For decades, controversy surrounded a deceptively common condition in older adults. Idiopathic normal pressure hydrocephalus (iNPH) affects nearly one million older Americans, yet more than 80% of cases go unrecognized or untreated, often misdiagnosed as Alzheimer's disease, Parkinson's disease, or dismissed as normal aging. The condition is commonly associated with a triad of symptoms consisting of difficulty walking, cognitive impairment, and impaired bladder control, although not everyone experiences all three symptoms. Left untreated, iNPH can lead to falls, loss of independence, and severe disability. The primary treatment has long been shunt surgery, but its effectiveness was disputed for years, leaving many patients without access to the care they needed.

That all changed in 2025. The Placebo-Controlled Efficacy in iNPH Shunting (PENS) Trial has become the first large, double-blind, placebo-controlled study of its kind, definitively demonstrating that shunt surgery improves walking and balance, reduces falls, and restores independence in older adults with iNPH. The results were published in The New England Journal of Medicine, one of the most prestigious peer-reviewed medical journals in the world. The trial was led by Johns Hopkins University School of Medicine and the Adult Hydrocephalus Clinical Research Network (AHCRN), a collaborative network that the Hydrocephalus Association helped establish and has funded since 2012. In total, there were 21 active sites in the United States, Canada, and Sweden in the study, with 17 enrolling patients. The PENS trial will continue to follow participants for 12 months to measure long-term outcomes, including cognition, daily functioning, and quality of life, with early findings already suggesting gains beyond walking.

The recognition this work has received reflects its extraordinary impact. The National Institute of Neurological Disorders and Stroke (NINDS) named the PENS Trial one of its Top 10 Research Advances of 2025, a distinction that spans basic, translational, and clinical research, further highlighting breakthroughs advancing neuroscience and improving care for people with neurological conditions. For the hydrocephalus community, this honor marks a turning point, one that will help ensure more patients are recognized, diagnosed, and treated in time to preserve their independence and quality of life.