Here is my summary of the Franken study (see here and a StutterTalk interview) after a first reading. Add your comments if you disagree!
The two most important clinically relevant statements are
- If your child has been stuttering for six months, does not have any obvious speech and language development issues and is treated by a specialist, it has a three-in-four chance to fully recover within 18 months of treatment.
- It is not important whether your child receives direct (Lidcombe) or indirect (DCM) treatment.
Here are safe statements:
- It is the outcome trial for close-to-onset kids with by far the largest sample size, 200, and best follow-up data, 18 months.
- It is about comparing the relative performance between two different intervention methods (direct and indirect)
- Both methods have similar outcome with no clear and significant difference.
- It is not about absolute performance comparing to natural recovery (i.e. recovery without professional therapeutic intervention).
- It contains no strong evidence whether they work, whether they only speed up natural recovery, whether they only improve psychosocial adaptation, and why they work.
- It is wrong to say that the direct method Lidcombe is the only scientifically tested method.
- It is by far superior in quantity and quality to the Lidcombe outcome trial but lacks the crucial control group out of ethical reasons.
Statements one cannot make safely but might be true:
- The trial might have picked up subtle differences between the two methods.
- The direct method might both be a bit better at dysfluency reduction in the short-term but also show relapse in the long-term.
- Only allowing kids who stuttered for six months or more in the trial should make the natural recovery rate lower in the treatment arms.
- Only allowing kids without other developmental issues in the trial should make the natural recovery rate higher in the treatment arms.
What still needs to be done:
- We absolutely need 3-year, 5-year, and 15-year (after teenage years) follow-up data to study relapse and recovery.
- A follow-up of the rejected kids or kids that did not do the treatment for various reasons. For example, they could be used to create a fake control group.
- An analysis of sex-specific differences. For example, we could give a more specific prognosis to kids depending on sex and family history.
Some concerns I have
- I cannot understand why the two samples were not randomized to %SS so that they both start with the same %SS, because the %SS is 4.9% for direct treatment arm and 4.0% for indirect treatment arm.
- The article's wording and arguments are a bit sloppy, e.g. "... that both direct and indirect treatment... reduced stuttering..." should be "that both treatment arms showed reduced stuttering" as it is not clear that it is the treatment method and not natural recovery or the claim that the follow-up period is double the time as in Jones et al. even though they have a follow-up paper with low quantity and quality or the natural recovery is "estimated to be 63%" but I have also seen much higher numbers.
- The lack of a control group due to ethical concerns.