Determining a biopotential of deep layer muscles
Determining a biopotential of deep layer muscles includes arranging electrodes on skin of a subject in a pattern corresponding to muscle tissue fibers of the subject, electrically coupling a subset of the electrodes to form a common reference node having a reference potential, and determining bipotential signal differences for separate electrodes that are not members of the first subset. For each of the separate electrodes, a biopotential difference is determined between a biopotential detected by each of the separate electrodes and the reference potential. An extent of the biopotential difference attributable to at least one deep-layer muscle is determined based on the biopotential differences. The pattern may be a two-dimensional array having columns of the electrodes arranged in a first dimension parallel with the muscle tissue fibers and a plurality of rows of the electrodes arranged in a second dimension that is orthogonal to the first dimension.
1 . A method of determining a biopotential of deep layer muscles, comprising:
arranging a plurality of electrodes on skin of a subject in a pattern corresponding to muscle tissue fibers of the subject;
electrically coupling a first subset of the plurality of electrodes to form a common reference node having a reference potential;
determining a plurality of bipotential signal differences for each electrode of a second subset of the plurality of electrodes that are not members of the first subset, including, for each of the plurality of the second subset of electrodes, determining a biopotential difference between a biopotential detected by each electrode of the second subset of electrodes and the reference potential; and
for at least one electrode of the second subset of electrodes, determining an extent of the biopotential difference attributable to at least one deep-layer muscle based on a difference between a first measured value at a first point in time of the biopotential difference at the at least one electrode and a second measured value at a second point in time different from the first point in time of a biopotential difference at an electrode of the second subset that is adjacent to the at least one electrode.
2 . The method of claim 1 , further comprising:
electrically coupling a third subset of the plurality of electrodes to form a global common mode potential that provides common mode noise mitigation, wherein the second subset of the plurality of electrodes is separate from the first subset of the plurality of electrodes and separate from the second subset of the plurality of electrodes.
3 . The method of claim 1 , wherein the pattern is a two-dimensional array having a plurality of columns of the electrodes arranged in a first dimension parallel with the muscle tissue fibers and a plurality of rows of the electrodes arranged in a second dimension orthogonal to the first dimension.
4 . The method of claim 3 , wherein the first subset of electrodes is one of the plurality of rows of electrodes.
5 . The method of claim 1 , further comprising:
storing in a first data structure, for each of the plurality of second subset of electrodes, a value indicative of the extent of the biopotential difference attributable to the at least one deep-layer muscle.
6 . The method of claim 1 , further comprising:
for each of the plurality of the second subset of electrodes, determining an extent of the biopotential difference attributable to at least one shallow-layer muscle based on the plurality of biopotential differences.
7 . The method of claim 6 , further comprising:
storing in a first data structure, for each of the plurality of the second subset of electrodes, a first value indicative of the extent of the biopotential difference attributable to the at least one deep-layer muscle and a second value indicative of the extent of the biopotential difference attributable to the at least one shallow-layer muscle.
8 . The method of claim 1 , wherein determining the reference potential and determining the biopotential difference for each of the second subset of electrodes includes using differential amplifier circuitry.
9 . The method of claim 1 , wherein the biopotential signals are triggered by motoneurons.
10 . The method of claim 1 , wherein multiple values are determined for the extent of the biopotential difference attributable to at least one deep-layer muscle by determining the difference between the first measured value at the first point in time of the biopotential difference at the at least one electrode and a plurality of measured values at a plurality of points in time different from the first point in time of a biopotential difference at the electrode of the second subset that is adjacent to the at least one electrode.
11 . The method of claim 1 , wherein each of the multiple values is analyzed to determine which of the plurality of points in time different from the first point in time result in a most accurate value for the extent of the biopotential difference attributable to at least one deep-layer muscle.
12 . A non-transitory computer readable medium containing software that, when executed by a processor, determines a biopotential of deep layer muscles using a plurality of electrodes on skin of a subject in a pattern corresponding to muscle tissue fibers of the subject where a first subset of the plurality of electrodes is electrically coupled to form a common reference node having a reference potential, the software comprising:
executable code that determines a plurality of bipotential signal differences for a second subset of electrodes that are not members of the first subset, including, for each of the plurality of the second subset of electrodes, determining a biopotential difference between a biopotential detected by each of the non-member electrodes and the reference potential; and
executable code that, for at least one of the second subset of electrodes, determines an extent of the biopotential difference attributable to at least one deep-layer muscle based on a difference between a first measured value at a first point in time of the biopotential difference at the at least one electrode and a second measured value at a second point in time different from the first point in time of a biopotential difference at an electrode of the second subset that is adjacent to the at least one electrode.
13 . The non-transitory computer readable medium of claim 12 , wherein multiple values are determined for the extent of the biopotential difference attributable to at least one deep-layer muscle by determining the difference between the first measured value at the first point in time of the biopotential difference at the at least one electrode and a plurality of measured values at a plurality of points in time different from the first point in time of a biopotential difference at the electrode of the second subset that is adjacent to the at least one electrode.
14 . The non-transitory computer readable medium of claim 13 , wherein each of the multiple values is analyzed to determine which of the plurality of points in time different from the first point in time result in a most accurate value for the extent of the biopotential difference attributable to at least one deep-layer muscle.
15 . A device that determines a biopotential of deep layer muscles, comprising:
a plurality of electrodes that are arrangeable on skin of a subject in a pattern corresponding to muscle tissue fibers of the subject, a first subset of the plurality of electrodes being coupled to form a common reference node having a reference potential; and
a digital signal processor that receives signals from the plurality of electrodes and determines a plurality of bipotential signal differences for a second subset of electrodes of the plurality of electrodes that are not members of the first subset, including, for each of the plurality of the second subset of electrodes, determining a biopotential difference between a biopotential detected by each of the second subset of electrodes and the reference potential and, for each of the second subset of electrodes, determines an extent of the biopotential difference attributable to at least one deep-layer muscle based on a difference between a first measured value at a first point in time of the biopotential difference at the at least one electrode and a second measured value at a second point in time different from the first point in time of a biopotential difference at an electrode of the second subset that is adjacent to the at least one electrode.
16 . The device of claim 15 , wherein the device is part of a system for detecting and processing biopotential signals.
17 . The device of claim 15 , wherein multiple values are determined for the extent of the biopotential difference attributable to at least one deep-layer muscle by determining the difference between the first measured value at the first point in time of the biopotential difference at the at least one electrode and a plurality of measured values at a plurality of points in time different from the first point in time of a biopotential difference at the electrode of the second subset that is adjacent to the at least one electrode.
18 . The device of claim 17 , wherein each of the multiple values is analyzed to determine which of the plurality of points in time different from the first point in time result in a most accurate value for the extent of the biopotential difference attributable to at least one deep-layer muscle.