An Examination of Cardiovascular Health and Hearing Case History
Although the association between cardiovascular health and the health of peripheral and central auditory systems was first shown in research 80 years ago, the movement to include heart health history in hearing examinations has been lacking. The connections between heart and hearing health are meaningful, as cardiovascular disease can affect auditory pathways in the inner ear in ways that negatively affect speech understanding and the speed and accuracy at which elements of speech are processed. Previous investigations have also shown a relationship between cardiovascular health and the structure and function of the brainstem auditory pathways and auditory cortex.
Poorer cochlear health is attributable to changes in blood supply to the peripheral and central auditory systems over time. A restriction of blood supply to these systems translates to poorer hearing health; this restriction is apparent during audiometry tests and conventional communication. Starving the cochlea of oxygen can compound other damaging influences, including noise, injury, and disease.
Prior studies reported that adults who had cardiovascular disease and signs of peripheral circulation disorders had significantly poorer hearing thresholds in the 500- to 8,000-Hz range. But even among younger adults, there’s support in the literature for a relationship between hardening of the arteries and physical changes within the cochlea. These changes are typically associated with high-frequency sensorineural hearing loss.
Previous studies have also confirmed a relationship between atrophy of the blood vessels in the cochlea and degenerative changes to the structure of the cochlea. These changes appear to lead to a decline in the electrosensory function of the organ — the cochlea has more difficulty sending electrical signals to the brain. A narrowing of the internal auditory artery also correlates with atrophy of the spiral ganglion and with degree of hearing loss.
Coronary infarction, heart surgery as a result of coronary blockage, congenital heart conditions, and high blood pressure should be added to a patient’s hearing case history. In addition to other research evidence that suggests that age and worse cardiovascular health can affect frontal and prefrontal areas of the brain and lead to poorer language processing, it’s likely that changes to the cochlea take place that permanently damage an individual’s ability to hear. Given the litany of research that suggests that hearing loss is in part responsible for worse cognitive function later in life, it is our job as medical practitioners to cover our patients’ bases more fully. Adding cardiovascular information to a patient’s hearing case history can help us do that.