When Does Dizziness Occur? Five Main Causes
Dizziness is actually the perception of a movement that does not truly exist. Many diseases can present with dizziness. Dizziness, or vertigo, is not a disease itself but a symptom. It may be experienced in different ways, such as the sensation that the surroundings or the person are spinning, imbalance, faintness, darkening of vision, lightheadedness, or a feeling of emptiness.
Balance is maintained through the coordinated functioning of three systems. A disruption in any one of these systems affects balance and may lead to dizziness or imbalance. Dizziness may occur alone or together with symptoms such as nausea, vomiting, a feeling of fullness in the ear, hearing loss, or tinnitus.
Vertigo and imbalance are among the top ten reasons for visits to emergency departments and outpatient clinics.
The etiology may involve various peripheral or central causes. In a study conducted in 2002, it was reported that 93% of vertigo cases were of peripheral origin.
How Is Balance Maintained in the Inner Ear Balance Organ?
The inner ear contains the organs responsible for hearing and balance. Within it are structures that are sensitive to sound waves, gravity, and head movements. The inner ear contains fluids, and when the head moves, these fluids also move. This fluid movement in the balance organ causes stimulation in areas where sensory receptors are located, generating various signals.
The information received from these receptors is transmitted via the vestibular nerve to the balance centers in the brain. By processing the data coming from both ears, the position of the head and body is perceived, and balance is maintained.
Even when we are not moving, the receptors in the inner ear send constant resting signals to the brain. These signals should come from the right and left ears at symmetrical frequencies. During movement, signals increase in some of these sensitive receptors and decrease in others. These signal changes are interpreted in the higher balance centers, creating the perception of motion. At the same time, to support environmental stability and visual clarity, the eyes fixate on a point and move at the same speed as the head but in the opposite direction, thereby stabilizing the gaze.
The Role of Other Systems in Balance
At the same time, proprioceptive input from internal organs, muscles, and tendons, as well as the visual system, is also active. Reflexes that regulate muscle contraction and relaxation—especially in the lower parts of the body—are engaged to prevent the body from collapsing during movement. In this way, even during rapid movements of the head and body, the visual field remains clear and stable, and the body moves without losing balance.
Why Does Dizziness Occur in Inner Ear Disorders?
In cases of unilateral dysfunction of the inner ear, the signals sent from the affected ear to the brain disrupt normal perception. These faulty signals may be either increased or decreased. As a result, even when the person is not moving, the brain perceives movement as if it were occurring. To stabilize gaze and maintain visual clarity, the eyes reflexively begin to move in the opposite direction of the perceived rotation. This reflexive eye movement is called nystagmus. Since there is no real movement, but the sensation of spinning persists, the eyes attempt to fixate on a point but fail to do so.
While the inner ear sends false movement information to the brain, no movement data is transmitted from the eyes or proprioceptive receptors. This discrepancy causes confusion in higher centers of the brain. Fortunately, the brain and cerebellum recognize these faulty signals, resolve them, and initiate an adaptation mechanism. The greater the defect in the data coming from the inner ear, the greater the confusion, and therefore the longer the adaptation process takes. Over time, even if the information from the inner ear remains asymmetric or defective, the brain modifies it to help keep the body upright. To enhance and accelerate this adaptation, balance exercises can be beneficial when necessary.
Are There Factors That Increase the Risk of Dizziness?
Advanced age, vascular problems, metabolic diseases, degenerative disorders, and tumors can predispose a person to dizziness.
Dizziness originating from the inner ear may or may not be accompanied by hearing problems.
Inner ear–related vertigo usually has a sudden onset and is severe.
The spinning sensation may be continuous or occur in attacks. It often worsens with head movements. Nausea and vomiting commonly accompany it. Although the patient may feel unwell, loss of consciousness does not occur.
How Is Vertigo Diagnosed?
In a patient presenting with dizziness, even the clinical history—such as the characteristics and onset of vertigo—can guide us toward the diagnosis. In approximately 90% of cases, vertigo is of peripheral origin, while about 10% is due to central nervous system causes. Distinguishing between these two is a priority.
If a diagnosis cannot be made based on history, physical examination, and simple tests, detailed balance and hearing tests are performed. If these detailed tests still do not lead to a diagnosis, neurological examination and imaging methods are considered.
One of the most important patterns in the evaluation of balance system disorders is the duration of vertigo. Classification according to duration is as follows:
If vertigo lasts for days:
- Vestibular neuritis
- BPPV (VBY)
- Multiple sclerosis (MS)
- Brainstem infarction
If vertigo lasts for minutes or hours:
- Endolymphatic hydrops
- BPPV (VBY)
- Cervical vertigo
- Migrainous vertigo
If vertigo lasts for seconds:
- Benign Paroxysmal Positional Vertigo
If the duration of vertigo is variable:
- Perilymph fistula
- Inner ear trauma