他這種沒有腦水腫,腦震蕩?
順便說下,自行車頭盔不保護腦震蕩(concussion)"While helmets don’t protect against concussions, they have consistently proven to reduce severe head injury and death for cyclists."
https://www.discovermagazine.com/health/the-science-behind-bicycle-helmets-protecting-cyclists