Changes in Walking Patterns Could Help Predict FAP, Portuguese Study Reports

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by Alice Melao |

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Changes in the way that people with a certain gene mutation walk could help doctors make an early determination that they have a neurodegenerative condition known as familial amyloid polyneuropathy, a study reports.

TTR mutation is a hallmark of transthyretin familial amyloid polyneuropathy, one of a number of versions of familial amyloid polyneuropathy. The disease that the mutation generates is called TTR-FAP.

Researchers titled the walking-patterns study they did “The First Transthyretin Familial Amyloid Polyneuropathy Gait Quantification Study – Preliminary Results.” They published it in the proceedings of the 39th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. The convention was on Jeju Island, Korea, in July 2017.

TTR-FAP is a rare disease that mostly affects peripheral nerves, or those outside the brain and spinal cord. It usually develops three stages: loss of sensation, walking disability, and severe physical impairment leading to wheelchair use or a patient becoming bedridden.

Several studies have reported that damage to nerve cells that control movement, muscle atrophy, walking impairment, and loss of balance can be early symptoms of the disease. No studies have addressed whether changes in walking patterns can help diagnose the condition. however.

A Portuguese research team led by João P. Cunha, an associate professor at Universidade do Porto, wanted to see if a non-intrusive video system could be used to assess TTR-FAP patients’ walking patterns.

The goal was to identify “gait differential characteristics” that could help doctors with “disease diagnosis or motor [movement] impairment onset prediction,” the team wrote.

They used a Microsoft Kinect system, which can capture joint and skeletal changes while a person is moving. The portable, low-cost system offers information similar to that collected with expensive, very precise laboratory equipment, studies have shown.

The Kinect system can measure both the timing of movements such as walking and how the movements appear in space. The team had already demonstrated the system’s potential in an assessment of Parkinson’s disease patients.

Researchers conducted their study at Hospital Santo António in Porto. The nine participants included four carriers of the TTR mutation and five healthy volunteers.

Three of the TTR-FAP patients were in the early stages of the disease while the fourth had yet to develop symptoms, neurologists said. Three patients were receiving Vyndaqel (tafamidis) for their condition.

Researchers captured patients’ skeletal movements and other information as they walked about 16 meters. The team asked the participants to walk five to 12 times, depending on their gait difficulties.

TTR mutation carriers walked slower, had a shorter stride, and took longer to complete a walking cycle than controls, researchers said. The differences could stem from TTR-FAP patients being more cautious about walking than healthy people, the team said. They called for additional studies on the matter.

“This preliminary study represents the first steps in the characterization, diagnosis, and follow-up of TTR-FAP based on gait parameters” using a camera-based system in a hospital, the researchers wrote.

The advantage of the camera set-up the team used was that it is “a non-intrusive and markerless system that enables the assessment to be performed at the hospital and without causing constraints or stress to the patients nor difficulties to the medical doctors or routine,” they wrote.

They are planning additional research on gait analysis’ potential to help doctors diagnose FAP in people with TTR mutations and help doctors predict its outcome.