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July 2005, Vol. 15, Iss. 3
Table of Contents
A Great Opportunity • Age of Confusion •
APMR Accepts CBP® Research • CBP® has 13 Published Clinical Trials • Chronic Back Pain, Your Brain, & Chiropractic •
Creating a Great First Impression • Evidence Based Exams •
Had Enough? • Lateral Head Flexion from Vestibular Dysfunction •
Letters to the Editor • Life's Rise from the Ashes •
PosturePrint™ is now a Validated Posture Analysis •
The Disease of Unrealistic Expectation • Thousands of Heroes •
When You Can't Critique CBP® in the Peer-reviewed Literature
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Head Lateral Flexion as a Consequence of Vestibular Dysfunction
by Marc Lamantia, D.C., DACNB
Marc Lamantia D.C.,DACNB holds a Diplomate from the American Chiropractic Neurology Board, and is a member of the Adjunct Faculty for New York Chiropractic College and Life Chiropractic College West. Dr. Lamantia is the co-founder of Scoliosis Systems™, and holds a position on the Science Advisory Board for the Non-Profit Scoliosis Care Foundation.
Normal posture is a consequence of a multifactoral sensory integration that requires normo-sensory activity, structural stability and an intact central nervous system for the purpose of modulating coordinated motoric output. Now, explain it in a way that means something! A more understandable explanation is to consider that normal posture requires not only normal anatomy, ligament and disc stability, but also intact vestibular and proprioceptive function. For the practitioner interested in restoring near normal posture, an expert understanding of vestibular neurology can serve to direct meaningful rehabilitation protocols which use Chiropractic procedures as well as appropriate postural re-education techniques. Although vestibular imbalances have long been identified in the Scoliosis population, this article will focus on the relationship of otolithic dysfunction and head tilts.
Static head tilts, or lateral flexion malposition in the cervical spine is a common postural deviation as a consequence of vestibular imbalance, specifically otolithic dysfunction.
The two otolithic organs (Saccule and Utricle) are housed within the inner ear and are part of the peripheral vestibular receptor. They signal the brain information about gravity and translational movement of the head. Due to the tonic nature of these receptors, hypofunction commonly leads to abnormal reflexive activity in the neck and extra-ocular musculature.
Neck complaints have been shown to be associated with vestibular imbalances, but more importantly, the cervical spine rehabilitation has been shown to be a viable approach to vestibular rehabilitation. Cervical spine manipulation and electric nerve stimulation are effective in reducing vestibular imbalances, and give the chiropractor a unique tool for postural rehabilitation. In-office evaluations of the vestibular system are easily performed, but require clinical expertise.
Vestibular reflexes (VOR, VSR, OOR) can be measured both in-office and with advanced neurodiagnostic testing. Clinical expertise in recognizing normal ocular counter-rolling, skew deviations and nystagmus are important to determine if a vestibular imbalance is present. One simple in-office test of otolithic function is the Subjective Visual Vertical test (SVV). SVV is tested with a laser line that can be projected in darkened room. The patient is asked to align the laser line so that it is completely vertical. Patients with otolithic dysfunction will perceive vertical to be tilted towards the side of the lesion. A resultant head tilt will be present. The direction of that head tilt is a consequence of the ocular counter rolling mechanisms. The literature shows supporting evidence the head tilt will be towards the side of the otolithic deficit. Cervical spine stimulations on the same side of head tilt will have a greater probability of causing plastic changes in the central otolithic pathways. If the only evaluation was radiological, the incorrect procedure of adjusting into the open-wedge, or adjusting the contralateral side is less likely to reduce the otolithic imbalance.
The differential in chiropractic analysis should include head tilts associated with midbrain lesions and superior oblique palsy. Midbrain related head tilts are typically contralateral to the lesion with an ipsilateral hypertropia. Superior oblique palsy may arise from head trauma, and can be detected during eccentric gaze testing. Observations will include elevation of the adducting eye on eccentric gaze.
Advanced balance testing includes the use of Video ENG (Electronystagmography) and Posturography. Video ENG is sensitive to very subtle brainstem dysfunction, and may show abnormalities in Mild Traumatic Brain Injury (MTBI), Parkinson’s disease, movement disorders, dystonia and scoliosis. Without doubt, it offers the Chiropractic profession a legitimate tool for scientific validation of central nerve interference, and a measure of functional outcomes.
Subluxation patterns associated with sagittal curves may also be a consequence of otolithic dysfunction. Pitch angles of the head and retraction of the skull may affect the absolute rotation angles in the upper cervical spine, and the skull position in relation to the thorax.
The further study of vestibular neurology can only serve to elevate our service to the public. Thank you for your interest.
[Thank you Titus Vilus of Western Ontario University: Written consent was received for use of all illustrations ]
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