gms | German Medical Science

76th Annual Meeting of the German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery

04.05. - 08.05.2005, Erfurt

Streamline fitting by the use of Nucleus System 4

Meeting Abstract

  • corresponding author Andre Morsnowski - HNO-Klinik, Christian-Albrechts-Universität, Kiel
  • Joachim Müller-Deile - HNO-Klinik, Christian-Albrechts-Universität, Kiel
  • Matthias Hey - St. Salvator Krankenhaus HNO-Kilinik, Halberstadt
  • Klaus Begall - St. Salvator Krankenhaus HNO-Kilinik, Halberstadt
  • Thomas Wesarg - HNO-Klinik, Universitätsklinikum, Freiburg
  • Roland Laszig - HNO-Klinik, Universitätsklinikum, Freiburg
  • Matthijs Killian - Cochlear AG, Basel
  • Andrzej Zarowski - University ENT Department, Sint-Augustinus Hospital, Wilrijk-Antwerp
  • Erwin Offeciers - Antwerpen
  • Petra Ambrosch - Kiel

Deutsche Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie. 76. Jahresversammlung der Deutschen Gesellschaft für Hals-Nasen-Ohren-Heilkunde, Kopf- und Hals-Chirurgie e.V.. Erfurt, 04.-08.05.2005. Düsseldorf, Köln: German Medical Science; 2005. Doc05hno140

The electronic version of this article is the complete one and can be found online at:

Published: September 22, 2005

© 2005 Morsnowski et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.



Different fitting methods to create speech processor maps are investigated as part of a multi-centric study to evaluate the Nucleus system 4.

In clinical practice, adult CI recipients are fitted with maps at stimulation levels based on psycho-acoustical measurements. For toddlers, stimulation thresholds (T-) and comfortable stimulation levels (C-levels) have to be estimated by the use of objective methods like Neural Response Telemetry (NRT). System 4 assists the partly automated creation of maps via recording the ECAP thresholds (T-NRT) automatically. These T-NRTs are interpolated and shifted onto the psycho-acoustically determined T-level of a single electrode to estimate the T-level-profile. The C-levels are estimated increasing all C-levels parallel to the T-levels until sufficient loudness of simultaneous live speech is reached. This map is called streamline map.

In a preliminary test intra-operative NRT-amplitude growth functions (AGF) and automatical NRTs were measured at 42 electrodes of 8 recipients. On average the automatically extracted TNRTs are 5,3 CL smaller than the TNRTs extracted manually by linear regression of the AGF.

10 post-lingually deafened adults with less than 15 years of deafness were fitted with a T-NRT based streamline map and a psycho-acoustically fitted (behavioural) map. One recipient has no measurable ECAPs on half of the electrode array and can not be programmed with a streamline map. Speech intelligibility thresholds of Freiburg number test as well as Freiburger monosyllable test scores at 60, 70 and 80 dB are statistically indistinguishable for behavioural and streamline maps. The same result holds for adaptively estimated speech intelligibility thresholds of Oldenburg sentences in 65 dB noise. On the other hand the recipients subjectively prefer behavioural maps significantly. Thus, the partly automated creation of maps was successfully implemented exhibiting the same results as with behavioural maps. But psycho-acoustical fitting is still necessary since these behavioural maps are much more preferred by the recipients.