It seems far more likely that your cheap hearing aids are sensitive to certain RF frequencies and the background javascript is causing different patterns of load on the phone's CPU.

I would suspect that this only happens when you're charging and it is likely the charger or cable not being properly shielded.

The cheap hearing aid cost $750 for one and is substantially the same as the same thing sold from standalone audiologists for much more. These are not cheap over the counter devices.

Charging only happens while in the cradle, not while worn.