Comment by bitshiftfaced

Not an expert, but see table 3. They use CANTAB as the test of cognition. Scores range from 0 (worst) to 1 (best). β = the standardized beta coefficient. You do a linear regression, where the cognition score is the dependent variable, and prebiotic status is an independent variable. The values are standardized first (x - mean)/(standard deviation). β is the slope of the regression line. They use the prebiotic group as the reference group.