Table 4

Assessment of relative power and connectivity differences on occipital electrodes between the PPR and non-PPR groups

MeasureNodeUncorrected p-valueU statisticz-scoreEffect sizeCI lower limitCI upper limit
Relative low alpha powerO10.79575−0.81−0.028−0.0950.047
Relative alpha powerO10.86562−1.10−0.078−0.130.049
Occipital connectivityO10.94543−1.52−0.76−2.180.48
  • The relative power was computed following the methods of Vaudano et al. (2017). We considered the following two frequency bands: low alpha power (6–9 Hz) as in the main analysis; and alpha power (7.5–12.5 Hz) as in the study by Vaudano et al. (2017). The occipital connectivity corresponds to the connection strength of the electrodes (i.e., sum of in-strength and out-strength; Rubinov and Sporns, 2010). The p-values, U statistics, and z-scores correspond to one-sided Mann–Whitney U tests assessing whether the relative power (or connectivity strength) is higher in the PPR group relative to the non-PPR group at a given occipital electrode. All p-values are not significant. The effect size (median difference) and confidence intervals further show that there are no statistical differences between the groups when using these measures.