Tuesday, October 22, 2013

Building the Musical Muscle: Music in Individuals with Cochlear Implants

Charles Limb: Building the Musical Muscle


In this talk, Dr. Charles Limb talks about cochlear implants, and the problem with these individuals perceiving music. 

The location of the cochlea is where we not only hear, but draw connections between what we hear and our emotional response to those things. Most people with a cochlear implant basically think music sounds bad, and will not listen to it, taking that element of beauty out of their lives. The "perfect" cochlear implant would obviously allow not only for language, but music as well, restoring the full range of hearing. Limb plays a short midi file excerpt of music to show an example of the difference between what an individual with full hearing perceives versus someone with a cochlear implant. Although the example he plays shifts pitches only up to a semi-tone, individuals with cochlear implants actually can perceive the pitches up to two octaves away from what is actually being played. 

Individuals with these cochlear implants not only have major problems perceiving pitch, but also differentiating the timbre of different instruments. Limb shows a slide of brain activity that happens with an individual during language, rhythm, and melody, and there is essentially no activity in the auditory cortex during a melodic example- like it is unrecognizable. Similarly when trying to distinguish between the sound of a trumpet and a violin, it is virtually impossible for an individual with a cochlear implant to do.

Capacity for music remains even when individual has hearing loss or complete deafness. Limb uses the example of Beethoven in this case to exemplify that he still composed music after his deafness, and still needed and wanted music to be a part of his life even when he could no longer hear it, or really perceive his own creations. Limb ultimately suggests that music can still be trained in those individuals with cochlear implants. He shows an example of a cat with the implant in. They have trained the cat to respond to the sound of a trumpet as a sign to get food, and although the cat responds to no other music sounds, it does recognize the sound of the trumpet when playing a melody.

Limb's suggestion that music can be trained in individuals is supported by an example that he shows of one of his deaf students playing piano. The student plays sensitively, and expressively although he cannot fully perceive what he is doing. In showing this, Limb jokes that the student can play piano, but that he knows he has  hearing problem because he has heard the student do karaoke, and it was horrible. 

This talk really emphasizes the importance of music as it relates to beauty and the quality of life. And that although technology has come quite far in this area, it still has further to go in order to restore full hearing to individuals with these implants, instead of only speech. 


I found this talk quite fascinating in several ways. First of all, that the restoration of hearing has already come so far is great, but to be honest having a cochlear implant sounds like a nightmare to me. To not have the ability to hear or perceive music in an enjoyable way would be horrible, and to have no way to remedy that is scary as well.

I was particularly interested by the brain scans that he shows, and the lack of activity exemplified during the sound of melody. Obviously the frequencies of music are much different from that of speech alone, and this is what creates the difficulty in developing a tool that will help to perceive all of these other frequencies in a pleasant way for the individual. Limb states that "there is very little cortical activity (during melody perception) compared to normal hearing control". In this scan, they said that they did each separate: speech, rhythm, melody. Because there was so little activity in the brain during melody, and there was similar activity during both speech and rhythm, it makes me wonder if the individual can perceive rhythm in the melody, or because of their perception of the melody if they cannot. I only wonder this because the scans basically show almost no activity in the brain during music.

Although I don't personally know anyone with a cochlear implant, it does make me interested in understanding what exactly they hear. I liked Limb's idea of "training" music into individuals with these implants, although he does not really give many ideas on how to do this, other than showing a cat who was trained to hear the trumpet. It also made me wonder about the ability to train music into these individuals, but then the difference between doing this with someone who developed hearing loss throughout their life, and someone who was born deaf and then got the implant. Would this change ones perception of the music, or not?

In summary, I think that this is an important area of research, and interesting to see the growth and developments in this area, especially as restoring music as a benefit of the full life experience in an individual with cochlear implants.

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