N Engl J Med

Does shunt surgery improve gait in idiopathic normal-pressure hydrocephalus?

September 24, 2025

Results of this randomized trial confirm that shunting improves gait and balance in idiopathic normal-pressure hydrocephalus (iNPH) patients responsive to cerebrospinal fluid (CSF) drainage. These findings support broader use of diagnostic CSF testing and early surgical intervention to reduce fall risk and improve mobility in older adults.

Study Details: The PENS trial (NCT05081128) was a double-blind, randomized, placebo-controlled study evaluating shunt surgery in older adults with iNPH who had shown gait improvement after CSF drainage. Ninety-nine participants were randomized to receive either an open-shunt valve (110 mm H₂O) or a placebo valve (>400 mm H₂O). Primary endpoint was change in gait velocity at 3 months; secondary endpoints included balance (Tinetti scale), cognition (Montreal Cognitive Assessment), and urinary symptoms (Overactive Bladder Questionnaire).

Results: At 3 months, the open-shunt group showed a significant improvement in gait velocity (+0.23 m/s vs. +0.03 m/s; P<0.001) and Tinetti scores (+2.9 vs. +0.5; P=0.003). No significant differences were observed in cognitive or bladder outcomes. In terms of adverse effects, a higher proportion of participants in the placebo group experienced falls (46% vs. 24%). Both groups had an equal incidence of cerebral bleeding (2%). However, subdural bleeding was more common in the open-shunt group (12% vs. 2%), as were positional headaches (59% vs. 28%).

Source:

Luciano MG, et al; PENS Trial Investigators and the Adult Hydrocephalus Clinical Research Network. (2025, September 16). N Engl J Med. A Randomized Trial of Shunting for Idiopathic Normal-Pressure Hydrocephalus. https://pubmed.ncbi.nlm.nih.gov/40960253/