1. Abnormal sensitivity to some sounds, sometimes resulting in pain even when only moderately loud sounds are in the area of the subject: Brett had been diagnosed with hyperacusia which made his job of monitoring crowds at band concerts too difficult for him to tolerate any more because the noise of the crowds and the music of the bands were too painful for his ears.

Deafness is not the only danger of noise exposure of hyperacusia, in fact stress causes some 45,000 fatal heart attacks a year in the developing world, according to researcher Dieter Schwela of the Stockholm Environment Institute.

2. Increased sharpness of hearing or a condition that exists when sounds are perceived as abnormally loud: Although Caroline always wanted to attend a live concert with her favorite band, she was advised not to do so because of the hyperacusia in her ears which would make going to the concert a terribly painful experience.