Coming soon: Force Sensor for gait cycle analysis and many other use cases
by Dr. Alex Kreilinger
Technical Product Manager (Brain Products)
With the addition of the Force Sensor to our sensor portfolio, we broaden the range of possible research scenarios.
The solution consists of
- a ~20 cm long flexible foil that ends in a flat sensor area of 9.5 mm diameter
- optional load concentrator discs (diameter: 7.1 mm) that can be used to better transfer external force on the sensor area
- a preamplifier that converts the signal from the sensor into a signal that makes it compatible with all the amplifiers in the Brain Products portfolio
- a strap to fix the preamplifier in place during mobility tasks
The most obvious use case of the Force Sensor is certainly gait cycle analysis. However, it can also be used in many other situations. The input range is high enough to allow measurements that require the detection of very low or high forces. For example, finger tapping to measure reaction times or jumping to obtain contextual information of the activity of a test participant.
The flexible sensor can be placed anywhere on a human participant, but also on objects that are handled by a person or that interact with other objects. For mobile scenarios, a combination with LiveAmp and the Sensor & Trigger Extension (STE) is the ideal fit, but of course the Force Sensor can also be used in lab-based experiments with an actiCHamp (Plus) or a BrainAmp amplifier.
We are very excited to soon offer this new sensor to help create even more possibilities for your future research.
Here are some suggestions where the Force Sensor may come in handy
1. Creating triggers while walking to analyze EEG signals depending on the pattern of the movement
Using the strap and the 150 cm long 5 pin sensor connector cable, it is easy to fix the preamplifier in a place close to the heels of the participant:
In such a scenario, the Force Sensor would be attached directly where the foot contacts the ground. Depending on the task, putting on socks and shoes is no problem. On the contrary, it even helps to keep the sensor in place and your participants won’t even notice its presence as they can move around freely.
With the detected force, it is easy to create triggers that indicate the start of each gait cycle:
Figure 1: Averaged walking force in relation to triggers created based on the force signal itself and signal of the force over time during a section of walking.
2. Using the Force Sensor to detect reactions and to measure reaction times
Another potential experiment involves attaching the Force Sensor to an object instead of a person, for example a button or a key on a keyboard:
Figure 2 shows results based on measuring the force while pressing a key as soon as an auditory cue was presented.
In this case, triggers were created by the stimulus presentation software.
Figure 2: Averaged force recorded during key presses (notice the reaction time of around 180 ms) based on auditory cues. On the right, the force signal is displayed over a short section of the experiment.
As you can see, the sensor provides easy to distinguish signals in high and low force scenarios.
Of course, these were just two ideas. We are curious to see what you will come up with and we are looking forward to reading about your reports and are happy to answer any questions or suggestions you might want to share with us.
Follow us on social media or keep in touch with your local distributor for information about the availability of the Force Sensor – soon to come!