Evaluation of Melodic Intonation Therapy for Developmental Apraxia of Speech

Abstract

Developmental Apraxia of Speech (DAS) is a neurological disorder of unknown etiology that affects the speech communication abilities (American Speech and Hearing Association [ASHA], 2007). This disorder, also known as Childhood Apraxia of Speech and Developmental Verbal Dyspraxia, involves a cluster of symptoms that ultimately affect a child's ability to produce speech. The definition of DAS is controversial because there are no validated criteria that differentiate DAS from other speech disorders (ASHA, 2007). ASHA (2007) has proposed three key features of DAS including inconsistent errors in sound production, disrupted transitions between sounds and syllables, and inappropriate prosody. Furthermore, children with DAS may exhibit difficulties with non-speech oral motor function, motor speech function, prosody, language, phoneme awareness, structure of speech sounds, and literacy (ASHA, 2007). These characteristics can impact the child's ability to develop expressive language and requires intensive treatment (ASHA, 2007).Despite intensive therapy, children with DAS often show little improvement in their ability to use speech for communication (Marion, Sussman, & Marquardt, 1993; Velleman, 2003). Speech treatment approaches include emphasizing movement sequences, intensive drills with many repetitions, targeting specific individual sounds, imitations of sounds, and touch cues (Edeal & Gildersleeve-Neumann, 201 1; Velleman, 2003). Additional therapies include dynamic motor approaches, involving sensorimotor cues for the production of syllables (Chumpelik, 1984; Velleman, 2003), linguistic approaches/phonological approaches (McNeill, Gillon, & Dodd, 2009), or a mix of approaches/protocols (luzzini & Forrest, 201 0). Although many different treatments have been attempted, a recent systematic review suggested that there is not enough evidence to consider any one method as best practice; therefore, further research is needed (Morgan & Vogel, 2008). One method that has been debated is the use of Melodic Intonation Therapy.The technique of Melodic Intonation Therapy was published in 1 973 by Albert, Sparks, and Helm and consisted of a progression of speech intoning exercises for persons with nonfluent aphasia. Since the original publication, this technique has been researched and used by speech- language pathologists, music therapists, and music neuroscientists. The original technique involves a hierarchically structured program that is divided into three linguistic levels (Table 1). The first two consist of multisyllabic words and short phrases and the third of more phonological ly complex phrases (HelmEstabrooks, Nicholas, & Morgan, 1989). In each level the words and phrases are intoned slowly using a high note-low note pattern that is similar to the rhythm, stress, and intonation of the natural spoken version (Helm-Estabrooks et al., 1989, p. 4). Researchers and clinicians have adapted the protocol, with a focus on the first level or the use of a truncated version of the entire protocol.MIT is reported to work best with persons who have a left hemisphere stroke that included Broca's area, good auditory comprehension, and poor repetition and articulatory abilities (Helm-Estabrooks et al., 1989). The success of this technique has been attributed to the activation of the unimpaired language areas of the right hemisphere (Helm-Estabrooks et al., 1989), and the distributed nature of singing in the brain (Thaut, 2005). A growing body of research has demonstrated improvements in propositional speech abilities of adults with nonfluent aphasia after MIT treatment (Baker, 201 1; Belin et al., 1996; Breier, Randle, Maher, & Papanicolaou, 2010; Schlaug, Marchina, & Norton, 2009; Schlaug, Norton, Marchina, Zipse, & Wan, 2010). These successes led to the exploration of this technique for children with DAS.Initial studies on MIT with DAS have indicated some gains; however, there is a limited amount of research. …