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I always had this view that noise cancellation demands doubling the energy in the system, to effect the cancellation. It may manifest as heat in the noise cancellation speakers, but also as pressure. In other words the eardrum system is exposed to "more" load, not less, it's just that it hears less.

However, the articles have been about neurological changes because of sound isolation which is different.

I'd be interested if the prior cohort of e.g. helicopter crew can show functional changes, deficits.

I’m pretty ignorant on human hearing and hearing damage but my understanding is that hearing damage from loud noise is caused when a loud sound mechanically vibrates little hairs in your inner ear and the product of the magnitude and duration of that vibration is high enough to cause damage.

Noise cancellation stops or reduces the magnitude of that vibration. So I have to disagree, I don’t think noise cancellation would cause more damage in the way you’re describing.

I didn’t read the whole article but from what I read it sounds like it’s a brain issue not a physiological one.

Also ignorant here, but if you want a body to stay at rest, you can either not push it at all, or push it with the same force from both sides. If you’re pushing from both sides, the body won’t move, but the forces acting on it can still crush it, deform it, and otherwise damage it.

I don’t know if this would be a factor at this scale.

I suspect the absolute pressure required to crush a hair would be measured in MPa, orders of magnitude more than the pressure difference from a sound level that would kill you. The damage probably comes from the vibration ripping apart nerves cells at the base of the hair, but again that’s speculation on my part. So no vibration, no damage.
If you don't like (loud) noise, being able to escape from it via noise-cancelling headphones makes you like it even less.

I wonder how many people actually use noise-cancelling headphones _that_ much. And wouldn't someone that lives in a quiet environment suffer the same thing _without_ having to use a noise-cancelling headphone?