We live our daily lives with a connection to what has happened before and anticipation of what will happen in the future. Those experiencing dementia have diminishing cognitive skills and lose this connection to the past & future. Therefore it is like they are living their lives one movie frame at a time.
As their dementia progresses, they will experience this more and more. They may not connect to what has just happened before and are instead living in the moment of now.
I encourage you to keep this in mind when connecting and interacting with your companion with dementia. Think about how they are experiencing the world and look to use more compassion and empathy in your time with them.