Inclusion Criteria:
1. Signed an Institutional Review Board (IRB) approved informed consent document indicating that they understand the purpose of and procedures required by the study protocol and are willing to participate in the study and comply with all its procedures and restrictions. Informed consent must be obtained from the patient and/or a designated representative prior to initiating screening procedures to evaluate their eligibility for the study.
2. Aged 50 - 79 years inclusive.
3. Meet the diagnosis of probable AD consistent with:
* Revised National Institute on Aging-Alzheimer's Association (NIA-ADA) criteria and
* Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) criteria.
4. Of mild to moderate severity: Mini-Mental Status Exam (MMSE) score 10 - 24 inclusive.
5. Rosen-Modified Hachinski Ischemia Score of ≤4.
6. Have a suitable caregiver to supervise the at-home administration of study drugs and observe for AEs.
7. Treated with donepezil 10 mg/day (given once daily) for at least 4 weeks just prior to study entry and to have safely tolerated, as judged clinically by the investigator.
8. Patients must be in generally good health as indicated by their medical history and physical examination, vital signs, electrocardiogram (ECG), and standard laboratory tests.
Exclusion Criteria:
1. Women of child bearing potential.
2. History or presence of a seizure disorder.
3. History of uncontrolled peptic ulcer disease, urinary or gastric retention; asthma or obstructive pulmonary disease.
4. History or presence of uncontrolled bladder outflow obstruction, gastrointestinal obstructive disorder or reduced gastrointestinal motility, or narrow-angle glaucoma.
5. Renal and hepatic dysfunction with:
* Total Bilirubin: \>1.5 x UNL
* AST: \>2.5 x UNL
* ALT: \>2.5 x UNL
* Serum Creatinine: \>1.5 x UNL
* Creatinine Clearance: \<30 mL/min (calculated by Cockcroft and Gault equation)
6. History or presence of myasthenia.
7. History of Prolonged QT Syndrome.
8. History of unexplained syncope.
9. Myocardial infarction or hospitalization for congestive heart failure within 6 months.
10. Patients has implanted cardiac pacemaker, implantable cardiac defibrillator (ICD), or metallic objects located in the eye, neck, ear, brain or blood vessel walls.
11. ECG findings of:
* Complete Left Bundle Branch block;
* Ventricular pacing;
* 2nd degree or 3rd degree AV block;
* Atrial fibrillation or atrial flutter;
* Heart rate \<45 or \>100;
* PR \>220 msec; or
* QTcF \>450 msec in male, \>470 msec in female
12. Patients treated with the following medications within 8 weeks of screening
* AChEIs (other than donepezil),
* Peripherally acting anticholinergics (such as drugs for the treatment of overactive bladder disorder),
* Psychoactive medications (including antipsychotics, antidepressants, anxiolytics or sedative hypnotics) having significant anticholinergic effects and/or believed to affect cognitive function.
Other medications are acceptable, at the investigators discretion, if dosage is held stable for at least 4 weeks prior to screening and throughout the study.
13. Claustrophobia
14. Patients considered unlikely to cooperate in the study, and/or poor compliance anticipated by the investigator.
15. Any other clinically relevant acute or chronic diseases which could interfere with patients' safety during the trial, or expose them to undue risk, or which could interfere with study objectives.
16. Patients who have participated in another clinical trial with an investigational drug within previous 30 days.
