One Saturday each month, I drive across town to pick up my old pal Leo for lunch, coffee, and some grocery shopping. The octogenarian poet, pundit, and provocateur, who has been struggling for years with Parkinson’s, climbs with some difficulty into the passenger seat and spends the duration of our drive to the restaurant trying to speak loudly enough to allow my malfunctioning ears to capture some of his words. Much repetition is required.
I recall these moments with some frustration and more than a little curiosity after stumbling the other day upon a couple of studies suggesting a rather complicated relationship between hearing loss and Parkinson’s. And the fact that I suffer from the former while Leo copes with the latter makes the research more confusing than comforting.
The conundrum involves the frequently fuzzy concept of cause and effect. Take, for instance, the results of a study released last week by the VA Portland Health Care System. Lee Neilson, MD, and his team argue that hearing loss raises the risk of developing Parkinson’s, a view at odds with earlier research suggesting that the disease itself damages our auditory capacity. In other words, I’m either on the road to joining Leo among the Parkinson’s crowd or I’ve already arrived — and just haven’t yet displayed the most visible symptoms (aside from hearing loss).
The issue became a bit more salient after a visit last week with my audiologist, who informed me after a thorough exam that my hearing loss can now be accurately described as “profound” — so bad, in fact, that my current hearing aids are no longer adequate. When I asked him about the connection between Parkinson’s and serious auditory malfunction, he seemed as clueless as the rest of us.
After delving more deeply into the conflicting research, I found his to be a completely understandable response. The VA Portland study, published in JAMA Neurology, can’t be faulted for the size of its sample — more than 7.2 million U.S. veterans who had undergone a hearing exam between 1999 and 2022. Nor am I in any position to question its conclusion: Those with any type of hearing loss were about 26 percent more likely than those with normal hearing to develop Parkinson’s during a 10-year tracking period.
Those with any type of hearing loss were about 26 percent more likely than those with normal hearing to develop Parkinson’s during a 10-year tracking period.
As Neilson notes, “The use of long follow-up times, showing persistently increased PD incidence rates, adds reassurance that our findings are unlikely to be due to reverse causation bias or referral bias.”
On the other hand, a 2023 study in the journal Brain Communications concluded there was no evidence that hearing loss presented a “significant risk” for developing Parkinson’s and instead held the view that hearing loss was simply “a nonmotor symptom of the disease.”
In that study, researchers from the University of Rome recruited 39 Parkinson’s patients, checked their hearing, and concluded that their cochlear dysfunction was probably caused by the same dopamine deficiency that has been linked to the development of the disease. So, neither hearing aids nor cochlear implants could likely prevent a gradual descent into the disease — though the authors acknowledge that more research is needed on that topic.
However, Neilson could argue that his team has delivered the required evidence: “Hearing loss appears to be an independent risk factor for later development of PD,” he writes. “Hearing aids attenuate this risk, and therefore widespread screening for hearing loss and appropriate use of hearing aids may reduce the incident of PD.”
Game over, right? I’ll return to my audiologist in a couple of weeks to get fitted for new hearing aids, secure in the knowledge that the move might reduce the chances that I’ll soon be joining Leo among the ranks of Parkinson’s sufferers.
But then it occurred to me that my old pal has never worn hearing aids. And I can’t recall the last time he asked me to repeat something.
This Post Has 0 Comments