Screening for vascular supply problems of the brain can assist in the clinician’s differential diagnosis and greatly benefit the dizzy and/or balance-impaired patient.
Incorporating Vertebrobasilar Insufficiency Screening Into Your Positioning and Positional Videonystagmography Routine
Screening for vascular supply problems of the brain can assist in the clinician’s differential diagnosis and greatly benefit the dizzy and/or balance-impaired patient. Vertebrobasilar insufficiency (VBI) or, so called, “beauty parlor syndrome” has been known for nearly a century as a basis for many vertigo, lightheadedness and imbalance problems. While the patient approximates provocative neck extensions during the course of routine tests for positioning and positional nystagmus and vertigo a simple, safe and very quick modification will allow for the screening of VBI syndromes.
Modifications to clinical test routines that maximize efficiency while maintaining patient comfort and safety are always welcome. Changes to clinical test routines have be the focus of germane publications in the past such as Dr. Barany’s and Dr. Nylen’s publications of the 1920’s and 1930’s, Dr. Dix’s and Dr. Hallpike’s publication of 1952 and recently entries into reference texts such as Dr. Brant’s 1999 suggestions in Dr. Jacobson, Dr. Newman and Dr. Kartush’s text, “Handbook of Balance Function Testing” as well as conference presentations. In most balance assessment clinics there is a large contingency of elderly patients suffering vertigo, dizziness and imbalance. Vertebrobasilar insufficiency (VBI) is a common contributing factor of vertigo and “dizziness” symptoms in the elderly1. Incorporating a vertebrobasilar insufficiency screening element into your positioning and positional electro- or videonystagmography routine takes literally seconds and provides benefit2.
Blood supply for the brain and vestibular structures is provided by four major arteries. The anterior arterial system, the two carotid arteries, which bifurcate into the internal and external carotid arteries are seemingly “straight through” with few convolutions and is associated with frontal and middle vascular perfusion of the brain. The posterior arterial system, the two vertebral arteries and higher order structures, are associated with posterior vascular perfusion of the brain. This posterior arterial system is more complex resulting in both internal and external threats to these vascular structures that can number 8-9 more than the anterior arterial system3. The vertebrobasilar arteries pass through spinal foramina which can externally threaten the vertebral arteries through disease processes such as bone spurs, the weakening or distortion of these boney structures. The joining and separation of these arterial structures to include ascending and descending branches can result in internal threats at the points of separation in the form of stenosis due to disease resulting in decreased blood flow1. These anatomic considerations make the routine assessment for VBI a prudent choice as a quarter of all strokes and transient ischemic attacks occur within the vertebrobasilar distribution. Further, all of the structure of interest during routine assessment of the vestibular and balance systems are within the vascular distribution area of this system. These areas of clinical interest include the labyrinth, the brainstem, the cerebellum and the occipital aspect of the brain as the vertebral arteries ascend from the heart to join together to form the singular basilar artery and then bifurcate to form the posterior cerebral arteries and then join the “Circle of Willis.”
The safe screening for VBI following the informed consent of the patent can benefit both your clinical practice and the balance-impaired patients you serve4. Screening for VBI symptoms while the patient is standing or seated on an unstable support is not recommended as the loss of control of the lower extremities and of consciousness are known symptoms of this syndrome. Estimates for serious complication for this type of manipulation ranged from one in 20,000 to five in 10,000,0005. The body, neck and head position that results from completing a proper Dix-Hallpike maneuver is precisely the provocative position subjects were in when the syndrome was first recognized and termed the so called, “beauty parlor syndrome.” Symptoms from lightheadedness to slurred speech and dysarthria to loss of consciousness have been noted as customers bent their head and necks backwards to wash or rinse their hair. Following the initial step of a head-lateral Dix-Hallpike maneuver the patent becomes supine with the head rotated 45 degrees to one side and hanging (but supported) off of the end of an examination table. Shortly after this positioning maneuver the clinician is assessing for benign paroxysmal positioning nystagmus and/or vertigo (BPPN / BPPV). While in this position and before returning to a seated position clinicians may question the patient about the maneuver experience and any resulting dizziness, determine if any resulting nystagmus is suppressed by visual fixation and other adopted clinical tasks including the resolution of any resulting BPPV. Now, setting BPPV aside, this is an opportune moment to screen for VBI by simply extending the rotation of the head from 45 degrees to a 45 degrees + rotation as possible. Extending the head and neck rotation just an additional 5-10 degrees is adequate. At this time alterations in function and consciousness are assessed as described above. In this laboratory VBI screening is completed during a ten second visual fixation period before returning to a seated position to complete a dix-Hallpike maneuver. VBI screening was initially a part of its own 40-60 second-long section within our VNG routine but it simply was easier and more practical to complete this seconds-long assessment as part of the Dix-Hallpike maneuver.
There are pitfalls and considerations with this proposed alteration of your clinical routine. Most of the time the VBI screening procedure is completed without any signs or symptoms or negative consequences. As with all clinical testing of human subjects there may be a very upsetting event and your facilities needs to be prepared for that. Limited mobility and/or flexibility of the back and neck and/or significant pain with movements such as these can eliminate the Dix-Hallpike and VBI screening from consideration. In this laboratory, when there are no explicit signs or symptoms of VBI, VBI screening is further assessed by determining if there is a new onset of lightheadedness. This lightheadedness would be a new and screening-maneuver-provoked symptom that is disassociated from BPPV. This new onset lightheadedness is magnitude estimated on a 10-point scale similar to common pain-rating scales, 10 being a loss of consciousness. New onset lightheadedness during this screening procedure is noteworthy for the referral source and increased values of the patient’s magnitude estimation of lightheadedness increase the suspicion for VBI syndromes. Chronic lightheadedness that is increased by the screening procedure may be noted in the same fashion. The increased head and neck rotation do not provoke any compromise of vascular structures when this complex vascular system is healthy and no signs or symptoms should result. One school of thought is that VBI is a constant undiscovered dysfunction such that when this posterior vascular system is unhealthy the additional neck rotation may alter the internal carotid arteries decreasing the volume of blood flow resulting in positive findings for this syndrome. An example would be turning the head to the right and slowing the volume of blood flow through the left internal carotid artery resulting in a new onset of lightheadedness or other symptoms. Positive and negative indications of your screening results are welcome information as referral sources attend to the formal diagnosis and management of VBI.
- Williams D, Wilson TG The diagnosis of the major and minor syndromes of basilar insufficiency. Brain. 1962; 85: 741-774.
- Mitchell JA. Changes in vertebral artery blood flow following normal rotation of the cervical spine. Journal Manipulative Physiological Theraputics. 2003; 26:347-351.
- Hardin CA, Williamson WP, Steegmann AT. Vertebral artery insufficiency produced by cervical osteoarthritis spurs. Neurology 1960; 10:855-858.
- Alshahrani A, Johnson EG, Cordett TK. Vertebral Artery Testing and differential Diagnosis in Dizzy Patients. Physical Therapy and Rehabilitation 2014; 1: 1-3
- Gross AR, Kay TM, Kennedy C, Gasner D, Hurley L, Yardley K, Hendry L and McLaughlin L. Clinical practice guideline on the use of manipulation or mobilization in the treatment of adults with mechanical neck disorders. Manual Therapy. 2002; 7:193-205.