In this interview with MEDICA.de, Stefan Lehnen explains how the zebris pressure sensor technology works, details the company’s available device solutions and describes what this type of measuring system is generally able to accomplish in the field of orthopedic care.
Mr. Lehnen, how does the zebris pressure distribution measurement platform for gait and stance analysis work?
Stefan Lehnen: The FDM measuring system uses premium capacitive force sensors that are arranged in matrix shape in various platform sizes. Each sensor has its own calibration curve. The capacitive measurement principle is similar to how a plate-type condenser works. The dielectric is located between two electrodes and determines the distance between these two electrodes. Thanks to the material properties of the dielectric and the exerted pressure on the platform, the distance between the electrodes and hence the capacity of the condenser changes.
If pressure is no longer being exerted, the dielectric returns to its original position. The advantage of the capacitive measurement principle over resistance measurement is its resistance to temperature variations.
Measurement accuracy is ensured by calibrating the individual sensors. Contrary to the resistance measurement principle, a capacitive sensor is less susceptible to wear and tear and can maintain its accuracy over years thanks to recalibration.
The resistive system relies on resistance. Exerted pressure changes the specific resistance in the measuring surface, allowing a change in voltage to be detected. The temperature must be compensated with a specific circuit. Unlike calibrated capacitive sensors, measurement with resistive systems is less accurate.
All measuring results are displayed in real-time on commercially available personal computers.
The measuring results and various automatically generated reports are displayed on the computer with just a mouse click. The report has several pages and includes a chart of the important location and time parameters, such as stance, swing and double stance phases as well as step lengths.
You have integrated this measuring system in various device technologies. What technologies does your company offer?
Lehnen: The device technologies have a broad range of applications. We offer our pressure measurement technology as a classic base plate or in addition to a treadmill.
The base plate, which is integrated under the treadmill belt, also includes a pressure sensor matrix with individually calibrated capacitive sensors. Thanks to a process that was specially designed by zebris, the movement of the treadmill is being compensated, enabling the analysis of totally stable gait and rolloff patterns.
Zebris technologies and measuring systems are already successfully implemented in medical technology but also allow valuable insights about motion sequences and human gait pattern in the sports realm. The detailed analysis of the individual parameters can help to optimize training sessions and schedules: conventional gait analysis is complemented with the avatar-aided balori e-coordination training for balance and coordination and effective training of the putter’s motion in golf.