title: Clinical evaluation of the xDP output compression strategy for cochlear implants.
abstract: Technological advances in the domain of digital signal processing adapted to cochlear implants (CI) are partially responsible for the ever-improving outcomes observed with this neural prosthesis. The goal of the present study was to evaluate audiometric outcomes with a new signal processing strategy implemented in Oticon Medical-Neurelec cochlear implant systems, the xDP strategy. The core of this approach is a preset-based back-end output compression system, modulating a multi-channel transfer function depending on the intensity and information content of input sounds. Twenty adult CI patients, matched for age and CI experience, were included in this study. Pure-tone thresholds and vocal audiometry scores were measured with their former signal processing strategy and with xDP. Speech perception was assessed using dissyllabic words presented in quiet, at different intensity levels: 40, 55, 70, and 85 dB SPL, and in a cocktail party noise at a signal-to-noise ratio of +10 dB. Results with the xDP strategy showed, as awaited, no major modification of pure-tone thresholds. A global increase of speech perception scores was observed after a 1-month habituation period, with significant improvements for speech perception in quiet for moderate (55 dB SPL), loud speech sounds (85 dB SPL), and speech-in-noise comprehension. Subjective signal quality assessment showed a preference for Crystalis(xDP) over the former strategy. These results allow the quantification of improvements provided by the xDP signal processing strategy.
authors.affiliation: Department of Head and Neck Surgery, CHU-University Hospital of Dijon, Dijon, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Bozorg-Grayeli
authors.affiliation: University Head and Neck Institute, CHU de Nice, Nice, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Guevara
authors.affiliation: ENT Department, Pellegrin Hospital, University of Bordeaux, Bordeaux, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bebear
authors.affiliation: Clinical and Scientific Research Department, Oticon Medical-Neurelec, 2720 Chemin Saint Bernard, 06220, Vallauris, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Ardoint
authors.affiliation: Clinical and Scientific Research Department, Oticon Medical-Neurelec, 2720 Chemin Saint Bernard, 06220, Vallauris, France.
authors.forename: Sonia
authors.initials: S
authors.lastname: Saaï
authors.affiliation: Clinical and Scientific Research Department, Oticon Medical-Neurelec, 2720 Chemin Saint Bernard, 06220, Vallauris, France. mhoe@oticonmedical.com.
authors.forename: Michel
authors.initials: M
authors.lastname: Hoen
authors.affiliation: Clinical and Scientific Research Department, Oticon Medical-Neurelec, 2720 Chemin Saint Bernard, 06220, Vallauris, France.
authors.forename: Dan
authors.initials: D
authors.lastname: Gnansia
authors.affiliation: University Head and Neck Institute, CHU de Nice, Nice, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Romanet
authors.affiliation: ENT Department, Nord Hospital, Marseille, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Lavieille
mesh_terms: D000328:Adult; D000368:Aged; D001299:Audiometry / Q000379:methods*; D019929:Cochlear Implantation / Q000009:adverse effects / Q000379:methods; D003054:Cochlear Implants; D017076:Computer-Aided Design; D005260:Female; D006311:Hearing Disorders / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D010700:Phonetics; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013067:Speech Perception
keywords: Automatic gain control; Cochlear implants; Digisonic SP; Intensity compression; Oticon medical; Saphyr Neo; xDP