Pratique du Shadowing: Sequential, Multiple Assignment, Randomized Trial Designs With Dr Kidwell - Apprendre l'anglais à l'oral avec la vidéo
Création de la leçon...
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Hello, and welcome to JAMA Evidence, our podcast series based on core issues in evidence -based medicine.
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Today, we will be discussing sequential, multiple assignment, randomized trial designs.
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I'm your host, Dr. Roger Lewis, statistical editor for JAMA and co -editor of the JAMA Guide to Statistics and Methods series.
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I'm here with Dr. Kelly Kidwell.
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Dr. Kidwell, thank you so much for joining us.
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Can you go ahead and tell our listeners a little bit about yourself?
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Sure.
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Thank you so much for having me, Roger.
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I'm Kelly Kidwell.
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I'm a professor of biostatistics at the University of Michigan School of Public Health, and my expertise is in clinical trial design and analysis,
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and in particular, the sequential multiple assignment randomized trials or SMART design.
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Well, again, thank you so much for joining us.
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So the name of this approach to a trial design is a bit daunting, so let's try to break it up a little bit.
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So for each of those terms, can you go ahead and tell us what it means and then how we put it together in designing a clinical trial?
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I completely agree with you that the vocabulary around smart design is quite daunting.
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So what an excellent first question to start with.
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So sequential is about a few things.
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One is that we're interested in sequences of treatments.
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And in this clinical trial design, we're going to have sequential randomization.
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So those terms aren't next to each other, but that's really what's happening and defines this trial,
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such that at least some group of participants will be randomized twice in sequence.
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So usually there's some upfront randomization
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and then a subsequent randomization for some group of participants based on their response to the initial treatment.
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And so that multiple assignment comes into the fact that we'll have this sequential treatment assignment.
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So individuals could be assigned to multiple treatments.
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And this is all wrapped up in a clinical trial.
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So we're going to use this SMART clinical trial tool to give us robust evidence for sequences of treatments
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that adapt to individual responses or patient status.
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So in contrast, in a traditional or a simpler clinical trial design.
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We just randomize once, and then the patient either does well
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or perhaps doesn't do so well on the treatment to which they are assigned.
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And if they don't do well, we often have some sort of rescue therapy or they have to leave the trial.
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So how is the experience of a patient or a participant different in a SMART design?
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Right.
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So in a general, standard, traditional randomized clinical trial, we're really looking at one point in time,
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sort of this trial in a vacuum.
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The SMART is going to say, let's look at that patient over the course of care.
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So in a standard trial where you might stop collecting their data and treating them off trial if they didn't respond, we actually want to use that data.
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And in fact, we might want to randomize the treatment to
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which rescue therapy they're getting so that we can collect unbiased evidence
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and use causal inference to better understand what the effect of that treatment is.
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And not just that treatment, but the entire treatment sequence.
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And so really for the patient,
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it might not be too different than a standard trial because we're going to treat you over the course of your care.
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But to the investigators, we're going to make sure that
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that data is collected for our trial and there might be randomization for the treatment assignment that follows for that patient.
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So, let's think a little bit about how we analyze or what we can learn from those two different approaches.
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So in the first, we randomize at a single point in time, and if the patient doesn't do well,
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they either drop out of the trial or we assign a rescue therapy.
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Whereas in the SMART design, if they require a change in therapy, we actually randomize what we do.
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So what's different about what we can learn from those two different approaches?
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That's right.
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Often in our standard clinical trial, in that one stage where the patient drops out or receives clinician or patient choice therapy,
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we no longer make inference or have any decisions or really robust results about that subsequent treatment or their outcome.
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Whereas in the SMART, by randomizing that individual and continuing to collect that data,
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we will be able to have really robust evidence over the course of care, over the sequence of treatments
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that could have adapted based on their response to allow us
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to give these sequential guidelines to clinicians to treat the patient not just up front at one point in time,
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but over time, and really tailor it to how they're doing, if they responded, if they adhered, if they engaged with that treatment.
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So in a sense, this more closely follows what happens in actual clinical care,
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where we make a series of treatment decisions based on the patient's prior response, but in this case, you're setting it up
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so we can rigorously learn about what is the best next
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thing to do based on what's happened to the patient so far.
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Is that a fair summary?
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Absolutely.
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We are looking at a type of clinical trial that more closely mimics the way in which treatment is practiced.
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And so that we can provide evidence for these treatment strategies
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that adapt to individual's response or patient status in the way that we would actually treat them in practice.
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Let's suppose that a SMART design is run and there's two points at which patients are randomized,
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maybe the initial therapy and then after some defined period of follow -up.
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What does the result look like in the publication that results,
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and how can clinicians utilize the results of the SMART in guiding their own clinical care?
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One of the amazing advantages of a SMART design is
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that it can answer many questions as opposed to just what is the best treatment at one time.
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We can think about what is the best treatment to begin with?
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What is the best subsequent treatment for those who respond?
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What is the best subsequent treatment for those who don't respond?
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And then we can think about that entire sequence of, okay, so what do we start with?
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How do we change?
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When do we change?
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For whom do we change and what treatment do we give them?
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And so we can really get from SMARTS this sequence of treatments adapted to patient response.
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Not only that, we can collect baseline information, so information up front at the start of the trial, and information about the patient and how they're doing with the treatment,
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how they're adhering, how they're engaging, if they're having side effects,
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and use that information to better tailor the treatment assignment to that individual so that after the trial, right, we have all this information.
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And we can look at what are the best sequences of treatments for which particular individuals.
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The fact that the SMART design more closely matches actual clinical care,
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which the sequences of therapies we offer patients is informed by their responses to prior therapies is an obvious advantage.
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But what are some of the limitations or challenges in either the implementation or the interpretation of a SMART clinical trial?
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I think there are a few limitations and also just lack of knowledge of this design and its opportunities that it offers.
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Some of the limitations are that individuals think, oh, now that we have multiple randomizations or multiple assignments in sequence,
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this is now logistically infeasible, or you're going to lose more people if you have to consent multiple times.
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So one thing is that we often just consent once at the beginning of the smart design.
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and we may randomize multiple times.
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Alternatively, you could randomize up front to that sequence that they may follow, whether they respond or do not respond.
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So logistically, this doesn't have to be very difficult.
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We also have lots of technology that helps us with complex trials, if you want to say that it's complex, although it's not.
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Number two is that individuals are worried about bias coming into play from a smart design
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because of these multiple randomizations and the subsequent randomization depending upon patient response or status.
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This is not a concern because we do not compare these treatment pathways or you first get A,
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you respond and you continue versus you first get A, you do not respond and you switch to B.
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We're not going to compare those people.
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We know that they're different.
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One responded and one didn't, and we can have some issues if we do those comparisons.
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We're looking at what we call adaptive interventions or dynamic treatment regimens that include that entire treatment sequence that's adapted.
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So start with A, and if you respond, continue.
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And if you don't, receive B.
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We're going to think about what are the effects of that entire sequence that's tailored to the response.
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Another misconception is that a SMART is an adaptive design.
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Usually a SMART is a fixed design, not an adaptive design, meaning
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that we're not going to use information from patients who have
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been through the trial to change the trial in some way for future patients.
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So we're not going to change randomization probabilities or eligibility criteria based on the information we've gained from the trial thus far.
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What does happen in a SMART is that patients' treatment might change based on their own response.
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So there might be a within -person adaptation, but there's no between -person adaptation.
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And so generally, these aren't adaptive designs.
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Since we're trying to learn more from a clinical trial that's a smart design versus a traditional design
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that just has a single point of randomization, it seems like we might need larger sample sizes to answer the additional questions.
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What are the challenges, if any, with respect to sample size requirements for a smart design?
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If you see pictures of smart designs, they look a little bit intimidating because there's a fair amount of branching that occurs due to these sequential randomizations.
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And often investigators are quite worried that we're going to require thousands of patients.
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The thing is that to size a SMART is just like sizing any other trial.
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And so it's really dependent on the primary aim, which can be similar to a standard one -stage trial and compare,
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for example, the initial treatments.
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Alternatively, the aim can be based on those embedded tailored sequences of treatments or the adaptive interventions.
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And for those perhaps more patients may be required than a standard trial.
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However, this really isn't an apples -to -apples comparison of a SMART design to a standard or traditional one -stage trial.
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As I mentioned before, the questions
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that we can answer in a SMART are much different and many more than we could with a standard design.
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And so perhaps we may need more depending on the primary aim, but we're going to get a lot more information,
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data, robust results, and more practical information that we can use after a smart design.
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In your article, you discuss a study that was performed by Fortney et al that used a smart approach.
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Can you tell us a little bit about what they did, what they found, and how they analyzed their data?
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Sure.
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So in this study, they had a design where individuals were sequentially randomized to better understand some effects of direct
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and indirect telecare.
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And what they did is they answered questions that are sort of more similar to one stage design.
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So they said, okay, so what's the best first thing to start with?
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And then subsequently, what do we do if individuals aren't responding well to that initial treatment or intervention.
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So they haven't yet pieced together that full sequence.
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It seems like that's subsequent analyses for this group in terms of figuring out,
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so what is the best overall sequences of treatment that can adapt to the individuals?
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While they answered those individually, what they could find when they move forward with the analysis of the adaptive intervention is
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that there might be interactions between the initial treatment
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and the subsequent treatment for
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which we can only really quantify in these types of SMART designs as opposed to individual randomized clinical trials.
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And so what they likely will subsequently do is look at
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that sequence of treatment over the course of the trial
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or those adaptive interventions to see if there are any interactions between the first step and the second step.
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I'm Roger Lewis, and I've been speaking with Professor Kelly Kidwell about sequential multiple assignment randomized trials.
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You can find a link to her article in this episode's description.
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This episode was produced by Daniel Musisi at the JAMA Network.
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To follow this and other JAMA Network podcasts, please visit us online at jamanetworkaudio .com.
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Thanks for listening.
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Vocabulaire et conseils d’expression pour cette leçon
Cette leçon d’expression orale s’appuie sur la vidéo « Sequential, Multiple Assignment, Randomized Trial Designs With Dr Kidwell ». Les mots qui reviennent le plus souvent : treatment, trial, design, smart, patient. Cette vidéo contient 103 phrases et 2153 mots à répéter en shadowing. La partie parlée dure 13:26. Le locuteur parle à un rythme naturel d’environ 160 mots par minute, proche d’une conversation courante. 84 % des mots font partie des 3 000 mots les plus courants en anglais ; le reste mérite d’être vu avant de commencer. 18 de ses 103 phrases sont des questions : un bon entraînement pour l’intonation interrogative et les réponses courtes.
Vocabulaire clé de cette vidéo
15 mots de la vidéo à retenir, avec leur prononciation et leur sens :
| Mot | Prononciation | Sens |
|---|---|---|
| sequence nom | /ˈsiː.kwəns/ | suite, séquence |
| assignment nom | /əˈsaɪn.mənt/ | affectation |
| subsequent adjectif | /ˈsʌbsɪkwənt/ | subséquent, suivant |
| adaptive adjectif | /əˈdæp.tɪv/ | adaptatif |
| adapt verbe | /əˈdæpt/ | adapter |
| collect verbe | /ˈkɑlɪkt/ | rassembler, recueillir |
| intervention nom | /ɪntɚˈvɛnʃən/ | intervention |
| robust adjectif | /ɹəʊˈbʌst/ | robuste, costaud |
| tailor nom | /ˈteɪlɚ/ | tailleur, tailleuse |
| rescue verbe | /ˈɹɛs.kjuː/ | délivrer, secourir |
| compare verbe | /kəmˈpɛɚ/ | comparer |
| participant nom | /pɑːɹˈtɪsəpənt/ | participant, participante |
| limitation nom | /lɪmɪˈteɪʃən/ | limitation |
| assign verbe | /əˈsaɪn/ | désigner |
| whereas | /(h)wɛɹˈæz/ | tandis que, alors que |
Les verbes à particule que vous entendrez
| Mot | Prononciation | Sens |
|---|---|---|
| go ahead verbe | /ˌɡoʊ əˈhɛd/ | vas-y, allez-y |
| figure out verbe | cerner |
Des phrases à répéter
Des phrases courtes et complètes de la vidéo, à réutiliser dans la conversation de tous les jours :
- Let's try to break it up a little bit.
- One is that we're interested in sequences of treatments.
- We can think about what is the best treatment to begin with?
- How do we change?
- When do we change?
La grammaire de cette vidéo
Les structures que le locuteur utilise le plus, avec les mots exacts de la vidéo :
| Structure | Dans la vidéo |
|---|---|
| Voix passive be + participe passé — l’accent est mis sur ce qui arrive, pas sur qui le fait | will be randomized · could be assigned · are assigned |
| Propositions relatives who / which + proposition — une précision sur une personne ou une chose | those who respond · those who don · aim, which can |
Prononciation à surveiller
Le locuteur utilise 44 contractions et formes réduites, comme we're, they're, I'm. Prononcez-les sous leur forme courte, telles que vous les entendez.
- Les sons « sh » et « zh »: intervention /ɪntɚˈvɛnʃən/, limitation /lɪmɪˈteɪʃən/, interaction /ˌɪn.təˈɹæk.ʃən/, adaptation /ˌæd.æpˈteɪ.ʃən/, contrast /kənˈt(ʃ)ɹæst/
- Mots longs — placez bien l’accent: intervention /ɪntɚˈvɛnʃən/, participant /pɑːɹˈtɪsəpənt/, limitation /lɪmɪˈteɪʃən/, interaction /ˌɪn.təˈɹæk.ʃən/, subsequently /ˈsʌb.sɪ.kwənt.li/
Les sons difficiles pour les francophones :
- /h/ — il se souffle, il n’est pas muet: whereas /(h)wɛɹˈæz/, adhere /ædˈhɪə/
- /tʃ/ et /dʒ/ — à ne pas adoucir en « ch » et « j »: engage /ɪnˈɡeɪd͡ʒ/, individually /ˌɪndɪˈvɪd͡ʒ(u)əli/, eligibility /ˌɛl.ɪ.d͡ʒəˈbɪl.ɪ.ti/, randomization /ˌɹændəməˈzeɪt͡ʃən/, sequential /səˈkwɛntʃəl/
- /r/ anglais — langue recourbée, sans frotter la gorge: robust /ɹəʊˈbʌst/, rescue /ˈɹɛs.kjuː/, participant /pɑːɹˈtɪsəpənt/, whereas /(h)wɛɹˈæz/, interaction /ˌɪn.təˈɹæk.ʃən/
Comment s’entraîner avec cette vidéo
- Écoutez la vidéo en entier une fois sans parler et notez les mots que vous ne connaissez pas.
- Commencez à la vitesse 0,75×, répétez phrase par phrase, puis revenez à la vitesse normale quand cela devient facile.
- Enregistrez-vous et comparez avec l’original, en faisant attention à des mots comme sequence, assignment, subsequent.
Qu'est-ce que la technique du Shadowing ?
Le Shadowing est une technique d'apprentissage des langues fondée sur la science, développée à l'origine pour la formation des interprètes professionnels. Le principe est simple mais puissant : vous écoutez de l'anglais natif et le répétez immédiatement à voix haute — comme une ombre suivant le locuteur avec un décalage de 1 à 2 secondes. Les recherches montrent une amélioration significative de la précision de la prononciation, de l'intonation, du rythme, des liaisons, de la compréhension orale et de la fluidité.