More than half of the population will see a doctor at some point in
their lives with symptoms related to the vestibular system (e.g.,
dizziness, vertigo, imbalance and blurred vision). The vestibular
system, made up of tiny canals in the inner ear, is responsible for
receiving information about motion, balance and spatial orientation.
A new study led by researchers at Massachusetts Eye and Ear found
that vestibular thresholds begin to double every 10 years above the age
of 40, representing a decline in our ability to receive sensory
information about motion, balance and spatial orientation. The report
was published online ahead of print in Frontiers in Neurology
‘Our ability to detect and perceive motion declines as we age; and it could be responsible for as many as 152,000 American deaths each year.’
"In our study, vestibular decline was clearly evident above the age
of 40," said senior author Daniel M. Merfeld, Director of the
Jenks Vestibular Physiology at Mass. Eye and Ear and a Professor of
Otolaryngology at Harvard Medical School. "Increased thresholds
correlate strongly with poorer balance test results, and we know from
previous studies that those who have poorer balance have much higher
odds of falling."
With the goal of determining whether sex or age affected the
function of the vestibular system, the researchers administered balance
and motion tests to 105 healthy people ranging from 18 to 80 years old
and measured their vestibular thresholds ("threshold" refers to the
smallest possible motion administered that the subject is able to
perceive correctly). While they found no difference between the
thresholds of male and female subjects, they found that the thresholds
increased above the age of 40 for all motions studied.
The researchers also found that these increasing thresholds strongly
correlated with failure to complete a standardized test for balance.
This correlation shows that fall risk is substantially impacted by
Using data from previous studies, the researchers
suggest that vestibular dysfunction could be responsible for as many as
152,000 American deaths each year. This estimate would place vestibular
dysfunction third in the United States behind heart disease and cancer
as a leading cause of death among Americans.
The correlation between vestibular thresholds and balance also
suggests that there may be better ways to screen vestibular function and
ways to develop therapies that may improve their thresholds.
"We've known for a long while that patients with vestibular
disorders have disturbed balance," said Dr. Merfeld. "If worse
vestibular function leads to falls, perhaps we can develop balance aids
or physical therapy exercises to improve balance or vestibular function
and prevent those falls."