At 24 weeks , there were significant treatment benefits in two independent populations at the 138 mg/day dose : in moderate subjects on the ADAS-cog scale ( treatment effect : -5.42 units , corrected p = 0.047 ) and two other clinical scales ; in mild subjects on the more sensitive regional cerebral blood flow measure ( treatment effect : 1.97 % , corrected p < 0.001 ) .