Evaluation of simplified programs using the MED-EL C40+ cochlear implant

Abstract

Abstract

The present study evaluated the benefit possible from a cochlear implant (CI) using a simplified map (with a set of default parameters), rather than the conventional approach of producing a ‘customized map’ from electrode-specific psychophysical measures. Young children are sometimes initially provided with such maps and the aim was to gain an insight into what level of benefit they might provide. Maps with upper stimulation levels set equally across the array (i.e. ‘flat’ maps) were compared with normal ‘customized’ maps in established adult users of the MED-EL C40+ device. Speech discrimination was significantly poorer for the flat maps overall (mean of 72.7% for customized map, and 60.5% for flat map) and loudness balance estimates showed a range of degrees of imbalance. These results suggest that flat maps may provide paediatric CI users with useful levels of performance when psychophysical or objective measures cannot be obtained. The poorer performance with the flat map suggests that customized maps should be fit as soon as possible to provide paediatric patients with the maximum benefit of the CI device.

Sumario

El presente estudio evaluó el posible beneficio de un implante coclear (IC) usando un mapa simplificado (con un set preestablecido de parámetros), en vez del enfoque convencional para hacer “mapas a la medida” a partir de mediciones electrofisiológicas específicas. Los niños pequeños reciben a veces inicialmente este tipo de mapas con el objetivo de ganar conciencia sobre el nivel de beneficio que pueden proveer. Los mapas con niveles de estimulación elevados, similares en todos sus puntos (p. Ej. mapas “planos”) se compararon con mapas normales “a la medida” de usuarios adultos del MED-EL 40. La discriminación del lenguaje fue de manera global significativamente más pobre con los mapas planos (media de 72.7% con mapas a la medida y 60.5% con mapas planos) y la estimación del balance de intensidad subjetiva mostró rangos de niveles no balanceados. Estos resultados sugieren que los mapas planos pueden dar a niños usuarios de IC, niveles útiles de rendimiento cuando no pueden obtenerse mediciones psicofísicas u objetivas. El rendimiento más pobre con mapas planos sugiere que los mapas a la medida deben adaptarse apenas sea posible, para que los niños tengan el máximo beneficio de su IC.

Key Words::

• Cochlear implant
• Speech processor fitting
• Electrode balancing

Acknowledgements

I would like to thank the following for providing fitting data on their C40+ users:

Deborah Mawman (Manchester Royal Infirmary, UK), Salim Khan (Bradford Royal Infirmary, UK), Dawn Webster (Southmeads Hospital, Bristol UK), Jonathan Joseph (Princess of Wales Hospital, Bridgend, UK), Tim Board (University Hospital of Wales, UK), and Chris Durst (MED-EL UK). I would also like to thank Professor Colette McKay (University of Manchester, UK) and Professor Blake Wilson (Duke University Medical Center) for constructive comments on an early version of this report.

The data contained in this report were presented at the Conference on Implantable Auditory Prostheses, Asilomar, California (July 2005) and at the British Academy of Audiology Annual Conference, Torquay, UK (November 2006A declaration of interest statement is required. Please add a statement directly in front of the References section.).

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.