Experimental and clinical research on the perceptual consequences of cochlear damage is conducted by a research group entitled GRAEC ("Groupement de recherche en audiologie expérimentale et clinique"). GRAEC is a GDR unit (GDR #2967) affiliated to CNRS and headed by Pr. Christian Lorenzi. It is based at Ecole Normale Supérieure (DEC, 29 rue d'Ulm, 75005 Paris, France). GRAEC is supported by CNRS, and industrial & private partners.
This group conducts research projects focusing on impaired auditory functions, using different and complementary approaches (psychoacoustics, assessment of speech & music perception abilities, experimental and clinical audiology). This core of this research group includes 1 Professor (C. Lorenzi), 5 CNRS scientists (D. Pressnitzer, W. Serniclaes, J. Bertoncini, S. de Schonen, C de Waele), 1 research engineer (D. Lancelin), and 2 PhD Students (D. Gnansia, CIFRE; M. Ardoint, MENRT). It also includes ENT clinicians (B. Meyer, B. Frachet, N. Garabedian, O. Sterkers, A. Chays, P. Tran Ba Huy, T. van den Abbeele, N. Loundon, C. Poncet, D. Bouccara, V. Couloigner) and three private companies or groups (Entendre SAS, Advanced Bionics, MXM, Med-EL). The GRAEC federates research in audiology across 2 CNRS units (LPP, LNRS, Paris 5 Descartes), and eight Hospitals of the Ile de France region and Reims. Its core is also part of the national RTRS-CTRS "Fondation de Recherche sur le Handicap Sensoriel" (FRHS) headed by Pr C. Petit and Pr J-A Sahel.
Pitch, timbre perception, and sound localization are highly influenced by the sound's temporal structure. This temporal structure plays also an important role in certain universal phonetic distinctions and in music perception. The main goal of the "GRAEC" is to investigate the perception of this temporal structure in hearing-impaired listeners and cochlear implantees. The GRAEC mainly focuses on the perception of the sound's temporal envelope, that is the slowest fluctuations (or modulations) in amplitude of incoming sounds (below about 50 Hz in speech sounds) and fine structure, that is the fastest fluctuations in amplitude of incoming sounds (between about 0.5 and 5 kHz in speech sounds) in listeners with cochlear damage, and listeners wearing a cochlear or a hybrid implant. This investigation is conducted using and combining different approaches (psychoacoustical methods, computer modelling, electrophysiological methods, development and assessment of speech processors for cochlear/hybrid implants or hearing aids).
The GRAEC aims therefore to (i) characterise speech & music perception deficits in terms of deficits in the ability to encode and/or use fast or slow temporal information in speech and music sounds; (ii) propose new strategies for the screening and rehabilitation of different forms of hearing impairments associated to speech and music perception deficits, and (iii) develop new signal processing schemes for hearing aids or speech processors.
Training and Scientific Communication in experimental audiology is also at the heart of GRAEC activities. Every year, the GRAEC unit trains young students in audiology (3ème année d'audioprothèse; mémoire de recherche), and organizes scientific workshops and meetings on recent topics in experimental audiology, open to a restricted or wide audience.
A network coordinating efforts across different regions (e.g. CNRS units in Lyon (UMR CNRS 5020), Toulouse (UMR CNRS 5549), & Bordeaux (UMR CNRS 5543)) will be built over the next years. Foreign, international-level auditory scientists and post-doctoral students will join regularly this new group. They will participate in the different research projects, the organization of annual meetings focusing on hearing impairment, training of audiology students, and the development of a European network of Research in Audiology.