A major confounder that may potentially impact the outcome of multicenter trials is the variability of the measurements between different investigators.
One of the key factors that complicates clinical trials of SAH is the variability of the initial injury and subsequent inflammatory response.
Both these trials were small and the variability of the study protocols, comparators, outcome measures and limitations in the studies design made it difficult to reach any definitive conclusions about the effectiveness of WBV in increasing functional capacity of older persons [ 41].
These coefficients reflect whether the trial-by-trial variability of the LEP amplitude was able to predict the subjective pain intensity (βInt) and the response time (βResp).
Therefore, the observation that both reaction and response times are predicted by the trial-by-trial variability of the N2 amplitude suggests that a subset of the neural activities reflected in the vertex potential is related to the motor planning of defensive actions.
We have also integrated this approach with simulatenously collected fMRI, correlating the trial-to-trial variability of the high-spatial resolution hemodynamic response with that of the high-temporal resolution EEG.
Anyway as a control analysis, the stability of the EEG signal was tested as follows: the power spectra of ten epochs lasting 2 s each were averaged both at the beginning at the end of the free-artefact EEG trace of any subjects, since testing for stationarity of the variability of trial-to-trial power spectra required equal time intervals between consecutive observations (Kipiński et al., 2011).
Other, yet uncertain factors may explain the divergent trial results, for instance, the variability of blood glucose levels.
In a pragmatic trial, this heterogeneity reflects the variability of implementation that would be observed in a wider rollout of telehealth, thereby increasing the generalisability of the findings.
The underlying mutations causing disease in the patients tested in the clinical trials were not revealed, and the variability of individual responses to these drugs is unknown.
