The primary objective of this study is to test the hypothesis that Nuedexta (20/10) administered orally will reduce Pseudobulbar Affect (PBA) frequency and severity (CNS-Lability Scale and PLACS), with satisfactory safety and high tolerability in patients with Alzheimer's Disease (AD). The primary objective will be evaluated using a study endpoint at 1, 13, 26 weeks after initiation of treatment. The secondary objective of this study is to evaluate the benefit of treatment with Nuedexta (20/10) on cognition and functionality as demonstrated in the Rey Auditory Verbal Learning Test (RAVLT), Trail making A and B, Wechsler Memory Scale (WMS) logical memory and delayed recall, Controlled Oral Word Association (COWA), Clinical Dementia Rating (CDR), Neuropsychiatric Inventory (NPI), Alzheimer's Disease Cooperative Study Activities of Daily Living Inventory (ADCSADL) and the 11-item Alzheimer's Disease Assessment Scale-Cognitive subscore (ADAS-Cog11).