Introduction to the Vestibular System
The vestibular system is a collection of sensory organs in the inner ear that help you maintain balance. Your brain receives information from your vestibular system, eyes, and body to maintain a sense of awareness of your movement. The organs that compose the vestibular system in the inner ear are three semicircular canals and two otolith organs. The semicircular canals are tube-like structures that detect rotational movement of the head, such as nodding, shaking, or tilting. The otolith organs are the utricle and saccule, which detect linear head movements. The inner ear is filled with endolymph, which shifts in response to head movement. The fluid moves the hair cells, which subsequently send signals to your brain. Dysfunction of the vestibular system can cause problems such as motion sickness, labyrinthitis, vestibular migraines, and vertigo.
Motion Sickness
Motion Sickness is a common condition, but some individuals are more sensitive than others. Motion sickness occurs when there is a difference between what you see and what you are feeling. For example, on a boat, you may feel the motion of the boat swaying; however, sensory input from your eyes tells your brain you are not moving. On the contrary, if you are riding a roller coaster in a virtual reality game, your eyes are telling your brain there is motion; however, your body is not moving at all.
Age, gender, alcohol and drug use, and hormonal changes in pregnancy are among common risk factors that affect the susceptibility of becoming motion sick. Poor ventilation, strong odors, sleep deprivation, and sitting in the back seat of a car can also impact the likelihood of getting motion sickness and the severity of the symptoms. Motion sickness can affect the gastrointestinal tract, nervous system, and autonomic system, causing nausea and vomiting, poor temperature regulation, headache, drowsiness, and loss of appetite. While there are many small steps to avoid feeling motion sickness, such as looking straight ahead in a car or taking medication, habituation towards the stimulus has shown to be the most effective method to avoid the onset of symptoms.
Why do some people experience severe motion sickness, and other people go on every ride at an amusement park and never get sick? While there is no clear genetic factor, motion sickness appears to be heritable. More conclusive research will help further explain potential genetic factors that influence the development of the vestibular system.
Other Vestibular System Conditions
Labyrinthitis: The labyrinth is a structure in the inner ear that can become inflamed due to a bacterial or viral infection, leading to labyrinthitis. The inflammation affects the functioning of the vestibular system, leading to symptoms such as nausea, dizziness, loss of balance, hearing loss, ringing, and mild headaches. Prompt treatment is important to prevent permanent damage to your inner ear structures.
Vestibular Migraines: Vestibular migraines are characterized by the typical migraine symptoms of a throbbing headache but may also be coupled with vestibular symptoms such as dizziness and loss of balance. Individuals who have migraines may have specific triggers that cause the onset of symptoms.
Vertigo: Vertigo is the feeling that the world around you is spinning even when you are not moving. Peripheral vertigo is caused by problems with the structures in your inner ear and problems with the brain cause central vertigo.
References:
Understanding Vestibular Testing: Assessing Inner Ear Balance & Function - THANC Hospital Assessed and Endorsed by the MedReport Medical Review Board