When you chose to study speech therapy, you may not have thought that you would also enter the world of science. This article explores why experience, common sense and good faith are not enough to guarantee effective intervention, and claims the importance of evidence-based practice in speech therapy. To provide quality care and protect the most vulnerable patients, it is necessary to adopt a critical perspective and base therapeutic decisions on contrasted data and validated methods.
[This text was published on the 41st issue (spring-2024) of the journal Logopèdia, under a Creative Commons by-nc-sa-nd license]
Let me guess: when you decided to study speech therapy, you thought about helping people who have some difficulty in some aspect. Your vocation was probably to assist someone with problems in order to improve their quality of life in this way. You probably didn’t think at that time that you were about to become a scientist, though. Understand me: I know that not all speech therapists lead research projects or publish articles in indexed journals. When I say that you would become a scientist, I mean that you probably didn’t think that you would be expected to use the methods and tools used in science with solvency. Other health professions came to the conclusion earlier that health intervention should be governed by evidence-based practices (medicine is the paradigmatic example). But don’t believe it: until the 1930s, even medicine was not very scientific, since it contemplated few truly effective remedies for the health problems of the time and used methods that were not only ineffective, but were extremely bizarre.
Now, why can’t we practice simply based on our experience, our common sense and our good faith, as has always been done? Well, simply because these three methods are not reliable. If we agree that we want to carry out effective therapies, we must distrust these three premises.
Experience. Human beings see patterns everywhere. Faced with a reality that offers us disordered and incomplete data, we are capable of making a heuristic analysis of complex problems that allows us to find useful solutions. As a species, this has surely worked in our favor. However, this way of analyzing reality does not allow us to see the whole picture, but only some details. The system causes errors, such as seeing the face of Jesus in a piece of toast or seeing causal relationships where there are none. Our own experience with reality (or, in our case, with patients) does not provide a set of systematic data and a controlled and randomized sample of cases. This is why the patterns we think we see are often false.
The professional experience of each speech therapist constitutes a sample that can give some initial intuitions, but which does not allow us to make statements about the effectiveness of the treatment with confidence. If we add to this the fact that our perception can be biased and only consider cases that confirm our beliefs or our initial hypotheses, it is clear that the process needs to be systematized: science is needed.
Common sense. This way of processing information makes us victims of multiple cognitive biases, since the evaluation we make of the data is affected by our prior beliefs. That is why doing science also involves going against common sense. A very popular example in recent years are the studies that show that non-verbal oromotor exercises are not effective in the treatment of articulatory disorders. Who was to say that? After all, it was common sense to prescribe them because the same organs are involved in both tasks, right?
Good faith. Speech therapists want the best for our patients, we want to help them and we want them to progress in the therapeutic process. However, this is not enough. It is necessary to objectify our practice or we run the risk of seeing progress or stagnation where there is none. Even more: our beliefs about the treatment have an effect on the patient. In the case of doctors, it has been observed that the strength of their beliefs about the treatment they prescribe participates in the placebo effect, since they transmit them to the patient through gestures and intonation. In our case, having erroneous beliefs about the patient’s performance in some area could transfer the error to him.
Perceptual biases and cognitive illusions are so omnipresent that even researchers have to take measures when they carry out their research. That is why it is good practice to quarantine what we see and what we think. In fact, the most valuable studies in health sciences are carried out through blind procedures.
Biases, on the other hand, do not only live within us, but can also come from external pressures, such as the promotion of health products or drugs, or even the sales strategies of pseudoscientific alternative therapies that have not been proven effective.
Evidence-based practice is necessary because we need interventions that really work. This way of working provides greater patient safety: when we use methods or tools that have been shown to work reliably in many people, there is a much greater chance that they will also work in the case of the patient in front of us. This is not trivial, since what is at stake is not only whether a therapy works or not, but we may be putting vulnerable patients at risk. Evidence-based practice is an ethical obligation.
[This text was published on the 41st issue (spring-2024) of the journal Logopèdia, under a Creative Commons by-nc-sa-nd license]