How widespread is age-related vestibular loss?

The inner ear balance system, also called the vestibular system, deteriorates with age just like the rest of the body. This may sound logical, but we are presently only starting to fathom the extent of the consequences of this process. Yuri Agrawal MD addressed this issue during the Academic Research Conference on March 25, 2015, linked to Audiology NOW! 2015 in San Antonio. “The problem doesn't only regard a small specific population, as was thought until recently, but perhaps a high percentage of all elderly to some degree. This is highly relevant, as vestibular loss has profound direct effects - for instance fall incidents. It has also indirect effects such as loss of confidence and anxiety disorders, resulting in decreased mobility and disability. We are increasingly recognizing vestibular loss as an important health issue.”

“Traditionally, loss of vestibular function is regarded from the perspective of specific diseases, that only affect a small part of the population”, says Yuri Agrawal MD, Assistant Professor in the Department of Otolaryngology at Johns Hopkins University School of Medicine. Examples of these specific diseases are Meniere’s, benign paroxysmal positional vertigo (BPPV) and vestibular neuritis. Agrawal: “But there is increasing evidence that vestibular loss may affect a larger segment of this population, specifically the elderly, caused by a more general deterioration of the peripheral and central vestibular systems.” This structural deterioration may cause vestibular reflex deficits and dizziness.

“Explanations for the gradual decline can be found in hair cell death and decline of the afferent nerves that innervate the hair cells”, says Agrawal. Everybody knows and expects that vision and hearing tend to decline when the number of years rises, and it now appears that the same happens with the vestibular system. “Instead of related exclusively to quite rare and specific afflictions, it looks very much like it that in reality it involves a much more widespread health problem”, Agrawal concludes.

Grave consequences

Apart from the prevalence of the problem, the gravity of its consequences makes it also something to take very seriously. Agrawal: “Vestibular loss leads to increased risk of falling. Because of this people lose confidence and their mobility is restricted.” Statistics show how grave these consequences are. Between twenty and forty percent of people over 65 years of age who live at home fall each year. Research by Hoffman and Sklare in 2006 has shown that older people with chronic dizziness or imbalance are two to three times more likely to fall in comparison with peers who don't experience these problems. Furthermore, a considerable percentage of the elderly who end up with a hip fracture because of such a fall, die within a year.

There is more scientific evidence to underline the seriousness of the consequences of vestibular loss, Agrawal indicates: “'Gait speed', or walking velocity in elderly people is a very important geriatric assessment tool. It provides a powerful prediction for both morbidity and mortality. There appears to be a link between vestibular dysfunction and reduced gait speed. Also, there is pretty robust evidence in literature about the relation between vestibular dysfunction and anxiety disorders.”

How much of these alarming facts should be contributed to vestibular loss? Agrawal: “It is difficult to isolate the influence of vestibular loss in the complex of origins behind lessened gait speed – and fall incidents, for that matter. Large population-based analyses can be helpful here: when you assess enough people, you can measure various factors and focus on the cases in which all other factors except gait speed and vestibular loss remain constant. And especially when you combine these large datasets with laboratory experiments including normal healthy people, you can get an estimate for the contribution of vestibular loss on this health problem.”

High prevalence

There is already some knowledge available, but there is more work to be done. As insight on the prevalence of the problem has just recently begun to be gained, the present statistical evidence is still rather limited. Agrawal: “In a German study conducted by neurology professor Hannelore Neuhauser of the Charité University of Berlin, based on a telephone interview survey with several thousands of adult participants, an overall prevalence of vestibular vertigo of seven to nine percent was found. This prevalence increased with age to fifteen percent in the oldest category of people over eighty-five. This is one estimate of the prevalence based on validated questionnaire data.”