Music and Language Conference: Musical Ear Training for Cochlear Implant Users

Last week I was lucky enough to travel to Aarhus in Denmark to attend the ‘Music and Language in the Brain’ conference, which was held at the Royal Academy of Music. For the next few blogs I intend to present summaries of some of the conference presentations including work by Professors Robert Zatorre and Stefan Koelsch; so I hope there is plenty for you to look forward to, dear reader.

But my first blog on the conference is reserved for a very special person, my kind host and friend Dr Bjørn Peterson. Bjørn is an associate professor at the Royal Academy and, I am lead to believe by his colleagues, is one of the most popular music teachers within the school. He has also recently completed his PhD thesis where he examined advances in music and speech perception after cochlear implantation (CI).

Bjørn, his wife Jytte, and his family, showed both me and my colleague Diana Omigie incredible hospitality when we were in Aarhus, for which we are both very grateful. Leaving aside mine and Bjørn’s most enjoyable chats about a shared love of Marx Brothers films, I was fascinated by the topic of his PhD. Bjørn has developed an ear training program in order to help develop musical and linguistic performance in adult CI-users. What follows is a summary of his work. If you want to contact him to discuss his findings and to obtain further details I know he would be very happy to hear from you. He can be reached at:  bjorn-at-pet.auh.dk.

According to Bjørn’s thesis there are now over 1500 CI-users in Denmark. In general, CIs are probably the most successful neural prosthesis with over 120,000 users worldwide.  CI works by mimicking the function of a normal cochlea, taking advantage of its tonotopic organisation. The device bypasses the outer ear, middle ear and hair cells of the cochlear in order to electrically stimulate the surviving auditory neurons directly. The CI has up to 22 channels, each representing a different frequency channel, which can transmit information about the auditory environment to the brain. 

The impact of CI on speech perception can be nothing short of miraculous – the average CI-user using the most up-to-date technology can recognise up to 90% of sentences and 55% of monosyllabic words in quiet conditions after 12 months of practice.  Speech perception in noise remains challenging

How about music? Perception of music is unfortunately often reported to be poor among CI-users, even though music listening is often a major reason for opting for the treatment in the first place. However, some CI-users report gaining more enjoyment from music listening over time, a finding which suggests that there may be training effects taking place.  

Bjørn reasoned that a program of music listening exercises may help to boost this ‘natural training effect’ and bring about advances in CI-users perception of music in a shorter period of time. There were also reasons to suspect that if such a program was successful with music then it may have positive transfer effects to the perception of speech.

In his study Bjørn tested 18 CI-users with a variety of hearing loss experiences, linguistic experience and musical training backgrounds. The participants took part in either 1 hour weekly music or no-music ear training for 6 months. It is a tribute to the participants but also to Bjørn’s kindness and teaching skills that such a program was brought to completion with not a single participant drop out.

The music ear training program aimed to provide active and passive experiences with 1) pitch, 2) rhythm, and 3) timbre. Pitch training consisted of singing, playing and listening exercises and was aimed at developing attributes such as high/low, up/down, and far/close. The rhythm training used drumming, energizing, and listening exercises to develop concepts of pulse/meter, beat/subdivision, fast/slow, and weak/strong. Finally, the timbre exercises aimed at improving the distinction between light/dark, attack/decay, and hard/soft in the quality of the tone of different instruments.

After 3 and 6 months the participants were re-tested on a number of musical and linguistic paradigms, including the identification of melodic contour, instrument identification, recognition of pitch and rhythm violation in novel melodies, and recognition of emotional prosody. They also completed the Hagerman speech perception test (HAG).

The overall music gain scores of the group who had received the 6 months of music training were significantly higher than the control group.

Both groups showed improvements in their emotional prosody perception, although the trend was towards larger gains for the music training group which were achieved at a faster rate. There were also significant relationships between the participants HAG scores and overall music scores, at all testing points (0, 3 and 6 months).

While the no-music group also showed gains in their perception ability (as you might expect over time) the significant group difference stood for tests of timbre and pitch. However, no significant effect of music training was found on the speech perception task (HAG).

So one-to-one training and active music making efforts may have great potential as a motivating and efficient method to improve overall music perception in CI-users, and may also influence ability to follow the more music-like aspects of speech which can be essential to effective comprehension, such as emotional prosody. At the moment Bjørn is looking into quality of life scores obtained from his participants, but he writes in his thesis that:

“…the proposed musical ear training program could form a valuable complementary method of auditory rehabilitation, and, on the long term, contribute to an improved general quality of life in CI-users” (p.11)

I couldn’t agree more. I wish him all the luck with his work and look forward to hearing about his future studies.