The present invention relates to compositions and methods of treating a cognitive disorder in a subject by administering an effective amount of a phenserine compound or a pharmaceutically acceptable salt or ester thereof and an effective amount of a HMG CoA reductase inhibitor or a pharmaceutically acceptable salt thereof to a subject, thereby treating a cognitive disorder in the subject. A level indicator inventories the storage containers. As examples, this could be an InGaZnO, InZnO, HfInZnO, or ZnInSnO body. The control factor is computed and stored when the EGR system is switched on and the control factor is computed and stored when the EGR system is switched off.