You are likely familiar with the phrase “the eyes are the window to the soul”, but recent work out of the UMMC Department of Otolaryngology and Communicative Sciences suggests that the “the ears may be the window to our health.”
In 2007, John Schweinfurth, MD and Charles Bishop, AuD, PhD were awarded a $1.5 M grant from the National Institute of Deafness and Other Communicative Disorders, part of the National Institutes of Health (NIDCD-NIH), to examine hearing and balance health in participants of the Jackson Heart Study. The Jackson Heart Study is an all African-American prospective cohort study of factors that influence the development and progression of cardiovascular disease in African Americans. The aims of the study were to determine the prevalence of hearing and balance deficits of the cohort and identify modifiable determinants. The data collection transpired over a 5-year period and has generated novel findings relative to hearing and balance function in this cohort. The dataset has also provided a wonderful opportunity for resident research in epidemiological analysis.
A recent study led by recently graduated resident Jonathan Sorrel, MD examined the relationship between stroke risk and hearing loss. Stroke risk was measured by the 10-year atherosclerotic cardiovascular disease (AVCD) risk estimator. The findings suggested that higher stroke risk was associated with higher prevalence of hearing loss even when adjusting for other factors (Sorrel et al. 2018).
In a follow-up analysis, distortion product otoacoustic emissions (DPOAEs), an objective measure of cochlear function, were found to have a comparable relationship, where higher stroke risk was predictive of poorer DPOAEs. Interestingly, this relationship was conserved even when participants were limited to those with normal audiometric thresholds (Sorrel et al. in review). In other words, despite meeting the clinical definition of normal hearing, participants with higher stroke risk still had poorer DPOAEs.
These findings suggest that the cochlea, as an end-organ in regards to vascularization and supplied by a single artery, may serve as a predictor of cardiovascular health, and that DPOAEs specifically, may serve as an objective measure to further inform cardiovascular risk. Further studies are needed to determine prospective relationships and clinical applications.
References: Sorrel JE, Spankovich C, Bishop CE, Su D, Valle K, Schweinfurth JM (in Review). Stroke risk in African Americans with subclinical auditory dysfunction evidenced by DPOAEs: The Jackson Heart Study. Sorrel JE, Bishop CE, Spankovich C, Su D, Valle K, Seals S, Schweinfurth JM (2018). Relationship of stroke risk and hearing loss in African Americans: The Jackson Heart Study. Laryngoscope 128, 1438-1444.