PHOENIX-Low-frequency hearing loss could be an early indicator that a patient has cerebrovascular disease or is at risk for cardiovascular (CV) disease. These are the key findings in a two-part study investigating whether there is a relationship between audiometric patterns and vascular disease. Findings were presented at this year’s Combined Otolaryngology Spring Meeting by David R. Friedland, MD, PhD, Associate Professor of Otolaryngology and Communication Sciences at the Medical College of Wisconsin in Madison.
Explore this issue:September 2009
There are various known risk factors for the development of cardiovascular disease, including diet and lifestyle, family history, and age, as well as conditions such as diabetes, hypertension, and other vascular disease. Of interest to Dr. Friedland and colleagues are the hypertension and vascular aspects of the disease.
Current guidelines look for hypertensive subclinical organ damage to try to predict which individuals may progress on to more clinically significant CV disease, Dr. Friedland said. Several organs are noted in current guidelines (as being associated with risk) but the ear is not one of them. Affected organs that are listed include the heart, brain, arteries, kidneys, and eyes.
However, the inner ear is highly vascularized, especially around the stria vascularis. Previous work in the medical literature has shown that abnormalities of the stria account for low frequency, or a flattened hearing loss sometimes known as strial presbycusis. It has also been shown that there is a relationship between cardiovascular disease and strial loss.
It is possible that a change in vessel health, potentially a sign of vascular disease, could affect hearing, he said. Indeed, the inner ear is so sensitive to blood flow that it is possible that any abnormalities in their condition could be noted earlier here than in other parts of the body that are less sensitive.
In addition, research from the Framingham Study showed an association between low-frequency hearing loss and numerous cardiovascular disease events. Their take on this was to determine whether individuals with cardiovascular disease may be more prone to hearing loss, therefore needing audiometric evaluation. Our take is a little bit of the opposite. Our hypothesis is that strial or low-frequency hearing loss is, in fact, a marker that may predict the presence or potential development of cardiovascular disease, he said.
Studies Analyze Audiograms
A retrospective study was launched in which researchers analyzed audiograms of 1168 patients over a five-year period. They categorized the audiograms according to five distinct audiometric patterns. A total of 186 were normal patterns, 168 were high-sloping, 358 were mid-sloping, 205 were low-sloping patterns, and 251 were strial.