Non-invasive measuring of load-induced electric potentials in diarthroidial joints
AssigneeCorporation De L'ecole Polytechnique De Montreal
InventorsPierre Savard, Michael Buschmann, John Hardin
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Abstract
There is described a method for non-invasively measuring electrical activity in a joint of a subject, the method comprising: removably attaching in a non-invasive manner at least two electrodes to a skin surface around an articulation comprising the joint; generating electroarthrographic potentials within the joint by loading the articulation; capturing the electroarthrographic potentials using the at least two electrodes; discriminating between electroarthrographic potentials originating from joint tissue activity and those from other sources; and generating measurement signals representing the electrical activity of joint tissue.
Claims24
1- A method for non-invasively measuring electrical activity in a joint of a subject, the method comprising:
- removably attaching in a non-invasive manner at least two electrodes to a skin surface around an articulation comprising the joint;
- generating electroarthrographic potentials within the joint by loading the articulation;
- capturing said electroarthrographic potentials using said at least two electrodes;
- discriminating between electroarthrographic potentials originating from joint tissue activity and those from other sources;
- and
- generating measurement signals representing the electrical activity of joint tissue.
2- The method of claim 1, wherein said generating electroarthrographic potentials comprises loading the articulation with one of electromechanical means, piezoelectric means and manual means.
3- The method of claim 1, further comprising displaying said signals generated in the form of an electroarthrogram.
4- The method of claim 1, further comprising placing at least one of goniometers, accelerometers and sensors adjacent to the joint to measure at least one of an angle of the joint and measuring forces exerted by the subject during loading.
5- The method of claim 1, wherein said discriminating between electroarthrographic potentials originating from joint tissue activity and those from other sources comprises subtracting at each instant in time a weighted average of electrical potentials originating from the electrodes so as to measure the electroarthrographic potentials with respect to an absolute reference.
6- The method of claim 1, wherein said discriminating between electroarthrographic potentials originating from joint tissue activity and those from other sources comprises band pass filtering.
7- The method of claim 1, wherein said discriminating between electroarthrographic potentials originating from joint tissue activity and those from other sources comprises low pass filtering.
8- The method of claim 1, wherein discriminating between electroarthrographic potentials originating from joint tissue activity and those from other sources comprises high pass filtering.
9- The method of claim 1, further comprising displaying said signals generated in the form of sequences, movies, isopotential maps or 3D potential surfaces.
10- The method of claim 1, further comprising calculating electrical sources within the joint and representing said electrical sources as electric fields, currents, polarization or charges.
11- The method of claim 1, wherein said discriminating comprises discriminating between potentials originating from cartilage and those from other sources.
12- The method of claim 1, wherein said removably attaching in a non-invasive manner at least two electrodes comprises selecting at least two electrodes from the group consisting of electroencephalographic electrodes, self-adhesive electrocardiographic electrodes and electrodes embedded in a cuff or a sleeve adapted to fit around the joint.
13- The method of claim 1, wherein said removably attaching comprises evenly placing the electrodes in contact with the skin surface around the joint.
14- The method of claim 1, wherein said removably attaching comprises attaching a reference electrode and a drive electrode to inject current so as to maintain an average potential of the subject similar to that of an electrical ground of an amplifier so as to minimize electrical interference.
15- The method of claim 1, wherein said removably attaching comprises attaching electrodes having low noise.
16- The method of claim 1, wherein said removably attaching comprises attaching electrodes made of Ag—AgCl.
17- A system for non-invasively measuring an electrical activity in a joint of a subject, the system comprising:
- at least two spaced apart electrodes for contacting the skin around an articulation comprising the joint and capturing electroarthrographic potentials generated within the joint by loading the articulation;
- a processing device adapted to receive the electroarthrogaphic potentials from the at least two electrodes and to discriminate between electroarthrographic potentials originating from joint tissue activity and those from other sources;
- and
- a signal generating module adapted to receive the electroarthrographic potentials originating from joint tissue activity and generate measurement signals representing the joint tissue activity.
18- The system of claim 17, further comprising a loading device for applying a load to the articulation and thereby generating the electroarthrographic potentials in the joint.
19- The system of claim 18, wherein the loading device is one of electromechanical and piezoelectric.
20- The system of claim 17, further comprising at least one of a goniometer, accelerometer and sensor to measure at least one of an angle of the joint and measuring forces exerted by the subject during loading.
21- The system of claim 17, wherein said at least two electrodes are selected from the group consisting of electroencephalographic electrodes, self-adhesive electrocardiographic electrodes and electrodes embedded in a cuff or a sleeve adapted to fit around the joint.
22- The system of claim 17, wherein the electrodes are made of Ag—AgCl.
23- The system of claim 17, wherein the processing device is adapted to discriminate between signals originating from cartilage activity and those from other sources.
24- (canceled)