Authors: Gottfried Schlaug, Andrea Norton, Sarah Marchina, Lauryn Zipse, and Catherine Y Wan
Publication: Future Neurology
Publication volume & date: 2010 September; 5(5): 657–665.
Link to full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2982746/
Abridged Abstract: …patients with severe nonfluent aphasia are better at singing lyrics than they are at speaking the same words. This observation led to the development of melodic intonation therapy (MIT). However, the efficacy of this therapy has yet to be substantiated in a randomized controlled trial. Furthermore, its underlying neural mechanisms remain unclear. The two unique components of MIT are the intonation of words and simple phrases using a melodic contour that follows the prosody of speech and the rhythmic tapping of the left hand that accompanies the production of each syllable and serves as a catalyst for fluency. Research has shown that both components are capable of engaging fronto–temporal regions in the right hemisphere, thereby making MIT particularly well suited for patients with large left hemisphere lesions who also suffer from nonfluent aphasia…
Scientists can determine how a treatment such as MIT might actually work, or at the least, who it really benefits. The authors propose the following as reasons why left-hand tapping might be beneficial:
“Left-hand tapping is likely to engage a right-hemispheric, sensorimotor network that may, in turn, provide an impulse for verbal production in much the same way that a metronome has been shown to serve as a ‘pacemaker’ in other motor activities (e.g., rhythmic anticipation or rhythmic entrainment) [67,68]. In addition, there may be a set of shared neural correlates that control both hand movements and articulatory movements [69–72], and furthermore, the sound produced by the tapping may encourage auditory–motor coupling .”
Studies such as this one may enable medical doctors to create additional effective aphasia treatments.