Chronic dizziness in those 65 and older is fairly common and presents symptoms such as lightheadedness, vertigo, disequilibrium, spinning, and faintness.[1] Because Mary’s dizziness was increasing, she made an appointment with her doctor. Dizziness in the elderly can be caused by multiple health issues, vision problems, over the counter medications, ototoxic effects of some drugs, hearing loss, cervical arthritis, anemia, or a combination of these.[2] After examination, her doctor referred her for vestibular function testing.
The vestibular system, located in the inner ear, enables us to maintain our balance and keep our gaze steady. It consists of the semicircular canals that sense angular acceleration on three planes: pitch, yaw, and roll. When the head begins to rotate, the endolymph in the affected canal places pressure on the cupula, which is a membrane packed with hair cell bundles called steriocillia. As the motion of the steriocillia moves toward or away from the tallest hair cell, the kinocillium, the tip links open or close ion channels to send nerve impulses via the vestibulocochlear nerve to the brain. Located beneath the semicircular canals in the common vestibule are the ottoconial masses that detect gravity and linear acceleration in the vertical and horizontal planes. The otolith organs are groupings of hair cells covered with a gelatinous substance. Movement of the head or body causes small particles called otoliths to bend hair fibers (steriocillia and kinocillium) sending signals to the brain interpreted as motion. The brain compares the incoming signals from the vestibular system with input from the eyes and proprioceptors to interpret where the head and body are oriented in space.
[1] Aman Nanda, MD, CMD, “Chronic Dizziness in Older Persons,” Geriatrics for the Practicing Physician Volume 90 (Sept 2007): 291.
[2] Aman Nanda, MD, CMD, 291-292.
Next: Mary’s Spinning Explained: A Story of Aging and Vertigo, Part 3
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