Almost 5 to 8 million people suffer from cochlear hearing loss in European countries such as France, Great Britain or Germany. Most of these people complain about strong difficulties in understanding speech in adverse listening conditions, even when clinical audiometry indicates a mild form of hearing loss. Unfortunately, current rehabilitation devices such as conventional hearing aids and cochlear implants cannot restore normal perception of speech in these conditions, although recent electroacoustical (E-A) devices combining amplified acoustic hearing and electrical stimulation show promising results. The HEARFIN project aims to investigate whether these difficulties in understanding speech in adverse listening conditions originate from an abnormal representation of “temporal fine structure” (TFS) information at central stages of the auditory system, resulting from acute loss of auditory nerve fibers and cochlear nucleus neurons. This project will use a multidisciplinary approach (psychoacoustics, electrophysiology and computer modelling) to demonstrate central deficits in TFS processing in regions of mild hearing loss. Part of this research, conducted in collaboration with an industrial partner, will lead to the development of a novel clinical test for auditory screening and a novel method quantifying the efficacy of hearing aids and E-A systems.