Home-Based Monitor for Gait and Activity Analysis

Summary

This innovative device uses magneto-inertial sensors to permit gait and activity analysis in uncontrolled environments. Currently in the qualification process as an outcome measure in the European Medical Agency, one of the applications will be to serve as a clinical endpoint in clinical trials in neuromuscular diseases.

Abstract

Current outcomes in neuromuscular disorder clinical trials include motor function scales, timed tests, and strength measures performed by trained clinical evaluators. These measures are slightly subjective and are performed during a visit to a clinic or hospital and constitute therefore a point assessment. Point assessments can be influenced by daily patient condition or factors such as fatigue, motivation, and intercurrent illness. To enable home-based monitoring of gait and activity, a wearable magneto-inertial sensor (WMIS) has been developed. This device is a movement monitor composed of two very light watch-like sensors and a docking station. Each sensor contains a tri-axial accelerometer, gyroscope, magnetometer, and a barometer that record linear acceleration, angular velocity, the magnetic field of the movement in all directions, and barometric altitude, respectively. The sensors can be worn on the wrist, ankle, or wheelchair to record the subject’s movements during the day. The docking station enables data uploading and recharging of sensor batteries during the night. Data are analyzed using proprietary algorithms to compute parameters representative of the type and intensity of the performed movement. This WMIS can record a set of digital biomarkers, including cumulative variables, such as total number of meters walked, and descriptive gait variables, such as the percentage of the most rapid or longest stride that represents the top performance of patient over a predefined period of time.

Introduction

A number of potential therapies are in development for treatment of genetic neuromuscular diseases. These diseases include Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA) type 3. Subjects with these diseases present initially with proximal lower limb weakness that leads to progressive difficulties in ambulation. The final step in translational research is the demonstration of efficacy of a potential treatment or approach in a clinical trial. Specific, quantifiable, objective, and reliable measures are required. The importance of such measures was recently emphasized by the failure of the phase IIb ataluren trial¹ and the pha....

Protocol

Any use of the device must be carried out in accordance with the rules established by the reference protocol, validated by the ethics committee and the national regulatory agencies of the country. The use of the device and the various elements attached to it must be done within the intended use described in the patient's manual.

NOTE: To be eligible to use of the WMIS, patient must be over 5 years old, be able to understand and follow the usage rules, provide informed consent, be affiliate or beneficiary of a social security scheme, and be able to comply with all protocol requirements. There are no specific exclusion criteria.

Results

Data presented here were acquired during clinical trials approved by the ethics committee and the French Regulatory Agency. All patient representatives signed an informed consent.

This WMIS was first used in a clinical study setting in 2012 for controlled and home-based monitoring of upper-limb movements in non-ambulant DMD patients (NCT01611597), which demonstrated the autonomy and feasibility of device use^10<.......

Discussion

In the past decade, a number of different systems have been developed, such as an activity monitor (Table of Materials [IV]), which uses accelerometric sensors to monitor activities of daily life for energy expenditure quantification¹³. A triaxial accelerometer (Table of Materials [V]) was used by Tanaka et al.¹⁴ to monitor activity of preschool children. Lau et al.¹⁵ showed through the combination of a dual-accelero.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
ActiMyo Sensors	Sysnav	SF-000080	Wearable magneto-inertal sensors attached to the patient for movment recording
Helen Hayes marker set	Vicon	NA	Whole body jumpsuit with predefined Vicon's spots
OrthoTrak (Motion Analysis, Santa Rosa, CA, USA)	Motion Lab Systems		Gait analysis software
ActiGraph	ActiGraph Corp	GTM1	Activity monitor, used by researchers to capture and record continuous, high resolution physical activity and sleep/wake information
ActivTracer GMS LTD	GMS Co. Ltd Japan	AC-301A	Triaxial accelerometer
ADXL202E dual-accelerometer	Analog Devices	ADXL212AEZ	High precision, low power, complete dual axis accelerometer with signal conditioned, duty cycle modulated outputs, all on a single monolithic IC.
ENC-03J gyroscope	Murata Electronics	ENC-03J	Vibration Sensors
DynaPort MiniMod	MCROBERTS		Small and light case containing a tri-axial accelerometer, a rechargeable battery, an USB connection, and raw data storage on a MicroSD card
MM-2860 Sunhayato	Sunhayato	MM-2860	3-axis accelerometer
MicroStone MA3-10Ac	MA3-04AC	Microstone Co.	Acceleration sensors
RT3 Activity monitor	Abledata	NA	Triaxial accelerometer
Aparito	aparito	NA	Wearables and disease specific mobile apps to deliver patient monitoring outside of the hospital; Elin Davies, Aparito: https://www.aparito.com/
Docking station	Sysnav	SF-000118
Sensor	Sysnav	SF-000080
Bracelet (black/grey L) (black/grey S) (black/yellow L) (black/yellow S)	Sysnav	ZZ-000093 ZZ-000094 ZZ-000247 ZZ-000248
Patient manual	Sysnav	FD-000086
Ethernet cable (2 m max.)	Sysnav	IC-000458
Power cable (EU) (UK) (US)	Sysnav	ZE-000440 ZE-000441 ZE-000442
Power supply unit	Sysnav	ZE-000443
Ankle strap	Sysnav	ZZ-000462
Small bag	Sysnav	ZZ-000033