HK1176844A - Two-wrist data gathering system - Google Patents

Description

Double-wrist data acquisition system

Cross Reference to Related Applications

Priority of the present application is in accordance with 35u.s.c. § 119 priority of U.S. application serial No. 61/300,435 entitled "Two-will data-gathering system", filed 2/1 2010. Said application is incorporated by reference in its entirety.

Background

It is not easy to know whether a patient has taken his or her medication.

The assignee of the present invention has been paying considerable attention in recent years to methods of detecting ingestion of drugs, such as pills. In great effort, the assignee of the present invention has devised systems involving pills each including a device having a communication means, e.g., an electrically conductive communication means, etc., and a receiver, such as a patch, affixed to the skin of a patient, such that when one of the pills reaches the stomach, stomach acid activates the device, which transmits a current signal. The patch acquires the current signal to detect ingestion of the pill. The patch may then communicate this event to other devices and systems. For example, the patch may send a message of the event to a mobile phone using the bluetooth protocol, which in turn may communicate the event to other devices. A typical patch location is the abdomen.

While the assignee of the present invention has achieved good results in systems using patches in this manner, patches are sometimes inconvenient. It may be uncomfortable. It needs to be able to flex because it is attached to the shrinkable skin. It is not easy to provide a so-called man-machine interface ("MMI") on a patch located on the abdomen. It is not feasible to place the keyboard and display on a flat surface that is attached to the abdomen.

The belly patch has a power source, typically a battery or electrochemical cell (for ease of reference herein, the term "battery" will be used to refer to both multi-cell batteries and single cells). The battery has only a limited service life, which is mainly defined by the battery capacity and the energy budget of the patch. When the battery runs out, the patch needs to be taken out of service and a different patch needs to be activated. This is also inconvenient.

When the pill is triggered, it signals, sends a communication, etc. Exemplary pills and communications are described in detail in, for example, the following U.S. patent publications:

each of the above U.S. patent publications is incorporated by reference herein for all purposes as if reproduced in full herein. Actual testing of real pills, real patches and real human subjects has enabled reliable detection of communications from such pills. This is significant considering the inability of the prior art to achieve such reliable detection, and the fact that nature, human physiology, and material science collectively have made these results difficult to achieve in a variety of ways.

Typically, conventional electromagnetic radiation is emitted by a dipole and detected and received by a dipole, and conventional models assume that the signal intensity decreases with increasing distance at a rate determined by the dielectric constant and permeability of the medium (here, human tissue). Many researchers in this general field have therefore followed the assumption that a receiver such as a patch needs to be as close as possible to the transmitter (i.e. to the stomach).

It would be desirable if some method of detecting the triggering of a pill transmitter could be found that achieved reliable detection with a patch while avoiding the inconveniences associated with patches as just described. Other physiological measurements are also ideal to perform, but only if they can be reliably and accurately performed without undue discomfort or inconvenience to the patient.

Disclosure of Invention

Considering that one might think in general that the receiver needs to be as close as possible to the transmitter, it is counterintuitive to perform the sensing at a position quite far from the stomach. However, this is exactly what is described here. Cooperating sensor electronics are placed at each of the patient's two wrists. Other potential benefits will become feasible, such as the ability to provide a human-machine interface, once the irrational nature of this arrangement is ignored. The potential discomfort and inconvenience of an abdominal patch is reduced or eliminated. And alternative power sources become available.

Drawings

The present invention is described in connection with the depictions of the several figures, wherein:

FIG. 1 illustrates a patient 101 having a watch 102 and a bracelet 103 according to one aspect of the invention;

fig. 2 shows the watch 102 with elastic band 203;

fig. 3 shows a bracelet 103 with elastic band 203;

fig. 4 shows the watch 102 in cross-section, with the electrodes 202 closely juxtaposed with the wrist 105 and the chip 401;

fig. 5 shows the bracelet 103 in cross-section, with the electrode 302 closely juxtaposed with the wrist 106 and the chip 501;

FIG. 6 illustrates, in functional block diagram form, chip 401; and

fig. 7 shows a chip 501 in functional block diagram form.

Identical elements are denoted by the same reference numerals whenever possible.

Detailed Description

Fig. 1 shows a patient 101 wearing a watch 102 and a bracelet 103 according to an aspect of the invention. Watch 102 is on right wrist 105 and bracelet 103 is on left wrist 106. (it will be appreciated that this left-right arrangement is arbitrary and the position of the watch and bracelet may be interchanged without departing from the invention). One of the primary purposes is to detect the signal or communication emitted from the pill 104 when the pill 104 is triggered by gastric fluid.

It will be appreciated that although the invention is described in terms of an exemplary aspect in which the pill is triggered by gastric fluid, other variations may be devised, such as aspects in which triggering does not occur until the pill reaches, for example, the small intestine. A staged approach may also be devised in which a first signal is triggered at a first point in the process of passing through the gastrointestinal system and a second signal is triggered at a second point in the process.

Turning now to fig. 2, we see an exemplary watch 102 with elastic band 203. The elastic band helps to bring the electrodes 202 into close contact with the patient's skin. A display 204, such as an LCD, is shown. A button 205 is also shown. In this way, a man-machine interface (MMI) is provided. Of course, it will be understood that the MMI need not be limited to that shown here. Other MMI components may be provided, such as a piezoelectric buzzer or other acoustic source. A touch screen or other manual input device (HID) may be used. The LCD and buttons are exemplary only.

Although the present aspect is described in terms of a bungee bracelet, other methods, such as Speidel twist-o-A wristband to bring each skin electrode into close contact with the skin.

Fig. 3 shows a bracelet 103 with elastic band 203. The elastic band brings the electrodes 302 into close contact with the patient's skin.

In the exemplary arrangement below, the electrodes 202, 302 are described as electrodes in intimate (conductive) contact with the skin. Perhaps a less preferred but also feasible arrangement is that the electrodes 202, 302 are capacitively coupled to the skin, i.e. with some dielectric between the electrodes and the skin, such as a plastic film. Perhaps a less preferred but perhaps also feasible arrangement is that the wristband 203 is not elastic at all, but rather has a constant circumference, thereby allowing the electrodes 202, 302 to have a spaced relationship with respect to the skin, sometimes with an air gap or partial air gap therebetween.

Fig. 4 shows the watch 102 in cross-section, with the electrodes 202 closely juxtaposed with the wrist 105 and the chip 401. The chip 401 is communicatively coupled with the skin electrode 202 and the second electrode 402, preferably in metallic connection. The second electrode 402 is open to air and provides a compensating ground (counterground) that can be molded for the skin electrode 202. The non-conductive housing 403 provides a structure between the two electrodes. Fig. 5 shows the bracelet 103 in cross-section, with the electrode 302 closely juxtaposed with the wrist 106 and the chip 501, the chip 501 being communicatively coupled with the skin electrode 302 and the second electrode 502. The bracelet electrodes together with the casing or housing 503 function similarly to the corresponding parts in the watch.

Fig. 6 shows a watch chip 401 in functional block diagram form. The aforementioned electrodes 202, 402 can be seen to be communicatively coupled with a transceiver 605. A battery 603 and power supply circuit 604 provide power to the transceiver 605 and controller 606. The controller 606 controls the transceiver 605 and provides MMI, such as the liquid crystal LCD 204 and the buttons 205, and optionally other MMI, such as a piezoelectric buzzer or other sound generators. The LCD 204 is controlled by a multi-line bus 607.

Interestingly, the seemingly fairly outdated technology of self-winding mechanical watches offers possible benefits here. As shown in fig. 6, when a human user moves anywhere, the pendulum 601 has an opportunity to move anywhere. The strong permanent magnet within the pendulum induces a current in one or more windings 602. This allows battery 603 to be a rechargeable battery or super capacitor regulated by power supply circuit 604. The bluetooth or other protocol system 607 may communicate with an external device such as a mobile phone or a personal computer.

Fig. 7 shows a bracelet chip 501 in functional block diagram form. The elements shown therein correspond closely to those in fig. 6.

The daily functionality of the system (pill, bracelet, watch and other devices such as mobile phones) will be described in exemplary aspects.

The main purpose is to detect the signal from the pill at the bracelet 103 and the watch 102. To this end, the bracelet may implement real-time near-continuous detection of signals at the skin electrode 302 relative to the compensating ground 502. This detection is an AD (analog to digital) conversion, e.g. by an ADC (not shown in fig. 7), preferably with a resolution higher than 16 bits, and the measured signal (transmitted digitally and preferably compressed data) is communicated with the watch 102 via a wireless link. The watch also implements real-time near-continuous detection of signals at the skin electrode 202 relative to the offset ground 402. This detection is an AD (analog to digital) conversion, preferably with a resolution higher than 16 bits. The data streams from the two sensors (one at the bracelet and one at the watch) are then transmitted out to other devices which can perform signal processing and can detect signals of interest, such as the signal from the pill when it is triggered.

In a preferred arrangement, all noise is common mode, and the signal of interest may be a differential signal measured at both arms.

As mentioned above, it is quite paradoxical to take the step of moving the sensor to the imaginable point away from the pill 104. Once this paradoxical movement is received and ignored, many other interesting capabilities will become available that may not be available at all in prior art arrangements such as belly patches.

Techniques suitable for such sensing are discussed in a paper entitled "all-noise, non-contact EEG/ECG sensor" incorporated herein by reference (Thomas J Sullivan, Stephen R.Dess and Gert Gauwenberghs, University of California, San Diego, biological Circuits and Systems Conference,2007, BIOCAS 2007, IEEE,2007, 11 months 27-30, p.154-157, Digital Object identification 10.1109/BIOCAS.2007.4463332).

Sensing things away from the body is discussed in PCT publication WO 2009/055733 entitled "Fluid transfer port information system" incorporated by reference herein, and in U.S. published application US 2009-0112178a1, also incorporated by reference herein by the same name of the invention. Sensing blood Volume is discussed in U.S. patent application No. 61/160,265 entitled "Volume-sensing device, system, and method" filed 3/13/2009, which is incorporated by reference herein. Other related art is discussed in U.S. patent application No. 61/240,571 entitled "Body-associated device" filed on 9, 8, 2009, which is incorporated by reference herein.

One potential benefit as described above is: moving to the wrist allows a viable MMI to be provided. The wrist is also more prone to movement than the abdomen, making the self-winding function more likely to work.

However, once the excitation/sensing platform of the bracelet and watch is provided, it shows a more subtle and interesting ability.

Cardiac function (essentially two-electrode EKG) can be measured.

Energy may be transmitted from one of the two points (e.g., at a bracelet) at a frequency that propagates through the body to the other point (at the watch in this example) with some measured delay and some measured absorption level or impedance. Additionally, energy may be transmitted at different frequencies from one of the two points (e.g., also at the bracelet), which propagates through the body to the other point (also at the watch in this example) with non-identical measured delays and non-identical measured absorption levels or impedances. This probing of the body is equivalent to spectroscopy (spectroscopy) and allows measurement of mass on the body, such as the amount of liquid in the body relative to other tissue material. In this way, blood volume can be measured indirectly. Measuring blood volume in real time is rarely, if ever, possible by keeping the patient still during the measurement by means of a large, bulky and stationary measuring device. The present method allows real-time measurements to be taken even when the patient is ambulatory.

These measurements may allow real-time measurement of cardiac output or stroke volume of the heart.

It will be appreciated that in the analysis of the data collected at the electrodes 202, 302 (at the bracelet and watchband), one of the important parts is the time-dependence of the measured data. The technician may think that this requires a highly accurate clock to be run in each of the bracelet and wristband, with the two clocks being in close proximity to being synchronized.

But in fact it is very feasible to allow these two clocks to be less expensive (and less power demanding), i.e. to be offset with respect to each other. At the watch, a synchronization event (e.g., simultaneous detection of a common mode pulse signal from the environment) allows for the receipt of a time signal from the bracelet, which will then be understood to match the time value at the watch. This can be used to detect and correct the skew of one clock relative to another.

Watches and bracelets may be fashion. These watches and bracelets do not have to look so "clumsy". The patient may actually prefer to wear an identifying or unique watch and bracelet.

The AD conversion at the two sensing locations may be 18 bits, but may also be 16 bits or 12 bits.

Communication from the bracelet to the watch may be open loop (unidirectional from bracelet to wristband), but preferably communication is considered bidirectional, at least handshake (handshaking) is provided.

The communication may utilize inductive coupling via the body at high frequency RF signals (higher than the sensed information expected in the range of 0.1Hz to possibly 100 Hz). Alternatively, the communication may be optical infrared (bouncing off surrounding walls and structures).

The MMI may provide reminders to take certain pills. Also, the MMI may provide an audible or visual confirmation when the patient has taken a particular pill.

Accelerometers in the bracelet or the watchband, or both, will allow for measurement of physical activity levels and may allow for detection of sleep times. These may also be reported outside the patient.

The allocation of computing resources may vary. For example, it is feasible to do most of the calculations in a watch, compare the measured signals at the bracelet and at the watch. Alternatively, it is feasible to perform the calculations elsewhere (e.g., at a remote computer) and only have the watch transmit the information it receives from the bracelet.

The bandwidth required from the bracelet to the wristwatch, and the bandwidth required from the wristwatch to a remote device, is such that a carrier wave of 10MHz should be sufficient.

The conscious reader will have no difficulty devising numerous obvious modifications and variants of the invention, all of which are intended to be covered by the appended claims.

Claims (24)

1. A method of data acquisition implemented with respect to a first device and a second device, each of the first device and the second device including a respective electrical signal detector having respective first and second electrodes, the method comprising the steps of:

placing the first device on a first limb of a living subject, the first device encircling the first limb, a first electrode of the first device being juxtaposed with the first limb, a second electrode of the first device being further from the first limb than the first electrode;

placing the second device on a second limb of the body, the second device encircling the second limb, the second limb being a different limb than the first limb, the first electrode of the first device being juxtaposed with the second limb, the second electrode of the second device being further from the second limb than the first electrode;

at the first device, measuring electrical signals at respective signal detectors differentially between respective first and second electrodes, thereby producing a first data stream indicative of the electrical signals;

at the second device, differentially measuring the electrical signals at the respective signal detectors between the respective first and second electrodes, thereby producing a second data stream indicative of the electrical signals; and

the first data stream and the second data stream are analyzed together to derive information of interest relating to the body.

2. The method of claim 1, wherein the analyzing step further comprises synchronizing the first data stream with the second data stream by aligning common mode events in the first data stream and the second data stream.

3. The method of claim 1, wherein the analyzing step is performed at a device separate from the first device and separate from the second device, the method further comprising the steps of:

transmitting a first data stream from the first device to the device, an

Transmitting a second data stream from the second device to the device.

4. The method of claim 1, further characterized in that the first limb is a first arm of the body and the second limb is a second arm of the body, and wherein the encircling of the first device comprises a wrist encircling the first limb, and wherein the encircling of the second device comprises a wrist encircling the second limb.

5. The method of claim 1, wherein the analyzing step comprises detecting at least one of a signal and a communication associated with the body ingested ingestible device.

6. The method of claim 1, wherein the first device has a rechargeable energy reservoir, the method further comprising the steps of: moving the first limb; and converting movement of the first limb into electrical energy that recharges the rechargeable energy storage.

7. The method of claim 1, wherein measuring an electrical signal at the first device comprises performing analog-to-digital conversion, the first data stream being digital, and wherein measuring an electrical signal at the second device comprises performing analog-to-digital conversion, the second data stream being digital.

8. The method of claim 7, wherein the analog-to-digital conversion is performed at a resolution of at least sixteen bits.

9. The method of claim 1, wherein the analyzing step comprises performing an electrocardiographic measurement with respect to the heart of the body.

10. The method of claim 1, further comprising the steps of:

transmitting, at the first device, first electrical energy within a first frequency band;

detecting the first power at the second device;

transmitting, at the first device, second electrical energy within a second frequency band, the second frequency band being different from the first frequency band;

detecting the second power at the second device; and

comparing the detected first electrical energy and the detected second electrical energy with each other, thereby deriving information of interest relating to the body.

11. The method of claim 10, wherein deriving information of interest related to the body comprises the steps of: presume a ratio of liquid to non-liquid within the body.

12. The method of claim 10, wherein deriving information of interest related to the body comprises the steps of: presume the blood volume in the body.

13. The method of claim 6, further comprising the steps of:

inferring a physical activity level of the body from the converted electrical energy, an

Communicating the inferred level of physical activity external to the first device and the second device.

14. The method of claim 1, further comprising the steps of:

transmitting a first data stream from the first device to the second device;

wherein the step of analyzing is performed within said second device.

15. The method of claim 14, wherein the transmitting step is performed by means of infrared light communication or by means of high frequency radio frequency communication.

16. A system comprising a first device and a second device,

the first device comprises a respective electrical signal detector having respective first and second electrodes;

the second device comprises a respective electrical signal detector having respective first and second electrodes;

the first device is shaped for encircling a limb of a subject, a first electrode of the first device is positioned in juxtaposition with the limb when the first device encircles the limb, a second electrode of the first device is positioned further from the limb than the first electrode when the first device encircles the limb;

the second device is shaped for encircling a limb of a subject, a first electrode of the second device being positioned in juxtaposition with the limb when the second device encircles the limb, a second electrode of the second device being positioned further from the limb than the first electrode when the second device encircles the limb;

an electrical signal detector of the first device responsive to signals at respective first and second electrodes to produce a first data stream indicative of a difference between the signals at the respective first and second electrodes;

an electrical signal detector of the second device responsive to signals at the respective first and second electrodes to generate a second data stream indicative of a difference between the signals at the respective first and second electrodes;

the system further includes an analysis device responsive to the first data stream and the second data stream for deriving information of interest relating to the body.

17. The system of claim 16, wherein the analysis device is separate from the first apparatus and separate from the second apparatus, the device further comprising:

a communication link from the first device to a device, an

A communication link from the second device to the apparatus.

18. The system of claim 16, wherein the first device further comprises a rechargeable energy storage, the first device further comprising means for converting movement into electrical energy, the electrical energy recharging the rechargeable energy storage.

19. The system of claim 16, wherein the first device further comprises an analog-to-digital converter that converts analog signals from the respective first and second electrodes into digital data, the first data stream comprising the digital data.

20. The system of claim 19, wherein the analog-to-digital converter has a resolution of at least sixteen bits.

21. The system of claim 16, wherein the first device comprises a transmitter that controllably transmits first electrical energy within a first frequency band at the first device and controllably transmits second electrical energy within a second frequency band at the first device, the second frequency band being different from the first frequency band;

and wherein the second device comprises a detector positioned to detect the first electrical energy and the second electrical energy;

the analysis means is arranged to compare the detected first electrical energy and the detected second energy with each other, thereby deriving information of interest.

22. The system of claim 18, wherein said analysis means infers a physical activity level of said body from said converted electrical energy, and

communicating the inferred level of physical activity external to the first device and the second device.

23. The system of claim 16, wherein the first device transmits the first data stream to the second device; and is

Wherein the analysis device is within the second apparatus.

24. The system of claim 23, wherein the transmitting is performed by means of an infrared light communication channel or by means of a high frequency radio frequency communication channel.