ACTIVITY MONITOR

• US 20140012143A1
• Filed: 05/30/2013
• Published: 01/09/2014
• Est. Priority Date: 05/30/2012
• Status: Active Grant

• Current Assignee: Mayo Foundation For Medical Education And Research (Mayo Clinic)
• Original Assignee: Daniel Schwab
• Inventors: Gilbert, Barry K., Schwab, Daniel, Haider, Clifton, Felton, Christopher
• Granted Patent: US 8,849,387 B2
• Time in Patent Office: Days
• US Class Current: 600/483
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 2562/182 Electrical shielding, e.g. using a Faraday cage
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02405 Determining heart rate variability
• CPC Class Codes: A61B 5/02438 with portable devices, e.g. worn by the patient
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/1101 Detecting tremor
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval

Abstract

A monitor of a physiological parameter of subject under test to which the monitor is attached, in operation. The monitor includes a set of accelerometers operating in different ranges of acceleration and a physiological sensor. The physiological sensor may include an ECG circuit producing an output data characterizing the subject as a function of a degree of motion and/or reorientation of the monitor or an oximeter device. The process of monitoring includes a determination of R-wave of the subject.

Claims

1. An article of manufacture, comprising:

a monitor unit including, on a single integrated board,

a motion sensor enabled to collect first data representing orientation and motions of the article in multiple ranges of acceleration, the motion sensor generating a first output,

a physiological sensor enabled to collect second data representing a physiological parameter and generating a second output,

a data-logging unit including tangible non-transitory storage medium, a

a controller in operable communication with the motion sensor and the physiological sensor, the controller receiving the first and second outputs and routing data associated with at least one of the first and second outputs to said data-logging unit, and

an electrically-conducting lead electrically connected to a port of the monitor unit.

2. An article according to claim 1, wherein the physiological sensor includes an electrocardiographic (ECG) circuit in a two-electrode configuration or a three-electrode configuration.

3. An article according to claim 1, wherein the motion sensor includes multiple accelerometer units enabling, aggregately and in response to an input applied to the monitor unit, said multiple ranges of acceleration.

4. An article according to claim 1, wherein the motion sensor and the physiological sensor are operable independently from one another, said being operable including at least one of being powered, having the first and second outputs sampled in frequency, and having the first and second outputs sampled in amplitude.

5. An article according to claim 1, further comprising a clocking device connected to the controller and producing a time stamp associated with the received at least one of the first and second outputs and synchronization data.

6. An article according to claim 1, further comprising a programmable data processor in communication with the data-logging unit,

wherein the physiological sensor includes an electrocardiographic (ECG) circuit, and

wherein said storage medium has computer readable program code disposed therein which causes the programmable data processor

to process raw data acquired from a sensor to form converted data mapped to a range of voltages defined by a predetermined minimum value of voltage and a predetermined maximum value voltage;

to remove a direct-current voltage baseline from the converted data; and

to calculate a time-derivative of resulting data to increase the sensitivity of detection of an R-wave associated with a subject with the monitor unit that has been juxtaposed to the subject.

7. An article according to claim 6, wherein program code further causes the programmable data processor

to set a threshold and a refractory period, of operation of the monitor unit, that are physiologically relevant for the detection of the R-wave;

to statistically evaluate the likelihood of the presence, as represented by the second output, of a useful R-wave as opposed to an artifact; and

to ignore, for the purposes of data processing and based at least in part on extreme amounts of motion at points of predicted artifact, a time-period associated with a measurement and corresponding to a statistically corrupted R-wave.

8. An article according to claim 1, wherein the monitor unit further comprises a transmitter in operable communication with the controller, the transmitter enabled to transmit the data associated with at least one of the first and second outputs to the programmable data processor.

9. An article according to claim 1, further comprising a display unit in operable communication with the programmable data processor and enabled to form a visually-perceivable representation of a status of at least one of the first and second outputs.

10. An article according to claim 1, further comprising

a housing shell defining an inner volume, said housing shell enclosing the monitor unit and dimensioned to allow juxtaposition of the monitor unit, with a portion of a body of a wearer of the monitor unit, where a motion of arms of the wearer as detected by the motion sensor is minimized, and where mechanical interference with clothing of the wearer is minimized.

11. An article according to claim 1, wherein the controller is operably compatible with a multitude of different power battery specifications.

12. An article according to claim 1, wherein the monitor unit further comprises electronic circuitry enabling at least one of activation and deactivation of the monitor unit in response to an predetermined external event to reduce the amount of at least one of the first and second data.

13. A method for characterizing a status of a subject with a monitor device, the method including:

acquiring, with a controller of the monitor device, a first output from a motion sensor of the monitor device, the first output representing orientation and motion of the monitor unit in multiple ranges of acceleration, the monitor unit having a port in electrical communication with the subject;

acquiring, with the controller, a second output from a physiological sensor of the monitor device, the second output representing a physiological parameter of the subject; and

sending data derived from the acquired at least one of the first and second outputs to a data-logging unit of the monitor device, the data-logging unit including tangible non-transitory storage medium.

14. A method according to claim 13, wherein the acquiring a first output include acquiring a first output from multiple accelerometer units that enable, aggregately and in response to an input applied to the monitor device. Said multiple ranges of acceleration.

15. A method according to claim 13, wherein the acquiring a second output includes acquiring a second output from an electrocardiographic (ECG) circuit in a two-electrode configuration or a three-electrode configuration.

16. A method according to claim 13, further comprising

transmitting data stored a the data-logging unit of the monitor device to a programmable data processor, and

mapping said transmitted data to a range of voltages defined by a predetermined minimum value of voltage and a predetermined maximum value of voltage to form mapped data.

17. A method according to claim 16, further comprising

removing a direct-current voltage baseline from the mapped data;

and

calculating a time-derivative of resulting data to increase a sensitivity of detection of an R-wave associated with the subject with the monitor device.

18. A method according to claim 16, further comprising

defining a threshold and a refractory period of operation of the monitor device with the programmable data processor, the threshold and refractory period being physiologically relevant for the detection of the R-wave;

statistically evaluating the likelihood of presence of a useful R-wave as opposed to an artifact, said presence being represented by the second output; and

modifying data acquired from at least one of the first and second outputs by removing a portion of data corresponding to a time-period associated with a measurement and a statistically corrupted R-wave, said modifying being based at least in part on extreme amounts of motion at points of a predicted artifact.