Significant interactions between pretreatment cognitive function and treatment were found for cognitive composite ( P = .01 ) , immediate recall ( P = .05 ) , delayed recall ( P = .004 ) , attention ( P = .01 ) , visuomotor skills ( P = .02 ) , and motor speed and dexterity ( P < .001 ) , with the benefits of donepezil greater for those who were more cognitively impaired before study treatment .