Pearls 
-    Idiopathic normal pressure hydrocephalus (iNPH) is characterized by the classic triad of gait disturbance, urinary incontinence, and cognitive impairment in the presence of ventriculomegaly without known risk factors for communicating hydrocephalus. Shunt surgery is indicated for iNPH patients who respond to the removal of CSF. 

Oy-sters
-    The striatal dopaminergic deficit on dopamine transporter (DAT) scan is not uncommon in patients with iNPH, which might be related to an unfavorable long-term outcome of shunt surgery. For iNPH patients with clinical features suggesting synucleinopathy such as REM sleep behavior disorder, DAT scan could be considered to identify concurrent synucleinopathy before shunt surgery. 
-    Repeated removal of CSF could be considered as an alternative treatment instead of shunt surgery in iNPH patients who are ineligible for shunt surgery or have sustained improvement after CSF removal.