The goal of this observational study is to develop a passive digital marker (PDM) for delirium severity and examine its performance in comparison to validated delirium severity tools in ICU patients \>50 years of age. The main questions it aims to answer are: * Is the trained convolutional neural network able to reliably measure delirium severity. * Is the Passive Digital Marker able to accurately measure delirium severity * Is the Passive Digital Marker acceptable and usable by frontline ICU nurse clinicians, patients, and their identified proxies (i.e., caregivers). Participants will: * Study participation involves a video camera recording you 24 hours per day while you are a patient in the Intensive Care Unit (ICU). * Study staff will visit you 4 times each day you are in the ICU. You will be asked questions each time they visit to train the digital marker and see differences between assessments and camera data.