How well can you do two things at once? For people with certain forms of dementia, the answer is quite telling.

Background: A neurological condition known as idiopathic normal pressure hydrocephalus (iNPH) causes symptoms that are often confused with other forms of dementia. When iNPH is misdiagnosed, it’s particularly troubling because the symptoms caused by this condition—unlike other forms of dementia—are reversible.

iNPH is caused by excess fluid in the brain, and its symptoms include walking, balance and thinking problems. Because it is so often misdiagnosed, researchers wanted to find a way to help doctors easily identify it. Here’s what they came up with…

Recent study: Among its symptoms, iNPH causes a distinctive gait disturbance (including difficulty starting to walk and a feeling that the feet are stuck to the ground), so researchers devised a test that involves walking while simultaneously performing a simple task that challenges a person’s thinking skills. The speed with which the tasks could be performed was surprisingly accurate in identifying people who had iNPH.

“It is important that people with idiopathic normal pressure hydrocephalus are accurately diagnosed so they can be treated, and their health can improve,” explained study author Charlotte Selge, MD, of the Ludwig Maximilian University of Munich in Germany.

Study details: In this study, published in Neurology, 27 people with iNPH…38 people with progressive supranuclear palsy (PSP), an incurable condition caused by damaged nerve cells in the brain…and 38 healthy people used as controls walked down a 22-foot-long pressure-sensitive carpet at three different speeds—slow, comfortable and as fast as possible. By assessing the awkwardness of their gaits, researchers were able to accurately identify 82% of the time which participants had iNPH and which had PSP.

The participants were then asked to repeat the walking test while also counting backward…and then while carrying a tray. When the results of the dual-task tests were added to the researchers’ original assessments, their diagnostic accuracy jumped to 97%.

Why this matters: When correctly diagnosed, a person with iNPH can receive a surgically implanted shunt that drains excess fluid from the brain to reverse symptoms. More than 80% of people who are properly diagnosed and screened before receiving the surgery will experience rapid improvement of their symptoms—though it may take weeks or months for the full benefits to become apparent, according to the Hydrocephalus Association. People diagnosed early have a higher chance of successful treatment. In future studies, researchers may add more tasks to the test or increase the difficulty of the tasks to boost its diagnostic power even more.

Bottom line: If you or someone you know has symptoms of dementia—including problems with memory, concentration and reasoning—talk to a doctor about the possibility of iNPH. A simple walking test could be an easy, inexpensive way to determine whether the cause of those symptoms is a treatable condition.