PHILADELPHIA — Pennsylvania Sen. John Fetterman has been diagnosed with atrial fibrillation, cardiomyopathy, stroke, and depression — common medical conditions that affect millions of Americans.
His latest diagnosis may be his most common one yet: hearing loss.
On March 31, when Fetterman was released from the hospital after being treated for depression, his office said he also had been diagnosed with "mild to moderate sensorineural hearing loss" and was fitted for hearing aids.
Hearing loss affects an estimated 50 million Americans, and sensorineural hearing loss is the most common form of it.
Yet by getting hearing aids, Fetterman is taking an uncommon approach: actually doing something about the problem. Four out of five people who could benefit from hearing aids do not wear them, according to the Hearing Loss Association of America.
For more on Fetterman's type of hearing loss, and whether it might be connected to his stroke and his related issues with auditory processing, we spoke to Linsday Bondurant, director of the Pennsylvania Ear Institute at Salus University in Elkins Park, and Alexandra Costlow, a clinical audiologist at Jefferson Health.
What is sensorineural hearing loss?
When sound waves enter the inner ear, they stimulate thousands of tiny hair cells, which transmit the signal to the auditory nerve, which in turn delivers it to the brain.
Sensorineural hearing loss is the result of a problem with either of those structures, the auditory nerve or the hair cells.
In most cases, it's the latter — typically the result of exposure to loud noise, Bondurant said. Over time, noise damages hair cells so much that they no longer are able to detect and transmit sound. Aging and genetics also can contribute to the deterioration, Costlow said.
Often, the first sign of hearing loss comes in the higher pitches. That's because the hair cells that detect higher frequencies are more vulnerable to loud noise than the cells that detect lower frequencies, Costlow said. Damage to the hair cells also can cause sounds to seem distorted.
Sensorineural hearing loss usually develops gradually. But it also can come on suddenly, as the result of medical conditions that include autoimmune disease, Lyme disease, multiple sclerosis, and non-cancerous tumors called acoustic neuromas, according to the American Academy of Audiology.
Is Fetterman's hearing loss from his stroke?
Sensorineural hearing loss also can be caused by a stroke, if the blockage occurs in the delicate blood vessels in the part of the brain that surrounds the inner ear, Bondurant said.
"The microvasculature around the inner ear is very delicate and susceptible to changes in blood flow," she said. "Changes in blood flow could result in hair cells dying."
Fetterman's office has not disclosed where the blockage in his brain occurred, or whether it contributed to his hearing loss.
But years of noise exposure is the more likely explanation for hearing loss in people in their 50s, Bondurant said. Fetterman is 53.
"In his age range, I would be more inclined to say noise exposure was a contributing factor," she said.
What about his auditory processing?
Even if Fetterman's stroke did not damage his hearing, it did impair his brain's ability to perform a suite of tasks known as auditory processing.
These skills include recognizing sounds as speech, mapping them against known words, and formulating a spoken response. He underwent months of therapy to improve his speaking ability, though he still has continued to stumble.
The added burden of a hearing loss means his auditory processing deficits must have been even more of a challenge, Bondurant said.
"Anything that results in a distorted signal reaching the brain, it's going to make it harder for the brain to decipher the incoming information," she said, "The brain has to work that much harder to comprehend what's coming in."
So his hearing aids, though they are meant to treat his hearing loss, also could help Fetterman to overcome unrelated auditory processing deficits, she said.
"The clearer we can make that incoming signal," she said, "the easier it's going to be for the brain to make sense of the information."
What is 'mild to moderate' hearing loss?
Fetterman's office said he was diagnosed with "mild to moderate" hearing loss.
The term is widely used, but Costlow is not a fan, as it makes it sound as if the patient has a minor issue.
"It's a bit of a misnomer," the Jefferson audiologist said. "Mild to moderate hearing loss could cause significant difficulty in communication."
According to the CDC, a person with mild hearing loss may have trouble with hearing soft sounds, whereas a person with moderate hearing loss may struggle to hear speech even at a normal level. People with mild to moderate hearing loss may first perceive the problem in crowds or other noisy settings.
Hearing aids can help, as they can be programmed with multiple customized settings to compensate for the wearer's surroundings — perhaps with one program that muffles the background noise in a noisy restaurant, and another setting that neutralizes the echoes in a large auditorium.
Until last year, people with mild to moderate hearing loss could get hearing aids only after being evaluated by an audiologist or licensed hearing-aid dispenser. In August, the FDA authorized the sale of "over-the-counter" hearing aids to people with mild to moderate hearing loss, meaning they no longer need to get tested by a professional.
Fetterman's office did not provide details about his hearing tests, saying simply that he was evaluated and fitted for hearing aids.
That suggests he got traditional prescription hearing aids from an audiologist, who could help him program, adjust, and learn to use the device as needed, Bondurant said.
"Someone who is in lots of meetings and different environments, like he is, would be better off going the prescription hearing-aid route," she said. "They can be tailored to all these different listening environments."
