Have you seen the documentary "7 second memory man" on BBC.

It is about an intelligent person who is confined to live with only 7 second memory. He keeps a diary recording his entries. As he reads past entries, he realises the predicament he is in and considers that his case would be interesting to doctors. Then forgets all about that. Rediscovering the whole thing again in the next 7 seconds for himself anew.

44:20 @ https://youtu.be/k_P7Y0-wgos