This study aims to compare the changes of Timed Up and Go (TUG) and its imagined version (iTUG) after CSF tapping between patients with idiopathic normal pressure hydrocephalus (iNPH) and its mimics. TUG and iTUG were performed before and 24 h after CSF tapping in 117 patients (75.8 ± 6.9 years; 35% female) with suspicion of iNPH (68 iNPH and 49 mimics). Mental imagery of locomotion was modified after CSF tapping in iNPH patients, but not in the mimics.