Cervicogenic dizziness is a controversial subject at best. The term tends to be used to describe a variety of entities, some of which are theoretically more likely than others, including cervical ataxia, cervical nystagmus, and cervical vertigo. Because vertigo is defined as the illusion of movement (rotation, tilt, or linear displacement) and is therefore restrictive, the term cervicogenic dizziness, rather than the older term “cervical vertigo,” is used in this chapter to refer to symptoms of dizziness (including vertigo, disequilibrium, and lightheadedness) arising from the cervical spine.
Several different processes have been hypothesized to be the cause of cervicogenic dizziness. These pathophysiological mechanisms include irritation of the sympathetic vertebral plexus, vertebrobasilar insufficiency (VBI), and altered proprioceptive afferent signals from the upper cervical spine. This latter potential cause of dizziness is of particular interest because of the large number of patients with either whiplash injuries or neck pain that are seen by physical therapists. This particular cause of dizziness is also perhaps the most controversial.
One of the major problems in identifying patients with cervicogenic dizziness is the lack of a concrete test that is sensitive and specific to this entity. From a therapeutic standpoint, however, the controversy surrounding cervicogenic dizziness may be academic. If an individual presents with cervical symptoms and dizziness, the holistic approach would be to treat the cervical problem as well as the dizziness. The aim of this chapter is to review the anatomical and physiological bases for cervicogenic dizziness, to summarize the scientific findings related to cervicogenic dizziness, to address the clinical methods of assessing cervicogenic dizziness, and to discuss possible management strategies for this condition.
Posterior Cervical Sympathetic Syndrome
Barré1 suggested that cervical problems could irritate the sympathetic vertebral plexus, leading to constriction of the internal auditory artery and decreased perfusion of the labyrinth, which would induce vertigo. There is little objective evidence, however, to support this hypothesis. In addition, the intracranial circulation is controlled independently of the cervical sympathetic system. Therefore, it is difficult to see how a cervical injury could lead to restricted blood flow to the inner ear.
Another possible cause of dizziness arising from the cervical spine is occlusion of the vertebral arteries by osteoarthritic spurs2 or occipitoatlantal instability.3 VBI and vertebrobasilar ischemia can arise from a variety of causes, including embolism, large artery atherosclerosis, small artery disease, and arterial dissection, and can occur at numerous sites along the course of the vertebral and basilar arteries.4 There are two sites where physical occlusion, or in the extreme, dissection of the vertebral artery can occur. One is in the upper cervical spine, after the vertebral artery exits the transverse foramen and courses around the mobile upper cervical vertebrae. The other potential site for occlusion is in the initial segment of the vertebral ...