WO2021260397A1

WO2021260397A1 - Wearable intraoral device and method

Info

Publication number: WO2021260397A1
Application number: PCT/GB2021/051634
Authority: WO
Inventors: Beren KAYALI; Paul Vinicio MENDIETA PRIETO; Lu YE; Lea MAROLT SONNENSCHEIN
Original assignee: Project Stealth Tech Ltd
Current assignee: Project Stealth Tech Ltd
Priority date: 2020-06-26
Filing date: 2021-06-28
Publication date: 2021-12-30
Anticipated expiration: 2022-12-26
Also published as: GB2611717B; GB2611717A; GB202009828D0; GB202301116D0

Abstract

A wearable device (100, 600) is provided, configured for concealed wearing within the mouth of a user and to authenticate a user by: an oral communications protocol and/or by reading oral biometric information. A wearable device (100, 600), configured for concealed wearing within the mouth of a user and comprising an oral biometric sensor (120, 610), configured to read the oral biometric information of the user, is also provided. A method of authenticating a user is further provided. The method comprises using a wearable device concealed in a mouth of a user to authenticate the user by communicating with the user via the wearable device and/or by the wearable device reading oral biometric information of the user.

Description

WEARABLE INTRAORAL DEVICE AND METHOD

FIELD OF THE INVENTION

The invention relates to a wearable intraoral device, and to methods of using a wearable intraoral device.

BACKGROUND

User authentication is important in many contexts. For example, user authentication may be necessary to operate a device, or to perform a specific (e.g. restricted) function with a device or system. A very common example is found in mobile devices, in which a device defaults to a locked state (e.g. after a predetermined time), and a potential user must authenticate themselves before the device becomes operable.

Existing authentication methods include challenge/response (based on something the user has, or knows), and biometric identification (based on something only the user is).

Challenge/response, at its simplest, involves challenging the user by asking for a passcode (which may be numeric, alphanumeric or pattern based). If the user provides the correct response, they may be authenticated. Some systems for authentication include a requirement for access to a security device in order to complete an authentication (i.e. something the user has).

Multi-factor authentication requires confirming a subject’ s identity using two or more different factors selected from: something they know, something they have and something they are. Existing security devices for multi -factor authentication may be vulnerable to theft and/or spoofing.

Some systems for authentication require biometric verification of a user. Existing forms of biometric information may be vulnerable to surveillance. For example, a finger print based authentication can be spoofed with knowledge of the user’s fingerprint, which may be relatively straightforward for a determined adversary to obtain (e.g. a state backed actor). Similar concerns apply to biometric authentication based on facial recognition and iris scanning. It may also be straightforward to observe what biometric authentication method is required if a subject is under surveillance (and video surveillance is increasingly pervasive and common, in some countries more than others).

In some contexts (for example where there are very serious consequences for access by a non-authorised user) a more robust authentication approach is desirable that avoids or ameliorates at least some of the above mentioned problems. Robust authentication may be a particular problem in the context of critical national infrastructure, military devices and financial systems.

Within the mouth environment the inventors have found that saliva is a complex matrix that, through different biomarkers, reflects the hormonal, immunological, metabolic and nutritional state of a person. The biomarkers in saliva include lactate, glucose and cortisol.

More generally, there are a wide range of applications for intraoral wearable devices that facilitate communication with the user.

SUMMARY

According to a first aspect, there is provided a wearable device, configured for concealed wearing within the mouth of a user. The wearable device may be configured to authenticate a user by: an oral communications protocol and/or by reading oral biometric information.

The wearable device may comprise an oral biometric sensor, configured to read the oral biometric information of the user.

According to a second aspect, there is provided a wearable device, configured for concealed wearing within the mouth of a user, the device comprising an oral biometric sensor, configured to read oral biometric information of a user.

The following may apply to either aspect.

The oral biometric information may comprise biomarkers such as glucose or the lactic acid and lactate content of the user’s saliva. The oral biometric information may comprise palate morphology.

The palate morphology may comprise a characteristic pattern of palatal rugae.

The oral biometric sensor may comprise a sensor region configured to substantially conform with a palate of the user.

The sensor region may comprise an array of capacitive sensors, for determining the palate morphology.

The wearable device may further comprise an oral input device for receiving user inputs (e.g. for the oral communications protocol).

The input device may comprise one or more touch/force sensors that are responsive to touch/force from the user’s tongue.

The input device may be configured to provide mechanical and/or tactile feedback to the user.

The wearable device may comprise an oral output device for providing information to the user from within the mouth (e.g. within the oral communications protocol).

The oral output device may comprise one or more taste transducers for imparting a taste to the user.

Each taste transducer may comprise a first electrode and a second electrode for applying a potential difference across a region of the user’s tongue.

There may be a plurality of taste transducers.

The wearable device may comprise a unique device ID associated with the device.

The wearable device may comprise a processor and a non-volatile memory communicatively coupled to the processor. The unique device ID may be stored in the memory. The processor may be configured to: receive an authentication request from an external system, and in response to the authentication request, check the identity of the user by: reading oral biometric information (e.g. via the oral biometric sensor) and/or receiving a response to a challenge via an oral communications protocol; in response to positively checking the identity of the user, transmitting an authentication of the user to the external system.

Transmitting the authentication may comprise providing an encryption key.

The wearable device may be configured to perform authentication using at least two factors, using at least two factors selected from: the oral biometric information, a passcode communicated via the oral communications protocol ; and a unique device ID associated with the device.

The wearable device may further comprise a wireless communication module, configured to communicate with a system outside the user’s mouth. The wireless communication module may be configured to receive a wirelessly communicated request to authenticate the user and to wirelessly transmit the result of an authentication check by the wearable device.

The wearable device may comprise a conformal layer, formed to fit the user’s palate and defining an upper surface of the wearable device.

The conformal layer may comprise a moulded layer formed from an impression of the user’s palate. The conformal layer may further comprise a physical salting pattern of additional bumps or recesses.

The device may be configured to be retained in contact with the palate of the user. According to a third aspect, there is provided a wearable device configured for concealed wearing within the mouth, the device comprising an oral output device for providing information to the user from within the mouth.

According to a fourth aspect, there is provided a wearable device configured for concealed wearing within the mouth in contact with a palate of a user, comprising a conformal moulded layer formed from an impression of the user’s palate, and a wireless communication module for communicating with a system external to the user’s mouth.

According to a fifth aspect, there is provided a wearable device configured for concealed wearing within the mouth in contact with a palate of a user, comprising a sensor for healthcare data collection.

The sensor may comprise a saliva sensor, configured to detect a saliva characteristic.

According to this aspect or embodiment, a mouth wearable device may be useful in monitoring the levels of biomarkers such as glucose or lactic acid and lactates (hereafter “lactates”) in the human body.

A biomarker sensor assembly may comprise a biomarker sensor for sensing one or more biosensors such as lactate, glucose, cortisol, and/or other biomarker sensor. The biomarker sensor may comprise an amperometric enzymatic biomarker sensor. The biomarker sensor may be configured/suitable for contacting a wearer’s saliva. The biomarker sensor may be configured, when one or more biomarkers are present in the user’s saliva, to produce an electrical potential and current indicative of the quantity of the biomarker in the saliva. The biomarker sensor may comprise a main control circuit. The control circuit may comprise a communications module e.g. a Bluetooth (BLE) module. The control circuit may comprise a measurement circuit e.g. an amperometric circuit configured to measure current from the sensor. The biomarker sensor may comprise a microcontroller. A power source such as a battery may be provided. The assembly may also comprise a battery charger. The sensor, control circuit, battery and/or battery charger may be mounted on a mounting sheet. The mounting sheet may be flexible to enable it and the sensor to conform to the inside of a wearer’s mouth and so be worn inside the mouth. The biomarker sensor assembly may comprise a data collection and analysis unit and portal. The data collection and analytics portal may allow the assembly to communicate continuous biomarker data via Bluetooth protocol to a nearby processor, e.g. a smartphone.

The biomarker sensor assembly may be self-contained or may share one or more elements of the wearable device of any other aspect. I.e. any/all elements of the biomarker sensor assembly of this embodiment/aspect are useable with/replaceable with/interchangeable with the wearable device of any other aspect.

The device according to the third, fourth and fifth aspect may comprise any of the features disclosed with reference to the first aspect or second aspect, including the optional features thereof. For example, the oral output device in any aspect may comprise a taste transducer, and any aspect may include at least one ofDIPdap an oral input device, oral output device, biometric scanner, wireless communications module (and so on, with the other features).

According to a sixth aspect, there is provided a method of authenticating a user, comprising using a wearable device concealed in a mouth of a user to authenticate the user by communicating with the user via the wearable device and/or by the wearable device reading oral biometric information of the user.

According to a seventh aspect, there is provided a method of communicating with a user, comprising using a wearable device concealed in a mouth of a user to communicate with the user via the wearable device.

The following optional method features are applicable to either the sixth or the seventh aspect.

Communicating with the user may comprise communicating covertly with the user. Communicating with the user may comprise performing challenge/response authentication via an oral communications protocol. Communicating with the user may comprise receiving non-verbal communication from the tongue. Communicating with the user may comprise communicating by taste.

The communication (e.g. challenge/response authentication) may comprise providing a code as one or more taste, and receiving a response comprising a pattern (e.g. of button activation) from the user’s tongue corresponding with a response.

The oral biometric information may comprise a palate morphology of the user.

The method may further comprise: wirelessly receiving a wireless communication (e.g. a request for user authentication or challenge) at the wearable device, and wirelessly transmitting a response from the device (e.g. the result of an authentication check). The response may be derived from oral user input and/or the reading of the oral biometric information.

The method may comprise using the wearable device according to any of the device aspects.

The authentication may be for accessing and/or operating an asset: of high value, related to critical national infrastructure and/or that is important for national security.

The device of any device aspect (lst-5th) may be configured to perform at least some of (or all of) the method steps described with reference to the sixth aspect. The method of the sixth aspect may comprise using a device with any of the features described with reference to the device aspects.

DETAILED DESCRIPTION

Embodiments of the invention will be described, purely by way of example, with reference to the accompanying drawings, in which:

Figure 1 is an exploded diagram of an example embodiment of an device according to an embodiment;

Figure 2 is a block diagram of the authenticator of Figure 1 ; Figure 3 is flow diagram illustrating a method of initial authenticator setup;

Figure 4 is a flow diagram illustrating a method of enrolling a user for authentication using the authenticator;

Figure 5 is a flow diagram illustrating a method of authenticating a user according to an embodiment;

Figures 6 and 7 illustrate example challenge/response patterns for a first user and a second user respectively

Figure 8 is a diagram of a sensor for measuring a biomarker content of a user’s saliva.

Referring to Figure 1, a wearable device 100 is shown, comprising: a conformal layer 110, biometric sensor 120, flexible printed circuit board 130, isolation layer 140 , lower layer 150, oral input device 160, and oral output device 170.

The device 100 will be described below with reference to a specific application relating to authentication, but other uses for the device and variants thereof are envisaged (for example, as disclosed above).

The wearable device 100 is configured to be worn within the mouth, in contact with the user’s palate. The device 100 is generally shaped to correspond with the shape of the user’s palate and is intended to be accommodated within the mouth without being obvious in use, so that the user can close their mouth and the device is entirely within the user’s mouth. The device 100 generally takes the form of a flexible, relatively thin sheet (e.g. less than 10mm and preferably less than 5mm thick) with a shape that corresponds with the user’s palate. The device 100 is intended to be tailored to the specific user to which it is assigned, as described below in more detail, further improving comfort and enhancing the reliability with which biometric information can be read.

The conformal layer 110 forms the top portion of the device 100, and it configured to mould to at least a portion of the user’s palate. In some embodiments, the conformal layer 110 may be shaped by forming an impression of the user’s palate with a suitable material (such as dental impression putty). In other embodiments, the conformal layer 110 may be formed by additive layer manufacturing or conventional moulding, based on a scan of the user’s mouth, or any other suitable approach. The conformal layer 110 preferably comprises a flexible material for contacting the user’s palate (e.g. with a shore hardness of 90 or less). The edges of the conformal layer may correspond with the outer edges of the user’s palate and the profile of the inner teeth, so that the device is retained in a specific registration with the mouth.

In addition to a region that conforms with the user’s palate, the upper surface of the conformal layer 110 may further comprise a region of salt features 111 that do not correspond with the user’s palate, and which are associated with that particular device 100. The salt features 111 may, for example, form dummy palatal rugae that are not found in the user’s mouth.

The salt features 111 may be used as salt, in the cryptographic sense, to add further information to the biometric data of the user. This increases the complexity of the geometry of the upper surface of the conformal layer 110, and further assists in obscuring the biometric information of the user (so that the biometric information of the user cannot be readily determined from examining the device 100).

The lower layer 150 may also be tailored to the user’s mouth, and may comprise a similar material to the conformal layer 110 (or the same material). In certain embodiments, the lower layer 150 and conformal layer 110 may encapsulate the biometric sensor 120, flexible printed circuit board 130 and isolation layer 140. The lower layer 150 and conformal layer 110 may, for example, be co -moulded around the biometric sensor 120, flexible printed circuit board 130 and isolation layer 140 within the user’s mouth (e.g. using dental impression putty or a similar material).

The biometric sensor 120 is configured to determine an oral biometric of the user (i.e. biometric information that can be determined from within the user’s mouth). In this embodiment, the morphology of the user’s palate is used as the oral biometric. Specifically, the palate includes palatine rugae, which are irregular ridges that are permanent and unique to each person. The biometric sensor 120 comprises an array of capacitive sensor elements. The capacitance between each sensor element of the biometric sensor 120 and the palate will be inversely proportional to the gap between the sensor element and the palate, so the profile of the user’s palate can be determined by the biometric sensor 120. There will be an interplay between the palate profile and the thickness of the conformal layer 110. Variations in thickness both arising from the salt features 111 and which may arise during forming of the conformal layer 110, may add further salt to the user’s palate morphology, and make it harder to reverse engineer the salted biometric from the user or the device (in isolation).

The biometric sensor 120 may take other forms, and is not restricted to an array of capacitive sensors. In principle the problem of assessing the palate morphology is somewhat similar to determining a fingerprint, and similar technologies can be applied, for example ultrasonic and/or optical scanning.

Furthermore other oral biometric information can be envisaged. For example, tongue morphology and/or dentition may be similarly distinctive, and may provide an alternative source of biometric information. Other embodiments may employ a biometric sensor capable of reading these, instead of palate morphology.

The flexible printed circuit board 130 comprises a wireless communications module 131, processor 132, and power source 133. The flexible printed circuit board 130 may, for example comprise a polyimide (or kapton) substrate.

The wireless communications module 131 is configured to facilitate communication to and from the device 100, so that enrolment and authentication messages can be transmitted to and from the device. In some embodiments the wireless communications module may be configured for communication via wifi, or Bluetooth. Any other wireless communication protocol may also be used. The wireless communications module 131 may be configured to use an encrypted communication channel, to prevent third party snooping of communications and interception of keys.

The power source 133 may comprise a battery. The battery may be rechargeable (e.g. LiPo, Lilon etc). An inductive charging module (not shown) may be provided to charge the battery (for example using the Qi standard). In other embodiments the power source may comprise a non-rechargeable battery or a supercapacitor. The processor 132 may comprise a microprocessor with a processing unit and memory. The processor 132 is configured to control the operation of the device 100, receiving and transmitting information via the wireless communication module, and communicating with each of the biometric sensor 120, oral input device 160 and oral output device 170.

The isolation layer 140 may be used to mechanically isolate the flexible PCB 130 from the user’s mouth and tongue, so as to provide a more comfortable fit. The isolation layer 140 may also protect the flexible PCB 130 from the environment of the mouth. The isolation layer 140 preferably consists of a material that is waterproof and not electrically conductive, such as a polymer or silicone. The isolation layer 140 may also protect the user from coming into contact with the electronics of the flexible PCB 130 and the power source 133.

The oral input device 160 comprises three tongue operable buttons 161. Each button 161 comprises a protrusion 163 that is disposed on the lower surface of the device. Each button 161 may comprise a force sensor 162 at the base thereof. In principle, any suitable touch or force receptive transducer may be used. The buttons 161 in this embodiment are effectively tongue operated keys, allowing the user to communicate orally to provide a response communication when requested as part of authentication.

In other embodiments the oral input device may take a different form. There may be a different number of buttons 161 (more or fewer than 3). In principle it is possible to use a single button, and rely on timings to distinguish different input symbols from the user. It is also not necessary for the input device to be contact based. For example, an acoustic sensor may be provided that receives non -vocal acoustic signals produced by the user with their mouth (e.g. clicks produced by teeth or tongue) , or a non-contact sensing modality such as inductive and/or capacitive sensing may be used to detect signals from the tongue.

The oral output device 170 comprises three taste transducers 171. Each taste transducer comprises a first electrode 172 and a second electrode 173, and the device 100 is configured to communicate orally with a user by imparting taste sensations to the user at different regions of their tongue (corresponding with the different locations of the taste transducers 171). Different potential differences and/or currents between the first and second electrodes 172, 173 may correspond with different taste sensations.

Figure 2 shows the functional elements of the device 100 of Figure 1 and their interrelationships. The processor 132 communicates with the wireless communications module 131 to both transmit and receive information (e.g. to/from an external system requesting authentication credentials). The processor receives power from the power source 133, and communicates with each of the biometric sensor 120, oral input device 160 and oral output device 170.

The example device illustrated in Figures 1 and 2 includes many features. Other embodiments are possible with fewer features. For example, a wearable oral device may be used which merely reads an oral biometric, and which omits the oral input device and oral output device. In other embodiments, a device may comprise only an oral input device, allowing a user to provide a covert response to a visible challenge (ensuring that security an authentication procedure remains opaque to surveillance). The embodiment of Figure 1 facilitates multi-factor authentication (i.e. oral biometric sensor and oral input and output devices), which is advantageous, but common to all embodiments is the concept of secure authentication using a wearable device concealed within the mouth.

Figure 2 illustrates a method by which a user can be enrolled with their personal device, in accordance with an embodiment. The enrolment process may be prompted by a user device such as a mobile phone or other computer, in wireless communication with the device (e.g. via Bluetooth or wifi).

At step 201, the user shapes the wearable device 100 to their mouth, to provide a comfortable and repeatable fit (thereby enhancing the reliability of reading the oral biometric). In embodiments like that shown in Figure 1, this may comprise moulding the shape of the conformal layer 110 and optionally the lower layer 150. A salting element may be placed on the conformal layer 110 before this moulding step and the conformal layer 110 subsequently moulded to conform with the user’s palate (with the subsequent profile modified by the salting element). At step 202, the device 100 is removed from the user’s mouth, and the salting element removed.

At step 203, the processor 132 reads the user’s oral biometric via the biometric sensor 120. In the example embodiment of Figure 1, this comprises obtaining readings from each capacitive sensor in the array that are characteristic of the user’s palatal rugae, in combination with the particular shape of the conformal layer 110 (which may be modified by the salting element), but other biometrics may be used (as already discussed). The user’s oral biometric may be stored by the processor 132, for example in processed and/or hashed form, for use in generating encryption keys. The oral biometric (and/or oral biometric hash) may be stored in a form (e.g. as a processed oral biometric) that is robust to expected variations in reading the oral biometric. The processed biometric may comprise features extracted from the raw biometric.

Once the oral biometric that is characteristic of the user has been stored (i.e. a factor based on what the user is), steps 204 to 206 relate to setting up suitable challenge/response information (a factor based on something the user knows) that can be communicated via the device 100.

At step 204, a challenge is communicated to the user by the oral output device 170. In embodiments where the device comprises taste transducers 171, each challenge may comprise a one or more tastes applied to the user’s tongue. In other embodiments, the challenge may be provided on an external device (such as a smart door or lock) in wireless communication with the device (e.g. a mobile phone).

For each challenge, the user (at step 205) provides a response of their choosing, via the oral output device 160. This may, for example, comprise pressing a particular pattern of buttons 161, or providing a particular sequence of button presses (or both).

The user may be asked to confirm each response, to ensure no communication mistakes have been made.

The process of challenge and response may be repeated (step 206) until a satisfactory number of challenge/response pairs have been obtained (analogous with secret questions/answers known for use in authentication). In principle, a single challenge/response may be sufficient, but more are better (e.g. forming a pool from which randomly selected challenge/response pairs may be employed by the device).

Figures 6 and 7 illustrate example challenge response pairs for a first user and a second user respectively. Each response in this example comprises three patterns of button presses, and there are three buttons from which to select a suitable pattern .

The first user chooses to respond to taste 1 with: a first pattern in which only the top button is pressed; a second pattern in which only the left button is pressed, and a third pattern in which only the right button is pressed. The first user chooses to respond to taste 2 with: a first pattern in which only the top button is pressed; and a second and third pattern in which only the left button is pressed. The first user chooses to respond to taste 3 with: a first pattern in which only the top button is pressed; a second pattern in which only the right button is pressed, and a third pattern in which only the left button is pressed.

The second user chooses to respond to taste 1 with: a first pattern in which only the top and left buttons are pressed; a second pattern in which only the left button is pressed, and a third pattern in which only the top button is pressed. The second user chooses to respond to taste 2 with: a first pattern in which only the top and right buttons are pressed; and a second pattern in which only the top button is pressed; and a third pattern in which only the top and left buttons are pressed. The second user chooses to respond to taste 3 with: a first and second pattern in which only the top button is pressed; and a third pattern in which all three buttons are pressed.

These challenge/response examples are merely illustrative, and other types of challenge and response are possible, as already discussed.

As discussed with reference to Figure 1, the method may comprise a subset of these steps, depending on how many factors are to be employed by the device. Methods according to an embodiment that provide a single factor (which may contribute to a wider multi-factor authentication procedure) may comprise only enrolling the oral biometric, or the oral challenge/response pairs. Figure 4 illustrates an enrolment method, by which a public/private encryption key pair can be generated (for subsequent use in accessing a particular secured system, for example).

At step 301, the user puts their personal device in their mouth (which they have already enrolled with their biometric information and oral challenge/response pairs).

At step 302, the device receives a request (e.g. via wireless communication) to enrol the user for authentication with a particular device or system using the device.

In response to the request to enrol the user, the device reads the oral biometric. This may comprise using an array of capacitive sensors to determine a pattern of readings characteristic of the user’s palate morphology.

At step 304 the oral biometric obtained by reading the user is compared with the stored oral biometric (e.g. as obtained according to the method discussed with reference to Figure 2). The comparison need not be based on the raw data obtained from the biometric sensor. In some embodiments the comparison may be based on processed biometric data: for example features may be extracted, and the features compared. In some embodiments hashes may be compared (obtained from raw or processed biometric data), rather than raw or processed biometric information.

If the oral biometric does not match, an error counter increments . At step 314 the number of errors is checked, and if this has not exceeded a predetermined threshold the oral biometric of the user is re-checked. In some embodiments the user may be prompted (via the wireless communication channel) to re -position the device in their mouth, in case it is misaligned, so that a better reading can be obtained.

If the oral biometric matches, at step 305, a random challenge may be selected from the available pool (corresponding with stored responses on the device), and communicated to the user. In embodiments where the device comprises an oral output device, the challenge may be communicated orally by an oral output device (e.g. employing taste). At step 306, the device receives a response from the user via the oral input device (e.g. by tongue operated buttons, as discussed with reference to Figures 3, 6 and 7.

At step 307, the response is checked by the device so see if it matches the response to that challenge, stored on enrolment of the user with the device. If the response is correct, a new key pair may be stored on the device (at step 308) and communicated wirelessly to the device or system requesting authentication using the device (at step 309).

If the response is not correct, and the number of incorrect responses does not exceed a predetermined threshold m, a different challenge may be communicated to the user and the method continues at step 305.

In other embodiments, the method may comprise a subset of these steps. For example, the authentication may only use oral biometric information, or only use challenge response information that is answered via an in -mouth oral device.

Figure 5 is a flow diagram illustrating an example authentication method. The method shares a number of features with Figure 4, and similar comments apply, mutatis mutandis.

The device is put in the user’s mouth at step 401. At step 402, a request for authentication is received by the device (e.g. from a system that requires authentication for use). At steps 403, 404 and 414, the oral biometric is read by the device and checked against the registered oral biometric (as discussed with reference to steps 303 and 304 in Figure 4). At steps 405, 406, 407 and 417 a challenge is communicated to the user (e.g. by the device using an oral output device, which may employ taste as a communication medium), the response of the user is received via an oral input device by the device, and checked against the enrolled responses stored on the device. These steps are similar to the corresponding steps already described with reference to Figure 4, and may include any of the features discussed there. If the responses are incorrect more than a predetermined number of times 112 the device may lock for a period. In some embodiments, the period of locking may increase if a subsequent re-try is also incorrect (to render brute force attacks infeasible). Embodiments of the present invention may be particularly useful in the context of securing high value assets, including critical national infrastructure, and systems and devices that are relevant to national security (for example, weapon systems, power systems and network infrastructure).

A device in accordance with an embodiment need not be used as an authenticator. In some embodiments, the device may be configured as a more general purpose communication interface. The oral output device, for example enables two way communication without the need for a further device outside the mouth, which may be useful in some contexts. The conformal layer is of general applicability to mouth wearable devices for wireless communication from within the mouth, since this renders the device more comfortable (e.g. for extended use). In certain embodiments the device may be for healthcare monitoring, and may comprise a sensor for measurement of physiological parameter that is relevant to healthcare (e.g. a property of saliva). Similarly, it may be useful for a device that is not a dedicated authenticator to include features disclosed herein, such as a biometric sensor (which may allow the device to be used, among other purposes, for authentication).

According to this embodiment, a mouth wearable device may continuously or periodically monitor saliva for personalised performance and/or health management. The mouth wearable device may be especially useful in monitoring the levels of biomarker concentration (e.g. lactate and/or glucose) in the human body since the inventors have found a strong correlation between the level of lactate and glucose in saliva and that in the body generally and especially in muscles.

Lactate is generated during intense physical activity within animal cells, especially in muscle cells, as a product of glucose metabolism. Lactate build up in muscles during exercise causes the muscles to ache which detracts from the performance of athletes, especially in endurance sports. Training regimes are available to control the build-up of lactate, but these require a knowledge of lactate levels in the athlete’s body. Currently, athletes mostly depend on laboratory-based blood tests every few months to measure lactate levels. Current lactate level detection methods are invasive, inaccurate or cannot provide frequent data collection which limits coaches, physicians and athletes in devising suitable training to improve an athlete’s lactate levels and prevent lactate accumulation. A biomarker sensor assembly 600 for use in an embodiment of the present invention is shown in Figure 8. The assembly 600 comprises a biomarker sensor 610. In an embodiment, the sensor 610 comprises an amperometric enzymatic lactate sensor 612. The sensor 612 may comprise a pair of Ag/AgCl electrodes 614 and platinum current collectors 616. A deposit of an enzyme in the sensor can break down lactate in a wearer’s saliva and would typically span the electrodes 614. The enzyme is immobilised on the electrodes to facilitate the chemical reaction. The enzyme may be lactate oxidase. When lactate is present in the user’s saliva, the enzyme breaks down the lactate, producing an electrical potential and current between the electrodes 614 that is indicative of the quantity of the lactate in the saliva. This in turn is indicative of the amount of the lactate in the wearer’s body and muscles. Such enzymes are known in the art. The electrodes 614 and current collectors 616 may be printed on a substrate 618, e.g. a PET substrate. The sensor 610 also comprises a main control circuit 620. The control circuit 620 comprises a communications module 622 e.g. a Bluetooth (BLE) module, a measurement circuit 624 e.g. an amperometric circuit linked to the electrodes/current collectors that measures the current from the sensor 610 and a microcontroller 626. The main control circuit 620 may be printed on a flexible PCB. A power source 630 is provided, such as a battery 630. The battery 630 may be an ultrathin flexible battery customised for output voltage and size.

The sensor 610, control circuit 620 and battery 630 may be mounted on a conformal mounting sheet 640. The mounting sheet may be flexible to enable it and the sensor 610 to conform to the inside of a wearer’s mouth and so be worn inside the mouth, as described above (depicted by box 645). The assembly may also comprise a battery charger 650. The assembly may be housed in a housing (not shown). The housing may be configured to provide an in-built contact battery charger 650.

The assembly 600 may comprise a data collection and analysis unit and portal 660.

The data collection and analytics portal 660 allows the assembly 600 to communicate continuous biomarker data via Bluetooth protocol 622 to a nearby processor, e.g. a smartphone. Software within the smartphone may provide: Real time biomarker data. The raw data goes through filtering, averaging and calibration and is logged in the portal. Individual basal biomarker readings in a resting time or before training starts. The portal will recognise the baseline during every use in the resting time and store the range, preparing for further comparison. The data may also be gathered from in vitro testing of the resting time saliva samples for calibration. For a certain intensity of training, the threshold (the time sustained or the overall intensity) is determined by the point after which the biomarker concentration rises abruptly. Data can also be gathered from in vitro testing of several saliva samples taken during a recorded training session for calibration.

In the embodiment shown, the assembly 600 is self-contained. Alternatively, the sensor assembly 600 may share one or more elements of the wearable device 100 shown in Figure 1. For example, it could use power from the power source 133 of Figure 1 instead of having a separate battery 630. Likewise, the processor 132 and wireless communications module 131 of Figure 1 could be used to transmit information instead of main controller 620. The sensor assembly 600 and the conformal sheet 640 may be sandwiched between layers 110 and 150 shown in Figure 1, although the sensor 600 should be in contact with saliva in the wearer’s mouth. Alternatively, the sensor assembly 600 may be adhered to an outside surface of the wearable device 100 shown in Figure 1.

I.e. any/all elements of the assembly 600 are useable with/replaceable with/interchangeable with the wearable device 100 of Figure 1.

Biomarker concentration monitoring of embodiments of the present invention may be used, for example: a. continuously during a training session of given workload. The data and its change over time can provide knowledge of an individual’s improvement and can provide a sign of overtraining. It can also provide reference data on for tailoring further training; b. to measure basal biomarker concentration when resting. The data may indicate overtraining and potentially overtraining syndrome ; and/or c. potentially biomarker monitoring can then be use for consumer-grade quantified-self for personalised healthcare monitoring.

The combination of the wearable device 100 shown in Figure 1 and the biomarker sensor 600 of Figure 8 provides the advantage of authenticating biomarker readings that produces certainty that the readings are from a specific, authenticated individual.

As such, the biomarker sensor 600 described above provides non -invasive and continuous monitoring of biomarkers in a person in real time and so can be used to help athletes train and recover more efficiently, by using insights from biomarker data measurements. This avoids the taking of biomarker readings from blood which is invasive and cannot provide continuous biomarker monitoring.

The biomarker sensing function can be used within a wide range of wearable devices, configured for concealed wearing within the mouth of a user, as set out in the embodiments described above and in the accompanying claims.

Further variations are possible, and the scope of the invention should be determined with reference to the appended claims.

Claims

1. A wearable device, configured for concealed wearing within the mouth of a user and to authenticate a user by: an oral communications protocol and/or by reading oral biometric information.

2. The wearable device of claim 1, further comprising an oral biometric sensor, configured to read the oral biometric information of the user.

3. A wearable device, configured for concealed wearing within the mouth of a user and comprising an oral biometric sensor, configured to read the oral biometric information of the user.

4. The wearable device of claim 2 or 3, wherein the oral biometric sensor is configured to read information comprising a constituent of the user’s saliva, optionally or preferably, the biomarker content of the user’s saliva, and optionally or preferably lactate content of the user’s saliva.

5. The wearable device of any of claims 2 to 4, wherein the oral biometric information comprises palate morphology, for example a characteristic pattern of palatal rugae.

6. The wearable device of any of claims 2 to 5, wherein the oral biometric sensor comprises a sensor region configured to substantially conform with a palate of the user; and, optionally or preferably, wherein the sensor region comprises an array of capacitive sensors, for determining the palate morphology.

7. The wearable device of any preceding claim, further comprising an oral input device for receiving user inputs.

8. The wearable device of claim 7, wherein the input device comprises one or more touch/force sensors that are responsive to touch/force from the user’s tongue.

9. The wearable device of any preceding claim, further comprising an oral output device for providing information to the user from within the mouth.

10. The wearable device of claim 9, wherein the oral output device comprises one or more taste transducers for imparting a taste to the user.

11. The wearable device of claim 10, wherein each taste transducer comprises a first electrode and a second electrode for applying a potential difference across a region of the user’s tongue.

12. The wearable device of claim 11, wherein there are a plurality of taste transducers, each disposed to correspond with a different taste sensing region of the user’s tongue.

13. The wearable device of any preceding claim, configured to perform authentication using at least two factors, using at least two factors selected from: oral biometric information, a passcode communicated via an oral communications protocol; and a unique device ID associated with the authenticator.

14. The wearable device of any preceding claim, further comprising a wireless communication module, configured to communicate with a system outside the user’s mouth.

15. The wearable device of any preceding claim, comprising a conformal layer, formed to fit the user’s palate and defining an upper surface of the wearable authenticator.

16. The wearable device of any preceding claim, wherein the conformal layer comprises a moulded layer formed from an impression of the user’s palate.

17. The wearable device of any preceding claim, wherein the conformal layer further comprises a physical salting pattern of additional bumps and/or recesses.

18. A method of authenticating a user, comprising using a wearable device concealed in a mouth of a user to authenticate the user by communicating with the user via the wearable device and/or by the wearable device reading oral biometric information of the user.

19. The method of claim 18, wherein communicating covertly with the user comprises performing challenge/response authentication via an oral communications protocol.

20. The method of claim 19, wherein communicating with the user comprises receiving non-verbal communication from the tongue; and optionally communicating with the user by taste.

21. The method of any of claim 20, wherein the challenge/response authentication comprises providing a challenge as one or more taste, and the response comprises a pattern of button activation with the user’s tongue corresponding with the challenge.

22. The method of any of claims 18 to 21, wherein the oral biometric information comprises a palate morphology of the user; and/or further comprising measuring a constituent of the user’s saliva, optionally or preferably, the biomarker content, and optionally or preferably lactate content.

23. The method of any of claims 18 to 22, further comprising: wirelessly receiving a request for user authentication at the wearable device, and wirelessly transmitting a result of an authentication check.

24. The method of any of claims 18 to 23, comprising using the wearable device according to any of claims 1 to 17.

25. The method of any of claims 18 to 24, wherein the authentication is for accessing and/or operating an asset: of high value, related to critical national infrastructure and/or important for national security.