What is the difference between vertigo and dizziness?
Vertigo is a false or distorted sense of motion when no motion is occurring. It is most commonly perceived as a spinning sensation, but it may also feel like swaying, rocking or bobbing like standing on a moving boat.
Dizziness is a false or distorted sense of spatial orientation within the environment affecting your perception of position or direction. There is no false or distorted sense of motion like there is with vertigo. Causes include hyperventilation or dehydration.
Another symptom is unsteadiness, which is postural instability when upright (sitting, standing, or walking). There is difficulty maintaining a stable posture, resulting in a person falling over or feeling like they are about to fall, or walking with an unsteady gait.
How does your brain control balance, posture and movement?
Your central nervous system (CNS) is made up of your brain, brainstem, cerebellum and spinal cord. It relies on input from your eyes, ears and sensory nerves to control balance, posture and movement of your whole body. This input comes from your:
- Visual system — your eyes detect movement and position.
- Vestibular system — the vestibular organs in your inner ears detect movement of your head in all directions, and position relative to gravity.
- Proprioceptive system — nerve receptors in your muscles, tendons and joints detect movement and position of your body parts.
Input from these 3 systems is integrated and compared in your brainstem and cerebellum. These inputs normally match. This information is then passed further up your brainstem to co-ordinate automatic movements of your eyes, as well as down your brainstem and spinal cord to automatically control posture, movement and balance of your head and body. A disorder affecting any one of these systems causes a sensory mismatch between the 3 inputs resulting in poorly co-ordinated movements or abnormal postures. Your brain perceives this mismatch as dizziness, vertigo or unsteadiness depending on which system is affected.
What causes the spinning sensation of vertigo?
Your vestibular system detects head movement and controls the very fast reflexes that automatically move your eyes. This allows you to maintain a steady gaze on something even while your head is moving, such as walking down the street. Vestibular system disorders can cause inaccurate reflexive eye movements resulting in a sensory mismatch between your vestibular and visual systems. As your eyes move to correct this mismatch your brain falsely perceives that your visual environment is moving. This is the false or distorted sense of motion responsible for vertigo. Vertigo worsens with head movement because it is dependent upon the vestibular system that detects head movements and controls accurate eye movements.
What causes dizziness or unsteadiness?
Neck pain or dysfunction impairs proprioception from the muscles, tendons, ligaments and joints in your neck, causing an inaccurate sense of head positioning relative to the rest of your body. This causes a sensory mismatch with your visual and vestibular systems, creating a false or distorted sense of your spatial orientation resulting in dizziness and disorientation. It doesn’t cause vertigo because there is no false or distorted sense of motion.
Similarly, low back pain or dysfunction impairs proprioception from the muscles, tendons, ligaments and joints in your lower back, causing an inaccurate sense of body positioning and posture. This results in a sensory mismatch with the visual and vestibular systems. Your brain and cerebellum rely on all 3 inputs to control the muscles of your body to maintain posture and co-ordinate movement. This mismatch results in poor control and co-ordination, leading to imbalance or unsteadiness when sitting, standing or walking, but not dizziness or vertigo.
There are many causes of dizziness and vertigo. These are 2 common causes:
This dizziness is caused by a disorder in your neck (cervicogenic means ‘beginning in the neck’). The joints, muscles and tendons in your neck contain the greatest amount of proprioceptors in your spine. This enables accurate positioning and movement of your head.
What causes cervicogenic dizziness?
- neck trauma such as whiplash or sports injuries
- joint or ligament sprains in the neck
- muscle strains in the neck
- disc injury in the cervical spine
- degeneration or arthritis of cervical joints
- muscle fatigue or spasm
- neck pain
What are the symptoms of cervicogenic dizziness?
- worse with neck movement or prolonged postures
- usually occurs after neck pain
- associated with a tight or stiff neck that restricts movement
- associated with disorientation
- may be associated with unsteadiness
- episodes last minutes to hours, but can persist for weeks, months or even years following trauma
- recurring over days, months or years
- accompanied by cervicogenic or tension-type headache
How do you treat cervicogenic dizziness?
Medications are incapable of correcting a sensory mismatch between the visual, vestibular and proprioceptive systems, or improving neck function. Research shows that cervicogenic dizziness responds well to manual treatments and specific exercises to improve balance, function and proprioception.
References for further information:
Grande-Alonso M, Moral Saiz B, Mínguez Zuazo A, Lerma Lara S, La Touche R. Biobehavioural analysis of the vestibular system and posture control in patients with cervicogenic dizziness. A cross-sectional study. Neurologia. 2018;33(2):98-106
Benign Paroxysmal Positional Vertigo (BPPV)
This is the most common cause of recurrent vertigo. It is benign (not caused by a dangerous pathology), but it causes one-third of all vestibular disorders. It affects 2.4% of the population, or about 625,000 Australians. Women are affected 3.2 times more than men, commonly during their 40s and 50s. By comparison, men may be affected at any age. The most common cause in those under 50 years of age is head trauma or whiplash.
What causes BPPV?
BPPV is caused by small crystals dislodging in your inner ear and knocking a sensory nerve receptor of one of the semicircular canals that make up part of your vestibular organ. This causes your vestibular nerve to send a false or inaccurate signal of head movement to your brainstem. Your brainstem uses this information to co-ordinate head and eye movements. This incorrect information causes your brainstem to reflexively move your eyes quickly to match the false sense of head movement. As a result, your eyes move their gaze to the wrong place. What your eyes see, and the false or inaccurate sense of movement detected by your inner ears don’t match. Your eyes then drift back to where they should be gazing before the brainstem quickly moves your eyes again to match the erroneous vestibular input. Your brain doesn’t perceive this as movement of your eyes, but as movement of your environment when no motion is occurring, resulting in vertigo.
Some factors predispose people to BPPV:
- head trauma
- advancing age
- physical inactivity such as bed rest
- low body mass index (BMI)
- ear disease or infection
- diseases of the blood vessels that perfuse the brain (cerebrovascular disease)
- genetic factors
- osteoporosis and osteopenia
- diabetes mellitus type I
What are the symptoms of BPPV?
BPPV occurs with head movements in a specific direction, depending on which part of your vestibular organ has been affected. Most BPPV causes vertigo when rolling over in bed, or getting up out of bed. It can also occur when looking up or bending forward. Vertigo begins 2–10 seconds after moving your head in the offending direction. The attack lasts less than 1 minute, usually about 20 seconds.
- poor balance or a sensation of tilting to the affected side
- difficulty walking
- visual disturbances such as blurred or jumping vision
- increased sensitivity to widespread pain
How do you treat BPPV?
Medications are not effective at treating BPPV, but they may be prescribed to suppress function of the vestibular system, anxiety, nausea and vomiting. They delay recovery and prolong rehabilitation when used for more than a few days.
Sensory mismatch causes your brainstem to compensate by increasing your reliance on your visual or proprioceptive systems. This compensation occurs within days, but compensation and medications do not improve the function of your vestibular system.
Research shows that 80-90% of BPPV resolves with specific gentle manual techniques that move the dislodged crystals away from the affected nerve receptor.
References for further information:
Hillier S, McDonnell M. Is vestibular rehabilitation effective in improving dizziness and function after unilateral peripheral vestibular hypofunction? An abridged version of a Cochrane Review. Eur J Phys Rehabil Med. 2016;52:541-56