[Universal hearing screening of newborn infants with the BERA-phone].

Background: Unidentified and untreated early infant hearing loss leads to speech-language deficits as well as to cognitive, intellectual, emotional and psychosocial handicaps. Targeted hearing screening programs may miss approximately 50% of all hearing impaired children.

Methods: In an universal hearing screening program with a two stage protocol, 1349 newborns were examined using the CRESCENDO Newborn Hearing Screener according to Finkenzeller and a clinical ABR system operating with a time course step stimulus algorithm.

Unanswered questions concerning the indication for cochlear implant.

In a discussion of the function of cochlear implant (CI), the following criteria should be mentioned: (1) If possible, all deaf persons (including the prelingually deaf and children) should benefit from CI. (2) Since the number of patients with late deafness is doubtlessly decreasing with better prevention and medical care (elimination of ototoxic damage, decrease of iatrogenic deafness), the percentage distribution of the deaf will be displaced in favor of the prelingually deaf. At present, the ratio of cases of late deafness to those of prelingual deafness among our CI candidates is 1:3.

The resolution of brief interaural time-difference changes: recordings from primary auditory cortical projection field AI of the cat.

The ability of the auditory organ to resolve brief changes in an acoustic signal presented either monaurally or binaurally is not only of great importance in the processing of speech, it is also involved in the localization of sound stimuli and in selective listening. In the latter context, the electric activity of the primary auditory cortical projection field AI of the cat has been studied with the aim of evaluating specific response patterns evoked by brief changes in interaural time difference. The differences in response of the neuron populations sampled by two recording electrodes indicate that, within this area, there are significant differences in temporal resolution ability.

Auditory prostheses--a challenge for neurophysiology.

To achieve speech discrimination with prosthetic stimulation, pre-processing of speech adapted to the function to be replaced is indispensable. This is demonstrated using the example of a phase-conserving frequency transposition for a more efficient use of residual hearing. The intelligibility of transposed speech was investigated by employing simulated residual hearing.

Grafting and electrical stimulation of the auditory nerve in cats.

The effect of implanting wire electrodes into the cochlea is limited by the deficit of nerve fibers in most diseases of the cochlea. Therefore, in a series of experiments it was tried, for the first time, to direct new outspreading nerve fibres into the afferent acoustic nerve by grafting a motor nerve to it. A second series of experiments should demonstrate the possibility of direct electrical stimulation of the eighs nerve by implanting wire electrodes via the transoccipital approach.