Summary: This research is being done to assess the quality of life and symptom burden in participants who receive (normal tissue sparing whole brain radiation therapy (NTS-WBRT). This research study involves: * NTS-WBRT (normal tissue sparing whole brain radiation therapy) * Memantine standard of care drug

Summary: The goal of this clinical trial is to demonstrate potential improvements in clinical trial methods relating to dementia and cognitive decline. The main questions it aims to answer are: * Can an intervention's outcome be better assessed by a latent variable (δ) integrating cognitive performance with functional status? * Can latent biomarkers of δ guide the selection of an intervention that will mod...

Summary: Stereotactic radiosurgery (SRS) is a commonly used treatment for brain tumors. It is a one-day (or in some cases two day), out-patient procedure during which a high dose of radiation is delivered to small spots in the brain while excluding the surrounding normal brain. Whole brain radiation therapy with hippocampal avoidance (HA-WBRT) is when radiation therapy is given to the whole brain, while tr...