Terminology report from the International Continence Society (ICS) Working Group on Underactive Bladder (UAB). Issue 8 (11th September 2018) - Chapple, Christopher R.; Osman, Nadir I.; Birder, Lori; Dmochowski, Roger; Drake, Marcus J.; van Koeveringe, Gommert; Nitti, Victor W.; Oelke, Matthias; Smith, Phillip P.; Yamaguchi, Osamu; Wein, Alan; Abrams, Paul