Power projections. The figure provides power projections for four different study designs in order to assess NeuroHAART effect on neurocognitive or CSF HIVRNA suppression (i.e., panel 1 illustrates a cross-sectional design; panel 2 a longitudinal design; panel 3 an univariate regression model design, and panel 4 a multi-variable regression model design). The first part of the power projection is dedicated to sample's comparisons and the second part to the testing of the magnitude of the neuroHAART effect on neurocognitive functions or CSF HIV RNA. For each panel, power projections were computed to detect a small, medium and large effect size. In each panel, the six studies found to be of "appropriate quality" were rated against the power's projection for their relevant design and arrows indicates the N enrolled for each study. In addition a red circle in each power panel indicates the criterion against which studies were defined as having "appropriate versus non-appropriate power" and this was selected for the medium effect size.