Monday, September 29, 2014

Neural pathways for language in autism: the potential for music-based treatments

Wan, C. & Schlaug, G. Neural pathways for language in autism: the potential for music-based treatments. Future Neurology, 2010, 5(6), pp797-805

In this special report, the authors present the clinical potential of a new experimental music-based therapy, termed Auditory Motor Mapping Training (AMMT). This novel therapy is considered a viable tool to facilitate expressive language in non-verbal individuals with autism, as well as in possible strengthening of the underlying neural connections.

The authors first describe the core diagnostic features of Autism Spectrum Disorders (ASD), highlighting the language deficits and impaired communication skills, which can be persistent. Subsequently, it is explained how these deficits have been studied using structural and functional imaging and neurophysiological techniques. Studies have reported structural differences in language-related regions between individuals with autism and controls, although with some inconsistency across these investigations. Nevertheless, the authors argue that these differences could be partly attributed to the complexity of the disorder, which may have different etiologies and intrinsic heterogeneity in linguistic abilities among individuals with autism.

After describing language processing in typically developing individuals and structural abnormalities in autism, the authors emphasize the possible existence of aberrant long-range connectivity in this disorder. They outline which anatomical pathways could be affected, such as the arcuate fasciculum (AF), the extreme capsule (EmC) and the uncinate fasciculus (UF). Therefore, both the language areas (Broca and Wernicke´s regions) and the neural connections between them might be abnormal, impaired or underdeveloped. It is explained how connectivity across brain regions have been examined through functional and structural imaging techniques, using functional Magnetic Resonance Imaging (fMRI) and Diffusion Tensor Imaging (DTI), respectively. As an example, the authors mention recent published studies using DTI tractography, which reported abnormalities in the corpus callosum and in frontal lobe tracts, such as the arcuate fasciculus (AF) in autistic children.

In addition, Wan and Schlaug present research in which music making and intensive musical training produced plastic changes in the brain (particularly, an increased number and volume of fibers of the AF). They suggest that a music-based intervention can also be used in autism, to engage and strengthen the connections between frontal and temporal regions bilaterally, and thus facilitating expressive language in nonverbal individuals.

Finally, the authors present AMMT as an innovative intervention with clinical potential in autism and characterize its three main components including singing, motor activity (using a set of tuned drums to engage both hands) and imitation.

The presented article by Wan and Schlaug conducted in the Music and Neuroimaging Laboratory at Harvard University provides deeper insight into the role of music therapy in the treatment of children with autism. Several questions crossed my mind while reading this article, such as: why music therapy is not common in clinical settings and how this field can be further developed?

The potential advantage of music interventions in autism is not a new finding. Many studies have previously reported the musical strengths of the individuals with autism, such as their superior music perception abilities and enjoyment in musical activities, such as singing or playing an instrument. Furthermore, musical stimuli have been shown to activate brain regions associated with the processing of emotions, emphasizing the therapeutic potential of musical activities in this disorder. A year after publishing the aforementioned article, they published a sequel entitled “Auditory-Motor Mapping Training as an Intervention to Facilitate Speech Output in Non-Verbal Children with Autism: A Proof of Concept Study” in which they reported reliable improvements in participant´s expressive language using auditory-motor mapping training.

However, most of the studies referring to efficacy on music therapy in autism have been anecdotal reports of single cases, lacking empirical support. Recently, a Cochrane review (2014) assessed the effects of music therapy for individuals with ASD. Only 10 out of 431 studies found in this field met the inclusion criteria, as relevant randomized controlled trials (RCTs) or controlled clinical trials (CCTs). The presented results provided evidence that music therapy may assist children with ASD to improve their skills in social interaction, verbal communication, initiating behavior, and social-emotional reciprocity.

For future studies, music therapists and researchers are required to carry out empirical investigations with larger samples sizes, controlled paradigms with longer periods of observation, statistical analysis to test the significance of improvements, proper follow- up and observations outside of therapy sessions. Nevertheless, studies will still have many sources of heterogeneity (e.g. patient´s age, intensity of therapy and type of treatment approaches) and limitations.

Although some animal models have been used for understanding the basic perceptual mechanisms in music processing, these models seem to be useless when it comes to study the effectiveness of music therapy in facilitating speech output.

A more robust approach would be the use of imaging techniques to investigate the structural and functional differences of the neural network, prior and after the music therapy, as well as during some follow-up period.

In conclusion, music-based therapies in autism have been underutilized and poorly studied. More empirical research and interdisciplinary collaboration are needed to reveal the strengths and weaknesses of this field. Moreover, the development of these innovative interventions will not only bring advancement of knowledge, but will also directly benefit individuals, their families and society. 

Wan C, Bazen L, Baars R, Libenson A, Lauryn Zipse, Zuk J, Norton A, Sclaug, G. “Auditory-motor mapping training as an intervention to facilitate Speech Output in non-verbal children with autism: A proof of concept study”, PLos ONE, 6, 2011, 1-7.
Geretsegger M, Elefant C, Mössler KA, Gold C. “Music therapy for people with autism spectrum disorder”, Cochrane Database of Systematic Reviews, 2014, Issue 6. Art. No.:CD004381. DOI: 10.1002/14651858. CD004381.pub3.


Eventide said...

You’re right - there is a need for further empirical research in this area, as highlighted by the Cochrane review. Another Cochrane review examining the effects of music therapy with patients who had acquired brain injuries yielded only seven studies that could be included, and of these seven, only two were determined to have low risk of bias (two by M. Thaut et al. involving rhythmic entrainment). You wonder why music therapy is not more common in clinical settings, and this could be an answer. As you report, most of the studies to date have been single case studies lacking empirical support. So far there just hasn’t been sufficient evidence-based research to satisfy the medical community. It is unfortunate, because there are so many benefits to be gained. The work of Wan & Schlaug is a step in the right direction, and yes, there has to be interdisciplinary collaboration. It would be helpful to have a music therapist as part of the research team in designing and implementing interventions, as music therapists would be able to provide perspective based on their clinical practice. I feel confident that in the next few years, with the help of research incorporating input from stakeholders as well as neuroimaging techniques, significant new understandings will emerge that will help guide practice, and improve the lives of persons with autism and their families.

Susan Raponi said...

I have had both success and failure when working with ASD students in the music classroom. For some students music is an escape, a joy, an opportunity to express oneself creatively and to contribute as part of a larger collaborative ensemble. There is certainly a great deal of experiential and narrative studies that show the profound impact that music can have on individuals in the autism spectrum. But music research is lacking in this area and it leaves a big gap in teacher training in differentiated classrooms. Thanks for this piece, it provides me with some references that will inform my own research!