Idiopathic Normal Pressure Hydrocephalus (iNPH) is a reversible form of dementia and gait imbalance in the elderly that has been treated with surgical ventriculoperitoneal shunting (VPS). Although VPS has been performed for decades, the effectiveness of VPS has not been tested in an appropriately run placebo-controlled clinical trial. Due to the lack of data from placebo-controlled trials, skepticism about VPS in the elderly has significantly limited its use. The primary goal of this research proposal is to gather data with the goal of a definitive answer on the question of whether shunt surgery offers a benefit to patients with iNPH. We will accomplish this through a prospective, blinded, randomized placebo-controlled clinical trial that uses a contemporary FDA approved adjustable shunt system. This valve allows a “virtual off” setting allowing for noninvasive and reversible assignment of patients to treatment with a functioning (active group) or non- functioning (placebo group) shunt. The trial will enroll 100 iNPH patients at 20 sites. Participants selected for shunt surgery will be chosen based on standard and widely used iNPH guidelines. The trial is a delayed treatment paradigm where all 100 patients will receive the same surgery and device, differing only in the initial valve setting (active or placebo). The Primary analysis will be a group comparison of change from baseline in gait velocity at three months after implantation. Secondary analysis will measure balance, cognition, and bladder control. Three months after implantation, all participants in both groups are blindly adjusted to the active setting and followed for 9 months. A secondary goal of the study is to evaluate clinical, imaging, and CSF biomarkers before surgery to identify associations with subsequent shunt response. MR imaging and extended neuropsychological testing are also repeated after shunting to evaluate specific anatomical and cognitive domain changes that may be associated with gait changes. We expect that if we demonstrate the effectiveness of shunting in iNPH we will establish an effective treatment and facilitate an increase in appropriate iNPH shunting. In addition, the study of patient biomarkers associated with successful outcomes will allow future testing of algorithms for more accurate and efficient patient selection. Identification of subgroups of iNPH patients with improvement may also be suggested. Data from this controlled trial can ultimately benefit the 300 to 700 thousand iNPH patients in the US to receive an effective surgical treatment. If data shows that shunting is found to be ineffective in the placebo group, elderly patients will be spared the potential morbidity and cost of an ineffective brain surgery.

This trial aims to provide strong evidence of the effectiveness of shunting excess fluid from the brain for the surgical treatment of Idiopathic Normal Pressure Hydrocephalus (iNPH), a potentially reversible form of dementia and imbalance in the elderly. In addition, this study evaluates patient features to accurately identify people who may benefit. With this evidence, there can be an increase in the number of the 300-700,000 patients in the US with iNPH that can be treated and live more independent lives.