Stroke Rehabilitation Through Music

Stroke and other significant brain injuries can take a long time to recover from, requiring numerous hours of therapy to regain motor function and other abilities. Several research organizations have been looking into ways to make the rehabilitation process more effective and engaging by giving patients audio feedback as they move, indicating whether or not the movement was a step in the correct direction.

A group of Danish researchers has recently taken this auditory feedback strategy a step further by developing a novel device that uses synthesized music to help patients through rehabilitation exercises.

Simple sound effects can be exhausting and meaningless, but musical feedback can enhance the rehabilitation process and tap into people’s innate need to move to the beat.

Prithvi Ravi Kantan, a Ph.D. student at Aalborg University Copenhagen’s Department of Architecture, Design, and Media Technology, assisted in the development and testing of the new system. The project is the culmination of his personal musical and rehabilitative experiences.
Over the previous 15 years, he had been highly involved in music performance and production, and he was working full-time in audio signal processing in Mumbai when his father was diagnosed with viral encephalitis. His father was paralyzed on one side as a result of the virus, and Kantan watched the arduous recovery process firsthand.

Stroke and other serious brain-related injuries can often require a long road to recovery, with countless hours of rehabilitation to regain motor function and other abilities. Various research groups have been exploring ways to make the rehabilitation process more efficient and engaging by providing auditory feedback to patients as they move, indicating—quite literally—whether the movement was a step in the right direction.

More recently, a group of researchers in Denmark has taken this auditory feedback approach one step further, with a new system that uses synthesized music to guide patients through their rehabilitation exercises. The new musical biofeedback system—and the results of pilot tests of the system with volunteers who have experienced a stroke—is described in a study published 10 January in IEEE Transactions on Human-Machine Systems.

Whereas simple sound effects may be fatiguing and lack meaning, musical feedback is a way to enrich the rehabilitation experience and tap into humans’ natural affinity for moving to the beat.

Prithvi Ravi Kantan is a Ph.D. student with the Department of Architecture, Design, and Media Technology at Aalborg University Copenhagen who helped design and test the new system. The project is a result of his own experience with both music and rehabilitation.

He has been heavily involved in music performance and production over the past 15 years and was working full-time in audio signal processing in Mumbai when his father suddenly contracted viral encephalitis. The infection left his father paralyzed on one side, and Kantan witnessed first-hand the lengthy rehabilitation process.

“Given the impact that this had on me and my family, it was a revelation when I discovered music therapy, as it gave me a way to channel my professional skills towards a cause that held some personal meaning to me,” Kantan explains.

He began working on the new musical biofeedback system with colleagues when he came to Aalborg University Copenhagen in 2018. It entails strapping wireless motion sensors to the patients’ ankles, backs, or both to track their movements. As the patients go through various physical rehabilitation activities, a software application synthesizes music to match their movements (for example, walking, balancing, or transitioning between sitting and standing positions).

Different musical-feedback training modes are available with the system. One approach is when the body generates music on its own. If the person is still, no sounds are made in this case. A musical song is synthesized when they walk a foot forward quicker; the tone becomes louder as the foot advances ahead faster.

Here’s an example with guitar strings that play as the user extends the leg from bent to straight. A bell rings if the user overextends the knee:

In another training mode, music is continuously played, and the tone or pitch changes as the person move the limb:

Finally, the researchers created a training mode that gives negative feedback if a person performs a movement that significantly deviates from the target. If a person slumps forward too much, for example, the music may become more dissonant:

Kantan and his colleagues evaluated the novel musical biofeedback system with six study participants (four men and two women) who were recuperating from a stroke and had weakness on one side of the body after developing the different training modes. Several doctors and musical therapists also observed the therapy sessions and were polled about the system’s viability.

The findings revealed that musical cues were an efficient means of expressing movement-related information in general–many of the volunteers were able to respond well to the musical cues and change their movements as needed. As the training progressed, two of the participants raised their speed dramatically.

However, there were a few issues with the strategy. One participant, for example, had problems hearing the musical cues, and the dynamic and layered sounds of the music were sometimes difficult to discern for the volunteers.

“Patients need to be at a cognitive level where they can interpret and act on input,” Kantan says, stressing that complex noises can easily overstimulate neurologically damaged persons. In addition, some of the volunteers found the negative feedback training mode to be disheartening.

The clinicians and musical-therapy experts involved in the study noted that the suitability of the approach might depend on the severity and location of the user’s brain injury. For example, they recommended that stroke patients with cerebellar or lower brainstem strokes may be better candidates for musical biofeedback therapy.

Although the results identified some limitations, the data suggest that musical biofeedback therapy is a feasible approach to rehabilitation and could open new avenues to recovery for people with brain injuries.

Notably, Kantan’s team designed its musical biofeedback system using a low-cost motion-sensing system and open-source tools, making it an easy tool to replicate and implement broadly. Their aim, Kantan says, is to accelerate the development and adoption of music-based feedback tools in rehabilitative practice.

“It would be extremely rewarding to contribute directly or indirectly to improving rehabilitation outcomes for patients,” says Kantan. “Although there is a lot of research to do before we see the widespread adoption of musical feedback in clinical practice, we at Aalborg University are determined to bring present efforts in the field to fruition in the coming years.”

What do you think?

Written by Emma Ava

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