ACQ Vol 12 no 1 2010

Motor speech disorders

What’s the evidence? Jenny Harasty

T his is the first of hopefully many future columns that will provide a forum for discussing evidence based practice (EBP) and its relevance to the practice of speech pathology. The “What’s the evidence?” column is to be coordinated by Jenny Harasty, Speech Pathology Australia National Advisor for Research and Evidence Based Practice. What’s the evidence? will feature in forthcoming editions of ACQ, and will align with the identified theme of the journal. It is anticipated that What’s the evidence? will provide a professional forum for members to think about EBP and reflect on their own clinical practice. In particular, the column will aim to: • provide a professional forum for EBP discussion and reflection; • provide a framework for appraising topics and published papers that relate to everyday clinical practice; • provide an overview and appraisal of current best evidence in the field, leading to a useable “clinical bottom line” or recommendations for practice. As an introduction to EBP, in this first column Jenny Harasty provides an outline of what EBP is and what the steps involved in incorporating the evidence into clinical practice are. Please feel free to contact Jenny with your thoughts, queries or reflections on issues raised in this column. Jenny is particularly keen to hear from practitioners regarding their experiences in relation to EBP and to provide practical support and advice to practitioners as they attempt to incorporate the best available evidence into their practice. What is evidence based practice? I was asked the other day what evidence based practice is. Is it ensuring that we have documented all that we do? Well no – that is accountability and while very important, it is not evidence based practice. Is it having data or other evidence that demonstrates the effectiveness of our treatment? No, that is evaluation of our interventions. Again crucial, but not evidence based practice. Evidence based practice is the integration of clinical expertise and the best available research and evidence into clinical interventions. Evidence may be found in published peer-reviewed articles in scientific journals and in verbal reviews at expert conferences and workshops. Evidence based practice does not negate clinical expertise and clinician judgement. However, it emphasises that clinical expertise must be informed by the best available evidence. The original definition of EBP is from the medical literature and says that: Evidence based … [practice] is the conscientious, explicit, and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence based … [practice] means integrating individual clinical expertise with the best available external clinical evidence from systematic research (Sackett et al., 1996, p. 71). Evaluating the scientific evidence Evaluating the evidence is easier than it used to be as there are now many guides available. The National Health and

Medical Research Council (NH&MRC) “Levels of Evidence” is one such guide that provides a hierarchy from which the different levels of scientific information can be evaluated (see box 1).

Box 1. Levels of evidence Level I

Evidence obtained from a systematic review of all relevant randomised controlled trials. Evidence obtained from at least one well-designed randomised controlled trial. Evidence obtained from well-designed controlled trials without randomisation. Evidence obtained from well-designed cohort or case control analytic studies, preferably from more than one centre or research group. Evidence obtained from multiple time series, with or without the intervention. Dramatic results in uncontrolled experiments.

Jenny Harasty

Level II

Level III

Level IV Opinion of respected authorities, based on clinical experience, descriptive studies, or reports of expert committees. Source: NH&MRC: http://www.nhmrc.gov.au/_files_nhmrc/file/ publications/synopses/cp30.pdf As shown in box 1, the highest level of evidence (Level I) is considered to be a systematic review of a number of randomised double-blind placebo controlled trials. In a randomised control trial, participants are randomly assigned to either a placebo group (which receives some form of intervention that does not include the intervention being evaluated), or a treatment group (that receives the intervention being evaluated). Outcome data from both groups are collected and analysed. “Double blind” means that neither the participants nor the researchers know which group the participants were in until after the data are collected/analysed. A systematic review is a review of all the randomised control trials published in an area and makes a general finding based upon their group results, using specific meta-analytic statistics (see http://udel.edu/~mcdonald/ statmeta.html). While systematic reviews of randomised controlled trials are said to be the gold standard in medical research (Greenhalgh, 2001), it is important to acknowledge that this type of research design will not be appropriate for all research studies (see Greenhalgh, 2001, p. 47). Indeed, many important and valid studies in the field of qualitative research do not feature the hierarchy of evidence as outlined above. For this reason, it is important that clinical practice be informed by information obtained from different sources, including research projects that incorporate other levels of evidence such as controlled trials without blinding or random allocation, cohort studies, cross sectional surveys and single case designs. Readers interested in finding out more about these research designs are encouraged to refer to Dollaghan (2007) and Greenhalgh (2001).

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ACQ Volume 12, Number 1 2010

ACQ uiring knowledge in speech, language and hearing