REACHING THE ROOT CAUSE OF VERTIGO
DIAGNOSIS BASED TREATMENT
Vertigo as a symptom means the illusion of motion which can be present due to many distinct reasons, ranging from the brain to the vestibular system.
Only when the cause of Vertigo is known can treatment for the disease be possible.
UNDERSTANDING VERTIGO
The Answers You Need
INSIGHTS IN BALANCE
Over the years there have been serious advancements in healthcare that have changed the face of medicine, however vertigo remains as misunderstood today as it was two decades ago.
The good news though is that more & more clinicians now consider vertigo as a ‘symptom’ that needs further evaluation and specific treatment; instead of an end diagnosis in itself.
The following text briefly expands on the common causes of peripheral vertigo, and provides possible hints towards diagnosis through evaluation of basic symptomology.
COMMON CAUSES OF VERTIGO
The Vestibular System is a part of the inner ear & sits next to the organ of hearing (cochlea). It detects rotational and linear motion & performs a vital role in maintenance of balance. Majority of all dizziness/ vertigo is because of problems with this part of the ear.
WHY DO PEOPLE GET MOTION SICK?
The brain expects all three sensor organs for balance (eyes, ears & joints) to give same information during rest & motion. Example if we are running, our eyes, ears & muscle-joint system, all sense & tell the brain that the body is in motion.
However if the sensors give conflicting information, the brain gets confused. This is the chief cause of Motion sickness.
For example if one is sitting in a moving car & reading a book, the Eyes are fixed on the book and don’t sense any motion. While the balance organs in the ears can sense the car moving, more so if it’s a hilly drive. In this case, the eyes tell the brain that there is no movement, & the ears tell it that there is ample movement. This conflict confuses the brain & causes motion sickness.
The solution is to ensure that eyes & ears give the same information to the brain. By asking the person to sit on the front seat & look at the road, the eyes sense the same motion as the ears & there is no conflict of sensation.
Alternate solution is to suppress the ear sensors through medication. This way the ears don’t sense much motion, and the sensory mismatch between the eyes and the ears is lesser . No sensory mismatch means no motion sickness.
CAN CERVICAL SPONDYLOSIS CAUSE VERTIGO
Mild to Moderate problems with Cervical spine do not lead to Vertigo. Often because the patient has vertigo on head movement, the brain reflexly stiffens the neck to reduce this motion. This is seen as straightening of cervical spine on x-ray.
The tightness at the neck & the resulting minor changes seen on Cervical Xray are wrongly labelled Cervico-genic vertigo.
WHAT ARE SOME OF THE VESTIBULAR INVESTIGATIONS THAT CAN BE USED TO DIAGNOSE THE REASON BEHIND VERTIGO?
1 ) Video-Nystagmo-Graphy and Video-Oculo-graphy
VNG is a collection of many tests. The ones which are of overwhelming importance are Spontaneous Nystagmus with and without visual fixation, which can tell us about a recent imbalance in the overall balance structures.
The other main test, called the Caloric Test records function of the Horizontal Semi-Circular Canals (HSCC) , the part that senses rotation in the yaw plane (like nodding head to say “No”. It tests very slow speed of head movement and broadly tells us if the balance organs on the left and the right side are working equally or not.
VIDEO HEAD IMPULSE TEST (VHIT)
One of the most important functions of balance organs is to make sure we can fix our eyes (gaze) on an object even if we are moving. This means if the head moves to one side, the eyes should move to the opposite side at an equal speed. This is important when we are looking at something while walking or running, or reading while in motion. Without this, we would be able to concentrate on something only if we were absolutely still, and any motion would disturb the visual field. The balance organs notice head movement, and send a very quick signal to the eyes to move in the opposite direction at the exact same speed. This function is called Vestibular Ocular Reflex (VOR). In case of imbalance because of the ears, the VOR gets affected and therefore people start to develop very stiff neck. Moving the neck causes an increase in imbalance. This can misleadingly be diagnosed as Cervical Spondylosis.
vHIT can test the Vestibular Ocular Reflex for all three SCC at fast head movements, and present results in terms of gain of VOR.
This means, if any one of the balance organs are weak, the weakness can be recorded.
VEMPS (VESTIBULAR EVOKED MYOGENIC POTENTIAL
This test is done to check the balance organs that record Linear Acceleration (Otolith Organs). These organs can be stimulated through Sound, and in response effect the muscle tone. We stimulate the left and the right organs, one at a time and record muscle tone changes, which tell us if they are working symmetrically, or if one is working better than the other. The Saccule is innervated by Inferior Vestibular Nerve.