ACQ Vol 12 no 1 2010

Motor speech disorders

Editorial Advances in motor learning: Emerging evidence and new ideas Patricia McCabe

that feedback in the prepractice phase should be about how the person is making the sound or the error. Speech pathologists use this type of feedback frequently; however, the rub is that in the practice phase, feedback should only be on whether the target was correctly produced. This will require a change of behaviour for most clinicians and PML tells us that clinicians will need to practise their own new behaviour to institute this change. In addition, the client should only be told whether they got it right or not on randomly selected productions at a rate of less than 100% of productions (Hodges & Lee, 1999). In the last three years there have been a number of papers which examine how these principles may apply generically to speech and voice interventions (e.g., Maas et al., 2008; McIllwaine, Madill, & McCabe, this issue), and new treatments which have been designed with PML as the underlying theoretical framework are being created (Ballard, Robin, McCabe, & McDonald, 2009). Therefore, PML may change our practice across movement disorders and provide a theoretical basis from which to make clinical decisions in the absence of high level evidence to guide practice. Returning to traditional articulation intervention, it is interesting that in the era of evidence based practice most speech pathologists unquestioningly accept it as being best practice even though there are no large-scale, high level studies to support this assumption. A recent search (30 October 2009) of speechBITE (www.speechbite.com) provided 100 treatment papers in which articulation was a keyword. In 14 of these, traditional articulation intervention was examined most commonly as a control intervention against which a newer treatment was being compared. Three were regarding children with cleft and 11 were about otherwise typically developing children. Of these 11 papers none were systematic reviews, 4 were small randomised control trials, 3 were other types of control trials and the remainder were lower levels of evidence. Eight papers had been rated by speechBITE, and only two papers scored 5/10 indicating moderately rigorous research; the other papers were rated between 1/10 and 4/10 (lower levels of rigour). Most papers supporting traditional articulation intervention are thus low level evidence. However, recognition of this issue does not help us make clinical decisions as, like many areas of speech pathology practice, there are no alternate treatments available. What clinical experience tells us is that traditional articulation intervention generally works; however, articulation is a motor speech task and therefore PML might be applied to improve treatment efficiency and effectiveness. To use PML in an articulation session we could, for example 1) only give cues about how to make the sound until the child gets a few productions correct (prepractice), 2) rapidly move on to feedback about correctness (practice), and 3) ensure that the client has mixed practice opportunities rather than repeated productions of the same

Motor learning in speech pathology could refer to any area of practice which changes how a movement is made in relation to a communication or swallowing outcome. This obviously includes speech issues associated with articulation, apraxia, dysarthria, and fluency. However we can also think about motor learning in relation to voice therapy, swallowing intervention, or skilled use of augmentative and alternative communication (AAC). These areas of practice are thus about motor learning in a broader sense, as we endeavour to institute, change, or repair a set of learnt movements. This motor speech issue of ACQ focuses on an area of practice that has often been neglected in both research and practice over the last couple of decades. Indeed, some of the treatments we use in motor speech come from the very foundation days of the profession. For example, most paediatric clinicians will use a variation of van Riper’s (1939) stimulus approach as the basis for traditional articulation intervention. We are now witnessing an explosion in theoretical knowledge about how motor behaviours are learnt, processed, perceived, and stored. This new knowledge will in turn influence therapeutic approaches to motor intervention. This editorial will review some of the most promising areas of research (principles of motor learning, neurological plasticity, and mirror neurones) and hypothesise how motor interventions may change in the coming years. Principles of motor learning In recent years the term ‘principles of motor learning’ (PML) has appeared in the speech pathology literature. These principles derive from research in the fields of learning and motor rehabilitation. For a detailed review of PML see Maas et al. (2008). What do these principles tell us about motor learning? This paper is too short to go through all of them but three examples follow. First, there are two phases in learning any new motor skill – called prepractice and practice. Prepractice is the introduction of a new skill and practice is the period in which the skill is embedded as a habitual behaviour and generalised where appropriate. Second, to learn any new motor skill lots of varied practice is required. This might seem like an old idea but research is consistently showing that practice needs to occur, not over tens or hundreds of blocked trials, but over thousands of disseminated ones. So if you want a new speech sound to generalise then the client needs to practise, practise, practise. Implied in the concept of varied (or disseminated) practice is also a notion that clients should practise on multiple, related, randomised production targets; that is, simultaneously target the sound in initial, medial, final positions and possibly clusters. Randomisation allows for the development of a general motor plan rather than a context specific motor plan and is the key to greater learning. Finally, we may need to change the way in which we provide feedback as well as its content. PML tells us

Patricia McCabe

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ACQ Volume 12, Number 1 2010

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