Tuesday, March 09, 2010

Watch the baseline!

Here is what you should watch out in the Pagoclone Phase IIb results: the baseline. I claim the baseline results will have a significant impact any outcome study. Why?

The Phase IIb is a random contol trial with participants randomly and blindly assigned to a group. One of the random group is the placebo group. They have been given an empty pill for 9 months (I believe), and can be considered the baseline. We should expect a baseline effect, i.e. the placebo effect, in the short term. The question is what happens after 9 months with the baseline. Is it back to zero or not? What are the implications?

If baseline after 9 months is zero:

1) no placebo effect after 9 months and the placebo is only in the short term.


2) no measurement bias in the sense that repeated measurement leads to increased fluency due to adaptation to measurement environment.

If baseline is significantly non-zero i.e. increased fluency:

1) placebo effect after 9 months. (I find this unbelievable. What does this say about stuttering?)


2) MEASUREMENT BIAS THAT MUST AFFECT ALL OUTCOME STUDIES. We need to reduce the outcomes by this measurement bias effect.


Gustaf said...

Good point. The Pagoclone trials will tell us more than whether Pagoclone itself works. I'd also be very surprised if the placebo effect wasn't gone in 9 months.

Ora said...

Or if the placebo bias is still non-zero after 9 months ... get me some of that placebo pill!

Mark B. said...


Stutterers who effectively "cure" themselves frequently report that the critical element to their success was "confidence." So there's your placebo.

Anonymous said...

Mark - Sounds great. Where can I get some of this "confidence"? I don't happen to have any myself. (That's my problem, I think.)

Anonymous said...

I was on the initial trial for 8 months. Minimal improvement, no side effects. Switched to open label, again minimal improvement, negative side effects that became too much. I dropped out 8 weeks into the Open Label phase. This pretty much showed me I was on the placebo for 8 months, or a very weak dosage