Sound, science and the medicine of movement: Exploring Bruce Turner's biomechanics PhD

Bruce Turner, the Innovation in Sound MA course leader at dBs Bristol, is currently working on his own innovative study around the 'medicine of movement'. We caught up with him to find out more!

The Innovation in Sound MA at dBs is where our third core value of developing 'sound-based solutions that make the world a better place,' really comes to life. Our students have created a 'neurofeedback art installation', plugins that 'decolonise music' and art projects that highlight the experiences of migrants living overseas.

This principle is not just unique to our students, either. Our staff are often involved in projects that seek to improve the world through technology, social mobility and everything in between. Bruce Turner, programme leader for the Innovation in Sound MA course in Bristol, is currently working on a PhD which seeks to highlight the symbiotic relationship between sound and movement and explore ways that music can help patients with motor dysfunction issues improve their health and well-being. We caught up with Bruce to find out more.

You’re currently working on a PhD on biomechanics and ‘the science and medicine of movement’. Can you tell me what that’s about?

BT: That's a nice way of putting it. Put simply, it’s a study founded on the basis that many people, including myself, are spending more time in front of a computer sitting still. We're not really moving as we naturally would have once done. I’m trying to think about ways in which sound can be used with movement. It's a commonly known thing that we like to move to music, but it's not exploited anywhere near as well as it could be. It's trying to understand precisely how sound influences body movement. That's what the study is.


What first got you interested in this topic and studying it?

BT: It was born out of trying to think about ways of combining things I enjoyed. I studied Tai Chi for a very long time. Very luckily, I met a grandmaster of Tai Chi in the year 2000 - a guy called Dr Shen - and started to explore anatomy in a scientific way. It really captured my imagination and my interest, so I studied that quite deeply for a long time. With music as well, I've been doing that since I was a kid. I started to think, ‘How can I bring these two worlds together?’ That process just so happened to coincide with a conversation I had with this chap who's a family friend who’s a quite high-ranking physiotherapist. He had that channel into the academic world and could see how it would work, so a conversation became more of a collaboration.

What is the purpose of your study?

BT: The purpose of the study is to try and understand the way that we perceive sound and the way that we respond to sound. In order to do this precisely, it's a question of trying to reduce things in a measurable way; a reductionist approach.  In music or in sound, that can be through things like timing or rhythm, sequences, sequentiality and temporality. Then, we can think about things happening at the same time, how we understand our environment and then polyphony or harmony - how things can be understood in relation to each other when they happen at the same time. Then there is understanding the sound source, which we can analyse in terms of tempo, loudness, dynamic range, articulation and timbre, and how we then measure that. There’s also muscle activity and brain activity as some examples of things that can be measured from the stimulation itself; how the body responds to sound. 

3. Reductionism

What kind of things can this measuring and analysis show?

BT: Understanding how pulse influences walking and the perception of time is the beginning of trying to understand this stuff. For example, you can set a pulse to try and measure how the body responds to it. We have a perception, almost like a ruler in our mind, of where things should be. So when beats happen, we can understand that it's early or late or just on time. There are different circuits in the brain that are active at interpreting that. I suppose it's an evolutionary thing, whereby we're trying to understand how events happen in life. You can see that on a survival basis; the ability to perceive when something will happen is important because it might be the difference between staying alive or being knocked over by an elephant or something! It's a very deep and ancient system in our brains. There was a study in 2000 or 2001, whereby the researchers were able to reduce this to understand that our beat perception is incredibly fine. It's subconscious. The study found that we perceive time shifts up to around 5% and it's completely subconscious. The resolution of our timing perception is remarkably well-tuned. 


Wow! That’s fascinating. So how does this then relate to movement and the body?

BT: It’s all linked to the motor system. When we hear something, it travels from the Cochlear Nucleus in the brainstem into the Inferior Olive, up to the Superior Olivary Complex, then into the Thalamus right in the middle of the brain and then immediately up to the motor area. There's such a quick correlation between sound and movement. It's a very complex system. It's so complex that if something goes wrong in the middle of the brain, it affects movement, as would happen with Parkinson's disease or stroke patients. Both of those instances affect the middle of the brain differently, but they share a malfunction of the motor system. What studies have proven is that you can kind of ‘hotwire’ that motor system by using sound. Sound can almost work as a cue, a way of kind of cueing and supporting body movement. So there are lots of studies that have been done on this and it has become one of the main foundations in my studies; a justification that sound can be used in mainstream medicine. We have done studies with Parkinsonian subjects and with stroke patients as well. It's been a great privilege to be able to work with these people. 

Brain GIF

What are the practical things that you have done in relation to all of this?

BT: We have worked directly with Stroke patients, which was more of a preliminary recreation of pre-existing experiments, however, we provided a good range of choices for the participants. There is another issue - it would make sense, in terms of efficiency, to use a participant’s favourite dance tune. However, this may evoke memories and so you end up not really knowing the effect of the sound, as memories and emotions come into play as well. So currently I am working on developing an algorithmic composer - in Max MSP - which constrains preferred elements from a participant that attune emotionally, to try and appeal to them enough to optimise their motor system, but without being familiar.

5 Chart of Perception

So in a real-life situation, you’re testing someone with motor dysfunction issues or Parkinson's and your algorithmic music would be playing whilst they're getting physiotherapy? 

BT: It is used by physiotherapists, not as accompaniment, but actually applied sonic components to movement tasks! What my study is doing is going a little bit further towards understanding and measuring the different qualities of music that can be brought into those environments. Ultimately, we have to understand the participant in the first instance. There are so many aspects to that. For example, they might be very sensitive within certain frequency ranges or might be deaf in certain frequency ranges. First, we have to understand that, but then get a sense of what music they enjoy moving to. That's so different for different participants, it's crazy. One person might enjoy listening to film music, other people might enjoy 50s rock and roll. So we have to have some kind of sense of that and then it becomes almost a categorization system of trying to work out what facets of sound would be appealing to them. Once that's understood, then we have a palette to work from and then we can measure the effect it has. You might have some kind of brain scanning happening to understand what the brain is experiencing and have a physical feedback system that ensues from that. In this project, because it's connected to movement, it could simply be a way of tracking how people respond to specific sounds; to understand what they enjoy and what they don't enjoy and try to increase specific parameters that will be useful for movement. It's a really interesting subject. It goes on and on, I’m afraid!

Moving away from the algorithmic elements, how does this then relate to improving movement?

BT: It's trying to think about how this connects up with the body. In this image, I've got a picture of a sensor on the heel. As you walk, that will then connect to the computer which would create its own way of interpreting the pulse that comes in from the trigger from the heel. Then, that would connect to a system that would support some musical information, quantize it and respond to the tempo of the person walking, and therefore, the music becomes adaptive to that. 

6. Heel Sensor

So depending on the way that people are walking, if the computer notices that the movement function isn't as strong as it should be, the system will kick in to provide music that encourages movement?

BT: That's it. It's the simplest explanation of how this could work. One of the justifications for this system is that, with hemiplegic stroke patients, what happens is half the body becomes paralysed, or compromised quite seriously. Most people walk and we have a strong foot and a weak foot and that's pretty much how Western music has evolved. You have a strong pulse and a weak pulse - right foot, left foot in most people. Music evolved with that. With conventional music, that's all fine for a healthy participant. They would respond to that perfectly well. But with stroke patients, what's been recognised in clinical studies, is frustration from the participant when you play music that's designed for healthy participants. So, it makes sense to have music that empathises with that dysfunction. It can be quite pronounced. You have one strong foot and then you can have a very, very prolonged duration in the other foot. So we have to have music that responds to that as well. However, in my studies, I'm looking at all movements. Not just the foot-heel strike. The heel strike is a very important one because it can define tempo but there are all sorts of elements within body movement that can be understood and tracked. Again, it's commonly known in music, especially in dance music, that groove is an important factor and that the grooviness stimulates a sympathetic response in the dancer. We can translate all kinds of facets of body movement - in the arms and the spine and the hips. So you can also understand it in someone's physiology - the subtleties in their body dynamics. So, on one level, we can understand all the components of music that someone likes. But on another level, we can understand how someone's physiology is something that is very, very personal. We could almost create music from a person just by understanding what they like, and sort of constraining those aspects and then plugging in some means of tracking their body movement in a way that then translates. All of the subtle movements can be converted into numbers, which can then be expressed through any musical parameter.

So you could almost reverse-engineer music from movement?

BT: Yeah, that's right. The justification for it is as a clinical application in mainstream medicine, which is the thing that's given me momentum and a change of life purpose from being a musician and just trying to churn out tunes to doing something that's actually of use to someone. I've explored so many dimensions of how this needs to be understood. It's such a complicated, multivariate thing that it's taken a long time. Hopefully, it's going to end up with something that's going to be very usable and can be adapted quite quickly and easily in lots of different ways, shapes and forms. I could imagine it being quite useful in the gym, for example.

X.1_MMF data graph_input only

So an application of this could be: You analyse what your general movement is in the gym and then, if you wanted to enhance it, you could create a sound that's unique to you. Is that right?

BT: A slightly crude example might be that you might have a dance tune playing when you're doing some running or cycling and the faster you go, the more likely the tune is going to drop.

That's a really interesting idea! When I've been cycling, I’ve noticed my feet would naturally fuse with the rhythm of the music I’m listening to. 

BT: Yeah, so there is a natural tendency for us to want to synchronise to auditory stimulation. I suppose within this system, it's going to be a little bit more sophisticated. There are all sorts of factors to consider in terms of your own state of health and how hard you should be pushing yourself. You need to understand your own physical constraints and what's sensible. It might also be that you need to slow down, so an intelligent system would be able to recognise that and facilitate that.

That’s really interesting. Is there anything else you think we’ve missed?

BT: This is really part of a much longer study. I'm not individually necessarily making such a substantial leap. It’s more about bringing together the work of many studies and helping it progress. Ultimately, it's a way of bringing music into mainstream practices. Whereas before, commonly, music therapy as a general term seems to be sniffed at a little bit. Experimental models are usually quite multivariate, and it's very easy to disprove things. Whereas, hopefully, this will be a little bit more detailed and charts more accurately the cause and effect of music. 

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