Despite being tended to on the pitch for several minutes at the Cardiff City Stadium, Demel admits that he has no recollection of the incident.
"I don't remember anything about it," he told the club's official website.
"It was hard to look at the video, but I saw some pictures so I know what happened, but I cannot remember anything for 48 hours before the incident happened. I don't remember travelling to Cardiff or the match or anything.
"I was very confused for a couple of days after it happened but now I'm feeling better. It is really hard when you cannot remember things, even if it was only for two days. I had a headache, so it was hard for a few days after, but now I'm feeling better."
West Ham are currently one point adrift of safety in the Premier League table.