Many individuals with tinnitus also experience a sound sensitivity disorder called hyperacusis. Hyperacusis makes common everyday sounds, such as a running vacuum, a barking dog, and even conversation with another person uncomfortable and painfully loud. The hypersensitivity to sound is almost always accompanied by a sensation of pain when the sound is heard. One individual described his intolerance to sound, stating, “The sound is so painful, it’s like having a knife in my ear.”
Hyperacusis occurs in approximately 25% of individuals with tinnitus and nearly all persons with hyperacusis have tinnitus.
Hyperacusis results from damage along the auditory pathways, likely originating from damage to the tiny cells in the cochlea. Commonly called hair cells, their purpose is to regulate loudness of sound traveling from the ear to the brain. Damage to these cells can be caused by longtime exposure to loud sounds, such as mechanical sounds in a factory, airbag deployment and gunshots. Also, diseases and disorders of the neurological system in which hyperacusis may be present include Lyme disease, myasthenia gravis and autism spectrum disorder.
Hyperacusis can be misidentified as other auditory disorders and requires differential diagnosis by an audiologist with background in sound sensitivity, tinnitus, and central auditory pathway disorders. Present research from otologists and neuroscientists is ongoing and using findings from published research, hyperacusis can be treated, though with varying degrees of success.