Singing in the key of life: A study on effects of musical ear training after cochlear implantation.

Abstract

This study investigated the effect of a 6-month one-to-one musical ear-training program on the perception of music, speech, and emotional prosody of deaf patients receiving a cochlear implant (CI). Eighteen patients who recently underwent cochlear implantation were assigned to either a musical ear-training group or a control group. The participants in the music group significantly improved in their overall music perception compared with the control group. In particular, their discrimination of timbre, melodic contour, and rhythm improved. Both groups significantly improved in their speech perception; thus, this effect cannot be specifically ascribed to music training. In contrast to the control group, the music group showed an earlier onset of progress in recognition of emotional prosody, whereas end-point performances were comparable. All participants completed the program and showed great enthusiasm for the musical ear training, particularly singing-related activities. If implemented as part of aural/oral rehabilitation therapy, the proposed musical ear-training program could form a valuable complementary method of auditory rehabilitation, and, in the long term, contribute to an improved general quality of life in CI users.Keywords: cochlear implants, music perception, music enjoyment, music training, music testingSupplemental materials: http://dx.doi.org/10.1037/a0031140.suppA cochlear implant (CI) is a neural prosthesis that helps deaf people to hear. The implant operates by an external signal processor, which breaks up sound into different frequencies, converts these into electrical signals, and transmits them to an internal receiver through a radio-frequency link. The receiver passes the stimuli onto an implanted electrode array, which stimulates remaining auditory nerve fibers in the cochlea (Loizou, 1999). The auditory nerve is hereby activated, allowing sound signals to reach the brain's auditory system. The clinical impact of the evolution of CIs has been nothing less than extraordinary. With current implant technology and up-to-date sound-processing strategies, the average CI listener recognizes 80% of sentences and approximately 55% of monosyllabic words, in quiet listening conditions, after 12 months of practice with a unilateral CI; some users even achieve the capability of talking on the phone (Friesen, Shannon, Baskent, & Wang, 2001; Wilson & Dorman, 2007). The variability in implant outcome, however, is large, with duration of hearing loss (HL) and residual hearing as important predictors of the result (Cosetti & Waltzman, 2012; Lee et al., 2007; Summerfield & Marshall, 1995; Waltzman, Fisher, Niparko, & Cohen, 1995). With the considerable improvements made in CI technology with regard to speech perception, it is natural that many existing CI users express hopes of being able to enjoy music. Moreover, because music has played an essential role in many of these patients' cultural and social life before deafness, CI candidates' hope of retrieving music enjoyment is an important reason for choosing this treatment (Gfeller et al., 2000).For the majority of CI users, however, the music experience is disappointing. Surveys have shown that a majority of adult CI recipients' self-reported levels of music listening and enjoyment are significantly lower after than before implantation (Gfeller et al., 2000; Lassaletta et al., 2007; Looi & She, 2010; Mirza, Douglas, Lindsey, Hildreth, & Hawthorne, 2003). This reduced music appreciation is due to a general difficulty with perceiving complex acoustic stimuli, which also includes speech perception in conditions involving background noise or competing talkers. Be- cause of the limited number of available electrodes and the mis- match between the pulse-rate of the electrical impulses and the sound input frequency coupled with the dominance of temporal processing for low-frequency sound, the CI signal is unable to adequately code the spectrum of sound needed to perceive musical pitch and timbre. …