Comparisons of the pitch perception abilities of adults and children using cochlear implants or hearing aids Valerie Looi 1,2 1
Department of Communication Disorders, The University of Canterbury, Christchurch, New Zealand, 2Sydney Cochlear Implant Centre, Sydney, Australia Keywords: Cochlear implant, Paediatric, Hearing aids, Pitch perception, Music, Pitch ranking
Introduction
Materials and methods
This paper compares the pitch perception abilities of adults to children fitted with a cochlear implant (CI) or a hearing aid (HA). It is well reported that adult CI recipients score significantly lower than normally hearing (NH) listeners on pitch-based tasks (Looi et al., 2012; McDermott, 2004). However, there is a paucity of research for children or for HA users. Results from adults cannot be directly translated to children as pre-lingually deafened children: (i) have no NH exposure to music and pitch information so they do not have a NH auditory memory; (ii) lack of exposure to high-resolution pitch cues, potentially impeding the development of pitch-related central auditory processing skills; (iii) are often implanted at a young age when cortical plasticity is high, potentially enabling them to adapt differently to electric stimulation; and (iv) have greater neuroplasticity. In addition, most of the existing research compares CI users to NH. The question must be asked as to whether this is appropriate given that CI users have significant sensorineural hearing loss, which has been shown to affect auditory filter bandwidths and the perception of pitch (Moore, 1995). Looi et al. (2008a) compared adult CI users to HA users who met CI criteria (i.e. severe-to-profound hearing loss) and found that although CI users had poorer results compared to HA users, the HA users were significantly worse than NH listeners. For example, HA users scored 75% in ranking three-semitone intervals, a task which NH listeners typically score 100%. Hence, this study aimed to compare the pitchranking skills of adults and children with CIs and/or HAs.
Four existing studies have utilized the same pitchranking task: (i) Looi et al. (2008a) compared 15 adult unilateral CI recipients to 15 adult HA users; (ii) Looi et al. (2008b) compared nine adults pre-topost implant (i.e. HA pre-surgery, then unilateral CI at 3 months post-mapping); (iii) Looi and King (2012) comparing 18 adult unilateral CI recipients to 13 adult HA users; and (iv) Looi and Radford (2010) involving seven unilaterally implanted children, eight children using bimodal stimulation (BMS), and six children with bilateral HAs. In all the four studies, participants undertook a two-alternative forced-choice (2AFC) pitch-ranking task, one-, half-, and a quarter-octave apart. Each test item consisted of two different sung /a/ vowels at the required pitch interval. The fundamental frequencies of the stimuli are given in Table 1. Each note had a linear rise/decay ramp of 30 ms, with the two notes being presented sequentially, ascending or descending, separated by 500 ms of silence. Each pitch pair was presented eight times – four ascending and four descending. The loudness levels were randomized, and the participants were required to state which of the two notes in each pair was higher in pitch, ignoring any difference in the loudness of the notes. Stimuli were presented at comfortable loudness levels, and the participants used their preferred listening programme for testing. The one-octave and halfoctave subtests provided scores out of 96, while the quarter-octave subtest was out of 128. With a 2AFC response format, the chance score was 50%. Participant demographics are presented in Table 2 (adult) and Table 3 (children). All CI participants used Cochlear Ltd Nucleus devices with the ACE or SPEAK speech processing strategy, and all HAs were digital behind-the-ear devices. All of the adults had >6 months experience with their device, and all paediatric participants had >12 months experience
Correspondence to: Valerie Looi, Sydney Cochlear Implant Centre, Macquarie University, Australian Hearing Hub, Ground Level, 16 University Avenue, Sydney, NSW 2109, Australia. Email: [email protected]
S14
© W. S. Maney & Son Ltd 2014 DOI 10.1179/1467010014Z.000000000186
Cochlear Implants International
2014
VOL.
15
NO.
S1
Looi
Pitch perception abilities of adults and children using CIs or HAs
Table 1 Fundamental frequencies of pitches incorporated into the pitch-ranking test Interval size One-octave Half-octave Quarteroctave
Fundamental frequency of pitches comprising each interval C4-C5 (262–523 Hz); D#4-D#5 (311–622 Hz); F#4-F#5 (370–740 Hz) C4-F#4 (262–370 Hz); F#4-C5 (370–523 Hz); C5-F#5 (523–740 Hz) C4-D#4 (262–311 Hz); D#4-F#4 (311–370 Hz); F#4-A4 (370–440 Hz); A4-C5 (440 523 Hz)
Table 3 Pre-lingually deafened children participant details
Group
Age (years)
n
Age implanted (years) M (SD)
CI
11–14 (M = 13) 10–15 (M = 12) 6–13 (M = 9)
7
5.3 (±2.3)
125 (±0)
6
(N/A)
66 (±15.9)
8
5.4 (±2.8)
88 (±12.7)
HA BMS
Better ear PTA (dB HL) M
Table 2 Post-lingually deafened adult participant details
Group CI
HA
Looi et al. (2008a)
Looi et al. (2008b)
Looi and King (2012)
n = 15; age: 36–75 years (M = 60.4) n = 15; age: 49–80 years (M = 64.7)
n = 9; age: 41–71 years (M = 54.3)
n = 18; age: 35–83 years (M = 60.2) n = 13; age: 48–84 years (M = 63.9)
with their devices(s). All the participants spoke English as their first language and did not have any concomitant impairments.
Results The percentage-correct scores for each participant group and each pitch subtest appear in Table 4. Fig. 1 is a comparison of the CI and HA data for both adults and children, excluding the BMS children. A two-way repeated-measure analysis of variance showed significant main effects for both group and
Figure 1 Comparison of pitch-ranking scores for adults and children with CI or HAs.
subtest (P ≤ 0.001), with no significant interaction. Post hoc analyses with Bonferroni corrections revealed that the CI children and the HA children performed significantly better than the CI adults (P = 0.021 and P < 0.001, respectively), and that the HA adults were significantly better than the BMS children (P = 0.046) and the CI adults (P < 0.001). There were no significant differences between the HA adults and HA children, the CI children and BMS children, nor the CI or BMS children and the HA children. As expected, the post hoc analyses also showed that the one-octave scores were significantly better than the half-octave scores, and similarly that the half-octave scores were significantly better than the quarteroctave scores (P < 0.001 for all comparisons).
Discussion and conclusions Overall, the children with CIs were better than the adults with CIs at pitch ranking. Various explanations may be proffered to account for this. Children learnt to hear with the implant and therefore learnt to use the pitch cues available to them with the implant; they do not have a NH ‘memory’ for sound, nor a NH acoustic template for musical stimuli. Children also have greater cortical plasticity than adults, and many of the children in the Looi and Radford (2010) study would have been implanted during the ‘critical period’ for learning. Furthermore, studies have shown that the spiral ganglion neuron (SGN) distribution varies between pre-lingually deafened children
Table 4 Percent-correct scores for the pitch-ranking test Adults (percent-correct) Looi et al. (2008a) Interval size One-octave Half-octave Quarteroctave
Children (percent-correct)
Looi et al. (2008b)
Looi and King (2012)
CI (n = 15)
HA (n = 15)
CI (n = 9)
HA (n = 9)
CI (n = 18)
HA (n = 13)
CI (n = 5–7)*
BMS (n = 7–8)*
HA (n = 6)
68 64 52
90 84 75
74 72 55
83 72 55
DNT 71 54
DNT 91 83
83 76 68
79 73 62
94 88 79
Looi and Radford (2010)
DNT, did not test. *Two CI and one BMS child(ren) were not tested on the quarter-octave test due to extraneous factors.
Cochlear Implants International
2014
VOL.
15
NO.
S1
S15
Looi
Pitch perception abilities of adults and children using CIs or HAs
and post-lingually deafened adults. Histological studies of adult temporal bones show progressive decreases in the size of the SGN population in the basal region of the cochlea (Nadol and Eddington, 2006; Zimmermann et al., 1995). In contrast, patterns of SGN loss in children are more uniform, and the size of SGN population is stable in the first 10 years of life (Miura et al., 2002). A larger, more evenly distributed SGN population may allow paediatric recipients to better discriminate changes in electrode activation along the array (i.e. use place-pitch cues), improving pitch-ranking abilities. The analysis also showed that adults with HAs were better than those with CIs, at least in part attributable to acoustic hearing providing more reliable pitch cues, more temporal fine structure information, less spectral smearing, no current spread, and better frequency resolution than electric hearing (Looi et al., 2012; McDermott, 2004). Interestingly, there were no differences between the CI, bimodal, and HA children’s pitch perception results, probably due to the small ‘n’ in conjunction with the large variability. The lack of difference between the CI and bimodal children is different to the findings for adults, where research has shown that residual hearing provides significant benefit for music (Gfeller et al., 2006). One possible explanation is that unlike post-lingually deafened adults who would have had extensive HA experience prior to implantation, children with CIs would not have had the same HA experience. They would not have learnt to hear with the HA and acoustic hearing, and hence may not be able to use (and/or interpret) the acoustic information as effectively as adults. Further research on the role acoustic hearing plays in pitch perception for pre-lingually deafened children is required. Two other interesting findings observed from this comparison of studies were that, firstly, for the adult recipients, there has been no significant improvement in pitch perception scores between the 2008a and 2012 studies, despite newer technology. Pitch-ranking scores for the quarter-octave stimuli were at chance
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for all three adult studies. Secondly, it should also be noted that the results from HA users (adult or paediatric) were not as good as NH results; NH individuals score at or near 100% for pitch-ranking quarteroctave intervals (Looi et al., 2008a; Sucher and McDermott, 2007). Hence, one should question whether comparing CI users to NH listeners for music perception is realistic. This is an important consideration for counselling recipients and/or their families, as well as for future research topics. In summary, the comparison of adults and children showed that, for these studies, children (both CI recipients and HA users) were significantly better than adult recipients at pitch ranking, and that adult HA users were significantly better than adult CI users.
References Gfeller K.E., Olszewski C., Turner C., Gantz B., Oleson J. 2006. Music perception with cochlear implants and residual hearing. Audiogy & Neuro-otology, 11(Suppl. 1): 12–15. Looi V., Gfeller K., Driscoll G. 2012. Music appreciation and training for cochlear implant recipients: a review. Seminars in Hearing, 33(4): 307–334. Looi V., McDermott H., McKay C., Hickson L. 2008a. Music perception of cochlear implant users compared with that of hearing aid users. Ear and Hearing, 29(3): 421–434. Looi V., McDermott H., McKay C., Hickson L. 2008b. The effect of cochlear implantation on music perception by adults with usable pre-operative acoustic hearing. International Journal of Audiology, 47(5): 257–268. Looi V., Radford C.J. 2010. A comparison of the speech recognition and pitch ranking abilities of children using a unilateral cochlear implant, bimodal stimulation or bilateral hearing aids. International Journal of Pediatric Otorhinolaryngology, 74: 472–482. McDermott H.J. 2004. Music perception with cochlear implants: a review. Trends in Amplification, 8(2): 49–82. Miura M., Sando I., Hirsch B.E., Orita Y. 2002. Analysis of spiral ganglion cell populations in children with normal and pathological ears. Annals of Otology, Rhinology & Laryngology, 111(12 Pt 1): 1059–1065. Moore B.C.J. 1995. Perceptual consequences of cochlear damage. Oxford: Oxford University Press. Nadol J., Eddington D. 2006. Histopathology of the inner ear relevant to cochlear implantation. Advances in Otorhinolaryngology, 64: 31–49. Sucher C.M., McDermott H.J. 2007. Pitch ranking of complex tones by normally hearing subjects and cochlear implant users. Hearing Research, 230(1–2): 80–87. Zimmermann C.E., Burgess B.J., Nadol J.B., Jr 1995. Patterns of degeneration in the human cochlear nerve. Hearing Research, 90(1–2): 192–201.
Department of Communication Disorders, The University of Canterbury, Christchurch, New Zealand, 2Sydney Cochlear Implant Centre, Sydney, Australia Keywords: Cochlear implant, Paediatric, Hearing aids, Pitch perception, Music, Pitch ranking
Introduction
Materials and methods
This paper compares the pitch perception abilities of adults to children fitted with a cochlear implant (CI) or a hearing aid (HA). It is well reported that adult CI recipients score significantly lower than normally hearing (NH) listeners on pitch-based tasks (Looi et al., 2012; McDermott, 2004). However, there is a paucity of research for children or for HA users. Results from adults cannot be directly translated to children as pre-lingually deafened children: (i) have no NH exposure to music and pitch information so they do not have a NH auditory memory; (ii) lack of exposure to high-resolution pitch cues, potentially impeding the development of pitch-related central auditory processing skills; (iii) are often implanted at a young age when cortical plasticity is high, potentially enabling them to adapt differently to electric stimulation; and (iv) have greater neuroplasticity. In addition, most of the existing research compares CI users to NH. The question must be asked as to whether this is appropriate given that CI users have significant sensorineural hearing loss, which has been shown to affect auditory filter bandwidths and the perception of pitch (Moore, 1995). Looi et al. (2008a) compared adult CI users to HA users who met CI criteria (i.e. severe-to-profound hearing loss) and found that although CI users had poorer results compared to HA users, the HA users were significantly worse than NH listeners. For example, HA users scored 75% in ranking three-semitone intervals, a task which NH listeners typically score 100%. Hence, this study aimed to compare the pitchranking skills of adults and children with CIs and/or HAs.
Four existing studies have utilized the same pitchranking task: (i) Looi et al. (2008a) compared 15 adult unilateral CI recipients to 15 adult HA users; (ii) Looi et al. (2008b) compared nine adults pre-topost implant (i.e. HA pre-surgery, then unilateral CI at 3 months post-mapping); (iii) Looi and King (2012) comparing 18 adult unilateral CI recipients to 13 adult HA users; and (iv) Looi and Radford (2010) involving seven unilaterally implanted children, eight children using bimodal stimulation (BMS), and six children with bilateral HAs. In all the four studies, participants undertook a two-alternative forced-choice (2AFC) pitch-ranking task, one-, half-, and a quarter-octave apart. Each test item consisted of two different sung /a/ vowels at the required pitch interval. The fundamental frequencies of the stimuli are given in Table 1. Each note had a linear rise/decay ramp of 30 ms, with the two notes being presented sequentially, ascending or descending, separated by 500 ms of silence. Each pitch pair was presented eight times – four ascending and four descending. The loudness levels were randomized, and the participants were required to state which of the two notes in each pair was higher in pitch, ignoring any difference in the loudness of the notes. Stimuli were presented at comfortable loudness levels, and the participants used their preferred listening programme for testing. The one-octave and halfoctave subtests provided scores out of 96, while the quarter-octave subtest was out of 128. With a 2AFC response format, the chance score was 50%. Participant demographics are presented in Table 2 (adult) and Table 3 (children). All CI participants used Cochlear Ltd Nucleus devices with the ACE or SPEAK speech processing strategy, and all HAs were digital behind-the-ear devices. All of the adults had >6 months experience with their device, and all paediatric participants had >12 months experience
Correspondence to: Valerie Looi, Sydney Cochlear Implant Centre, Macquarie University, Australian Hearing Hub, Ground Level, 16 University Avenue, Sydney, NSW 2109, Australia. Email: [email protected]
S14
© W. S. Maney & Son Ltd 2014 DOI 10.1179/1467010014Z.000000000186
Cochlear Implants International
2014
VOL.
15
NO.
S1
Looi
Pitch perception abilities of adults and children using CIs or HAs
Table 1 Fundamental frequencies of pitches incorporated into the pitch-ranking test Interval size One-octave Half-octave Quarteroctave
Fundamental frequency of pitches comprising each interval C4-C5 (262–523 Hz); D#4-D#5 (311–622 Hz); F#4-F#5 (370–740 Hz) C4-F#4 (262–370 Hz); F#4-C5 (370–523 Hz); C5-F#5 (523–740 Hz) C4-D#4 (262–311 Hz); D#4-F#4 (311–370 Hz); F#4-A4 (370–440 Hz); A4-C5 (440 523 Hz)
Table 3 Pre-lingually deafened children participant details
Group
Age (years)
n
Age implanted (years) M (SD)
CI
11–14 (M = 13) 10–15 (M = 12) 6–13 (M = 9)
7
5.3 (±2.3)
125 (±0)
6
(N/A)
66 (±15.9)
8
5.4 (±2.8)
88 (±12.7)
HA BMS
Better ear PTA (dB HL) M
Table 2 Post-lingually deafened adult participant details
Group CI
HA
Looi et al. (2008a)
Looi et al. (2008b)
Looi and King (2012)
n = 15; age: 36–75 years (M = 60.4) n = 15; age: 49–80 years (M = 64.7)
n = 9; age: 41–71 years (M = 54.3)
n = 18; age: 35–83 years (M = 60.2) n = 13; age: 48–84 years (M = 63.9)
with their devices(s). All the participants spoke English as their first language and did not have any concomitant impairments.
Results The percentage-correct scores for each participant group and each pitch subtest appear in Table 4. Fig. 1 is a comparison of the CI and HA data for both adults and children, excluding the BMS children. A two-way repeated-measure analysis of variance showed significant main effects for both group and
Figure 1 Comparison of pitch-ranking scores for adults and children with CI or HAs.
subtest (P ≤ 0.001), with no significant interaction. Post hoc analyses with Bonferroni corrections revealed that the CI children and the HA children performed significantly better than the CI adults (P = 0.021 and P < 0.001, respectively), and that the HA adults were significantly better than the BMS children (P = 0.046) and the CI adults (P < 0.001). There were no significant differences between the HA adults and HA children, the CI children and BMS children, nor the CI or BMS children and the HA children. As expected, the post hoc analyses also showed that the one-octave scores were significantly better than the half-octave scores, and similarly that the half-octave scores were significantly better than the quarteroctave scores (P < 0.001 for all comparisons).
Discussion and conclusions Overall, the children with CIs were better than the adults with CIs at pitch ranking. Various explanations may be proffered to account for this. Children learnt to hear with the implant and therefore learnt to use the pitch cues available to them with the implant; they do not have a NH ‘memory’ for sound, nor a NH acoustic template for musical stimuli. Children also have greater cortical plasticity than adults, and many of the children in the Looi and Radford (2010) study would have been implanted during the ‘critical period’ for learning. Furthermore, studies have shown that the spiral ganglion neuron (SGN) distribution varies between pre-lingually deafened children
Table 4 Percent-correct scores for the pitch-ranking test Adults (percent-correct) Looi et al. (2008a) Interval size One-octave Half-octave Quarteroctave
Children (percent-correct)
Looi et al. (2008b)
Looi and King (2012)
CI (n = 15)
HA (n = 15)
CI (n = 9)
HA (n = 9)
CI (n = 18)
HA (n = 13)
CI (n = 5–7)*
BMS (n = 7–8)*
HA (n = 6)
68 64 52
90 84 75
74 72 55
83 72 55
DNT 71 54
DNT 91 83
83 76 68
79 73 62
94 88 79
Looi and Radford (2010)
DNT, did not test. *Two CI and one BMS child(ren) were not tested on the quarter-octave test due to extraneous factors.
Cochlear Implants International
2014
VOL.
15
NO.
S1
S15
Looi
Pitch perception abilities of adults and children using CIs or HAs
and post-lingually deafened adults. Histological studies of adult temporal bones show progressive decreases in the size of the SGN population in the basal region of the cochlea (Nadol and Eddington, 2006; Zimmermann et al., 1995). In contrast, patterns of SGN loss in children are more uniform, and the size of SGN population is stable in the first 10 years of life (Miura et al., 2002). A larger, more evenly distributed SGN population may allow paediatric recipients to better discriminate changes in electrode activation along the array (i.e. use place-pitch cues), improving pitch-ranking abilities. The analysis also showed that adults with HAs were better than those with CIs, at least in part attributable to acoustic hearing providing more reliable pitch cues, more temporal fine structure information, less spectral smearing, no current spread, and better frequency resolution than electric hearing (Looi et al., 2012; McDermott, 2004). Interestingly, there were no differences between the CI, bimodal, and HA children’s pitch perception results, probably due to the small ‘n’ in conjunction with the large variability. The lack of difference between the CI and bimodal children is different to the findings for adults, where research has shown that residual hearing provides significant benefit for music (Gfeller et al., 2006). One possible explanation is that unlike post-lingually deafened adults who would have had extensive HA experience prior to implantation, children with CIs would not have had the same HA experience. They would not have learnt to hear with the HA and acoustic hearing, and hence may not be able to use (and/or interpret) the acoustic information as effectively as adults. Further research on the role acoustic hearing plays in pitch perception for pre-lingually deafened children is required. Two other interesting findings observed from this comparison of studies were that, firstly, for the adult recipients, there has been no significant improvement in pitch perception scores between the 2008a and 2012 studies, despite newer technology. Pitch-ranking scores for the quarter-octave stimuli were at chance
S16
Cochlear Implants International
2014
VOL.
15
NO.
S1
for all three adult studies. Secondly, it should also be noted that the results from HA users (adult or paediatric) were not as good as NH results; NH individuals score at or near 100% for pitch-ranking quarteroctave intervals (Looi et al., 2008a; Sucher and McDermott, 2007). Hence, one should question whether comparing CI users to NH listeners for music perception is realistic. This is an important consideration for counselling recipients and/or their families, as well as for future research topics. In summary, the comparison of adults and children showed that, for these studies, children (both CI recipients and HA users) were significantly better than adult recipients at pitch ranking, and that adult HA users were significantly better than adult CI users.
References Gfeller K.E., Olszewski C., Turner C., Gantz B., Oleson J. 2006. Music perception with cochlear implants and residual hearing. Audiogy & Neuro-otology, 11(Suppl. 1): 12–15. Looi V., Gfeller K., Driscoll G. 2012. Music appreciation and training for cochlear implant recipients: a review. Seminars in Hearing, 33(4): 307–334. Looi V., McDermott H., McKay C., Hickson L. 2008a. Music perception of cochlear implant users compared with that of hearing aid users. Ear and Hearing, 29(3): 421–434. Looi V., McDermott H., McKay C., Hickson L. 2008b. The effect of cochlear implantation on music perception by adults with usable pre-operative acoustic hearing. International Journal of Audiology, 47(5): 257–268. Looi V., Radford C.J. 2010. A comparison of the speech recognition and pitch ranking abilities of children using a unilateral cochlear implant, bimodal stimulation or bilateral hearing aids. International Journal of Pediatric Otorhinolaryngology, 74: 472–482. McDermott H.J. 2004. Music perception with cochlear implants: a review. Trends in Amplification, 8(2): 49–82. Miura M., Sando I., Hirsch B.E., Orita Y. 2002. Analysis of spiral ganglion cell populations in children with normal and pathological ears. Annals of Otology, Rhinology & Laryngology, 111(12 Pt 1): 1059–1065. Moore B.C.J. 1995. Perceptual consequences of cochlear damage. Oxford: Oxford University Press. Nadol J., Eddington D. 2006. Histopathology of the inner ear relevant to cochlear implantation. Advances in Otorhinolaryngology, 64: 31–49. Sucher C.M., McDermott H.J. 2007. Pitch ranking of complex tones by normally hearing subjects and cochlear implant users. Hearing Research, 230(1–2): 80–87. Zimmermann C.E., Burgess B.J., Nadol J.B., Jr 1995. Patterns of degeneration in the human cochlear nerve. Hearing Research, 90(1–2): 192–201.
