OMAR TAOAAAA
`
`US 20050116820A1
`
`as) United States
`a2) Patent Application Publication 0) Pub. No.: US 2005/0116820 Al
`
` Goldreich (43) Pub. Date: Jun. 2, 2005
`
`
`(54) METHOD AND DEVICE FOR MEASURING
`PHYSIOLOGICAL PARAMETERSAT THE
`WRIST
`
`716
`(76)
`
`.
`.
`.
`:
`.
`Inventor: Rami Goldreich, Rosh Ha’ayin (IL)
`
`.
`Correspondence Address:
`Martin Moynihan
`Anthony Castorina
`Suite 207
`2001 Jefferson Davis Highway
`Arlington, VA 22202 (US)
`
`(21) Appl. No.:
`
`10/497,169
`
`(22)
`
`Filed:
`
`Jun. 9, 2004
`
`Related U.S. Application Data
`
`(63) Continuation-in-part of application No. 10/006,357,
`filed on Dec. 10, 2001, now abandoned.
`Publication Classification
`
`TIM. C0 eeeeeecccssssssssseeecceeceessneeeeessennee GO8B 1/08
`.
`
`340/539.12; 600/300
`
`(SV)
`(52)
`ABSTRACT
`(57)
`A wrist-mounted device for measuring at least one physi-
`ological parameter of a subject. The present
`invention
`enables such a measurement to preferably be transformed
`into clinically useful information about the subject. Such
`information may then optionally be sent to medical person-
`nel, for example at a contact and/or monitoring center,
`through a gateway device. The gateway device preferably
`communicates with the wrist-mounted device of the present
`invention through a wireless communication channel.
`
`400
`
`Wearable Device
`
`
`108
`
`107
`
`112
`
`1
`
`APPLE 1062
`Apple v. Masimo
`IPR2022-01291
`
`
`
` 102
`
`
`119
`
`123
`
`Physio.
`Sensor
`
`Processing
`Unit
`
`101
`
`APPLE 1062
`Apple v. Masimo
`IPR2022-01291
`
`1
`
`

`

`Patent Application Publication
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`Jun. 2, 2005 Sheet 1 of 6
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`US 2005/0116820 A1
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`Patent Application Publication
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`Jun. 2, 2005 Sheet 2 of 6
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`US 2005/0116820 Al
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`300
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`
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`FIG.2 -
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`3
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`

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`Patent Application Publication
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`Jun. 2, 2005 Sheet 3 of 6
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`US 2005/0116820 Al
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`FIG. 3
`
`
`
`mode
`
`Watchdog
`
`Initiation Wait For Trigger
` Technical
`
`RCV Time
`* Out
`Command
`
` Timeout
`Reached
`
`
`Auto Alarm
`
`
`
`
`
`
`Timeout
`Timeout
`
`
`|. Reached
`
`
`Reached
`
`‘| ACK Received
`
`Timeout
`
`
` Comm.
`
`
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` Wait For ACK Wait For ACK
`
`Send-ACK
`
`4
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`

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`Patent Application Publication
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`Jun. 2, 2005 Sheet 4 of 6
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`US 2005/0116820 Al
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`FIG. 4
`
`
`
`Addr(mi|Addr(is_|CM|Data Data|CRC(ms|CRC(si ET
`
`
`
`_Addr(m
`
`‘sb)
`
`d)
`
`b)
`
`D
`
`(0)
`
`(a)
`
`|b)
`
`x
`
`STX
`
`Len
`
`Start ofTX indicates the beginning ofthe message ( 7E hex).
`
`indicates the numberofdata bytes that the message contains(0 ton +2
`bytes).
`
`Len = 0 — No command.
`
`Len = 1 — command only; the message not include data(0) through
`
`data(n)
`
`Len >2 —the message includes command and data.
`Flag_statusbits (1 byte)
`Addr
`the userID ofthe bracelet, 24 bits (0 t016777216).
`CMD
`command description.
`Data(n) the data ofthe message.
`CRC
`the CRC (2 bytes) for the message beginning ‘from STX byte to
`Data(n) byte
`EndofTX indicates theend ofthe message ( 7Bhex)
`
`‘ETX
`
`5
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`Patent Application Publication
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`Jun. 2, 2005 Sheet 5 of 6
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`US 2005/0116820 Al
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`‘FIG. 5
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`500
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`6
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`Patent Application Publication
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`Jun. 2, 2005 Sheet 6 of 6
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`US 2005/0116820 Al
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`FIG. 6
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`600
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`568
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`- 566 620 —.
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`US 2005/0116820 Al
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`Jun. 2, 2005
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`METHOD AND DEVICE FOR MEASURING
`PHYSIOLOGICAL PARAMETERS AT THE WRIST
`
`CROSS-REFERENCE TO RELATED
`APPLICATION
`
`[0001] This application claims benefits under 35 U.S.C. §
`120 ofpriority from U.S. patent application Ser. No. 10/006,
`357 filed Dec. 10, 2001 entitled,“METHOD AND DEVICE
`FOR MEASURING PHYSIOLOGICAL PARAMETERS
`
`AT THE WRIST,” the subject matter of which is hereby
`incorporated by reference.
`
`FIELD OF THE INVENTION
`
`[0002] The present invention is of a method and device for
`measuring at least one physiological parameter of a subject
`at the wrist, preferably for extracting clinically useful infor-
`mation thereof. More specifically, the present invention is of
`a device which may be wornat the wrist of the subject with
`a strap or other fastening article, and which may then be used
`to monitor the subject through measurement of the physi-
`ological parameter.
`
`BACKGROUND OF THE INVENTION
`
`[0003] Currently, a number of different types of devices
`are available for monitoring human subjects in a non-
`invasive manner. For example, heart function can be moni-
`tored in a user through the use of electrodes, which must be
`attached to the skin of the user. Although non-invasive, such
`equipmentis nevertheless uncomfortable for the user, who is
`attached to a network of cables and wired sensors.
`In
`
`addition, such equipmentis very expensive, limiting its use
`to hospitals and other medical settings in which both the cost
`and the discomfort of the patient can be justified. Further-
`more, patients may become anxious when examined by
`medical personnel, thereby significantly altering the normal
`readings for these patients. It should be noted that the terms
`“subject”, “patient” and “user” are used interchangeably
`herein.
`
`there are many different situations in
`[0004] However,
`which non-invasive monitoring of a human subject
`is
`desired. For example, such monitoring could be very useful
`as part of the overall health maintenance of the human
`subject, and could be used in orderto detect a deterioration
`in the physiological condition of the subject before a con-
`comitant deterioration in the health of the subject becomes
`noticeable. Examples of adverse physiological conditions
`which could be detected with regular non-invasive monitor-
`ing include but are not limited to excessive weight gain or
`less; arrhythmia and other heart conditions; incipient diabe-
`tes in the form of improper glucose metabolism; and loss of
`lung capacity or other problems with respiration.
`
`[0005] Heart rate and blood pressure are important factors
`in determining the state of a person’s health and the physical
`condition of a person’s body in response to physical or
`emotional stress. Periodic monitoring of these physical
`parameters is particularly important for individuals having
`cardiac disease and/or lowered cardiac functioning, or high
`blood pressure. However, physically healthy individuals
`may also wish to periodically monitor their heart rate and
`blood pressure in stressful situations, for example when
`engaging in strenuous exercise.
`
`In order to support regular monitoring of human
`[0006]
`subjects in their normal environment, such as in the home
`and at
`the office for example,
`the equipment must be
`non-invasive and easy to use. The equipment would then be
`able to monitor at least one physiological parameter of the
`user, without requiring the user to perform any complicated
`actions and/or to operate complex devices. Indeed, it would
`be highly preferred for the equipment to be incorporated as
`part of the regular daily living routine of the subject, since
`the requirement for any additional or special actions on the
`part of human subject is likely to result in decreased com-
`pliance. In addition,
`the equipment should be robust yet
`inexpensive.
`[0007] One example of such a device incorporates a
`wristband to attach a physiological sensor to the wrist of the
`subject. Currently, a number of different
`types of such
`wristband devices are available, most of which are intended
`to be used as stand-alone devices to provide information
`about the subject’s own physical condition, mainly for heart
`rate and blood pressure. Most of these devices obtain such
`measurements by using an inflating cuff, which is bulky and
`awkward for the subject.
`[0008] Wrist-mounted heart rate monitors are known to
`the art and have been disclosed, for example, in the patent
`to Orr et al, U.S. Pat. No. 3,807,388, wherein the duration of
`a heart beat
`is measured by counting electrical pulses
`recurring at a known frequency. The duration of the heart-
`beat is then related to a particular average heart beat rate.
`However,
`the disclosed measurement system does not
`directly measure the heart rate and, therefore, is subject to
`inaccuracies of measurement due to the instability of heart
`beat duration over brief intervals of time.
`
`[0009] A blood pressure measuring device is disclosed in
`the patent to Petzke et al, U.S. Pat. No. 3,926,179, in which
`a probe is applied adjacent to the radial artery of a wrist. A
`pressure-sensitive transducer on the probe generates electri-
`cal signals correspondingto the blood pressure pulses of the
`radial artery. The electrical pulses are applied to analog
`circuitry that generates a systolic signal corresponding to the
`integrated voltage at the peak of the electrical pulse signal
`and a diastolic signal correspondingto the voltage at the low
`point of the pulse signal. The analog device of Petzke et al
`requires a substantial amount of power to operate and,
`therefore, is not suitable for use in a small, compact stand-
`alone device for being worn on the wrist.
`[0010] A blood pressure and a heart rate measuring wrist
`watchis also disclosed in the patent to Broadwater, U-S. Pat.
`No. 4,331,154,
`in which a digital watch is employed to
`measure systolic and diastolic blood pressure as well as
`heart rate. The band of the watch supports a piezoelectric
`transducer that is held in contact with the wrist adjacent to
`the radial artery when a switch on the bandis activated. The
`absolute values required for this method to evaluate blood
`pressure cause the device to be subject to inaccurate read-
`ings, since the tissues of the hand and wrist may be expected
`to expand and contract according to such factors as the time
`of day, and the condition of the external environment such
`as the atmospheric pressure. Such expansion or contraction
`may cause different degrees of tension on the wrist-mounted
`device, which is therefore not suitable for use without daily
`calibrations.
`
`[0011] Other wrist-mounted devices are for wireless panic
`alarm systems, mainly for elderly people who live alone.
`
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`US 2005/0116820 Al
`
`Jun. 2, 2005
`
`These devices are usually shaped as a wristband or a
`pendant. Whenever the user becomes distressed, the user
`presses a panic button located on the device. The device then
`sends a digitally coded wireless message to a gateway
`device located nearby, usually in the same room, by using a
`unidirectional wireless data communication link. The gate-
`way device then contacts a manually operated contact cen-
`ter, for example with a land based or cellular telephone
`connection. A particular identifier for the user is usually sent
`first, after which the human operatoris allowedto talk to the
`user through a speaker and to listen through a sensitive
`microphone located within the gateway. However, none of
`the above systems contains any physiological measurement
`device within, in order to learn about the current physiologi-
`cal status of the user.
`
`Insuch a situation as described above, the operator
`[0012]
`at the call center learns about the user’s condition only by
`speaking with the user. However, this is only possible if the
`user is actually able to speak. High levels of background
`noise may also prevent the user from being heard by the
`microphoneof the gateway device.
`SUMMARYOF THE INVENTION
`
`[0013] The background art does not teach or suggest a
`device which can conveniently, non-intrusively and autono-
`mously measure one or more physiological parameters, in
`order to extract medical information such as heart rate,
`breathing rate and blood pressure, and which may be worn
`on the wrist of the user. The background art also does not
`teach or suggest such a wrist-mounted device, which can
`measure such parameters and then send the information to a
`contact center or other location containing medical person-
`nel. The backgroundart also does not teach or suggest such
`a wrist-mounted device which is compact, non-invasive, and
`light.
`[0014] The present invention overcomesthese deficiencies
`of the background art by providing a wrist-mounted device
`for measuring at least one physiological parameter of the
`user. The present invention enables such a measurementto
`preferably be transformed into medical information about
`the user, and/or displays the results on a LCD display. As
`used herein, the term “physiological parameter”refers to the
`signal which is received from the sensor, while the term
`“medical information” refers to the information which may
`be extracted or otherwise obtained by analyzing this signal
`and/or a combination of signals. Such information may then
`optionally be sent to medical personnel (for example at a
`contact monitoring center) and/or
`to a remote server,
`through a gateway device. The gateway device preferably
`communicates with the wrist-mounted device of the present
`invention through a wireless communication channel.
`[0015] The present invention has the option to display the
`medical informationto the user on a local LCD display, such
`that the user is optionally and preferably able to read the
`result locally. Examples of medical information which may
`be extracted from the measured physiological parameter or
`parameters include, but are not limited to: heart rate; regu-
`larity in heart rate; breathing rate; arrhythmia of the heart(if
`any), as well as the general rhythm and functioning of the
`heart; blood pressure; presence of abnormal body move-
`ments such as convulsions for example; body position;
`general body movements; body temperature; presence and
`level of sweat; oxygen saturation in the blood; and glucose
`levels in the blood.
`
`In addition to the physiological parameters, the
`[0016]
`present invention may measure other parameters that may
`affect the subject’s physical condition, including but not
`limited to ambient temperature and humidity, lighting con-
`ditions, smoke or other material in the air, distance from
`homeetc.
`
`[0017] Optionally and more preferably, the present inven-
`tion also features an alarm signal for being transmitted
`through the gateway device in order to indicate an emer-
`gency or otherwise dangeroussituation for the user. The
`alarm signal may optionally be transmitted according to a
`manualaction of the user, such as pressing a “panic button”
`for example.
`
`[0018] Upon receipt of the manually activated alarm sig-
`nal, the gateway would preferably initiate immediately a call
`to a human operated call center. Then the device would
`preferably automatically collect one or more current mea-
`surements of physiological parameters of the user. These
`measurements may be sent directly to the gateway, or
`alternatively may be analyzed in order to compute the
`medical information of the user before sendingthe results to
`the gateway. The human operator would then preferably be
`able to assess the user’s medical condition from the received
`information.
`
`the alarm signal is transmitted
`[0019] Most preferably,
`automatically upon measurementof one or more physiologi-
`cal parameters ofthe user, even if the user is unable to press
`the panic button. Optionally, the alarm signal may be given
`to the user, additionally or alternatively, for example by
`sounding an audible alarm, more preferably from the wrist-
`mounted device itself.
`
`[0020] The device of the present invention also monitors,
`at least periodically or continuously, one or more physi-
`ological parameters of the user. Continuous monitoring
`would more easily enable the device to transmit the alarm
`signal if one or more physiological parameters are deter-
`mined to be outside of predefined criteria, which may
`represent such medical information as unstable or excessive
`heart rate, or very high or low blood pressure.
`
`[0021] According to an exemplary embodiment of the
`present invention, the wrist-mounted device features one or
`more sensors attached to a wristband or other fastening
`article. The sensor(s) may optionally be connected to a
`microprocessor, optionally by a wire but alternatively
`through a wireless connection. The microprocessor may
`optionally also be located within the wristband, or otherwise
`attached to the wristband. The sensor(s) may optionally
`support automatic collection of the measurement of the at
`least one physiological parameter, while the microprocessor
`is able to execute one or more instructions for extracting
`medical information about the user from such measure-
`ment(s).
`
`[0022] The microprocessor more preferably operates a
`software program to process and analyze the data which is
`collected, in order to compute medical information. The
`extracted information, optionally also with the raw data, is
`then preferably transferred to the previously described gate-
`way device. The gateway device may optionally relay such
`information to a remote server, which more preferably is
`able to provide such information to medical personnel, for
`example as part of a contact center. Therefore, continuous
`
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`

`US 2005/0116820 Al
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`Jun. 2, 2005
`
`monitoring of the medical information and/or physiological
`parameters of the user may optionally and more preferably
`be made, enabling better medical care for the user. Accord-
`ing to the present invention there is provided a device for
`measuring at least one physiological parameter of a subject,
`comprising: (a) a fastening article for being fastened to a
`wristof the user; (b) at least one sensor for measuringatleast
`one physiological function of the user, the sensor may be in
`contact with at least a portion of the wrist and the sensor
`being attachedto the fastening article; and (c) a processor for
`receiving a signal from the sensor and for converting at least
`one measurement to form the at least one physiological
`parameter. Optionally, the data may be stored on a non-
`volatile memory for being downloaded later by the user or
`by an operator.
`
`[0023] According to another embodiment of the present
`invention, there is provided a system for measuring at least
`one physiological parameter of a subject, comprising: (a) a
`device for measuring the at least one physiological param-
`eter, comprising: (i) a fastening article for being fastened to
`a wrist of the user; (ii) a sensor for measuring at least one
`physiological parameter of the user,
`the sensor being in
`contact with at least a portion of the wrist and the sensor
`being attached to the fastening article; (iii) a communication
`unit for at least transmitting data; and (b) a gateway device
`for receiving the transmitted data for being monitored.
`
`[0024] According to another embodiment of the present
`invention,
`there is provided a method for monitoring a
`physiological parameter of a user, comprising: providing a
`device for monitoring the physiological parameter,
`the
`device being attached to at least a portion of the user at a
`pulse point of the user; monitoring the physiological param-
`eter through the pulse point; and if a level of the physiologi-
`cal parameter of the user is outside of an expected range,
`transmitting an alarm.
`
`[0025] According to still another embodiment of the
`present invention, there is provided a device for measuring
`at least one physiological parameter of a subject, compris-
`ing: (a) a fastening article for being fastenedto a wrist of the
`user; (b) a piezoceramic sensor for measuring at least one
`physiological parameter of the user at a pulse point of the
`wrist and the sensor being attached to the fastening article;
`and (c) a processorfor receiving a signal from the sensor and
`for converting the at least one measurement to form medical
`information.
`
`the term “microprocessor” includes,
`[0026] Hereinafter,
`but is not limited to, general-purpose microprocessor, a DSP,
`a micro-controller or a special ASIC designed for that
`purpose.
`
`invention could be
`[0027] The method of the present
`described as a process for being performed by a data
`processor, and as such could optionally be implemented as
`software, hardware or firmware, or a combination thereof.
`For the present invention, a software application could be
`written in substantially any suitable programming language,
`which could easily be selected by one of ordinary skill in the
`art. The programming language chosen should be compat-
`ible with the computational device (computer hardware and
`operating system) according to which the software applica-
`tion is executed. Examples of suitable programming lan-
`guages include, but are not limited to, Visual Basic, Assem-
`bler, Visual C, standard C, C++ and Java.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0028] The invention is herein described, by way of
`example only, with reference to the accompanying drawings,
`wherein:
`
`[0029] FIG. 1 is a schematic block diagram of a system
`according to an exemplary embodiment of the present
`invention;
`
`[0030] FIG. 2 shows an exploded view of an exemplary
`device;
`
`[0031] FIG. 3 describes a general state flow diagram;
`
`[0032] FIG. 4 describes a bi-directional message format
`between the device and the gateway;
`
`[0033] FIG. 5 shows an exploded view of an exemplary
`device with ECG option; and
`
`[0034] FIG. 6 is an exploded view of an exemplary
`device, which illustrates the installation of a SpO2 sensor.
`DESCRIPTION OF THE EXEMPLARY
`EMBODIMENTS
`
`[0035] The present invention is of a wrist-mounted device
`for measuring at least one physiological parameter of the
`user. The present invention enables such a measurementto
`preferably be transformed into medical information about
`the user. Such information may then optionally be sent to
`medical personnel (for example at a contact monitoring
`center) and/or to a remote server, through a gateway device.
`The gateway device preferably communicates with the
`wrist-mounted device of the present invention through a
`wireless communication channel.
`
`[0036] Examples of medical information which may be
`extracted from the measured physiological parameter or
`parameters include, but are not limited to: heart rate; regu-
`larity in heart rate; breathing rate; arrhythmiaof the heart (if
`any), as well as the general rhythm and functioning of the
`heart; blood pressure; presence of abnormal body move-
`ments such as convulsions for example; body position;
`general body movements; body temperature; presence and
`level of sweat; oxygen saturation in the blood; and glucose
`levels in the blood.
`
`[0037] Optionally and more preferably, the present inven-
`tion also features an alarm signal for being transmitted
`through the gateway device in order to indicate an emer-
`gency or otherwise dangeroussituation for the user. The
`alarm signal may optionally be transmitted according to a
`manualaction of the user, such as pressing a “panic button”
`for example.
`
`the alarm signal is transmitted
`[0038] Most preferably,
`automatically upon measurement of the one or more physi-
`ological parameters of the user, preferably even if the user
`is unable to press the panic button. Optionally, the alarm
`signal may be givento the user, additionally or alternatively,
`for example by sounding an audible alarm, more preferably
`from the wrist-mounted deviceitself.
`
`[0039] An exemplary embodiment of the present inven-
`tion may measure also parameters that may affect
`the
`subject’s physical condition, including but not limited to
`ambient
`temperature and humidity,
`lighting conditions,
`smoke and/or other material in the air, distance from home
`etc.
`
`10
`
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`

`

`US 2005/0116820 Al
`
`Jun. 2, 2005
`
`[0040] Upon receipt of the manually/automatically acti-
`vated alarm signal, the gateway would preferably initiate
`immediately a call to a human operated call center. Then the
`device would preferably automatically collect one or more
`current physiological measurements of the user. These mea-
`surements may be sent directly to the gateway, or alterna-
`tively may be analyzed in order to compute the medical
`parameters of the user before sending the results to the
`gateway. The gateway may also analyze the measurement,
`for example when the measurements are transferred directly
`to the gateway. The human operator, at the medical center,
`would then preferably be able to assess the user’s medical
`condition from the received information. It should be noted
`that the terms “medical center” and “call center” are used
`
`interchangeably herein.
`
`invention may also
`[0041] The device of the present
`monitor, at least periodically but more preferably continu-
`ously, the value or condition of one or more physiological
`parameters of the user. Continuous monitoring would more
`easily enable the device to transmit
`the alarm signal if
`measurements of one or more physiological parameters are
`collected and analyzed by the microprocessor to form medi-
`cal information, which then could be determined to be above
`predefined criteria, such as unstable heart rate, or very high
`or low blood pressure, for example.
`
`[0042] According to a non-limiting exemplary embodi-
`ment of the present invention,
`the wrist-mounted device
`features one or more sensorsattached to a wristband or other
`fastening article. The sensor(s) are preferably connected to
`a microprocessor, optionally by a wire but alternatively
`through a wireless connection. The microprocessor may
`optionally also be located within the wristband, or otherwise
`attached to the wristband. The sensor(s) preferably support
`automatic collection of at least one physiological measure-
`ment; more preferably, the microprocessoris able to execute
`one or more instructions for extracting clinically useful
`information about the user from such measurement(s).
`
`[0043] The microprocessor more preferably operates a
`software program to process and analyze the data which is
`collected, in order to compute medical information. The
`extracted medical information, optionally also with the raw
`data,
`is
`then preferably transferred to the previously
`described gateway device. The gateway device then prefer-
`ably relays such information to a remote server, which more
`preferably is able to provide such information to medical
`personnel, for example aspart of a contact center. Therefore,
`continuous monitoring of the physiological parameters of
`the user may optionally and more preferably be made,
`enabling better medical care for the user.
`
`[0044] A general, non-limiting example of suitable meth-
`ods for measuring the heart rate and/or other heart-related
`physiological parameters of a subject who is wearing the
`device according to the present invention may be found in
`the article “Cuff-less Continuous Monitoring of Beat-To-
`Beat Blood Pressure Using Sensor Fusion”, by Boo-Ho
`Yang, Yi Zhang and H. Harry Asada—IEEE(also available
`through
`http:/Aveb.mit.edu/zyi/www/pdf/
`TEEETrans2000.pdf as of Dec. 9, 2001), hereby incorpo-
`rated by referenceas if fully set forth herein, where systolic
`and diastolic blood pressure are calculated using the pulse
`pressure shape per heartbeat. The disclosure does not
`describe a device which has the functionality according to
`
`the present invention, but the disclosed method is generally
`useful for determining blood pressure from an external
`measurementof pressure from the pulse through the skin of
`the subject.
`
`[0045] The principles and operation of a device and
`method according to the present invention may bebetter
`understood with reference to the drawings and the accom-
`panying description.
`
`[0046] Referring now to the drawings, FIG. 1 is a sche-
`matic block diagram of a system according to the present
`invention. As shown, a system 100 features a wearable
`device 101 to be worn by a user, preferably as a wrist-
`mounted device, for example by being attached with a
`wristband or other fastening article to the wrist of the user.
`Device 101 features at least one physiological sensor 102 for
`measuring at least one physiological parameter of the user.
`The function of an exemplary sensor 102 is described in
`greater detail below.
`
`[0047] The device 101 mayoptionally feature a vibration
`sensor 123, preferably a piezoceramic sensor, whichis not in
`direct contact with the skin of the user. Sensor 123 measures
`the movementof the wrist. The output of sensor 123 can be
`used by a processing unit 103 to capture the movement of
`the wrist and to recover somenoise received by sensor 102,
`which is caused by such movement.
`
`[0048] Device 101 may include additional ambient sen-
`sors 130 or additional measuring routines for measuring
`other parameters. For example, device 101 may optionally
`have a humidity sensor for measuring the ambient humidity.
`An exemplary humidity sensor may be the Humidity Gauge
`manufactured by Honeywell.
`
`In order to support processing of the measured
`[0049]
`physiological parameter or parameters, processing unit 103
`may optionally include internal RAM and non-volatile pro-
`gram memory (not shown). Also processing unit 103 may
`optionally include an extended data memory 105 located
`externally to processing unit 103. Processing unit 103 pref-
`erably executes at least one instruction for processing the
`data obtained by sensor 102.
`
`[0050] Examples of such processing units 103 include but
`are not limited to PIC18LC452 by Microchip Technology
`Inc., which contains 10 channels of 10 bit A/D converters,
`a 1.5 K bytes of internal RAM and 32 K Bytes of non-
`volatile program memory.
`
`[0051] Extended memory component 105is preferably an
`electrically erasable non-volatile external memory compo-
`nent. Examples of such a memory component include but
`are not limited to FM24CL64-S (Ramtron, USA), with 64
`Kbit of fast access read/write serial memory for storing
`temporary data related to the sampled physiological param-
`eter.
`
`time
`[0052] Device 101 may optionally feature a real
`clock 117 in order to provide an accurate time and date for
`each measurement, as device 101 can optionally store a few
`measurements before transmitting such data and/or infor-
`mation to a gateway device 110, as described in greater
`detail below. Stored data and/or information may also
`optionally be used for such applications as reminding the
`subject to take medication, perform a prescheduled mea-
`surement, and so forth. An A/D converter 109 with multiple
`
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`US 2005/0116820 Al
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`Jun. 2, 2005
`
`inputsis also optionally and preferably present if sensor 102
`is an analog sensor, in order to convert the analog signal to
`a digital signal.
`
`[0053] Device 101 preferably features an internal commu-
`nication unit 104,
`for at
`least unidirectional, but more
`preferably bi-directional, communication with gateway
`device 110. Gateway device 110 may feature a communi-
`cation unit 107. Communication unit 104 may optionally
`communicate with communication unit 107 through a wire
`or alternatively through a wireless communication link 121.
`According to a non-limiting exemplary embodimentof the
`present invention, gateway device 110 is located relatively
`close to the user and hence to device 101, for example by
`being located at
`the user’s premises. As a non-limiting
`example, gateway device 110 could optionally be installed
`in the homeof the user.
`
`[0054] Gateway device 110 also optionally and preferably
`features a controller 108 for controlling functions of gate-
`way device 110, such as communication with device 101 for
`example.
`
`[0055] Gateway device 110 preferably communicates with
`a remote server 114 through a data link 120, which could
`optionally be a direct dial-up modem connection with
`DTMF coding or TCP/IP using regular LAN or dial-up
`modem connection to an ISP, for example. In any case, data
`link 120 may optionally be a wired or wireless link, for
`example through a cellular telephone and/or land-based
`telephone system, or a combination thereof.
`
`[0056] Remote server 114 may be controlled by a system
`administrator 112, which may be a person (for manual
`operation) or a software program (for automatic operation),
`or a combination thereof. Remote server 114 also preferably
`features a database 113 for storing data received from
`gateway device 110.
`
`[0057] Device 101 may also feature a manually operated
`panic alarm button 116 to be manually activated by the user,
`for example if the user is in distress. Device 101 may also
`optionally feature a LED display 118, for example in order
`to indicate of alert activation or a low battery level.
`
`[0058] Physiological sensor 102 is preferably part of a
`sensor assembly. Without the intention to limit in any way,
`the following discussion centers on such a physiological
`sensor 102, which contains a piezoceramic transducer for
`generating an electrical signal, having amplitude corre-
`sponding to the magnitude of applied pressure. Therefore, if
`at least a portion of the transduceris located adjacent to, and
`in physical contact with, an area of the wrist where blood
`pressure pulses may be detected, the transducer generates
`electrical pressure pulses corresponding to the detected
`blood pressure pulses. Each of the electrical pressure pulses
`preferably defines a maximum voltage over a systolic inter-
`val and a minimum voltage over a diastolic interval.
`
`[0059] Although a piezoceramic sensor is used as a pres-
`sure transducer according to a preferred embodimentof the
`invention, it should be appreciated