Simple Walking Test Helps Diagnose a Cause of Dementia

As the population ages and the number ofpeople with dementiarises, work intensifies to find tools for making early and on-target diagnoses of the illness. Anarticle published inNeurologyonline February 21, 2018, adds to this body of research by showing how a simple analysis of how people walk — their gait — can easily help distinguish between twocauses of dementiathat often are undiagnosed and misdiagnosed.

The test, administered to 38 people diagnosed withprogressive supranuclear palsy (PSP), 27 people diagnosed with idiopathic (of unknown cause)normal pressure hydrocephalus (NPH), and 38 healthy people, was able to show who had which illness relatively early in the course of the disease.

The added effort of carrying a tray or counting backward while walking improved the accuracy of the diagnosis even more (to 97 percent accuracy). This is an “inexpensive and effective way to improve diagnosis of iNPH," says one of the study's authors, Charlotte Selge, MD, of the Ludwig Maximilian University of Munich in Germany, in a press release.

An estimated 700,000 Americans have NPH, which is caused by a fluid increase in the cavities (ventricles) of the brain. In many cases the condition can be cured by draining the fluid.

As many as 15 percent of Americans diagnosed with dementia are believed to have NPH, according to theHydrocephalus Association.

In addition to developing in older people for unknown reasons, hydrocephalus can appear in younger adults. The condition can be present at birth, be present but undiagnosed (and without symptoms for years), and develop because of an infection, brain tumor, or brain bleed.

Exact numbers aren’t available, but far fewer people are believed to have PSP, according to the National Institute of Neurological Disorders and Stroke. Nerve cell damage causes the symptoms of this incurable disorder, which involves gradual deterioration of cells in the brain stem and other specific areas. It tends to develop in males, and to start causing symptoms in people after age 60. It’s still unclear exactly what leads to PSP.

The Diagnostic Challenge of NPH and PSP

Most experienced neurologists have seen both types of disorder, saysMichael A. Williams, MD, a professor of neurology and neurological surgery at the University of Washington Medical Center in Seattle, and the vice chair of the Medical Advisory Board of the Hydrocephalus Association.

Dr. Williams says diagnosing NPH can be challenging given that the condition’s three main signs and symptoms — gait imbalance,urinary urgency and incontinence, and cognitive difficulties or dementia — are also associated with simply getting older.

When it comes to figuring out if a person has NPH or PSP, the doctor often hears and sees signs of similar issues, especially loss of balance while walking.

With PSP, falling is common, as is an unusual awkwardness and stiffness in a person’s gait. Other symptoms include eye problems, such as slowness in moving the eyes, and difficulty maintaining eye contact through the course of a conversation.

如何走研究工作

The average age of participants with PSP was 69. The average age of the control group, and of participants with NPH, was 72. All the participants had a neurological exam, an eye exam, and anMRI, and underwent tests to assess their memory and thinking.

The researchers then examined how people walked — literally how they put one foot in front of the other, and how quickly — on a 22-foot-long, pressure-sensitive carpet. They studied the participants’ gait at a slow speed, a preferred (natural) speed, and when the person was walking as fast as possible.

Researchers then asked participants to simultaneously walk the carpet while counting backward. Results showed that the walking speed of participants with PSP slowed more than that of those with NPH during this exercise.

When asked to walk while holding a tray, gait improved for people with NPH and worsened for those with PSP.

For Williams, the analysis “demonstrates things I already know; for example, in terms of gait, the feet of people with hydrocephalus tend to get farther apart, while those with PSP get closer together.” But while interesting, he says gait should be evaluated as one part of a larger picture, and that it’s vital to look at the whole person when diagnosing neurological conditions.

Dr. Selge says the next steps for her research team are to make the findings applicable in the clinical setting by “defining standard protocols and interpretation (thresholds) in guidelines.”