Home-Based Monitor for Gait and Activity Analysis

Our innovative device uses Magneto Inertial sensors to precisely capture movements and dedicated algorithms to precisely qualify and quantify the motor activity of specific subject within a non-controlled environment. The use of a continuous in-home-based activity measurement device, allows an objective, and more globally representative assessment of both ambulant and non-ambulant subjects. This device was initially developed to precisely measure the activity of neuromuscular patients.

But, it can be used for a broad variety of pathologies in patients suffering movement, gate, and activity disruptions. Currently, the device is being used as an exploratory outcome measure in clinical trials for neuromuscular and neurologic diseases. Visual demonstration allow an accurate explanation of the main steps of the device set-up, including sense of placement and orientation, according to the required configuration.

To prepare for a participant’s visit to the clinical center, first check the suitcase contents. The suitcase should contain the docking station to plug in the sensors during the night for data uploading onto a USB key and the battery recharging;The power cord, divided into two pieces, to connect the docking station to a power supply;The ethernet cable to permit interface with a router;the two sensors to permit daily activity recording;one participant manual, and one task reminder, bands for attachment of the sensors depending on the chosen configuration and ambulatory status of the participant;a second participant manual and an investigator manual, a screw driver to enable replacement of the USB key;and blank USB keys. Then print and prepare the assignment form to record the assignment of a device to a participant, to enable data reconciliation with a subject ID.To position the wearable Magneto Inertial sensor on an ambulant participant, fix one sensor on the wrist of the dominant hand using the provided bracelet, so that the waves are pointing towards the fingers.

Place the second sensor on the ankle, on the same side as the wrist sensor, above the external malleolus with the waves pointing in the forward direction. For the ankle-ankle configuration, place one shoe sticker on each sensor, following the curve of the wave, and place the appropriate sensor on each ankle above the external malleolus. The sensors are placed appropriately if the stickers are upright and pointing in the forward direction.

To position the wearable Magneto Inertial sensor on a non-ambulant participant, place one sensor on the wrist of the participant’s dominant hand using the provided bracelet, so that the waves are pointing towards the fingers. Place the second sensor in the provided bag, and attach the bag to a safe place on the wheelchair. The sensor should fit tightly, but not too much to the wrist and/or the ankle to prevent them from spinning around.

Also, the participants should not switch the sensors’positions. After explaining the sensor positions to the participant, explain the daily routine for the sensors use. The first evening, the participant should plug the docking station into the power supply, and attach the docking station to the router, if an internet connection is available.

Every evening, the participant should insert the sensors into the docking station. The two Light Emitting Diodes, or LEDs on the docking station, should become orange, to indicate that the sensor batteries are charging, and that the data is being downloaded from the sensors to the USB drive. Every morning, the participant should verify that the LEDs are green, indicating that the sensor batteries are fully charged, and the data has been cleared from the sensor memory.

The participant should then remove the sensors from the docking station, and put on the sensors in the configuration demonstrated by the evaluator. The participant should keep the sensors on throughout the day, before placing the sensors back on the docking station at the end of the day. The sensor should be removed, and kept on a safe, firm surface during activities involving water, special medical examinations, or any other activity that could be damaging.

At the end of the recording period, the participant should place all of the items neatly back into the suitcase and bring the device back to the clinical center. The participant should then complete a dedicated assignment form. If the docking station cannot be connected to the internet, use the screwdriver to remove the USB drive from the docking station, and replace the drive with a blank USB drive at the end of the recording period.

Then send the USB drive to the support team for analysis. At selected time points during the study, have the analyst extract the data from the cloud storage, and analyze the data using a dedicated algorithm, adjusting the analysis periods and the monitoring reports based on the clinical study. The wearable Magneto Inertial sensor allows variables, such as the norm of angular velocity, the ratio of the vertical component of the acceleration to the overall acceleration, the elevation rate, and the computed power to be identified for the clinical characterization of the upper limb activity of the participants in a controlled environment.

The device also allows the identification and measurement of each single stride of a participant over a long time period, enabling analysis of the distribution of all of the captured strides, as well as the calculation of the centile of stride speed and length. Several parameters measurable by this wearable Magneto Inertial sensor, are less sensitive to change than the 95th centile stride velocity, but are closely related to quality of life, such as the distance walked per hour, and the number of falls per hour. Testing of the precision of the gate trajectory in controlled participants using an optokinetic system confirmed an excellent agreement between the trajectories measured by the optokinetic system, and the Magneto Inertial sensor.

Remember to use the device according to the manual and clinical trial requirements, and to make sure each participant meets the eligibility criteria for using the device. Additional applications of our device include the evolution of patients with multiple sclerosis or Parkinson’s disease. In these conditions, connected devices have already been tested, but we’re still missing validated, sensitive, and reliable outcome measures that could be qualified by the regulators.