When Jill Knaus arrived at the Adult Hydrocephalus Program at the University of Calgary, she was desperate for answers. Once active and independent, she suddenly needed a cane or walker to move about safely. Her gait had become unsteady, her balance unreliable, and her quality of life had deteriorated. “I wasn’t walking anymore, not properly. I wore through five pairs of shoes because my feet were dragging when I tried to step,” she recalls. “I couldn’t go for daily walks with my dog, Lucy.”
Worried about falling, Knaus reluctantly made the difficult decision to move into an assisted living facility. At 79, she felt the move had come far too soon, but she wanted the reassurance that someone would be nearby if she needed help. Her experience mirrors that of many older adults who unknowingly live with idiopathic Normal Pressure Hydrocephalus (iNPH), a brain condition often mistaken for normal ageing.
Dr Mark Hamilton, Director of the Calgary Adult Hydrocephalus Program at the Cumming School of Medicine, explains that iNPH occurs when cerebrospinal fluid builds up in the brain’s ventricles. The condition causes problems with walking and balance, cognitive decline, and bladder difficulties. Unlike other forms of hydrocephalus, which may be caused by trauma or bleeding, iNPH has no known cause. It affects about 1.5 per cent of people in their late sixties and nearly 8 per cent of those in their mid-eighties. Left untreated, it can strip away independence, increase the risk of falls, and lead to severe disability or premature death.
For years, uncertainty surrounded treatment. Many neurologists and neurosurgeons questioned whether shunt surgery—a procedure in which a small tube diverts excess fluid from the brain—was truly effective. A groundbreaking international trial has now put an end to that debate. Published in the New England Journal of Medicine, the double-blind, randomised, placebo-controlled study found that patients who received an active shunt experienced remarkable improvements in walking speed and balance after just three months. The results were so compelling that the trial was halted early.
“Completing this randomised clinical trial was necessary because many specialists were unsure whether shunts could effectively treat iNPH, which meant patients were often denied diagnosis and care,” says Hamilton, who is also a neurosurgeon at the Foothills Medical Centre and one of the study’s principal investigators. “Now, there is no doubt. Shunt surgery for iNPH improves mobility, reduces falls, and restores independence. It is both safe and effective.” Conducted at 17 centres in Canada, the United States, and Sweden, the trial showed that 80 per cent of the 49 participants with open shunts had significant clinical improvements. At the same time, those in the placebo group saw little or no change.
Although she was not part of the study, Knaus underwent shunt surgery in 2024 and has felt the benefits first-hand. “I’m walking my dog again up to four times a day without the use of a cane or walker. I’ve lost 20 pounds,” she says. “I feel much younger and happier. I’ve got my life back.”
More information: Mark Hamilton et al, A Randomized Trial of Shunting for Idiopathic Normal-Pressure Hydrocephalus, New England Journal of Medicine. DOI: 10.1056/NEJMoa2503109
Journal information: New England Journal of Medicine Provided by University of Calgary
