I am trying to understand my dad who is in his 66 years old. The early signs you wrote here were what he had too, like sudden falling down and so on. I wanted him to go for a medical checkup but it is so difficult. He refused. My mom termed him as dementia but we are not doctors and health professionals. While i am in isolation now, I happened to remember what my mom suspected of my dad's recent behavior. At least this article gives some insights to it. I did not even know Alzheimer disease is under Dementia. Thank you for sharing your thoughts and findings. My dad still won't go see a doctor.