Hyperacusis: case studies and evaluation of electronic loudness suppression devices as a treatment approach.

Hyperacusis, as defined here, is a relatively rare condition in which the patient, with or without hearing loss, experiences severe loudness discomfort to everyday environmental sound levels. The case studies of 14 patients with severe hyperacusis are described; all wore passive attenuators (earplugs and/or earmuffs) in an attempt to alleviate their discomfort, frequently producing communication difficulties. These subjects were fitted binaurally with experimental electronic loudness suppression devices housed in in-the-ear casings. The devices supplied low-level amplification followed by an extreme form of amplitude compression for moderate or high-level inputs in an attempt to reduce loudness discomfort without reducing audibility. Many of the subjects were found to function with a wider dynamic range with the active devices compared with passive attenuators or the unoccluded ear, and most reported that they benefited from the devices in at least some listening situations.