gms | German Medical Science

Introduction: The frequency of occurrence of questions regarding recommendations for mobile phones and accessories to improve sound quality for Cochlear Implant (CI) users increased in the last years. An acute trial was initiated to evaluate sound quality and speech understanding with various connections between the CI system and a mobile phone.

Method: 12 adult Cochlear implant users participated in this study. They used a CII or HiRes90K implant system in combination with the Harmony behind-the-ear sound processor. The subjects had a mean age of 56.0 years, a mean duration of deafness of 9.7 years and a mean age at implant of 52.9 years.

The Freiburger monosyllables speech test was performed via telephone in four conditions: direct connection between CI and telephone via cable, the pinnar microphone TMic, the in-built microphone as well as a bluetooth headset in combination with the TMic. In a questionnaire the general use of the telephone in everyday life was assessed. After the tests the subjects were asked for their preference for one of the four conditions.

Results: The Freiburger monosyllables test [1] showed similar results for the in-built microphone (57.3%), the TMic (56.9%) and the bluetooth headset (58.8%), but significantly poorer speech perception for the direct connection via cable (37.1%). Six of the subjects rated the TMic as their favorite solution, because of good sound quality, subjectively good speech understanding and convenience. Three subjects scored best for the built-in mic or the bluetooth headset, respectively.

Summary: The cable connection between CI and telephone complicated the handling and subjects reported poor sound quality. The other three configurations showed better results and seemed to be more comfortable to use. Both, objective and subjective results, led to the recommendation to use the regularly used microphone in combination with a mobile phone. A bluetooth headset is a good solution e.g. in a car when a hands-free set is required.