Aim to Improve Functionality
Expert suggests treating vertigo patients with stimulants, not sedatives
I think the basic idea is that if you lose a part of your labyrinthine function, it implies that you also lose functionality in many things."
This vertigo expert Dr. Herman Kingma noted, as he stressed that optimal management of vertigo and imbalance should be able to restore or improve the patient's functionality. Speaking in a series of interactive sessions on vertigo organized by the Philippine Society of Otolaryngology, Head, and Neck Surgery and Solvay Pharma late last year, the secretary general of the International Society for Posture and Gait Research said that when patients complain of dizziness, they are not only reporting a symptom. They are also telling the doctor that their function in daily living has been impaired.
"It has been said that loss of labyrinthine function can very well be centrally compensated, and the symptoms would go away," said Kingma. But this is old school of thought, he argued, enjoining physicians instead to remember that treating vertigo is more far-reaching than simply eliminating dizziness. Treatment should also address improving functionality, hence the use of rehabilitation exercises and drugs that stimulate neuroplasticity.
But management of a vertigo patient requires more than actual treatment. It is informative in nature, said Kingma. "It is very important that you inform the patient of what is going on in them, explain the relationship between the assumed deficit and the complaints and impairments, understand their expectations, and give them reassurance about their condition," he told Filipino physicians. "If you can explain these to your patients, you can better help them," he added.
Multilevel Problem
But the difficulty with vestibular dysfunction, he said, is that problems exist at all levels of management. Due to the complex nature of vestibular dysfunction, the problem already begins at the level of the patient's complex history and goes down the line to the diagnosis of the problem, its pathophysiology, and finally its treatment. To understand the dysfunction and how to manage it, it is important to thoroughly understand how the vestibular system works and the implications of the pathology of each dysfunction.
Kingma outlined three major functions of the vestibular system and the implications of each function.
Spatial orientation. The vestibular system enables a person to correctly
orient themselves and their movements in space relative to the other stationary and moving objects around them.
Balance control. It regulates the muscle tone relative to gravity, ensuring a certain rigidity of muscle and joints that prevents an individual from collapsing. It also regulates the center of mass that allows the body to compensate for movements that might otherwise cause loss of balance. The labyrinths add speed and precision to control these systems. Losing labyrinthine function causes an individual to lose speed because the vestibular spinal reflexes are faster than visual spinal reflexes, orientation, and propriocepsis. The labyrinths are also more precise in detecting gravity. A defect in the system means that a person will react late to correct balance and have a higher chance of falling.
Gaze stabilization. This allows an individual to have stable visual images during head movement. Kingma acknowledged that it is very easy to stabilize images that move very slowly just by the compensation of a person's visual system. However, gaze stabilization is important for fast head movements because the labyrinths are faster in controlling the eyes compared to the visual system.
A patient will likely present a vestibular problem at three levels. Not only will they have a problem in rotatory vertigo, but also in orientation and visual control. The patient may even present with anxiety and fatigue because of vestibular symptoms.
Diagnosis
Kingma discussed a variety of tools for diagnosing vestibular dysfunction.
Clinical tests such as the Romberg, Unterberger, and the Babinski-Weil (Figure 1) have been used to detect problems in balance and posture, but he pointed out that in many patients complaining of vertigo and balance, the tests yield normal results. To address that problem, craniography, posturography, and ultrasound techniques were developed.
Stabilometry is a new technique used to measure postural control. A camera compares the patient's movements when eyes are open and closed. But one limitation is that findings overlap between healthy subjects and those with vestibular problems.
Dynamic posturography measures balance control (Figure 2). The technique manipulates the sensory inputs into the system and sees how the patient reacts. A patient with a labyrinthine defect will be more dependent on visual information compared to a subject with healthy labyrinths. But this is more a test of functionality than diagnosis. The doctor can measure if the patient has good balance and use the information to see if the patient's progress when undergoing balance training.
Other techniques are the subjective visual vertical and the subjective proprioceptive horizontal. In the former, the patient is required to identify the relative position of a line projected on a screen, whether it is vertical or horizontal. In the latter, the patient is set on a movable platform and required to identify the point at which he feels most at his horizontal. Clinical application is quite simple. If both subjective visual of vertical and subjective proprioceptive horizontal are normal, then it means that there is no major vestibular or proprioceptive origin of the sensation of imbalance in the patient.
Kingma cited a few tests of image stabilization like video eye trackers, vestibular auto rotation test, and the head shaker test.
The complex nature of vestibular pathology will not allow its function to be fully measured. According to Kingma, only 10 to 20 percent of function can be measured using even the latest diagnostic tests. Many patients with vestibular dysfunction may test normal in all these. Thus, in spite of technological advances, Kingma still believes that the gold standard in diagnosis is caloric testing paired with good history-taking.
To get a good history, he adheres to the use of positive criteria that can help the clinician recognize patterns that identify common diseases. Questions that will aid in the search for positive signs include those that center on the onset of the problem, time course, associated symptoms, and type of complaint.
Multilevel Management
Kingma said management of vertigo involves two aspects: informative and actual treatment.
Doctors should ask their patients about their expectations and try to fulfill those expectations. The complaints should be explained in relation to the deficits. Patients should be informed of their prognosis and therapy options.
Kingma cited four treatment options:
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causal treatment: solving the problem and preventing progression
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stimulation of adaptation (neuroplasticity)
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physiological (optimizing function): rehabilitation
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symptomatic (relief of symptoms)
He highlighted the importance of stimulating adaptation or neuroplasticity either by medication or vestibular habituation training.
For medication, the choice is between sedatives and stimulants, he said, stressing that his general guideline is never to sedate patients complaining of vertigo so as not to interfere with neuroplasticity or central compensation. Administering a sedating agent will only provide temporary relief and even cause irreversible damage to the central compensating mechanism. While it is important to deal with uncomfortable symptoms of dizziness, nausea, and vomiting, the patient should be advised to forego sedatives.
He noted that most of his patients agree that it is better to suffer for a week and be well for the rest of their lives than to be well for a week but suffer loss of function in the future. If medication needs to be prescribed, Kingma recommends an antiemetic instead of a sedative-but for no longer than two days since the critical phase of central compensation is on the second or third day.
Among the drugs that promote neuroplasticity is betahistine HCI, which he said has been proved to speed up neuroplasticity and compensation with almost no side effects. Drugs promoting neuroplasticity will restore the functionality of the impaired labyrinth by encouraging the formation of new synapses and reprogramming the neural connections.
Aside from neuroplasticity, rehabilitation and habituation exercises such as yoga and tai-chi, and liberation techniques like Epley maneuver, also improve functionality. Liberation techniques, he said, are effective 80 to 90 percent of the time.
In extreme cases, like persistent BPPN, Kingma advised doing magnetic resonance imaging to exclude vestibular lesion, and then performing canal plugging. Some Meniere's cases would require elimination of peripheral function through gentamycin therapy or gamma knife or linear accelerator radiotherapy. Surgery may be required for central tumors.
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