I believe that memories are recorded at two levels. Every memory synapse has a factual core and an emotional context. The emotions can take up much more “RAM” so to speak, than the simple facts themselves. The more sensitive a person you are, the more emotions are stored with each memory. Post Traumatic Stress Disorder is a condition in which a huge load of negative emotions are recorded. I have personally found a remedy in my two knees that have bone-on-bone contact. If I focus the sharp knee pain on the painful negative memories, they slowly lose their strength and the mind clears. As they say, no pain no gain! In my own situation, when I do not do my knee exercises then the pain in my knees becomes quite bad and I am able to use this pain to clear the fuzz from the brain after prolonged stressful periods. The moral is that older people with arthritis and chronic pains can use this pain to clear the unnecessary emotions out of their mind and avoid Alzheimers that way. It’s not an easy thing to do, this emotional focusing; but with practice and a little training in medication and relaxation (or prayer, if you are a religious person) you will get there OK.