The field of music therapy is an emerging one in medical practice. Nevertheless, there is a growing body of research to support the use of music therapy in a wide range of instances, one of which includes patients who are suffering from brain injury. This paper will review some of the literature on the subject in an attempt to understand how music affects the brain and is therefore useful in therapy.
The idea of music therapy is ancient, and was extolled by the likes of Plato. The Roman god Apollo was god of music and medicine, further cementing the link between the two in Western civilization. Non-Western cultures were also known to use music to attempt to heal people. Certain forms of music could drive out evil spirits or demons, according to the lore of many cultures. It is from these myriad traditions that the modern use of music in therapy evolved. When subjected to scientific rigor, the concept of music therapy held up. What has long been known anecdotally in terms of the therapeutic value of music has been proven. Thaut et al. (2009) outlines the case for how music can enhance the cognitive function and emotional adjustment in brain-injured persons. How this particular study manifested not only draws conclusions about the correlation between music therapy and recovery from brain injury, but also sheds light as to the specific processes at work. For example, patients in the control group showed improvements in some areas, like emotional adjustment and lessening of hostility, but they did not show improvement in all of the areas where the music patients improved. Music, therefore, help these brain injury patients improve in terms of depression, sensation seeking and anxiety.
Thaut and McIntosh (2010) take this information and build on it in a later study. The use of brain-imaging techniques can help us to understand how the brain works. The authors note that there are a number of different types of brain injury that are subject to study, including Parkinson's, strokes and others, but that music therapy is generally successful at addressing these injuries. Neuroscience models, the authors note, allow researchers to study music perception and the influences of music on non-musical brain functions and behaviors. This goes beyond simply recording, anecdotally, outcomes that are observed -- this data is more coherent in terms of explaining causation.
An example that the authors cite is with respect to musical rhythms and the role they play in non-musical timing and motor control. Using rhythmic auditory cues, they studied the synchronization of walking to music and found that this occurred. The use of music to help with motor recovery in brain injured patients flows from this. The rhythms in music assist in rebuilding the damaged neural pathways for motor control. That these improvements help up over the long run was something that encouraged the researchers.
Bradt et al. (2010) note that multiple studies have demonstrated this relationship. Music therapy or rhythmic auditory stimulation is associated with positive outcomes in stroke patients, rebuilding the pathways that lead to improved outcomes for gait velocity, gait cadence, stride length and gait symmetry, all of which will contribute to a faster and more thorough emergence from the stroke for the patient.
Thaut and McIntosh (2010) also note that music therapy has been used to improve speech and cognitive function. There is plasticity in shared brain systems leveraged in motor therapies, and therefore a link that can be created between music and the brain even in terms of cognition. The authors note that "the brain systems underlying music are shared with other functions," so music improves all brain function, not just that associated with motor skills.
Another explanation for the success of music therapy on brain-injured patients is the auditory scaffolding model. This model, as outlined by Thaut and McIntosh (2010), "proposes that the brain assigns nearly everything that deals with temporal processing, timing and sequencing to the auditory system." The auditory system is better at short-term memory than the visual system, so spoken words are more effective than written ones at making an impact on the short-term memory.
Key to the success of music therapy is the auditory system. Thaut and McIntosh (2010) note that deaf people have trouble developing non-auditory temporal skills. However, coma patients do usually have a functioning auditory system, and there has been research into how music therapy can help coma patients to develop improved brain function and therefore recover faster. Formisanco et al. (2001). The authors found that intensive music therapy over an extended period led to positive outcomes for such patients in terms of a reduction of inertia and psychomotor agitation. Such outcomes can help to speed the pace and improve the quality of recovery.
The positive results can also be found with children. For example, Hamilton, Cross and Kennelly (2001) showed that music therapy can aid in the treatment of acquired neurological speech and language difficulties in children. Their paper also contains implications for clinical practice. It is worth considering, then, how music therapy is able to be so effective in treating patients with brain injuries.
The basic elements of communication are source, sender, channel, receiver, destination, message and feedback. We can examine how each of these manifests in music therapy. Music is the channel, but in a brain injured person there are issues with the links between the receiver and the destination. The destination is the brain, and most types of channels are not received as effectively as music is. Music is the superior channel because the auditory system works more quickly than other receiver systems, and it works more effectively.
In addition, music is one of the most complex forms of communication. If we attempt to communicate to a brain injured person using simple channels, that person may prove largely unresponsive to the channel we have chosen. Music provides many channels by which the communication can take place. There are multiple instruments playing, a combination of rhythms and melodies, and while we can never been certain which is having the most impact, something in the complex message is being received and the destination is interpreting the message. Music is often indirect in the way it conveys its message as well, open to significant interpretation. The receiver, therefore, may be able to interpret the message according to whatever his or her pathways are capable of. If there is brain injury, these methods and logics may be different from what it expected -- almost certainly they are or conventional channels would be effective. There is something in the complexity of music that enables the receiver to take some sort of message to the destination. This may be all that is required to spur the process of neural repair and stimulation.
Other media do not have the same effect on the brain. It has been established that music is more effective than visual stimuli (Thaut & McIntosh, 2010). Touch is also an effect medium, but is not necessary as complex as music. Moreover, touch lacks the ability to stimulate critical motor pathways, which in turn allow for the spillover effect where the stimulus works on cognitive pathways as well. Likewise, taste is not necessarily the most effective, nor smell, because they are not as indelibly linked to motor function as music is.
Music therapy is highly effective for dealing with brain injured persons because it leverages the most powerful channel for communication. The sender is not sending an explicit message, but one that must be interpreted by the destination, and this interpretation can be done any number of different ways. The complex manner in which music stimulates the brain, beginning with motor function and extending to cognitive function, is something that other channels lack.