[Successful outcome of VP shunt operation in 3 cases of idiopathic normal pressure hydrocephalus with long duration of illness].

Three cases (70- and 83-year-old females and 77-year-old male) with cognitive impairment, gait disturbance and urinary incontinence for 8 to 15 years were diagnosed as idiopathic normal pressure hydrocephalus (iNPH) according to the iNPH guideline in Japan (2004). All were operated by ventriculo-peritoneal shunt and had a good outcome despite their long duration of illness. Two of the three cases had been earlier diagnosed as progressive supranuclear palsy (PSP). because they had vertical gaze palsy. Some iNPH patients with vertical gaze palsy clinically might be misdiagnosed as PSP.