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ing a speaking task were located in the right hemisphere. More importantly, the magnitude of this activation was greater after the patient was treated with MIT, indicating therapy-induced brain changes. (see Fig. 4)
In terms of structural changes, our preliminary data show modifications of the right arcuate fasciculus following MIT. As described in the preceding section, the arcuate fasci- culus, a fiber tract that connects the superior temporal lobe with the posterior inferior frontal gyrus, is very important for auditory-motor mapping and plays a crucial role in language development (Glasser and Rilling, 2008; Rilling et al., 2008). Figure 5 shows a diffusion tensor imaging study of a patient who underwent MIT. The treatment-induced increase is evi- dent when the before-therapy (Fig. 5a) and after-therapy (Fig. 5b) images are compared against each other: the arcuate fasciculus is larger in volume after therapy. We believe that the intensity of MIT may be important for facilitating plas- ticity and remodeling of this fiber tract (Schlaug et al., 2009). (se Fig. 5)
Music-based intervention in the treatment of nonverbal children with autism
In addition to facilitating the language recovery in stroke patients, music-based interventions can also be used to induce plasticity and to restore cognitive functions in children with developmental disorders, such as Autism Spectrum Disorders (ASD). ASD affects 1 in 110 children, and one of its core diag- nostic features relates to impairments in language and com- munication. It has been estimated that up to 25% of individu- als with ASD lack the ability to communicate with others using speech sounds (www.autismspeaks.org). Despite their verbal communication deficits, children with ASD enjoy auditory- motor activities such as making music through singing or playing an instrument (Trevarthen et al., 1996). In addition, they often display enhanced music and auditory-perception abilities (e.g., Heaton, 2003). Such positive responses to music suggest that an intonation- or singing-based intervention may have great therapeutic potential by tapping into an activity that these children enjoy.
At present, there are no established techniques that reli- ably produce improvements in speech output in nonverbal children with ASD (Francis, 2005). Two published case stud-
ies have shown that an intonation or singing-based technique has great potential. One study used an adapted version of MIT involving intoned questions and statements (Miller and Toca, 1979). Another study reported using pitch matching and singing to encourage vocalizations, which eventually led to the articulation of words (Hoelzley, 1993). Although the results of these single case studies are encouraging, the effi- cacy of these methods have to be tested in a controlled design which would allow us to determine whether these approach- es can be generalized to a broader population of affected individuals, and whether effects in the trained words/phrases transfer to untrained items.
Our laboratory has recently developed a similar intona- tion-based intervention, termed Auditory-Motor Mapping Training (AMMT), to help nonverbal children with ASD develop verbal expressive language (Wan et al., 2010a; Wan et al., 2010b). This type of training builds upon the seemingly inherent musical strengths that have been observed in chil- dren with ASD. Furthermore, AMMT is an adaptation of an intonation-based technique (MIT) that has been successful in facilitating speech output in patients with Broca’s aphasia. As described earlier, recent studies have shown that com- pared to speaking, singing engages a bilateral fronto-tempo- ral network in the brain, and that this network contains some components of the mirror neuron system (Brown et al., 2004; Ozdemir et al., 2006). Some researchers have argued that the communication deficits associated with ASD may be caused by a dysfunction of the mirror neuron system (e.g., Hadjikhani, 2007; Iacoboni and Dapretto, 2006). Combining sounds with actions, in particular, could play an important role in the engagement and repair of the “hearing-doing” (auditory-motor mapping) network that may be dysfunc- tional in autism.
The application of MIT to the treatment of autism requires some procedural modifications from its original form in the treatment of aphasia. Our AMMT intervention involves repeated trials of bimanual sound-motor mapping through the use of tuned drums (Wan et al., 2010). For chil- dren with autism, it is important to first establish a comfort- able treatment environment. The session includes a vocaliza- tion procedure, during which the child is encouraged to vary the intensity and length of speech sounds. A series of picture
Fig. 5. Diffusion tensor images of a patient who received melodic intonation therapy (MIT), showing the arcuate fasciculus in green. a) Before therapy. b) After therapy.
Reprinted with permission from Schlaug et al. (2010).
Neurological Bases and Applications of Singing 33