discrepancy between those with severe neck pain with no vertigo and those with moderate neck pain with severe vertigo.<ref name="Li">
Cervical facet joints densely innervated, 50% of all cervical proprioceptors in joint capsules C1-C3. Dense mechanoreceptors in gamma-muscle spindles of deep segmental upper cervical muscles Direct connections to vestibular and visual systems. Mechanoreceptor function can be altered by pain, trauma, fatigue, degeneration.
The vestibulospinal tract is a descending motor pathway (extrapyramidal) that gives motor commands that control posture. The medial tract is for neck muscles, head stabilisation / coordination, and eye movement. The lateral tract is for antigravity muscles, the leg extensors for upright posture. The vestibulospinal reflex helps maintain balance, posture, and stability. There is no objective test for detecting deficient or excessive vestibulospinal activity. An example:
- Sensory: Head tilted to one side, stimulates vestibular canals and otoliths
- Afferent: vestibular nerve and nucleus stimulation
- Efferent: lateral and medial vestibulospinal tracts
- Result: Movement opposed that which is registered by the vestibular system ๏ฟฝ(Extensor effects in muscles on side of neck to which it is bent, and flexor effects in muscles on opposite side)
There are multiple models of cervical dizziness. Abnormal sensory input from neck, cervical cord abutment, or high cervical disease, vertebral artery compromise (Bow Hunters syndrome), sympathetic dysfunction (Barre-Lieou syndrome), Cervicogenic migraine, CSF leak, neck interaction with other types of vertigo, and inner ear damage associated with neck injury.
In whiplash there may be damage to tonic neck reflexes, secondary to pain.
