Hyper what? Hyperacusis is an oversensitivity to certain sounds.
Most people can't stand the sound of chalk scratching [kkkchchch] the black board a certain way, some have the same reaction to cutlery scraped across the surface of a plate. Add to that screeching children, barking that's loud, and high pitched, and even someone with sound ears will at some point say: that's enough.
With the popularity of clip-on microphones for telephones (worn at chest height, right over, say the sink or dish-pan), the hyper sensitive are subjected to more attacks on their ears then ever before. Sounds made thousands of miles away, can penetrated the ear of the person who suffers from hyperacusis in an extreme and concentrated way.
What is nothing but regular household noise (piling of dishes, clanging cutlery, taking plastic foil of a bunch of flowers) to one, may be an assault of the nerve system for the person on the other end.
Knowing of the handicap is crucial for sufferers as well as bystanders. Ironic that caregivers in Belgium offer better guidelines for sufferers as well as bystanders to deal with this phenomenon. Something that might call for another "Belgium Joke" in the Netherlands. But meanwhile Readers of Dutch or Flemish can read all about this Hyperacusis and learn what to do and what to avoid (translation may follow).
As is often the case, ignorance can create hostility and relationships may be saved by knowledge.