GB2590498A

GB2590498A - Blood glucose monitor

Info

Publication number: GB2590498A
Application number: GB1919015.6A
Authority: GB
Inventors: Reid Steven
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2021-06-30
Also published as: GB2591609A; GB202020122D0; GB2591609B; GB201919015D0

Abstract

An over-ear blood-glucose measurement apparatus 108 comprises: a first portion 110 arranged to contact a measurement region 102 on a first face 104 of an outer ear portion 100 of a user; a second portion 112 arranged to contact the measurement region on a second face 106 of an outer ear portion of the user, the second face diametrically opposing the first face. The first portion comprising a light source 116, positioned to emit light in a direction toward the second portion. The second portion comprises a light sensing member 120 arranged to receive the light through the measurement region, and further arranged to transmit light data characteristic of the received light. The apparatus further comprises a memory 122 arranged to receive and store the light data; and a transceiver 124 arranged to transmit the stored light data to a remote device. The measurement region on the outer ear may be selected from the helix, scapha, antihelix, triangular fossa, concha cymba or concha cavum. The light source may emit 780nm-2500nm wavelength near infrared light. The apparatus may be substantially water-resistant or water-proof. The remote device transceiver may transmit an actuation signal to an artificial pancreas.

Description

Intellectual Property Office Application No. GII1919015.6 RTM Date:10 June 2020 The following terms are registered trade marks and should be read as such wherever they occur in this document: Intellectual Property Office is an operating name of the Patent Office www.gov.uk/ipo

BLOOD GLUCOSE MONITOR

Field of the Invention

The present invention relates to a blood glucose monitor. Particularly the present invention relates to a non-invasive, continuous blood glucose monitor.

Background to the Invention

A majority of diabetes sufferers use finger-prick testing in order to measure their blood glucose levels. This invariably requires blood to be drawn and applied to a disposable test strip, from which a compatible test device then estimates or determines a glucose concentration of the blood. Test devices are often a one-time purchase for a user and as such are relatively inexpensive. The disposable, test device-compatible test strips by contrast, are by their very nature a consumable product and as such require repeat purchase. The cost of such ongoing purchases can be prohibitive for many diabetes sufferers, many of whom are either forced to minimise their blood glucose monitoring, or discontinue their blood glucose monitoring altogether. In many cases, it may be necessary to seek alternative solutions to monitoring their blood glucose. In any case, such deviation from a healthy standard of blood glucose monitoring can have a variety of deleterious effects on the long-term health of a diabetes sufferer.

Solutions to the "disposables" business model have been trialled in the form of continuous glucose monitoring (CGM) products. Such products can supplement or even replace the finger-prick test and there are several types of CGM products which have been marketed. In most cases, such products require a similar action for measuring blood glucose concentrations, particularly that the skin be broken.

In some CGM solutions, a subcutaneous sensor is inserted through the skin using a probe which perforates the skin. The sensor is positioned in interstitial fat, and the probe is used to take readings of glucose levels. Such products can have a single test point, but some (such as, for example, the Dexcom G6) have multiple test points.

Some alternative CGM products include a sensor which requires invasive surgical implantation, and as such presents various issues related to maintenance and replacement of the device. A relatively recent example of such a solution can be found in the Eversense CGM product.

Another class of CGM solutions are "wearables", examples of which are "watch-like" devices. Such products use one or more needles to pierce the skin to obtain body fluids, which are subsequently used to measure blood glucose levels.

Finger-pricking or other forms of skin piercing in all cases lead to pain, and repeated skin piercing is known to cause callouses over time. While tolerable for adults, such a practice deters from, what is in some cases a strict requirement for, adherence to a regular repeated monitoring program. For young children and infants, such a practice can be extremely uncomfortable and distressing. In some cases, the CGM product requires a violent insertion process, and can have a short window of usefulness On many cases as little 5 to 10 days) before requiring removal followed by insertion of a replacement sensor.

In some CGM products, an adhesive (such as a glue) is required to adhere the product to a user's skin. Continuous removal and replacement of the products from the skin can lead to irritation and persistent sores. Such irritation can be exacerbated in cases where a user's skin suffers a negative (and sometimes quite dramatic) reaction to the adhesive used. Solutions such as barrier sprays have been trialled but are by no means effective for all users and CGM products.

Current CGM products typically require a warm-up period, meaning that a diabetes sufferer is required to wait following initial sampling, sometimes for two to three hours, prior to being provided with an initial reading.

Current CGM solutions are costly and their price can be exclusionary to those on low incomes. In the cases of surgically-implanted technology, a surgical operation is of course required for insertion and removal, and the cost of such procedures is significant.

A burgeoning area within the glucose monitoring field is that focussing on non-invasive blood glucose monitoring, which can be devices providing a one-time reading, such as devices which can be attached to a finger (similar to a pulse oximeter), or ongoing monitoring devices.

Such devices are generally portable and in most cases use some form of electronic or electromagnetic detection means. Examples include those which use a dielectric sensor to detect chemical signatures relating to blood glucose values; those which use light spectrometry to calculate glucose concentration; and those which use an electric current to draw a small number of molecules from the skin, including glucose, for measurement.

Another device claims to use machine learning to calculate an estimated HbAl c value -providing an estimate of the average blood glucose concentration over a three-month period.

Such recent, wearable CGM devices are naturally highly complex in nature and carry a high cost for those with low disposable income, thereby biasing the availability of a suitable means by which to maintain this life-long condition. Replacement of such devices in particular can be highly costly, and calibration of the replacement device can, in many cases, be a laborious procedure. Wearables such as watches can be conspicuous and in cases where a diabetes sufferer wishes to keep their condition confidential, such devices make this difficult.

It is therefore desirable to provide a solution which overcomes the disadvantages of the current glucose monitoring products. Particularly, it is desirable to provide a simple, discreet, non-invasive product which is available to a wider range of diabetes sufferers.

Summary of the Invention

In accordance with a first aspect of the present invention, there is provided an over-ear blood-glucose measurement apparatus for continuous blood glucose monitoring, the apparatus comprising: a first portion arranged to contact a measurement region on a first face of an outer ear portion of a user; a second portion arranged to contact the measurement region on a second face of an outer ear portion of the user, the second face diametrically opposing the first face; the first portion comprising a light source, the light source positioned to emit light in a direction toward the second portion; the second portion comprising a light sensing member arranged to receive the light through the measurement region, and further arranged to transmit light data characteristic of the received light; the apparatus further comprising a memory arranged to receive and store the light data; and a transceiver arranged to transmit the stored light data to a remote device.

Light spectroscopy and spectrometry typically use reflective properties of a substrate for determination of a particular measurand. Outer ear regions generally permit passage of light there through. The visible properties of said outer ear regions, upon illumination, have been found to be indicative of blood glucose concentration flowing through the ear region. Such indications have been found to be particularly effective for determining blood glucose concentrations, when taken from the receipt of passage of said light through translucent ear tissue, contrasting with receipt of reflected light from said tissue.

In some embodiments of the present invention, the properties of light received from the light source, through the measurement region of the outer ear portion, by the light sensing member can be analysed from light data obtained by the light sensing member. The analysis, or any portion thereof (such as, for example, pre-processing, normalisation, background correction, polishing, or any other downstream processing step), may be performed by a processor comprised within the over-ear apparatus, or on a remote device. In some preferable embodiments, computationally intensive analysis steps are performed on a remote device. Embodiments will be appreciated wherein less computationally-intensive upstream analysis steps may be initially performed on the over-ear apparatus prior to transmission of the semi-analysed light data to the remote device by the transceiver for completion of the analysis.

In the context of the present invention therefore, the term "light data" will be understood by the skilled addressee to mean any of "raw, unprocessed light data" or "light data having undergone any form processing".

The measurement region is preferably located on an outer ear region selected from the group: helix; scapha; antihelix; triangular fossa; concha cymba; concha cavum. The measurement region comprises a measurement region thickness, the measurement region thickness being selected from the range: less than 10 mm. In particular, cartilaginous regions of the ear are preferred over an ear lobe, preferably due to their comparative thickness and translucent properties -potentially leading to a more effective use of the present invention.

The light source is preferably a near infra-red light source, arranged to emit near infra-red light having a wavelength selected from the range: 780 nm to 2500 nm. In most preferable embodiments, the wavelength is approximately 980 nm.

Near infra-red light, in the wavelength spectrum of 780 nm to 2500 nm, has been identified as particularly effective in indicating blood glucose level. Such indication appears most effective when the wavelength used is in the region of 800 nm to 1100 nm, and most preferably around 980 nm.

In preferable embodiments, the light sensing member may be an image capturing member arranged to receive the light through the measurement region, and further arranged to capture the light data from the measurement region as image data, prior to transmitting said image data. In such embodiment, the light data may be, or may comprise, image data.

In the context of the present invention, the term "image data" will be understood by the skilled addressee to mean either "one or more images", or "any data relating to, or resulting from analysis or pre-processing of, one or more images". As such, the image data transmitted to the remote device by the transceiver may include one or more images obtained by the image capturing member, or any image data relating to said one or more images.

The apparatus of the present invention may therefore look to provide a simple, non-invasive, discreet, over-ear solution which uses light transmission, from the light source, toward a first surface of an outer ear region of a user, to illuminate the opposing surface of said region. The light sensing member (which may be an image capturing member) can then obtain light data (which may be, or include, image data) from the illuminated opposing surface. The light data can then be stored on the memory, from where it may be transmitted to a remote device by the transceiver. The present invention preferably circumvents the need for ongoing finger-pricking or skin piercing, and thereby preferably reduces or eliminates fear, anxiety, pain and other potential causes of non-adherence to a healthy blood glucose monitoring regime. The reduced need for creating a wound for monitoring blood glucose preferably additionally reduces the likelihood of infections. The over-ear nature of the apparatus preferably also facilitates its discreet qualifies, and a user's need for a blood glucose monitoring regime can therefore be kept confidential if desired. The comparatively simple design, which preferably offloads many of the complexities of current blood glucose monitors (such as hardware-heavy computations) aids in reducing the size and manufacturing complexity and cost of the apparatus, thereby providing a less complicated, more affordable solution promoting uptake and continued maintenance of healthy blood glucose monitoring. By offloading light data or image data from the apparatus to a remote device, the apparatus may additionally therefore support scalability of processing said light data or image data, as remote device analysis and hardware capabilities improve.

The light sensing member is preferably arranged to sequentially capture the light data (which may be, or include, image data) at a predetermined time interval. In order to provide an apparatus for facilitating or contributing to an effective continuous blood glucose monitoring regime, it may be preferable to provide chronologically sequential capturing of light data (which may be in the form of images by an image capturing member) from the measurement region over time. Such increased sampling can often permit more reliable conclusions to be drawn from the light data, and may be useful in providing a time-based assessment of blood glucose.

The predetermined time interval is preferably freely selectable by a user. It may be the case that different users may require a different frequency of observations per unit time, which may be driven by, for example, a medical condition such as diabetes. Conditions of differing severity may each additionally require a corresponding frequency of observation per unit time. In such embodiments, it may be advantageous for a user to freely select a time interval between observations. Such flexibility in the number observations captured per unit time may optionally provide improved compatibility of the present invention with devices having different memory capacities. As an example, a device having a low amount of available memory may wish for more infrequent sampling by the image capturing member, in order to make most efficient use of said available memory.

The predetermined time interval is preferably selectable between the range: 10 seconds to 24 hours. Most preferably, the predetermined time interval is 5 minutes. In some embodiments it may be beneficial to provide one or more thresholds for said time interval. Such thresholds may be driven by clinical factors, and may ensure that frequency of sampling by the light sensing member does not subceed a healthy threshold in order to maintain healthy monitoring of blood glucose.

The transceiver is preferably a wireless transmitter. The transceiver of the over-ear apparatus is preferably arranged to transmit the stored light data wirelessly, and can thereby preferably permit greater flexibility in use, particularly if the remote device is not readily/easily accessible or an encumbrance. Any suitable wireless technologies will be appreciated by the skilled addressee. Preferably the wireless transceiver is arranged to transmit the stored light data using one selected from the group: Bluetooth; infra-red communication; near-field communication; WiFi; radio frequency communication; mobile or cellular communication technology; 3G; 4G; 5G; GSM; EDGE; LTE; CDMA; FDMA; TDMA; GPRS.

The apparatus is preferably substantially water-resistant or water-proof. Preferably the apparatus comprises an IPX rating selected from the range: IPX1; IPX2; IPX3; I PX4; IPX7; or IPX8. As an over-ear apparatus, the present apparatus may in some embodiments be beneficial for use outdoors, in a sporting environment such as a gym, or even in a shower, bath or swimming pool. In the case of a sporting environment or swimming pool, for some users suffering from diabetes it may be beneficial to continue use of the apparatus in said environments. As such, the apparatus is preferably arranged to withstand perspiration and splashing, and in some embodiments, short-term or prolonged submersion.

The apparatus preferably further comprises a bridge portion arranged to connect the first portion to the second portion. The bridge portion preferably comprises a wire permitting electrical or digital communication between one or more components of the first portion and one or more components of the second portion. The bridge portion may comprise a biasing member, such as a torsion spring for example, arranged to bias the first portion toward the second portion, which may be arranged to hold the apparatus in place on a measurement region during movement of the user. Any suitable bridge portion will be appreciated by the skilled person, and may comprise a detachable connection such that the first portion and the second portion are reversibly detachable from one another. In most embodiments, the first and second portions, the memory and the transceiver form a single unit in use. The apparatus thereby preferably provides a self-contained, wireless apparatus for facilitating a healthy blood glucose monitoring regime.

In some embodiments, the first portion forms a shape having a first surface which is complementary to the first face of the outer-ear region, said first surface being arranged to abut the first face of the outer-ear region in use. Additionally, the second portion preferably forms a shape having a second surface which is complementary to the second face of the outer-ear region, said second surface being arranged to abut the second face of the outer-ear region in use. The first and second portions thereby preferably provide a comfortable fit for the user. Said shapes of the first and second portions, and optionally a shape of the bridge portion, may be formed using additive manufacturing processes, such as 3D printing. Such processes may permit "colour-matching" of components of the apparatus to a user's skin colour and tone, thus improving the discreetness of the present invention.

In some embodiments, one of the first portion and the second portion may comprise a magnet, and the other of the first portion and the second portion may comprise a ferromagnetic material. In such embodiments, the first portion and the second portion may be held in place on the outer-ear region of the user, with magnetic forces acting between the magnet and the ferromagnetic material (which may be a second magnet) acting to hold the first portion and the second portion stationary on the outer-ear region of the user. In many cases, firm coupling of the apparatus to a user's ear is preferable, particularly for maintaining the apparatus in place on the measurement region during exercise. Any suitable coupling of the apparatus to a user's ear will be appreciated by the skilled addressee, and may be user-dependent.

The individual component parts of the apparatus may, in some embodiments be detachable from one another, and therefore provides a modular solution which aids replacement of nonfunctioning parts, or placing components such as the light sensing member, the light source, the memory, and/or the transceiver into a differently-shaped first and/or second portion. This can be particularly useful for children, whose ear shape and thickness may change over time. Additionally, the reduced need to replace an entire apparatus, rather than individual component parts separately, preferably improves the cost-effectiveness of the using the apparatus.

Any suitable remote device will be appreciated by the skilled addressee, and is in most embodiments mechanically disconnected from the over-ear apparatus. In most embodiments, the remote device is preferably one selected from the group: a mobile device; a mobile telephone; a tablet; a smart watch; a laptop; a desktop computer; a server.

The remote device preferably comprises: a processor; a remote device transceiver arranged to receive the light data from the transceiver; and a memory having an available memory size, the memory arranged to receive and store the light data.

In some embodiments of the first aspect of the present invention, the apparatus further comprises the remote device. Preferably the remote device memory comprises computer-executable code stored thereon, the code operable when executed to: by the remote device transceiver, detect a request for transmission of light data, the request comprising an light data size; by the processor, compare the size of said light data and an available memory size; by the remote device transceiver, request transmission of the light data to the remote device transceiver; by the memory, store the received light data; by the processor, analyse the light data and provide analysis results; and by the processor, issue a blood glucose value according to the analysis results, the blood glucose value being characteristic of an estimated blood glucose concentration.

In preferable embodiments, the memory of the over-ear apparatus may be arranged to store light data captured by the light sensing member, and the transceiver may be arranged to transmit the light data only when a suitable or paired remote device becomes available. Said availability of the remote device may be determined by its proximity to the over-ear apparatus (the transceiver); by the "on/off' status of the remote device; and/or by the availability of sufficient memory in the remote device memory. In the case where the availability is determined by the availability of sufficient memory, the transceiver of the over-ear apparatus may only transmit the light data following receipt of a request from the remote device transceiver, or following receipt of confirmation of sufficient over-ear apparatus memory.

The code may preferably be further operable when executed to: by the remote device memory, store the analysis results.

The code may preferably be further operable when executed to: by the remote device transceiver, request deletion of light data from the memory.

The memory of the over-ear apparatus may act merely as a temporary or transient storage medium for the light data, pending effective transmission to the remote device. In some embodiments, following effective transmission of the light data to the remote device from the memory, the memory may delete the light data either following confirmation of successful transmission, or following a request from the remote device. In this way, in such embodiments the memory of the over-ear apparatus may be minimised and as such costs of manufacture may be minimised.

The code preferably further comprises a machine learning module, and wherein analysing the light data (which may be, or include, image data) comprises: by the processor, determining one or more characteristics of the light data; by the processor, using the machine learning module carry out a comparison of the one or more characteristics to stored analysis results; by processor, using the machine learning module to determine a blood glucose value from the comparison the blood glucose value being characteristic of an estimated blood glucose concentration.

Many off-the-shelf solutions provide a one-size-fits-all approach to the determination of blood glucose concentrations. Such solutions may, for example, compare readings to universally applied standards, controls, or noise levels for background correction or normalisation or readings in order to maintain accuracy. This can have potential drawbacks on the accuracy and effectiveness of the blood glucose readings provided, particularly as to ensure accuracy across individuals, such processing will be required to be tailored to each individual. The present apparatus preferably offers a personalised determination of blood glucose monitoring by a machine learning module making use of stored analysis results to adapt readings to an individual. Such stored analysis results may, in some embodiments, include those derived from another form of blood glucose monitoring (such as another continuous glucose monitor or finger-prick tests) in combination with the light data of the present invention. In such embodiments, it may be the case that a user enters a blood glucose reading obtained from said other form of blood glucose monitoring (for example a finger-prick blood glucose value) into the remote device, which may transmit a trigger signal to the over-ear apparatus to capture light data (such as image data) by the light sensing member. Said light data, and any analysis results obtained from analysing said light data, may subsequently be attributed to said blood glucose reading, thereby developing and training a personalised model of blood glucose and corresponding light data characteristics for each individual user. Said model may then be used by the apparatus and/or remote device, such that the invention may be used independently of said other form of blood glucose monitoring. Other forms of training may occur via a central application on said apparatus or remote device, wherein said other form of blood glucose monitoring (such as an alternate smart CGM product) is arranged to obtain a blood glucose value and update the application with said blood glucose value automatically. The application may then trigger capturing of light data by the light sensing member of the invention, characteristics thereof being attributed to said separately-obtained blood glucose value. In the example training embodiments described above, said training occurs actively, through triggering of the apparatus of the invention to capture light data corresponding to a known blood glucose value. Such training may, in some embodiments, occur passively, such that synchronously obtained blood glucose values and image data (which may be obtained within a predetermined time window of one another) may be automatically paired for the purpose of training said model. For example, if a blood glucose value is obtained by a separate blood glucose monitor, and a light sensing member of the apparatus of the present invention captures light data within 60 seconds of obtaining said blood glucose value, characteristics of said light data may be paired with said blood glucose value for the purposes of training said model. Said pairing may occur using a processor of the apparatus, or on the remote device.

Training may not be limited to personalised, separately-obtained blood glucose data from an individual user, and may include any suitable consideration of possible compounding factors, which will be apparent to the skilled addressee and may, for example, include ambient light level. Embodiments may, for example, comprise an ambient light sensor arranged to obtain an ambient light reading at the same time as light data is captured by the light sensing member. Such ambient light data may be suitable in providing a correction of any light data obtained by the light sensing member according to the ambient lighting environment (which may change depending upon time of day or setting). Such a correction may occur on-board by the light sensing member, or by a processor of the over-ear apparatus, ahead of, or following, storage of the light data on the memory, or may occur post transmission of the light data to the remote device. In such cases, said ambient light data may be coupled to the light data, which may additionally include a time-stamp, either prior to or post transmission to the remote device. Other suitable light data correction and pre-processing methods will be appreciated by the skilled addressee.

The code may further be operable when executed to: with a predetermined - using the processor, compare the blood glucose value blood glucose threshold; artificial pancreas, the - by the remote device transceiver, transmit a signal to an signal arranged to actuate said artificial pancreas.

The present apparatus may be particularly useful for diabetes sufferers, some of whom may use an artificial pancreas to control insulin secretion. In such cases, it may be beneficial for the apparatus to inform the artificial pancreas of any blood glucose thresholds which have been exceeded, and may additionally be arranged to actuate the release of insulin from the artificial pancreas.

In some embodiments, the determined blood glucose values may be sharable across applications and platforms in order to provide additional contextual data for a wider assessment of a user's ongoing health status.

Examples of data available from the present invention may include: a display of a most recently determined blood glucose value, and a timestamp of the corresponding light data (the time of capture) relating to said value; display of all blood glucose values determined for light data captured over a previous time period (for example, 2 hours, 6 hours, 12 hours, 24 hours etc.); - a graphical representation of blood glucose value plotted against corresponding time stamp of related light data, or a correlation/trend of said plot; an indication of a rate of change of determined blood glucose values over time; - raw light data obtained by the light sensing member, or the actuation of the light sensing member by the user (for example, from within an app of the remote device); and/or a raw image file obtained by an image capturing member, or the actuation of the image capturing member by the user (for example, from within an app of the remote device).

The present invention, and associated apps or remote devices may permit the generation or presentation of any suitable data which will be appreciated by the skilled addressee.

Preferable embodiments preferably comprise a power supply arranged to power the image capturing apparatus, the light source, the memory and the transceiver. The power supply in most preferable embodiments is a battery, which may preferably be rechargeable. Other embodiments may make use of other suitable power sources, such as renewable power sources arranged to act directly or to charge a rechargeable battery. Such renewable sources may, for example, include kinetic energy captured from movement of the user, or a solar cell arranged to obtain solar power.

In accordance with a second aspect of the present invention, there is provided a method of obtaining a blood glucose measurement, the method comprising the steps of: by a light source, directing light through a translucent measurement region of an outer ear of a user; by an light sensing member, receiving the light through the measurement region and transmitting light data characteristic of the received light; by a memory, receiving and storing the light data; by a transceiver, transmitting the light data to a remote device.

It will be understood that the steps of the method may additionally include any features described for the over-ear blood-glucose measurement apparatus in accordance with the first aspect of the present invention. The method of the second aspect may be performed by an over-ear blood glucose measurement apparatus in accordance with the first aspect.

In the context of the present invention, the terms "first portion" and "second portion" are used to define distinct regions of the apparatus. It will be appreciated that in embodiments of the invention, the terms "first portion" and "second portion" may not rigidly define any specific portion of the apparatus (e.g. right or left), and may be interchangeable.

Detailed Description

Specific embodiments will now be described by way of example only, and with reference to the accompanying drawings, in which: FIG. 1 shows an example view of a user's ear and a measurement region suitable for use with the present invention; FIG. 2 shows an example embodiment of an over-ear blood glucose measurement apparatus in accordance with the first aspect of the present invention, positioned on the ear of FIG. 1; FIG. 3 shows a sectional view of the embodiment of FIG. 2, depicting the passage of light form the light source to an image capturing member; FIG. 4 shows a schematic diagram of an example embodiment of the present invention; FIG. 5 shows a flowchart depicting steps in an example method of the second aspect of the present invention; FIG. 6 shows a flowchart depicting additional steps in the example method of FIG. 5; and FIG. 7 shows a flowchart depicting steps in an alternate method of the second aspect performed by an apparatus of the first aspect.

Referring to FIG. 1, a view of an ear 100 is shown having a measurement region 102 designated on a cartilaginous region thereof. The measurement region 102 extends through the full thickness of the cartilaginous region from a front face 104 of the ear 100 to a rear face 106 of the ear 100.

Fig. 2 shows an example embodiment of an over-ear blood glucose measurement apparatus 108 in accordance with the first aspect of the present invention, positioned on the ear 100 of FIG. 1. The apparatus 108 comprises a first structural portion 110 having a primary surface shaped to complement the front face 104 and positioned adjacent the front face 104. The apparatus 108 further comprises a second structural portion 112 having a primary surface (not shown) shaped to extend across the rear face 106 and further shaped to complement the rear face 106. The second structural portion 112 comprises a second portion body 114 which is supported along an upper surface of the ear 100.

The first portion 110 houses a near infra-red light source 116 positioned to emit near infrared light 117, at a wavelength of 980 nm, toward and through the measurement region 102 of the ear 100. The first portion 110 further comprises a supporting cable 118 protruding from a first end thereof, distal to an opposing free end, the cable 118 extending around the ear 100 toward the second portion 112 and into a first end of the second portion 112. The cable 118 houses a copper signalling wire (not shown), connecting the light source 116 to a processor (not shown) accommodated within the body 114 of the second portion 112.

The second portion 112 houses a near infra-red camera 120 positioned adjacent the primary surface of the second portion 112 and oriented to detect the near infra-red light 117 through the measurement region 102 and to capture an image of the measurement region 102. The second portion 112 further comprises a memory 122 in digital communication with the camera 120 and arranged to store images captured by the camera 120. The memory 122 and the processor are in digital communication with a Bluetooth transceiver 124 located within the second portion body 114. The second portion body 114 additionally comprises a rechargeable battery (not shown) housed therein which is in communication with the light 116 via the cable 118, and the camera 120, processor, memory 122 and the transceiver 124.

In use, the light source 116 is arranged to direct the near infra-red light 117 through the measurement region 102 toward the camera 120, which is arranged to simultaneously image the illuminated rear face 106 superimposing the measurement region 102 as shown in the sectional view of FIG. 3. The processor is arranged to simultaneously actuate the light source 116 and the camera 120 every 5 minutes. Once taken, the processor is arranged to couple the image with a time stamp corresponding to the time that the image was taken by the camera 120. The image is transmitted from the camera to the memory 122 to be stored. In the example shown, upon receipt of a request for transmission of the image received by the transceiver 124 from a remote device (e.g. a mobile phone, not shown), the transceiver 124 is arranged to access the memory 122 and transmit the image to the remote device via Bluetooth. In the example shown, the remote device provides a signal to the transceiver confirming safe receipt of the image. After receipt of said confirmation signal, the processor is arranged to delete the image from the memory, thereby maintaining available storage space for future images.

In the example embodiment shown, the first portion 110 and the second portion 112 are manufactured according to the shape of the user's ear using 3D printing. The colour of the first portion 110 and the second portion 112 in the embodiment shown can be matched to the colour of the user's skin to maximise discreetness of the apparatus. The cable 118 ensures a snug fit of the first portion 110 and the second portion 112 against corresponding front and rear faces 104, 106 of the ear 100 respectively. Other embodiments will be appreciated wherein the first and second portions may each comprise a complementary magnetic element to hold each portion in place. In such embodiments, digital communication between the first portion and the second portion may occur wirelessly, negating the need for the cable or the wire therein.

The example method in accordance with the second aspect of the invention, and performed by the example embodiment of FIG. 2 as described above, can be seen in flow chart form in FIG. 5. The method comprises the steps of: by a light source, directing light through a translucent measurement region of an outer ear of a user 134; by an image capturing member, receiving the light through the measurement region and capturing image data of the measurement region 136; -by a memory, storing the image data 138; -by a transceiver, transmitting the image data to a remote device 140.

FIG. 4 shows a schematic representation of interaction between the apparatus 108 of FIG. 2 with a remote device (a mobile phone) 126 by transmitting the image captured by the camera 120 via Bluetooth. In FIG. 4, the apparatus 108 comprises on-board memory 122 for data storage to enable data collection when the apparatus 108 is not connected to the mobile phone 126. The mobile phone 126 houses a processor and memory (not shown). The memory comprises, stored thereon, processor-executable code portions defining an image analysis module 128 and a machine learning module 130. In use the image received by the mobile phone 126 is stored on the memory thereof. The image analysis module 128 (when executed by the mobile phone processor) is arranged to identify one or more characteristics of the image for comparison with historic image data and determination of a blood glucose value 132 by the machine learning module 130. Once determined, the blood glucose value 132 is displayed by the mobile phone 126 to the user.

The method performed by the example of FIG. 4 is shown depicted in the flow charts of FIG. 6 and FIG 7, and comprises the steps of: by the remote device transceiver, detect a request for transmission of image data, the request comprising an image data size 142; by the processor, compare the size of said image data and an available memory size 144; by the remote device transceiver, request transmission of the image data to the remote device transceiver 146; by the memory, store the received image data 148; by the processor, analyse the image data and provide analysis results 150; and by the processor, issue a blood glucose value according to the analysis results, the blood glucose value being characteristic of an estimated blood glucose concentration 152.

More detail is provided in FIG. 7 which shows that at five minute intervals the apparatus (the non-invasive glucose monitor (NIGM)) initiates a photograph to be taken by the image capturing member, following near infra-red (NIR) light transmission (at 980nm) from the light source (an NIR LED) through the measurement region of the patient's ear tissue. The photograph is then saved on the memory of the apparatus, combined with corresponding date and time tags.

At five minute intervals (which may include a +10 seconds lag after the previous photograph time), the mobile device app will detect available memory on the mobile device, and pull all new photographs (and corresponding data) from the apparatus since the time of the previous transfer. Following successful transfer of the image data, the mobile device app then initiates deletion of the transferred/pulled photographs (and corresponding time/date tag data) from the memory of the apparatus.

The image analysis module of the remote device processes the photographs and corresponding data to determine characteristics of each photograph. The machine learning module of the remote device then compares the characteristics to characteristics of stored image data. The machine learning module then estimates a blood glucose value associated with the image data of each photograph. The machine learning module then attributes or tags the image data of each photograph with the corresponding blood glucose value. The mobile device app then displays the blood glucose value to the user and updates any additional health-related applications or devices with the blood glucose value (which may include interaction with, or actuation of, an artificial pancreas).

In some embodiments, there may be a "learning" period, during which glucose values from finger-prick tests (or other suitable form of alternate blood glucose detection) are used to define user-specific baseline characteristics of images taken, to allow the self-contained, accurate and consistent future determination of blood glucose values by the apparatus. As an example, an initial model developed from a series of test subjects may be sufficient to provide comparison/baseline data for the correction stage of the image analysis. Such test subjects may be selected according to skin type and may act to training the machine learning module to detect skin type of the user and use the corresponding test subject baseline characteristics for correction of the user's images. Multiple methods of blood glucose measurement may be used to inform the training of the machine learning module in order to provide an effective model by which to baseline/correct a future user's images. Other embodiments may require each new user to carry out a "learning" period using, for example, a combination of the presently-described image analysis with known finger-prick testing.

It will be appreciated that the above described embodiments are given by way of example only and that various modifications may be made to the described embodiments without departing from the scope of the invention as defined in the appended claims.

Claims

CLAIMSAn over-ear blood-glucose measurement apparatus for continuous blood glucose monitoring, the apparatus comprising: a first portion arranged to contact a measurement region on a first face of an outer ear portion of a user; a second portion arranged to contact the measurement region on a second face of an outer ear portion of the user, the second face diametrically opposing the first face; the first portion comprising a light source, the light source positioned to emit light in a direction toward the second portion; the second portion comprising an light sensing member arranged to receive the light through the measurement region, and further arranged to transmit light data characteristic of the received light; the apparatus further comprising a memory arranged to receive and store the light data; and a transceiver arranged to transmit the stored light data to a remote device.
An apparatus as claimed in claim 1, wherein the light sensing member is an image capturing member arranged to capture image data of the measurement region, and wherein the light data comprises said image data.
An apparatus as claimed in claim 1 or claim 2, wherein the measurement region is located on an outer ear region selected from the group: helix; scapha; antihelix; triangular fossa; concha cymba; concha cavum.
An apparatus as claimed in claim 1, claim 2 or claim 3, wherein the measurement region comprises a measurement region thickness, the measurement region thickness being selected from the range: less than 10 mm.
5. An apparatus as claimed in any one of claims 1 to 4, wherein the light source is a near infra-red light source arranged to emit near infra-red light having a wavelength selected from the range: 780 nm to 2500 nm.
An apparatus as claimed in claim 5, wherein the wavelength is approximately 980 nm.
7 An apparatus as claimed in any one of the preceding claims, wherein the light sensing member is arranged to sequentially capture the light data at a predetermined time interval.
An apparatus as claimed in claim 7, wherein the predetermined time interval is freely selectable by a user.
9. An apparatus as claimed in claim 8, wherein the predetermined time interval is selectable between the range: 10 seconds to 24 hours.
10. An apparatus as claimed in any one of the preceding claims, wherein the transceiver is a wireless transceiver.
11. An apparatus as claimed in claim 10, wherein the wireless transceiver is arranged to transmit the stored light data using one selected from the group: Bluetooth; infra-red communication; near-field communication; WiFi; radio frequency communication; mobile or cellular communication technology; 3G; 4G; 5G; GSM; EDGE; LTE; CDMA; FDMA; TDMA; GPRS.
12. An apparatus as claimed in any one of the preceding claims, wherein the apparatus is substantially water-resistant or water-proof and comprises an IPX rating selected from the range: IPX1; IPX2; IPX3; IPX4; IPX7; or IPX8.
13. An apparatus as claimed in any one of the preceding claims, wherein the apparatus further comprises a bridge portion arranged to connect the first portion to the second portion.
14. An apparatus as claimed in any one of the preceding claims, wherein the remote device is one selected from the group: a mobile device; a mobile telephone; a tablet; a smart watch; a laptop; a desktop computer; a server.
15. An apparatus as claimed in claim 14, wherein the remote device comprises: a processor; a remote device transceiver arranged to receive the light data from the transceiver; and a memory having an available memory size, the memory arranged to receive and store the light data.
16. An apparatus as claimed in claim 15, wherein the memory of the remote device comprises computer-executable code stored thereon, the code operable when executed to: by the remote device transceiver, detect a request for transmission of light data, the request comprising an light data size; by the processor, compare the size of said light data and the available memory size; - by the remote device transceiver, request transmission of the light data to the remote device transceiver; by the memory, store the received light data; - by the processor, analyse the light data and provide analysis results; and by the processor, issue a blood glucose value according to the analysis results, the blood glucose value being characteristic of an estimated blood glucose concentration of the measurement region.
17. An apparatus as claimed in claim 16, wherein the code is further operable when executed to: - by the memory, store the analysis results.
18. An apparatus as claimed in claim 17, wherein the code comprises a machine learning module, and wherein analysing the light data comprises: - by the processor, determining one or more characteristics of the light data; by the processor, using the machine learning module carry out a comparison of the one or more characteristics to stored analysis results; - by processor, using the machine learning module to determine a blood glucose value from the comparison the blood glucose value being characteristic of an estimated blood glucose concentration.
19. An apparatus as claimed in any one of claims 16 to 18, wherein the code is further operable when executed to: by the processor, compare the blood glucose value with a predetermined blood glucose threshold; by the processor, provide an actuation signal to the remote device transceiver, the actuation signal according to the comparison; by the remote device transceiver, transmit the actuation signal to an artificial pancreas, the actuation signal arranged to actuate said artificial pancreas
20. A method of obtaining light data for use in providing a blood glucose measurement, the method comprising the steps of: by a light source, directing light through a translucent measurement region of an outer ear of a user; by an light sensing member, receiving the light through the measurement region and transmitting light data characteristic of the received light; by a memory, receiving and storing the light data; by a transceiver, transmitting the light data to a remote device.
21. A method as claimed in claim 20, the wherein the steps of the method are performed by an over-ear blood-glucose measurement apparatus as claimed in any one of claims 1 to 19.