Peter Morgenstern, MD was the PI for Mount Sinai, an enrolling site for the multi-institutional PENS trial.
Idiopathic normal-pressure hydrocephalus (iNPH) is a disorder that primarily affects older adults, leading to difficulty with walking, balance problems, cognitive decline, and urinary incontinence. While shunt surgery to drain excess cerebrospinal fluid (CSF) has long been used as a treatment, uncertainty has remained about its true effectiveness, in part because of inconsistent results from earlier studies and the possibility of a placebo effect.
In the PENS randomized, placebo-controlled trial, researchers evaluated patients with iNPH who had first shown improvement in gait after temporary CSF drainage – a standard method for identifying likely surgical responders. Participants were assigned either to a functioning (open) shunt or to a placebo (closed) shunt, and outcomes were measured three months later. Those who received open shunts showed significant gains in gait speed and balance, confirming the motor benefits of shunting. However, no measurable improvements were seen in cognitive function or urinary control over the same short-term period.
These findings provide the strongest evidence to date that shunting offers clear and meaningful improvement in mobility and balance for appropriately selected patients with iNPH. The results also highlight the importance of careful patient selection and reinforce that the primary benefits of shunting are physical rather than cognitive in the early months after surgery.