Impaired Perception of Sensory Consonance and Dissonance in Cochlear Implant Users

Hypothesis:

In light of previous research demonstrating poor pitch perception in cochlear implant (CI) users, we hypothesized that the presence of consonant versus dissonant chord accompaniment in real-world musical stimuli would not impact subjective assessment of degree of pleasantness in CI users.Background:

Consonance/dissonance are perceptual features of harmony resulting from pitch relationships between simultaneously presented musical notes. Generally, consonant sounds are perceived as pleasant and dissonant ones as unpleasant. CI users exhibit impairments in pitch perception, making music listening difficult and often unenjoyable. To our knowledge, consonance/dissonance perception has not been studied in the CI population.Methods:

Twelve novel melodies were created for this study. By altering the harmonic structures of the accompanying chords, we created three permutations of varying dissonance for each melody (36 stimuli in all). Ten CI users and 12 NH listeners provided Likert scale ratings from −5 (very unpleasant) to +5 (very pleasant) for each of the stimuli.Results:

A two-way ANOVA showed main effects for Dissonance Level and Subject Type as well as a two-way interaction between the two. Pairwise comparisons indicated that NH stimuli pleasantness ratings decreased with increasing dissonance, whereas CI ratings did not. NH pleasantness ratings were consistently lower than CI ratings.Conclusion:

For CI users, consonant versus dissonant chord accompaniment had no significant impact on whether a melody was considered pleasant or unpleasant. This finding may be partially responsible for the decreased enjoyment of many CI users during music perception and is another manifestation of impaired pitch perception in CI users.