Tupelo3, thanks for your latest report.

We need to measure the placebo effect. My point was to ask whether there's any cheaper ways of doing it.

Cross over testing is one way of doing it.

Another way is to use the results from the placebo group of an earlier study. So, suppose in a trial for drug A the placebo group showed an improvement of 10%, this figure could be used to estimate the placebo effect in a trial of drug B. Before doing this we would have to be careful to ensure that both A and B were similar in regards to the placebo effect - both, for instance, carried the same hype.

The results from PDMeasure suggest that the learning effect (the improvement of test scores with practice) continues for a long time in PD. This tends to inflate the results of both the active and placebo groups. However, its magnitude could be reduced by doing more practice tests.

We need trials to measure the placebo effect.

(Would the placebo in a placebo trial be an active treatment?)

John