This article is from the Tinnitus FAQ, by email@example.com (Mark Bixby) with numerous contributions by others.
Currently all treatments for hyperacusis are experimental. The most
promising treatment comes from Dr. Pawel Jastreboff who have patients with
hyperacusis listen to static (white noise) from ear appliances called
maskers. The theory is that by listening to a specific kind of white noise
at a barely audible volume for a disciplined period of time each day that
the efferent system of the auditory nerve will be retrained through
desensitization to once again tolerate normal environmental sounds. The
treatment has been somewhat successful on a select number of patients but
usually no improvement is seen during the treatment period for at least the
first 3 months. Treatment may take as long as 2 years.