Method for characterising a gait

Patent metadata

Field	Value
Publication number	US-11229380-B2
Application number	US-201615750309-A
Country	US
Kind code	B2
Filing date	Aug 5, 2016
Priority date	Aug 6, 2015
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

A method is provided for characterising a gait comprising steps of: receiving a signal measuring the movement of a target subject measured beforehand; comparing (204) at least one section of the measuring signal with a plurality of reference signals, the plurality of reference signals comprising at least one movement signal measured beforehand on a reference subject different from the target subject, each comparison of the measuring signal with a reference signal producing a similarity coefficient representative of a probability of similarity between the compared signals; and selecting (208) at least one local maximum of interest among the similarity coefficients produced, wherein the plurality of reference signals comprises at least one movement signal measured beforehand on a reference subject afflicted with a gait disorder, and at least one movement signal measured beforehand on a healthy reference object.

First claim

The invention claimed is:

1. A method for characterizing gait comprising steps of:
receiving, by one or more processors, a target motion signal previously acquired from a target subject, wherein the target motion signal is representative of a motion of a foot of the target subject;
comparing, by the one or more processors, at least one portion of the target motion signal with a plurality of reference signals,
wherein at least one of the plurality of reference signals is compared to several portions temporally shifted relative to each other of the target motion signal, so as to produce a sequence of similarity coefficients ordered according to time positions of the several portions of the target motion signal,
wherein each of the similarity coefficients is representative of a similarity probability between the target motion signal and said at least one signal of the plurality of reference signals,
wherein the plurality of reference signals comprises:
at least one motion signal previously acquired from a reference subject afflicted by a gait disorder, and
at least one motion signal acquired from a healthy reference subject;

selecting, by the one or more processors, at least one local maximum value in the sequence of similarity coefficients;
selecting, by the one or more processors, data in the at least one of the plurality of reference signals, wherein the data is associated with the at least one local maximum value, and wherein the data comprises at least one of two predetermined marker instant characteristics of a step;
identifying, by the one or more processors, at least one of two marker instant characteristics of a step of the target subject in the target motion signal, using the selected data; and
outputting, by the one or more processors to a user, the identified at least one of two marker instant characteristics to be used in diagnosis or prognosis of gait disorder.

2. The method according to claim 1 , comprising calculating, by the one or more processors, a ratio between a dimensional characteristics of the at least one of the plurality of reference signals and a dimensional characteristic of the target motion signal, and wherein identifying the at least one of two marker instant characteristics of a step of the target subject is not carried out whenever the ratio exceeds a predetermined threshold.

3. The method according to claim 1 , further comprising counting, by the one or more processors, the number of selected local maximum values corresponding to a given reference signal.

4. The method according to claim 1 , further comprising:
comparing a first similarity coefficient of the sequence of similarity coefficients and a second similarity coefficient preceding the first similarity coefficient in the sequence, so as to produce a first comparison result; and
comparing the first similarity coefficient and a third similarity coefficient following the first similarity coefficient in the sequence, so as to produce a second comparison result;
wherein
the first similarity coefficient of the sequence is selected as the at least one local maximum value depending on the first comparison result and on the second comparison result.

5. The method according to claim 1 , wherein the sequence of similarity coefficients comprises a first local maximum produced from a first portion among the several portions and a second local maximum value produced from a second portion among the several portions, wherein selecting the at least one local maximum value in the sequence of similarity coefficients comprises selecting the first local maximum, then not selecting the second local maximum whenever the first portion and the second portion temporally overlap.

6. A system for characterizing gait, comprising:
a receiving interface configured for receiving a target motion signal previously acquired from a target subject, wherein the motion signal acquired from the target subject is representative of the motion of a foot of the target subject, and
at least one processor configured to:
compare the motion signal with a plurality of reference signals,
wherein each comparison of the motion signal with one of the plurality of reference signals produces a similarity coefficient representative of a similarity probability between the compared signals,
wherein at least one of the plurality of reference signals is compared to several portions temporally shifted relative to each other of the target motion signal, so as to produce a sequence of similarity coefficients ordered according to time positions of the several portions in the target motion signal, and
wherein the plurality of reference signals comprises at least one motion signal previously acquired from a reference subject afflicted by a gait disorder, and at least one motion signal previously acquired from a healthy reference subject;

select at least one local maximum value in the sequence of similarity coefficients;
select data in the at least one of the plurality of reference signals, wherein the data is associated with the at least one local maximum value;

identify at least one of two marker instant characteristics of a step of the target subject in the target motion signal, using the selected data; and
output the identified at least one of two marker instant characteristics to be used in diagnosis or prognosis of gait disorder.

Assignees

• Univ Paris Descartes
• Centre Nat Rech Scient
• Ecole Normale Superieure Cachan
• Etat Francais—Ministere De La Defense—Direction Centrale Du Service De Sante Des Armee
• Univ Paris Xiii Paris Nord Villetaneuse

Inventors

• Dadashi Robert
• Moreau Thomas
• Truong Charles
• Vidal Catherine
• Yelnik Alain
• Barrois-Muller Rémi
• Vayatis Nicolas
• Oudre Laurent
• Vidal Pierre Paul
• Ricard Damien

Classifications

• A61B5/6831

  Straps, bands or harnesses · CPC title

• A61B2562/0219

  Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches · CPC title

• A61B5/112 Primary

  Gait analysis · CPC title

• A61B5/6829

  Foot or ankle · CPC title

• G01C22/006

  Pedometers · CPC title