Can a walking test spot pre-dementia condition?
22nd February 2018 – Doctors say they may have found a test for a cause of dementia that can sometimes be reversed.
They say analysing how someone walks could hold the key.
A condition called idiopathic normal pressure hydrocephalus (iNPH), caused by excess fluid in the brain, shares symptoms like walking, balance and thinking problems with other brain conditions, particularly progressive supranuclear palsy (PSP), which is caused by damage to nerve cells in the brain.
There is no cure for PSP, although treatment can ease symptoms. However, some patients with iNPH do recover if treated.
Older people are often wrongly diagnosed with disorders such as Parkinson's disease and dementia when their symptoms are actually caused by iNPH. An accurate diagnosis is challenging.
A small German study, published online in the journal Neurology, involved 27 people with iNPH, 38 people with PSP, and 38 healthy people in a 'control' group.
Those with PSP and people in the control group had an average age of 69. Those with iNPH had an average age of 72.
All those taking part received brain scans, eye examinations, and took part in thinking and memory tests.
All the participants were asked to walk on a 22-foot long carpet fitted with pressure sensors. First, they were asked to walk very slowly, then at a speed they felt most comfortable at, and finally as fast as they could manage.
As they walked, they were also asked to count backwards, and later walk while carrying a tray.
Researchers found that walking while counting backwards resulted in a greater reduction of walking speed in those with PSP than in those with iNPH. Walking speed was reduced by 34% in those with PSP but only by 17% in those with iNPH.
The team, led by Ludwig Maximilian University of Munich, say that they were able to accurately diagnose who had PSP and who had iNPH 82% of the time by just examining participants' gait.
However, when adding both dual-task tests to the assessment, diagnostic accuracy increased to 97%.
The authors note an additional discrepancy in the findings. When walking while carrying a tray, gait worsened for those with PSP. But it improved for those with iNPH. They say this might reflect that a dual-task test is not sufficiently challenging for those with iNPH.
"In future studies, it would be interesting to increase the task complexity (i.e., by adding a glass filled with water) to test whether the improvement trend observed here becomes significant," they write.
Dr James Pickett, head of research at the Alzheimer’s Society, comments in an emailed statement: "Many people experience unacceptable delays in getting a diagnosis, so any test or technique that can improve this is a welcome development."
He adds: "If people are worried about their memory or thinking, it’s important that they have access to a timely and accurate diagnosis in order to find out the cause."