Endoscopic Third Ventriculostomy vs. Ventriculoperitoneal Shunt in Idiopathic Normal Pressure Hydrocephalus (ENDOVEST)

Inclusion Criteria: * \>40 years of age * Symptom duration ≥3 months, \<24 months * No antecedent head trauma, ICH, meningitis, or other cause of secondary hydrocephalus * MUST show gait/balance disturbance, PLUS cognition impairment AND/OR urinary dysfunction. * Ventricular enlargement (Evans Index \> 0.3) not attributable to cerebral atrophy or congenital enlargement * No macroscopic obstruction to cerebrospinal fluid (CSF) flow Spinal Tap-Test * Opening pressure (on lateral decubitus): \<24cmH2O * Clinical improvement in at least one of the main symptoms after 40-50ml withdrawal of CSF Exclusion Criteria: * ≤40 years of age * No informed consent * Other neurologic, psychiatric or general medical condition which is sufficient to explain the presenting symptoms. * Previous cranial neurosurgical interventions * Other associated dementia syndromes * Incapacity to walk * Pregnancy and breastfeeding women