Delayed onset hearing loss in a two-year old.

This paper describes a delayed onset sensorineural hearing loss in a baby known to have normal hearing until at least 13 months. A mild high-frequency loss was discovered quite by accident at 25 months. The bilaterally symmetrical loss progressed over the next 6 months to no measurable high-frequency hearing and a 70 dB threshold at 500 Hz. To our knowledge this is the youngest completely documented case of what has been called hereditary delayed onset hearing loss. However, in this instance, and perhaps unsuspected in others, this child had bilateral oval and round window fistulas whose repair may have not only arrested the progression of her loss, but even improved her residual hearing sensitivity.