Day 4 – Recent findings on amusia

As you might expect, dear reader, I have a slight bias towards any conference symposium on congential amusia. I enjoyed all the symposia at M&N IV of course, but there is nothing quite like the engagement you get from hearing speakers you know inside out from years of reading their papers and admiring their work. So I sat near the front row (like a proper geek), pen at the ready and brimming with excitement to hear the latest developments.

WARNING: This blog will be longer than usual – I just can’t help myself!

For those whose lives are not so connected with the topic I should outline first of all that all the speakers in this blog discussed ‘congenital amusia’, a neurodevelopmental disorder that impacts negatively on pitch perception and production. As a gentleman pointed out to me during my poster presentation, we should state more clearly that this is a different condition to acquired amusia, whereby an individual develops music processing difficulties as a result of neural damage (stroke or injury) or degeneration.

1)      Simone Dalla Bella: Memory disorder and vocal performance

Simone began by discussing his studies of vocal performance in amusia. Whereas most people learn to sing in tune, this is in fact a complex behaviour that is underpinned by several brain components which all need to function optimally in order to bring about successful production. There are two ways in which singing can fall down:

• Failure in perception – this is thought to be the primary cause of poor pitch singing in amusia
• Failure in auditory motor mapping – this is a more common cause of poor pitch singing and may be behind all those people who are not amusic but couldn’t carry a tune in a bucket

But what about memory? Simone pointed out that there are now a handful of studies showing memory problems in individuals with amusia (at this point I went my usual scarlet colour upon seeing my name on the screen!) But no one had yet looked at how their memory problems influenced their poor pitch production or the poor production of ‘poor pitch singers’ who do not have amusia.

Simone showed two studies that convincingly demonstrate that singing with lyrics and singing with a model (i.e. imitation of a song) can positively influence performance in both amusics and poor pitch singers as compared to singing on a new syllable (such as ‘ta’) or singing from long-term memory. This opens the possibility for future singing aids that aim to compensate for the influence of poor memory representation of the ability to sing.

2)      Lauren Stewart (AKA ‘the boss’ to me!): Congenital amusia – is there potential for learning?

Lauren presented work she completed this year with one of our masters students, the lovely Sue Anderson. Sue is simply the best singing teacher I have ever seen, and for her masters project on the Music, Mind and Brain course (Goldsmiths) she wanted to see if she could improve the amusics ability to sing. This went in tandem with a challenge from Professor Graham Welch (Institute of Education) who had told us for years that he didn’t believe there was such a thing as amusia and that all these people needed was proper exposure to music to allow them to perform like anyone else.

So Sue embarked on a 7 week singing program with 5 of our amusic individuals. She tested their perception and production abilities before and after the intervention. She based her training on breathing exercises, building vocal strength, improving pitch response to feedback and a number of other tasks.

Before I even knew the results of the study I was impressed, as the feedback from the amusics who took the program was all really positive; they loved it! The results showed a rather mixed bag of changes, with most of the participants making small improvements in their abilities, but on average still remaining in the amusic range for perception. But there were certainly larger gains in confidence, vocal control and also willingness to try to listen to music in the future rather than simply ignore it. All in all, a fascinating study that shows the real potential of a learning experience, beyond that of simple skill gains.

3)      Psyche Loui – Behavioural and neural correlated of normal and disordered singing  

Psyche is well known for her brain imaging work in the field of amusia, and in particular for her findings regarding the disrupted organisation of one particular brain pathway in amusia, the arcuate fasciculus (AF). Today she was presenting some new work looking at the source of musical knowledge and how well we learn when exposed to a completely new musical scale.

She was interested in testing implicit learning, the principle by which we all absorb the knowledge of our own musical system without explicit conscious knowledge. This is how we find it so easy to listen to the music of our own culture (which follows the rules we have internalised) over the music of another culture which can sounds strange and disorganised to our ears.

In order to test this system she did a really clever thing – she invented a new musical grammar! She used a variant of the little known Bohlen-Pierce musical scale which is a 3/1 scale with 13 logarithmic divisions and composed a new finite state grammar. By this method she created a new musical system that she calls the “Martian system” (with one of my favourite cartoon characters as its mascot!)

So how do amusics and controls compare on their ability to learn this new music? Using both behavioural and brain imaging (DTI) studies she showed that controls can learn the structure of the new music quite well after minimal exposure (30mins) whilst amusics did not.  Once again she showed reduced AF volume in the amusics and significant correlations between AF tract volume and learning ability. She concluded by saying that the acquisition of musical structure (i.e. the ability to learn about music) depends on brain structures like the AF, and this may be one reason why the amusics in her study found it difficult to learn implicit rules about a new musical structure.

4)      Isabelle Peretz – Learning speech but not musical sounds in amusia

I can’t help but be a bit in awe of Isabelle. Not least because without her initial work on amusia I would not have a job! But the sheer output of her lab and the scope of her ideas cannot fail to impress (even when you are not directly financially grateful)

During this session she presented the results of studies conducted in collaboration with Jenny Saffran, who is famous for her work on language learning. In particular, she is known for the development of a paradigm that shows our ability to learn transitional probabilities in a continuous stream of sound (with around 21mins exposure). You can expose people to either syllable streams or tone streams and they seem to be able to spot the hidden patterns within them, even in the absence of conscious knowledge. So can amusics do this?

She presented 5 experiments (yes, 5!) where she tested amusics and matched controls, although you got the feeling she had done quite a few more while struggling a little with the paradigm. Her results were as follows:

• Simple tone streams – both groups can learn syllable streams. Nobody learned the tone streams
• Diatonic piano tones – as above, expect this time the controls learned the tone streams
• Reduced number of targets – as above (although it appeared from the graph that half the amusics did learn the tones here)
• Sung sequences (combined) – Much better learning overall, but amusics still worse
• Sung sequence without amusics – Everybody learns well

Overall, the amusics seem to learn the language stimuli as well as the controls but they are much poorer with the tone stimuli. She argues that this result illustrates how lack of musical exposure cannot explain amusia, although it must be said that she is working with an already compromised system in adult amusics – it is not clear how children with amusia would perform in similar circumstances. But Isabelle is soon to publish the first case of amusia in children (a very good paper that I was lucky enough to review) which will hopefully bring forward new tests that will enlighten the role of development and exposure in congenital amusia.

In the meantime I’m off back to my lab to chat to the people who really matter, those with amusia, about these findings and see what they think. I’m really looking forward to seeing them again in the lab over the summer and to exploring their music abilities together. What a super bunch of people they are to work with – I’m a jolly lucky psychologist!