Measurements of frequency-discrimination ability of severely and profoundly hearing-impaired children

The pure-tone audiogram gives a limited information about the r esidual hearing of hearing-impaired subjects. This i s especially the case when the hearing loss is severe or profound. In these cases often wide variations a r e obtained in results on speech-discrimination tests for the same degree of hearing loss. In some cases it i s likely that the puretone audiogram only shows tactile sensations in the ear. One possibility to improve the diagnosis of a hearing impairment might be to measure the fr equency-dis crimination ability of the impaired ear . Measurements have been made on two groups of severely and profoundly hearing-impaired subjects. The total number of measured ea r s i s 58. Measurements have also been made in the palm of the hand on a group of normal-hearing subjects. The results show that the audio1 gram area can be divided into three parts. In the f irst part normal or almost normal fr equency-discrimination ability i s found. In the second part frequency discrimination varies very much for the same degree of hearing loss and in the last part frequency-discrimination ability is the same a s in the palm of the hand. Measurements of speech discrimination by means of a spondee test show that the results a r e good for subjects with a frequency-discrimination ability, better than 7 70 at 1000 Hz, but very poor for subjects with a discrimination ability that i s worse than 7 %.