Cognition with fancy features from hearing aids
Hearing aids are arriving with increasingly impressive features — noise reduction, AI-based sound categorization, adaptive environment classification. I was genuinely excited by these developments, but as they have accumulated, I have grown somewhat skeptical of their potential long-term effects on cognition. I think the field needs more research on this before we take these features for granted.
As we know, untreated hearing loss causes certain advanced auditory processing functions to become dormant: discriminating a signal from noise, extracting meaning from sound, habituating to persistent background noise of lesser significance, and so on. When hearing aids are fitted and amplified sound is reintroduced, these functions begin to reawaken — starting with the brain's categorization of sounds that had been absent due to auditory deprivation. In other words, cortical regions that had gone underactive begin to re-engage. But what happens when we delegate that very process to the hearing aid's algorithm, rather than allowing the brain to do it?
We know the brain remains plastic even in older adults. We know that consistent cognitive engagement helps preserve function over time. And from Jack Katz's work on auditory processing disorders and the Buffalo Model, we know that auditory processing can be meaningfully enhanced through targeted rehabilitation and training. My concern is this: by offloading these higher-order functions to hearing aid features, are we inadvertently depriving the brain of the stimulation it needs to stay engaged?
I want to be clear that the prevailing research supports hearing aids as cognitively protective overall. The most prominent example is the ACHIEVE trial, published in The Lancet in 2023, which showed that hearing intervention slowed cognitive decline by 48% over three years in older adults at increased risk. However, a closer look at the protocol reveals that the trial used a standardized professional fitting model with Phonak devices and did not examine or control for specific hearing aid features such as noise reduction or AI-based sound categorization. In other words, the most-cited evidence for hearing aids being cognitively beneficial tells us nothing about what those advanced algorithmic features specifically contribute — or take away. That gap, frankly, adds to my skepticism. The question of whether delegating higher-order auditory processing to hearing aid algorithms affects cortical engagement remains genuinely unexamined in the literature. I may be wrong. But I think it is worth asking.
