The girl K. A. is the fifth child in a businessman's family. The family history is quite ordinary and contains no case of deafness. The child's birth and development during the first year were quite normal, but at the age of two or three her mother noticed that she developed more slowly than the other children. Not until she was five did the family notice that she did not respond to sounds as the other children did, and she was sent to be examined. At that time her bodily state corresponded to her psychical development and was somewhat not quite up to her age. The only thing that could be stated was that she talked very badly, and especially the consonants were indistinct. She seemed more attentive than children of her age and always looked very interested at everything around her. The appearance and movements of the tympanic membranes were normal. Her hearing is shown in the audiogram in fig. 1. The conversation distance was about 0,1-0,2 m for ordinary conversation. She was extremely good at speech-reading and one could talk to her at a few meters' distance which explains why her parents had not become aware of her bad hearing. A speech audiogram could not be taken because of her limited and very deficient vocabulary. The diagnosis was conductive loss of unknown etiology. As the tympanic membrane was quite normal and no otitis had been present in anamnesis, early otosclerosis seemed to be the most likely cause, and so this was given as a preliminary diagnosis, but with two question marks. It did not seem possible to take any special steps, and the girl was given a hearing aid with which she made rapid progress and soon had acquired the vocabulary of other children of her age.