Dizziness and Vertigo are among the commonest symptoms leading to a hospital visit. The two terms are used interchangeably and sometimes are confused with each other. That is why, I always ask patients to describe their symptoms by using words other than “dizzy.” This clarifies whether she is talking of light-headedness, unsteadiness, motion intolerance, imbalance, floating, or a tilting sensation, generalized weakness, or something more specific – VERTIGO – in which there is an intense sense of rotation, and is due to a disturbance in the VESTIBULAR SYSTEM.
The VESTIBULAR SYSTEM includes some very specific and exquisitely sensitive motion – sensing organs situated in the inner ear, along with the nerve – the Vestibular nerve – which carries the information from these sense organs to the brain. This nerve connects to various parts of the brainstem, but especially to parts of the cerebellum called the vestibulocerebellum.
VERTIGO is caused by asymmetric input to the vestibular system, and commonly caused by conditions such as Vestibular neuritis (or neuronitis) in which there is disruption of the input from the vestibular organs, due to an unknown disturbance in the nerve – believed but not confirmed to be due to inflammation; some people believe it to be a reactivation of latent Herpes Simplex Type 1 viral infection.
The most common cause for true Vertigo is Benign positional vertigo (BPV), which is caused by calcium carbonate particles called otoliths that are inappropriately displaced inside the inner ear structure which senses head motion and acceleration (called the semicircular canals) These otoliths are normally attached to the sense organs (the hair cells). Changes in head movement vertically causes the otoliths to tilt the hair cells, which triggers a nerve that send a signal to the brain letting the brain know that the head is tilting up or down. Changing head position causes the otoliths to move through the canal. The fluid inside the inner ear organ – called Endolymph is dragged along with the movement of the otoliths, and this stimulates the hair cells of the affected semicircular canal, causing vertigo. When the otoliths stop moving, the endolymph also stops moving and the hair cells return to their baseline position, thus terminating the vertigo and nystagmus. Reversing the head maneuver causes the particles to move in the opposite direction, producing vertigo in the reverse direction of rotation. The patient may describe that the room is now spinning in the opposite direction. Repeated head movements disperse the otoliths, so their effectiveness in producing vertigo becomes progressively less, an effect called fatigability, which is the basis for Vestibular exercises and the ultimate improvement of the condition by adaptation. When dizziness is non – specific, without the rotatory sensation, then it may be due to disease of the nervous system (CNS ), cardiovascular system, or other systems.
Vertigo is treated medically using various drugs to suppress the vesibular system; this treatment is important especially if the dizziness is severe and incapacitating, putting the individual at risk of falling. Ultimately, the symptom disappears once the brain adapts to the asymmetric input from the vestibular apparatus, and prolonged use of vestibular suppressants may be detrimental by preventing this adaptation happening early. That is why it is important to use these medicines judiciously, and only when the symptom is too intense.
Read more >>> for vestibular exercise videos
The mainstay of the treatment is Vestibular Rehabilitation Exercises. An example is the Dix-Hallpike maneuver illustrated below.
Here is a link to the Brandt-Daroff Exercises
The videos below demonstrate the Epley and Semont Maneuvers which are extremely useful for re-positioning of the otoliths.