gms | German Medical Science

26. Wissenschaftliche Jahrestagung der Deutschen Gesellschaft für Phoniatrie und Pädaudiologie e. V.

Deutsche Gesellschaft für Phoniatrie und Pädaudiologie e. V.

11.09. - 13.09.2009, Leipzig

Evaluation of music perception in adult users of HiRes® 120 and previous generations of Advanced Bionics® sound coding strategies

Evaluierung der Musikwahrnehmung von Erwachsenen mit HiRes® 120 und früheren Generationen der Sprachverarbeitungsstrategien von Advanced Bionics®

Vortrag

Deutsche Gesellschaft für Phoniatrie und Pädaudiologie. 26. Wissenschaftliche Jahrestagung der Deutschen Gesellschaft für Phoniatrie und Pädaudiologie (DGPP). Leipzig, 11.-13.09.2009. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc09dgppV11

DOI: 10.3205/09dgpp17, URN: urn:nbn:de:0183-09dgpp171

Published: September 7, 2009

© 2009 Gazibegovic et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Zusammenfassung

Im Jahr 2007 hat Advanced Bionics® die neuartige Sprachverarbeitungsstrategie HiRes® 120 eingeführt. Erste klinische Ergebnisse mit HiRes 120 deuten auf ein verbessertes Sprachverstehen in Umgebungen mit Störgeräusch sowie eine verbesserte Musikqualität und -natürlichkeit hin.

Ziel der Evaluierung ist es, zu untersuchen, ob es unterschiede in der Musikwahrnehmung, Hörhäufigkeit und der Fähigkeit zum Unterscheiden bestimmter musikalischen Merkmale zwischen drei verschiedenen Generationen der Sprachverarbeitungsstrategien von Advanced Bionics gibt.

Die Evaluierung wird basierend auf einem Fragebogen als Umfrage durchgeführt. Dabei sind 43 Fragen zu verschiedenen Bereichen zu beantworten. Einer der Bereiche befasst sich mit der Fähigkeit des Teilnehmers bzw. der Teilnehmerin, die melodische und harmonische Struktur von Musik zu verfolgen und ihre emotionale Stimmung zu erfassen.

Eine Gruppe von 25 normal hörenden Erwachsenen hat an der Pilot-Phase als Kontrollgruppe teilgenommen.

Die Teilnehmer hatten keine größeren Schwierigkeiten bestimmte Aspekte von Musik herauszuhören, bis auf einige wenige Fragen wie („Wie viele Instrumente Spielen gleichzeitig“ oder „Text verstehen bei neuen Liedern“). Somit scheint die Evaluierung ein passender Weg zu sein, um größere Datensätze innerhalb kürzerer Zeitspanne zu erheben. Des Weiteren sollen die Ergebnisse helfen zu verstehen, inwiefern neuere Entwicklungen im Bereich der Sprachverarbeitung zur verbesserten Musikwahrnehmung führen.


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Overview

Research on music perception has shown that cochlear implant (CI) users can easily follow basic rhythms of up to

160 beats per minute (bpm), while the differentiation of rhythmical patterns appears to be more challenging. Moderate results are obtained in instrument identification or timbre tasks. Most difficult tasks are the differentiation of pitch without rhythmical cues and the perception of harmonic content of music. However, in all tasks there is a large variability in results between subjects’ scores, which implies that additional factors such as duration of deafness, age at implantation and duration of implant use may also play an important role [1], [2], [3]. There is still little evidence on the relationship between sound coding strategies and music perception. Nevertheless, recent research indicates that increased temporal and spectral resolution may improve pitch discrimination, melody and harmony recognition, timbre perception and music quality overall [1], [4], [5], [6].

In 2007 Advanced Bionics® launched the novel sound coding strategy HiRes® 120. The strategy incorporates the concept of current steering and offers up to 120 stimulation sites using only 16 electrode contacts [5]. Based on the well evaluated HiRes platform, which still sets standards in the cochlear implant industry with respect to the temporal resolution, HiRes 120 further improves the representation of the sound spectrum.

Early clinical results with HiRes 120 are showing improved speech understanding in noisy environments and improved quality and naturalness of speech [6]. Subjective spontaneous feedback indicates that music sounds more natural with HiRes 120.

Objectives

The objective of the evaluation is to investigate if there is a difference in music perception, listening frequency, enjoyment and ability to differentiate special musical features, between the three main groups of subjects using different generations of Advanced Bionics’ sound coding strategies:

  • CIS / MPS / SAS (conventional strategies)
  • HiRes
  • HiRes 120.

Methods

The evaluation is based on a questionnaire. A set of 43 questions is divided into different sections:

  • Subject’s profile
  • Past experience with music
  • Present experience with music
  • Experience with special musical features.

Individual sections will allow collection of information on aetiology, equipment used for listening to music, sound coding strategy, frequency of listening to music, musical activity, and enjoyment of music before deafness and after implantation. The last section assesses the subject’s ability to follow melodic and harmonic structure of music and also investigates the impact of music on emotions.

Subjects using any generation of Advanced Bionics’ implants and sound processing, who are older than 16 years and have a minimum experience of six months with their current sound processing strategy may be involved in the evaluation.

Results

A control group of 26 normal hearing subjects was assessed with the questionnaire. The evaluation is being performed as a European multicentre project and preliminary results at this early stage are available for 21 subjects implanted with a Advanced Bionics cochlear implant.

  • 1 C1 user with SAS strategy (not included in the present analysis)
  • 4 CII or HiRes90K users fitted with HiRes 120 (0.5–2 years experience; age 41–60+ years)
  • 16 CII or HiRes90K users fitted with HiRes (2–5 years experience; age 31–60+ years)

Figure 1 [Fig. 1] illustrates how often subjects listened to and enjoyed music before deafness and after implantation. Both the HiRes 120 and the HiRes groups appear to listen less to music now then before deafness but have equal level of enjoyment. As expected the normal hearing group is listening more often and is also enjoying music more than any of the CI groups.

Recognizing the musical style of a music heard for the first time is less challenging to the users of the latest technology (HiRes 120), who are performing closer to normal hearing listeners than the users of HiRes (Figure 2 [Fig. 2]). The difference between the two CI subject groups in identifying if there is a singer in a piece of music heard for the first time is relatively small but the HiRes120 group appear to be able recognizing singer’s gender more easier then the HiRes group when hearing a song for the first time.

Further data shows that HiRes 120 users are outperforming the HiRes users in understanding words in new and known music, identifying a change on scene on TV based on background music and recognizing familiar film music. In many occasions the HiRes120 group is very close to the normal hearing control group in their ability to recognize special musical features.

Normal hearing subjects do quite often decide to listen to music with the purpose of eliciting a certain mood, which is less prominent in the CI users’ group.

Discussion

Although the sample size is relatively small at this stage, it is remarkable to observe that almost all cochlear implantees are listening regularly to music (average listening frequency: 5.3 on the 1 to 10 scale). Both the HiRes and HiRes 120 groups could almost achieve their initial musical habits and enjoyment they had before deafness through their cochlear implant. One should note that the HiRes group is having longer duration of deafness and longer device experience than the HiRes 120 group, which may impact their memory on how music sounded before.

In the section about recognizing special musical features the HiRes 120 group appears to score higher than the HiRes group. Further the HiRes 120 users seem to be more able over the HiRes group recognizing individual instruments, identifying how many instruments are playing together, or recognizing the singer’s gender and understanding lyrics in known as well as new songs. All these tasks are requiring high accuracy in reconstructing the temporal and spectral components of the sound, which explains why the HiRes 120 group outperforms the HiRes group. Larger groups of patients are needed for more funded statistics.

Conclusion

Preliminary results indicate that the evaluation material is suitable measure for identifying musical experience and ability to recognize special musical features in users implanted with Advanced Bionics system. The users of HiRes120 sound processing appear to benefit from the more precise delivery of the spectral content of sound when listening to music.


References

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