Time distribution of last seen normal (LSN) to thrombolysis in patients with unknown time of onset (UTO). DUS, daytime-unwitnessed stroke; WUS, wake-up stroke. Time distribution of last seen normal (LSN) to thrombolysis in patients with unknown time of onset (UTO). DUS, daytime-unwitnessed stroke; WUS, wake-up stroke. Jie Zhao et al. Stroke Vasc Neurol 2019;4:3-7 © Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.