[Hearing aids rehabilitation: state of the art]. / Réhabilitation auditive par prothèse acoustique état actuel.

OBJECTIVES: The three-dimensional characteristic of heari ng as a neurosensory loss can be associated with distortions in the axes of intensity, frequency and also temporal. This type of distortions can be isolated or combined, with many functional characteristics which complicate the fixing of the hearing aid and makes its result extremely variable. The ENT specialist in charge of the prescription of the hearing aid must know the various types of available devices, its indications and limitations. The different current hearing aids by acoustic stimulation are described, behind the ear, intra-auricular, intra-canal, micro-behind the ear with receiver in the canal (RIC). Some clinical and audiometric elements make it possible to envisage the difficulty of such equipment as the air bone gap, the dynamic, the frequential shift, the hearing discrimination. Concerning the hearing aid itself, the amplifier represents the fundamental part allowing the compensation of the quatitative loss; it presents however many possibilities of adaptation (multifrequential compression, the adaptive directionnality coming from the directional microphones, the suppression of the acoustic feedback, the increase of the bandwidth and software of statistical analysis of environmental acoustics as well as procedures of decision). Finally software of treatment of the signal like the software of suppression of acoustic feedback, identification of the speech and noise, of adaptive directionality, of measurement of the hearing thresholds (which is possible on certain prosthesis for each channel) refine the adjustment of the hearing aid. CONCLUSION: The knowledge of these technological possibilities currently available, like their indications and limitations, allows the ENT specialist to get an active role in the process of acceptation of the hearing aid.

[New potentialities of the hearing aids: the frequential transposition in high frequencies sensorineural hearing losses]. / Nouvelles potentialités des appareils auditifs: transposition en fréquence dans la surdité de perception avec amputation des aiguës.

OBJECTIVES: Hearing aids are becoming very complex instruments with amplification combining numerous signal processing. Digital equipment allows a transposition of acute frequencies towards lower frequencies. The goal of this study is to extend the possibilities of this transposition based on results obtained on 8 patients. MATERIAL AND METHODS: With these new systems, the frequential transposition involves tiny artifacts but the relation of frequency between the various components of the original signal is preserved. The transposition must be done only in the frequencies which are necessary and must as selective as possible. The structure of the original sound must be preserved which implies a certain flexibility and specificity to guarantee the individual needs of the patient. These complex adjustments are assisted by a linear transposition algorithm; Audibility Extender (Widex). This system was used to fit 8 patients presenting a significant acute frequency loss. RESULTS: The improvement is evident on the level of perception of sounds of the environment and consonant recognition. The improvement is significant as well on the tonal sensitivity as on the threshold of vocal intelligibility with a conservation of the percentage of speech discrimination for monosyllabic words. CONCLUSION: The frequential transposition is an alternative to cochlear implants in certain indications and has its place alongside hybrid implants. The indications are reserved to patients presenting dead cochlear zones in the acute frequencies. The algorithm with its various adjustments allows an adaptation preserving the characteristics of the transposed sounds. The adaptation to such a system of hearing amplification requires an adaptation, and rehabilitation is essential in all the cases.