Cochlear implants (CIs) have allowed users to understand speech and interact with the auditory world. However, CI recipients still have difficulty perceiving nonspeech sounds, especially music. Music appreciation is important to evaluate in CI users because of its association with quality of life, personal expression, and social connectedness.
Cochlear implant recipients have difficulty recognizing musical melodies, identifying instrument sounds, and differentiating pitch. However, perceptual accuracy is not the only important aspect in music listening. The way music sounds as a whole through the cochlear implant has clinical relevance, as it relates to the user's ability to appreciate and enjoy music in everyday life.
While one might anticipate a direct link between cochlear implant recipients’ ability to perceive music accurately and their degree of music appreciation, the early literature has not supported this idea. In fact, some studies suggest exactly the opposite—that there is little to no relationship between music perception and appraisal in CI users ( J Am Acad Audiol 2012;23:350-365 http://aaa.publisher.ingentaconnect.com/content/aaa/jaaa/2012/00000023/00000005/art00006). However, these previous results were obtained from small cohorts of cochlear implant recipients in controlled laboratory settings, with tests that require significant time to administer, limiting their applicability in clinical settings.
In a new study, Ward R. Drennan, PhD, and colleagues evaluated the correlation between music perception and appraisal among a large cohort of CI users in clinical settings. The authors used shorter music tests to determine if these assessments could be administered in the clinic and whether findings would be consistent with previous results from smaller sample sizes.
Clinical Evaluation of Music Perception, Appraisal, and Experience in Cochlear Implant Users
Drennan WR, Oleson JJ, Gfeller K, et al
Int J Audiol
Sept. 1, 2014; e-pub ahead of print http://informahealthcare.com/doi/abs/10.3109/14992027.2014.948219
The Clinical Assessment of Music Perception (CAMP) test is commonly used in some laboratories to study CI users’ music perception ( Otol Neurotol 2008;29:149-155 http://journals.lww.com/otology-neurotology/Abstract/2008/02000/Clinical_Assessment_of_Music_Perception_in.10.aspx; Ear Hear 2009;30:411-418 http://journals.lww.com/ear-hearing/Abstract/2009/08000/Development_and_Validation_of_the_University_of.4.aspx).
The CAMP includes three separate perception tests, each designed to evaluate a different element of music perception ability: pitch direction discrimination, familiar melody recognition, and timbre recognition. Since these three elements are relevant to music listening and enjoyment, Dr. Drennan et al used the CAMP test to study music perception.
To assess music appraisal, the researchers used the Iowa Musical Background Questionnaire (IMBQ). In the IMBQ, CI recipients described the quality of music heard through their cochlear implant by rating six bipolar adjectives on a scale of zero to 10: clear versus fuzzy, easy to follow versus difficult to follow, like versus dislike, sounds unlike music versus sounds like music, unnatural versus natural, and unpleasant versus pleasant. Prior research identified these comparisons as relevant to music listening.
The CAMP test and IMBQ were administered to 145 CI listeners across 14 clinical sites in the United States and Canada. It took 30 minutes to 35 minutes to administer the CAMP test, and another 15 minutes to 25 minutes to complete the IMBQ. These time frames are reasonable for administration in the clinic—a major advantage in terms of practical feasibility, the authors noted.
WEAK RELATIONSHIP REPORTED
In their group of cochlear implant users from several clinical settings, Dr. Drennan and colleagues found weak relationships between CAMP results and IMBQ musical sound quality scores. There was a statistically significant but slight correlation between the CAMP's timbre test component and music appraisal, suggesting a relatively weak association between the two. All other relationships were deemed insignificant.
This lack of a strong association, which is consistent with the findings of previous studies ( J Am Acad Audiol 2012;23:350-365 http://aaa.publisher.ingentaconnect.com/content/aaa/jaaa/2012/00000023/00000005/art00006; J Am Acad Audiol 2008;19:120-134 http://aaa.publisher.ingentaconnect.com/content/aaa/jaaa/2008/00000019/00000002/art00003) means that in order to fully evaluate CI music functionality, it is not sufficient to test either music perception or music appraisal alone. Both measures need to be evaluated, as sufficiency or deficiency in one aspect does not correlate with the same result in the other aspect.
These results also highlight the limitations of subjective musical sound quality assessment and the possible benefits of objective approaches ( Otol Neurotol 2012;33:319-327 http://journals.lww.com/otology-neurotology/Abstract/2012/04000/Assessment_of_Sound_Quality_Perception_in_Cochlear.7.aspx). In an objective approach, the goal is not to evaluate how pleasant or unpleasant music may sound, or whether the CI user enjoys it. Rather, the goal is to measure the capacity of a cochlear implant user to detect a deterioration of sound quality in response to experimental manipulation of any given sound parameter.
MANY FACTORS AFFECT ENJOYMENT
Dr. Drennan and colleagues noted limitations of their study design. For example, the CAMP was conducted without hearing aids, even if listeners used hearing aids regularly.
While the IMBQ questionnaire asked about music appraisal based on real-world musical listening experiences, the CAMP used simple, controlled sound stimuli to assess basic music perception abilities instead of using real-world stimuli.
To some extent, these study design decisions might have affected CI users’ music test scores. Despite these potential limitations, the authors make a compelling argument that perceptual acuity is not closely related to music appraisal ratings.
In other words, cochlear implant users can have poor perceptual abilities and still feel that music sounds good or is highly enjoyable. Conversely, CI users can perceive various aspects of music well while feeling that music sounds poor or not enjoying what they are able to hear.
The study by Dr. Drennan and colleagues underscores the notion that the musical experience is linked to many factors. Furthermore, these findings suggest that studying individual elements of music in isolation may not accurately reflect the perceptual salience of music when it's presented in its natural form—a composite of a wide range of components.
In this study, the authors demonstrated that there is little to no relationship between music acuity and music appraisal. Both aspects are important clinical outcomes, as one addresses patient functionality and ability (acuity), while the other addresses patient feeling and overall satisfaction with music quality (appraisal).
These findings strongly suggest the need for further research to overcome limitations in cochlear implant users’ ability to perceive music, and to understand the factors that limit enjoyment or satisfaction in music listening.