Background

Wearable devices, such as wearable medical devices, or other “smart” devices are a well established field of technology. These may include heating devices, transcutaneous electrical nerve stimulation (TENS) machines, cardiotocograph (CTG) machines, smartwatches, or any other device.

An example of a wearable heating device which may also be used to increase blood flow to a particular area of the body is described in GB 2580947 A, the entire contents of which is hereby incorporated by reference. This increased blood flow can then be beneficial for wound healing, for example following mastectomy.

In a particular example, patients with breast cancer who undergo mastectomies and reconstructive breast surgery often have issues with skin necrosis. This can have significant effects upon wound healing and eventual scarring of the area. This skin necrosis can result in further operations being necessary which further extend a patient’s hospital stay and ultimately result in an inferior cosmetic result. The extension to the hospital stay is both inconvenient for the patient and introduces further pressures on to the health system. Trials such as those in Local Heat Pre-Conditioning in Skin Sparing Mastectomy; a Pilot Study of Mehta et aL, 2013 and A randomised controlled feasibility trial to evaluate local heat preconditioning on wound healing after reconstructive breast surgery: the preHEAT trial of Mehta et aL, 2019, the entire contents of each of which is hereby incorporated by reference, have shown how a pre-surgery heating regime using hot water bottles and thermometers can reduce the incidents of skin necrosis following mastectomy by as much as 24%.

Heat treatment can also help with the healing of chronic wounds. For example, venous leg ulcers can be healed at a faster rate with heat being applied.

A further particular example where heat application may improve results is following the removal of fat from elsewhere in a patient’s body and injection into the face or breast for cosmetic procedures. This transferred fat achieves a more natural and permanent look but needs to establish a blood supply in order to survive. Typically, patients are over-corrected to allow for some of the fat which does not end up receiving a blood supply to be absorbed by the body. Heat pre-conditioning could improve the survival of fat in this region.

Such wearable devices are often worn by the user in their own home, and the user must locate the device themselves against their body. However, this introduces the risk that the user will incorrectly fit the device such that the desired effect is not achieved.

For example, for a heating device the heating may not be applied correctly. This will result in inefficient heat transmission between the device and the user. This could for example mean that significant heat is being lost to the environment if there is a large air gap between the device and the user. In another example the device may be providing heat to an undesirable location.

There is therefore a need for a method to fit a wearable device, and a system incorporating this.

US 2009 0163787 A1 discloses a sensor which may be adapted to provide information related to its position on a patient's tissue. Positioned adjacent a sensor may be provided with tissue contact sensors which may relay a signal related to placement of the sensor relative to the tissue of a patient. Such a sensor may provide information to a clinician regarding the location of the sensor in relation to the skin of a patient in order to provide measurements. A temperature sensor is provided and the reading from this sensor is compared to a threshold in order to determine whether the sensor is engaged or not. There is also a disclosure of the use of two sensors and a determination that when the temperature readings differ by greater than a predetermined value misfitting of the sensor may equally be determined. This is a simple system which does not take into account that not every sensor may necessarily need to be in good contact in order for the device to still operate as intended. It is particularly relevant that this is a monitoring device for use primarily in a hospital setting where a more secure alignment may be the goal.

EP 1 829 580 A1 discloses a therapy device in the form of a support belt which includes heating apparatus in combination with electrical current body stimulation apparatus, providing heating and electrical body stimulation during therapy. The device includes a control unit for selectively controlling an amount and/or duration of therapy provided. A user can create a preferred therapy regime using the control unit. The control unit has means for detecting the attachment of the therapy device to the body of a user.

US 2016/0150965 A1 discloses a physiological signal analysis device and method to detect and analyse physiological information of a subject.

WO 2014/01 1159 A1 discloses a sensing system for detecting incorrect placement, or placement disruption, of a medical or physiological sensor relative to a patient, such as the patient's skin.

US 2016/0278647 A1 discloses technology for detecting whether a wearable device is misaligned.

Summary

A method for fitting a wearable device to a region of a user is provided according to claim 1 or clause 1.

This method allows for a wearable device to be correctly fitted to a user, with tests performed to ensure that the fit is correct. The wearable device may be, for example, a wearable medical device. One example of such is a heating device fitted on the use to heat the region of the user.

This average may be any suitable type of average, for example the mean, median or mode. In certain examples, the average is the mean of the sensor readings from each of the primary sensors.

The method may further comprise: repeating step (b) for claim 1 or step (a) for clause 1 until each of the sensor readings from the one or more primary sensor(s) are within the predetermined range, before proceeding to step (c) for claim 1 or step (b) for clause 1 . This prevents the wearable device from being operated before the wearable device is correctly fitted. For example, where the wearable device is a heating device this may prevent heat from being applied until the heating device is correctly fitted. The one or more primary sensor(s) may comprise two primary sensors. A plurality of primary sensors can result in more data points and hence a greater chance of detecting an incorrect fit.

The method may further comprise the step of: (b-i) for claim 1 or (a-i) for clausel comparing sensor readings from each of the primary sensors and generating a notification to the user indicating that the wearable device is incorrectly fitted if any of the sensor readings from the primary sensors differ from another of the sensor readings from the primary sensors by more than a second pre-determined threshold. This may further identify incorrect fit in the event that only a certain region, and hence a certain primary sensor, is not properly contacting the user’s body.

The method may further comprise: repeating step (b-i) for claim 1 or (a-i) for clause 1 until none of the sensor readings from the primary sensors differs from another of the sensor readings by more than the second pre-determined threshold. This can be used to prevent the wearable device from operating until the wearable device is correctly fitted. For example with a heating device this can prevent heat from being applied until the heating device is correctly fitted.

The one or more secondary sensor(s) may comprise two secondary sensors. A plurality of secondary sensors can result in more data points and hence a greater chance of detecting an incorrect fit.

The method may further comprise the steps of: (c-i) for claim 1 or (b-i) for clause 1 discarding the sensor reading of or disabling each secondary sensor which has a sensor reading which differs from the average sensor reading by more than the first predetermined threshold; and (c-ii) for claim 1 or (b-ii) for clause 1 operating the wearable device if the number of secondary sensors which are disabled or have their reading discarded is less than or equal to a threshold number. The secondary sensors may be spaced from the region where operation of the wearable device is desired. As a result, it may be that natural body variations are more significant. Additionally, it may be less important for the wearable device to be fitting closely to the user’s body in these regions. This can mean that although not perfectly fitted, the wearable device may be fitted to a satisfactory level for the wearable device to be operated. In order to achieve this, some secondary sensors may be ignored. By ignoring these secondary sensors their readings do not affect the rest of the method. For example, with a wearable heating device the operation may be heating of the region of the user. In certain examples the primary sensor(s) and/or secondary sensor(s) may be temperature sensors arranged to detect a skin and/or body temperature of the user, and hence the variations may be due to natural variations in the user’s skin and/or body temperature in the region.

The pre-determined range may be set based on one or more sensor readings from the primary sensor(s) and/or the secondary sensor(s). This allows for the wearable device to be tailored for the particular user and typical sensor readings for the user may be used to confirm that wearable device is correctly fitted to that user.

Each of the primary sensor(s) and/or the secondary sensor(s) may be skin-contact sensors. That is, sensors which contact the user’s skin to detect a physiological parameter relating to the user.

The primary sensor(s) may be primary temperature sensor(s) and the secondary sensor(s) may be secondary temperature sensor(s). These sensors may be configured to detect a user’s skin and/or body temperature. This may be used for a heating device, or any other wearable device including other wearable medical devices. Such temperature sensors may be a particularly suitable way to locate a wearable medical device since the expected body temperature of the user in the region can be predicted.

The pre-determined range which the sensor reading of the primary temperature sensor(s) is compared to may correspond to typical body skin temperature range for the region. Since the heating device is meant to be applied to a region of a user’s body, a body skin temperature range may be particularly suitable.

The pre-determined range which the sensor reading of the primary temperature sensor(s) is compared to may be 30°C to 40°C, preferably 33°C to 37°C. Temperatures in these ranges may correspond to body skin temperature.

The second pre-determined threshold may be ±3°C, preferably ±1 °C. Variations of temperature readings in this range may be expected for a human body, while variations beyond this range may indicate that the heating device is incorrectly fitted. The wearable device may be a heating device comprising a heat source for applying heat to the region of the user. This heat source may be arranged at or near to a centre of the wearable device. Heating devices may be particularly useful in wound healing, for example, where the user is required to locate the device without medical assistance. This method allows them to accurately fit the wearable device.

Particularly, the heat source may be suitable for and/or configured to heat the region of the user to a supraphysiological level. For example, to more than 40°C. In a particular example, between 40°C and 50°C, such as 43°C. This can result in the up-regulation of heat shock proteins, such as HSP-32. These proteins maintain capillary perfusion and increase tissue tolerance to ischaemia.

A system for fitting a wearable device to a region of a user is provided according to claim 15 or clause 15.

This system allows for a wearable device to be correctly fitted to a user, with tests performed to ensure that the fit is correct.

The remaining area may generally surround the reference area. The reference area may be where the output of the wearable device is desired, with the remaining area outward of there. For example, where the wearable device is a heating device heat will radiate in the user’s body, the remaining area can correspond to regions outward of the reference area.

The processor may be arranged on a remote device and the system may further comprise a transmitter for transmitting signals to the remote device. This reduces the processing on the wearable device, thereby allowing its size to be minimised to make it less intrusive.

The one or more primary sensor(s) may comprise two primary sensors. A plurality of primary sensors can result in more data points and hence a greater chance of detecting an incorrect fit.

The one or more secondary sensor(s) may comprise two secondary sensors. A plurality of secondary sensors can result in more data points and hence a greater chance of detecting an incorrect fit. The one or more secondary sensor(s) may comprise three secondary sensors, arranged in a circle generally centred on the reference area. A circle of secondary sensors allows the reference area to be generally surrounded. For example, this may be particularly useful where the region is a user’s breast, particularly where the wearable device is a heating device to heat the user’s breast.

The one or more primary sensor(s) may be centrally arranged on or around a centre of the wearable device, with the one or more secondary sensor(s) arranged radially outward from the centre. This allows both the primary sensors and the secondary sensors to generally surround the centre of the wearable device, where operation of the wearable device may be being directed.

This may be particularly useful where the wearable device is a heating device with the heat source at or near the centre of the wearable device. The primary sensor(s) may be primary temperature sensor(s) and the secondary sensor(s) may be secondary temperature sensor(s). The region may then be a region to be heated which is a user’s breast and, for example, the temperature sensors are arranged in concentric circles.

Each of the primary sensor(s) and/or the secondary sensor(s) may be skin-contact sensors. That is, sensors which contact the user’s skin to detect a physiological parameter relating to the user.

The primary sensor(s) may be primary temperature sensor(s) and the secondary sensor(s) may be secondary temperature sensor(s). These sensors may be configured to detect a user’s skin and/or body temperature. This may be used for a heating device, or any other wearable device including other wearable medical devices. Such temperature sensors may be a particularly suitable way to locate a wearable medical device since the expected body temperature of the user in the region can be predicted.

The wearable device may be a heating device comprising a heat source for applying heat to the region of the user. This heat source may be arranged at or near to a centre of the wearable device. Heating devices may be particularly useful in wound healing, for example, where the user is required to locate the device without medical assistance. This system allows them to accurately fit the wearable device. The region may be the user’s breast, and the reference area may correspond to the user’s nipple and areola. Heating of a user’s breast may be useful to assist wound healing following breast surgery such as mastectomy.

Brief Description of the Drawings

The present specification will make reference, by way of example only, to the accompanying drawings in which:

Figure 1 shows a first example of a wearable device, in the form of a heating device;

Figure 2 shows a second example of a wearable device, also in the form of a heating device; and

Figure 3 shows a remote device displaying information relating to the wearable device of Figure 2.

Detailed Description of the Drawings

The present detailed description makes reference to the accompanying Figures in which wearable devices 100 are shown in Figures 1 and 2. These wearable devices 100 are heating devices 100 and will be referred to as such in the following description. Nevertheless, the present disclosure is equally applicable to any wearable device and particularly any wearable medical device. These may include heating devices, transcutaneous electrical nerve stimulation (TENS) machines, cardiotocograph (CTG) machines, smartwatches, or any other device.

The wearable device 100 may be any device for use in advance of, during, and/or after many types of surgeries such as abdominoplasties, mastectomy, vascular surgery, caesarean section, spinal surgery, foot surgery, ankle surgery, knee surgery, or wounds following sternotomy, laparotomy, complex free tissue reconstructions or other cosmetic procedures.

Of course, other wearable devices may not include one or more features of these heating devices 100. This includes but is not limited to the heat source(s) discussed in more detail below.

The heating devices 100 of Figures 1 and 2 will be described together. Unless expressly indicated otherwise, any feature described in relation to the heating device 100 of one of these Figures is equally applicable to the heating device 100 of the other Figure. Again, although described in relation to heating devices 100 the present method and system are equally applicable to any wearable device and the following disclosure must be considered accordingly.

These heating devices 100 are suitable for application to a human body in order to provide heat to that body. This heat may be, for example, provided for comfort. Alternatively, the heat may have one or more medical or therapeutic benefits. For example, the heat may be provided to encourage blood flow to a corresponding region of the user’s body where the heating device 100 is applied. This increased blood flow could be desired, for example, if there is a wound in the region where the heating device 100 is applied. Increased blood flow may lead to improved wound healing outcomes. That is, the heating device 100 may be for improving wound healing in the region, and/or increasing blood flow to the region.

The heating device 100 comprises a controllable heat source, such as an electric heat source. Such an electric heat source may be, for example, a resistive wire extending through the heating device 100. A current can then be passed through this resistive wire in order to provide heat to the user. In alternative examples the heat source may be one or more conduits which receive a heated fluid, such as water, or any other heat source.

Particularly, the heat source may be suitable for and/or configured to heat the region of the user’s body to a supraphysiological level. That is, a temperature greater than normal body temperature. For example, this may be to more than 40°C. In a particular example, this may be between 40°C and 50°C. In a further example, this may be around 43°C.

Without being bound by theory, heating to such a level can result in the up-regulation of heat shock proteins, such as HSP-32. These heat shock proteins catalyse the breakdown of haemoglobin into carbon dioxide in the skin, to thereby increase vasodilation. These proteins maintain capillary perfusion and increase tissue tolerance to ischaemia. In other words, the temperature is hot enough to cause stress but to not burn the user.

The heat source may be controlled to heat the region of the user’s body to this temperature, such as by using feedback control with one or more temperature sensors such as those described herein. The heating device 100 may comprise multiple heat sources for generating heat. Additionally, or alternatively, the heating source may further comprise multiple heating elements for generating heat. The transfer of heat from the heat source to the user may be suitable for and arranged to increase the blood flow of the user in the region being heated.

When this heating device 100 is applied by the user, there is a risk that the user may incorrectly position the device 100. This could lead to inefficient heat transmission between the heating device 100 and the region of the user which is intended to be heated.

The heating device 100 may heat any suitable region of the user. For example, Figure 1 shows an example of a heating device 100 which is generally in the form of a rectangle which may be used in one example as a bandage. This bandage could be applied to any region of the user’s body.

Figure 2 shows an example of a heating device 100 which is generally circular. This generally circular heating device 100 could also be used as a bandage. However, in specific examples this generally circular heating device 100 could be applied to a user’s breast. While the heating device 100 may be a single cup (i.e. intended to receive a single breast) it is also anticipated that a dual cup design for the heating device more similar to a traditional bra may be used. The heating device 100 may comprise attachment means for attaching to the user’s breast or may be arranged to be inserted/attached into a conventional bra. This heating device 100 may then be used to provide heating to a user’s breast.

For example, this may be in a pre-operative method or post-operative method to increase blood flow in the user’s breast to improve wound healing after breast surgery such as mastectomy. An example of such pre-operative methods and post-operative methods is provided in GB 2580947 A, the entire contents of which is hereby incorporated by reference.

The advantages of heat treatment may also be applied to recovery from many types of surgeries such as abdominoplasties, mastectomy, vascular surgery, caesarean section, spinal surgery, foot surgery, ankle surgery, knee surgery, or wounds following sternotomy, laparotomy, complex free tissue reconstructions or other cosmetic procedures. Of course, the heating device 100 can be used to provide heat to the region of the user’s body for any reason, including simply for comfort.

The heating device 100 comprises one or more primary sensor(s) 12 and one or more secondary sensor(s) 14, each able to provide a sensor reading. There may be a plurality of primary sensors 12. Separately, there may be a plurality of secondary sensors 14. Each of the primary sensor(s) 12 and secondary sensor(s) 14 will be discussed in the plural below, but unless otherwise specified any disclosure is equally applicable to examples with a single primary sensor 12 and/or or a single secondary sensor 14.

In certain examples, the heating device 100 may comprise at least three sensors 12, 14. That may be two or more primary sensors 12 and one or more secondary sensor(s) 14, or one or more primary sensors 12 and two or more secondary sensor(s) 14. In other words, there is a plurality of primary sensors 12 and/or a plurality of secondary sensors 14.

The primary sensor(s) 12 and/or the secondary sensor(s) may be any type of sensor, including but not limited to: temperature sensors; bioimpedance sensors; pulse oximetry sensors; pressure sensors; capacitance sensors; heartrate sensors, electrical resistance sensors, skin conductivity sensors, pH sensors; and/or laser doppler sensors; or any other type of sensor. In certain examples, the primary sensor(s) 12 and the secondary sensor(s) may be skin-contact sensors. That is, sensors which contact the user’s skin to detect a physiological parameter relating to the user.

In particular examples, the primary sensors 12 may be primary temperature sensors 12 and/or the secondary sensors 14 may be secondary temperature sensors 14. While the following specification will make reference to primary temperature sensors 12 and secondary temperature sensors 14, this is not a requirement. Particularly the disclosure may be put into effect using any type of sensor and the following disclosure is equally applicable to any other sensor type. For example, the primary sensors 12 and/or the secondary sensors 14 may be blood flow sensors those disclosed in Epidermal devices for noninvasive, precise, and continuous mapping of macrovascular and microvascular blood flow to Webb et aL, 2015.. Alternatively, the primary sensors 12 and/or the secondary sensors 14 may be one or more of: bioimpedance sensors; pulse oximetry sensors; pressure sensors; capacitance sensors; heartrate sensors, electrical resistance sensors, skin conductivity sensors, pH sensors; and/or laser doppler sensors; or any other suitable sensors.

The primary temperature sensors 12 and secondary temperature sensors 14 may be any suitable temperature sensors which can sense temperature in a useful range for the human body. In particular examples, the primary temperature sensors 12 may be the same as the secondary temperature sensors 14. That is, the same model or type of sensor. Each of the primary temperature sensors 12 and the secondary temperature sensors 14 are able to provide a temperature reading. These temperature readings correspond to the temperature of the region of the user’s body that the respective sensor is adjacent to.

The primary sensors 12 may be generally arranged, in use, to overlie a reference area corresponding to the region of the user on which the wearable device 100 is intended to operate. For example, the wearable device 100 may be a heating device 100 and the region may be an area of the user to be heated. This reference area may closely correspond to the area to which heat is to be delivered. For example, the reference area could correspond to a location of a wound to which increased blood flow is desired. The secondary sensors 14 may be generally arranged, in use, to overlie a remaining area of the region which is spaced from the reference area.

In particular examples the primary sensors 12 may be centrally arranged on or around a centre of the wearable device 100, with the secondary sensors 14 arranged radially outward from the centre. This could be, for example, in one or more generally concentric circles. The circles may be defined with at least three primary sensors 12 forming a first circle, with a second circle concentric to the first formed of at least three secondary sensors 14.

In a specific example the wearable device 100 may be a heating device 100 which may be for delivering heat to a user’s breast. In this context, the region of the user’s body is the user’s breast, and the reference area may correspond to the user’s nipple and/or areola. Such a heating device 100 may comprise primary temperature sensors 12 and secondary temperature sensors 14. As such, the primary temperature sensors 12 may overlie, in use, the user’s nipple and/or areola. The secondary temperature sensors 14 may be spaced from these primary temperature sensors 12 so as to overlie an outer region of the user’s breast. Such a heating device 100 may comprise a heat source. This heat source may be arranged at or near to the centre of the wearable device 100.

The temperature readings of each of the primary sensors 12 and the secondary sensors 14 may be transmitted to a processor for analysis. This processor may be located on the wearable device 100. Alternatively, or additionally, the processor may be located on a remote device which the wearable device 100 communicates with. For example, the wearable device 100 may include a transmitter for transmitting signals to the remote device. This remote device may be for example a user’s mobile phone. Of course, any reference to a processor must be understood to encompass examples with multiple processors carrying out any element of the method.

A method of fitting this wearable device 100, such as heating device 100, is provided. Any reference to the user carrying out a step in this method generally refers to the user of the wearable device 100 which is the person that the wearable device 100 is operated on. For example, for a heating device 100 this is the person to whom heat is being applied from the heating. However, it is acknowledged that one or more steps of the method could be carried out by the user themselves or a third party and the method must be read and understood in this context. The wearable device 100 may be located adjacent to a region of the user’s body for operating the wearable device 100 on that region. This locating may be carried out by the user themselves or by any other third party. Although the wearable device 100 is generally located in this region the wearable device 100 may be incorrectly fitted for delivering efficient operation of the wearable device 100. For example, when the wearable device 100 is a heating device 100 it may be incorrectly fitted for delivering efficient heat transfer.

A sensor reading is taken from each of the primary sensors 12. The sensor reading from each of the primary sensors 12 is then compared to a pre-determined range. The sensor reading from each primary sensor 12 may be classified as a primary sensor reading. The classification of a sensor reading may simply be defined by how the reading is processed. This is to determine whether any of the sensor readings from the primary sensors 12 falls outside this pre-determined range. For example, in examples with two primary sensors 12, a sensor reading from each primary sensor 12 will be compared to the pre-determined range. The heating device 100 for the method may comprise at least three sensors 12, 14. These at least three sensors 12, 14 are made up of the one or more primary sensor(s) 12 and the one or more secondary sensor(s) 14. A sensor reading may be taken from each of the at least three sensors 12, 14. Each sensor reading is then classified as either a primary sensor reading from a primary sensor 12 or a secondary sensor reading from a secondary sensor 14.

In examples where the primary sensors 12 are primary temperature sensors 12, this predetermined range may correspond to a typical body skin temperature range since the heating device 100 will generally be in contact with the user’s body. This temperature range may be defined based upon an expected temperature range for the region of the user’s body that the heating device 100 is expected to be applied to. In some examples, the predetermined range may be adjustable. For example, it may be possible to select a predetermined range which is appropriate for the intended region of the user’s body to which the heating device 100 is going to be used to heat. In some examples the pre-determined range may be approximately 30°C to 40°C. In further examples the pre-determined range may be 33°C to 37°C.

The method may further comprise a calibration step in which an expected temperature range for the particular user is determined or selected. This may be selected from a predetermined list or as a variable input. In further examples, the expected temperature range may be based on temperature readings of the region. For example, from one or more of the primary temperature sensors 12 and/or the secondary temperature sensors 14. In certain examples the heating device 100 may be correctly fitted on the user as a first step, such as by a medical professional, and these calibration sensor readings may then be taken. These can be stored on a memory unit, which may be local to the heating device 100 or the heating device 100 may communicate with the memory unit, and referenced to determine the expected temperature range for the region of the user’s body. For example, maximum and minimum temperature readings in a given period may be taken and used as the predetermined range. A threshold may be applied either side of these maximum and minimum temperature readings, such as 10% of values either way, or an absolute threshold such as ±3°C, preferably ±1 °C. Of course, in examples where the primary sensors 12 and/or secondary sensors 14 are not temperature sensors, a temperature range would not be used and instead an appropriate parameter based on the type of sensor would be used.

If the sensor reading from any of the primary sensors 12 is outside of the pre-determined range, then a notification is generated to indicate to the user that the wearable device 100 may be incorrectly fitted. This notification, and any notifications discussed below, may be generated and delivered in any suitable form. Particularly the notification should deliver a clear and complete indication to the user that the wearable device 100 may be incorrect fitted. For example, the notification could be delivered by the wearable device 100 such as in the form of a visual and/or audible notification. Alternatively, or additionally, the wearable device 100 could communicate with a remote device which delivers the notification in any suitable form. For example, the notification could be in the form of a notification on the user’s mobile phone.

As a result of this notification, the user may then relocate the wearable device 100. This relocation may then achieve a better fit of the wearable device 100.

This comparison of the sensor readings of the primary sensors 12 is thus generally a first step of the method for fitting the wearable device 100. The method may in some examples not continue to any subsequent steps until this first step is satisfied.

That is, after the wearable device 100 has been relocated this first method step may be repeated. The user may provide an input to the wearable device 100 to indicate that they have relocated the wearable device 100. This input could be via an input on the wearable device 100 such as a button. Alternatively, or additionally, this input could be provided in any suitable manner such as via a remote device such as a user’s mobile phone.

This method step can be repeated any number of times until each of the sensor readings from the primary sensors 12 is within the pre-determined range. If the sensor readings from the primary sensors 12 are not all within the pre-determined range the wearable device 100 may be prevented from proceeding with an operational step. For example, where the wearable device 100 is a heating device 100, the heating device 100 may be prevented from proceeding with a heating step. This first method step may further comprise a secondary check on the sensor readings of the primary sensors 12. In this sense, the comparison described above between the sensor readings of each of the primary sensors 12 and the pre-determined range may be considered as a primary check for the first method step. This secondary check may be carried out in examples where there is a plurality of primary sensors 12.

A sensor reading, which may be the same as the sensor reading taken for the primary check or may be a new sensor reading, is taken for each of the primary sensors 12. If any of the sensor readings from the primary sensors 12 differs from any other of the sensor readings from the primary sensors 12 by more than a pre-determined threshold, then this secondary check may be failed. This pre-determined threshold may be identified as a second pre-determined threshold, compared to a first pre-determined threshold discussed below in relation to the secondary sensors 14. This second pre-determined threshold may be any suitable range, and may be selected for a particular application.

For example, where the where the primary sensors 12 are primary temperature sensors 12, in particular examples the second pre-determined threshold may be ±3°C. In further examples the second pre-determined threshold may be ±1 °C.

For example, in an example with three primary sensors 12, there would be three sensor readings T _Pi , T _P2 , and T _P3 - one for each of the three primary sensors 12. This secondary check would involve comparing each sensor reading of the primary sensors 12 against each other sensor reading of the primary sensors 12 to see whether they differ from one another by more than the second pre-determined threshold.

In one method to achieve this check, T _Pi would be individually compared to T ₂ to confirm that the two readings are within the second pre-determined threshold. T _Pi would also be individually compared to T _P3 to confirm that the two readings are within the second predetermined threshold. T _P2 would also be individually compared to T _P3 to confirm that the two readings are within the second pre-determined threshold.

In another method to achieve this check, the maximum sensor reading of the primary sensors 12 may be compared to the minimum sensor reading of the primary sensors 12. If the maximum sensor reading and the minimum sensor reading are within the second pre- determined threshold, then each individual comparison must also be within this second predetermined threshold.

Of course, any other suitable method for carrying out this secondary check may be used as appropriate.

If any of the sensor readings from the primary sensors 12 differs from another of the sensor readings from the primary sensors 12 by more than the second pre-determined threshold, a notification may be generated indicating that the wearable device 100 may be incorrectly fitted. This notification may be the same as discussed above, or may be different.

In alternative, or additional, examples the sensor reading from each of the primary sensors 12 may be compared to an average sensor reading of the primary sensors 12. This average may be any suitable type of average, for example the mean, median or mode. In certain examples, the average is the mean of the sensor readings from each of the primary sensors 12. This average sensor reading may exclude the sensor reading being checked. In the example discussed above, TH may be compared to the average value of T _P2 and T _P3 . If the sensor reading differs from this average sensor reading, then a notification may be generated indicating that the wearable device 100 may be incorrectly fitted.

Again, as a result of this notification the wearable device 100 should be relocated. After this relocation the first method step incorporating one or both of the primary check and the secondary check can be repeated. As above the method may be repeated any number of times until none of the sensor readings from the primary sensors 12 differ from another of the sensor readings from the primary sensors 12 by more than the second pre-determined threshold. The method may in some examples not continue to any subsequent steps until this first step is satisfied.

A second method step can be defined with reference to a check involving the secondary sensors 14. As noted above, each of the secondary sensors 14 may be spaced from the primary sensors 12.

A sensor reading may be taken for each of the secondary sensors 14. The sensor reading from each secondary sensor 14 may be classified as a secondary sensor reading. The classification of a sensor reading may simply be defined by how the reading is processed. An average sensor reading for the primary sensors 12 is calculated. This average may be any suitable type of average, for example the mean, median or mode. In certain examples, the average is the mean of the sensor readings from each of the primary sensors 12. This average sensor reading may be based upon any of the sensor readings discussed above in relation to the primary sensors 12. Alternatively, a new sensor reading may be taken for the primary sensors 12 for the purpose of calculating this average sensor reading. In examples with a single primary sensor 12 the average sensor reading will just be the sensor reading of that single primary sensor 12.

Each sensor reading from the secondary sensors 14 may then be compared to the average sensor reading from the primary sensors 12. If any of the sensor readings from the secondary sensors 14 differs from the average sensor reading of the primary sensors 12 by more than a first pre-determined threshold a notification may be generated to indicate that the wearable device 100 may be incorrectly fitted.

This first pre-determined threshold may be any suitable range, and may be selected for a particular application.

For example, if the secondary sensors 14 are secondary temperature sensors 14, in particular examples the first pre-determined threshold may be ±3°C. In further examples the first pre-determined threshold may be ±1°C.

As above, any suitable method may be used for carrying out this check. Including, for example, individually comparing each sensor reading from the secondary sensors 14 to the average sensor reading of the primary sensors 12. Alternatively, a maximum sensor reading from the secondary sensors 14 and a minimum sensor reading from the secondary sensors 14 may be identified and compared to the average sensor reading of the primary sensors 12.

The notification generated for this second method step may be the same as the notification discussed above in relation to the first method step. Again, this notification may cause the wearable device 100 to be relocated and one or both of the method steps may be repeated after this relocation. The user may indicate that they have carried out this relocation in a manner as described above. However, it may be possible in certain examples to override notifications generated as a result of this second method step. In this context, overriding the notification may mean forcing the wearable device 100 to begin its operation even if the second method step indicates that one or more of the sensor readings of the secondary sensors 14 differs from the average sensor reading of the primary sensors 12 by more than the first predetermined threshold. For example, where the wearable device 100 is a heating device 100, overriding the notification may mean forcing the heating device 100 to begin a heating cycle.

The user may be able to override this notification by inputting an override command. This may, for example, be via a user input on the wearable device 100 or via a remote device such as a user’s mobile phone. Alternatively, or additionally, the wearable device 100 may automatically override this notification. For example, if the second method step is repeated and it is the same secondary sensor 14 which differs from the average sensor reading of the primary sensors 12 by more than the first pre-determined threshold then the wearable device 100 may override this notification.

To override the notification, the sensor reading of each secondary sensor 14 which differs from the average sensor reading of the primary sensors 12 by more than the first predetermined threshold may be discarded. Alternatively, or additionally, each secondary sensor 14 which has a sensor reading that differs from the average sensor reading of the primary sensors 12 by more than the first pre-determined threshold may be disabled.

In particular examples, it may only be possible to override this notification if the number of sensor readings from the secondary sensors 14 which differ from the average sensor reading of the primary sensors 12 by more than the pre-determined threshold is less than or equal to a threshold number. For example, the threshold number may be 1 or 2.

In this sense, the second method step provides a further check on the fit of the wearable device 100. This further check can be overridden in certain circumstances if appropriate.

Once the method has been performed, if the wearable device 100 is a heating device 100 then a heat source may be activated to apply heat to the region of the user. As noted above, while this method has primarily been described with regard to a heating device 100 it is equally applicable to any wearable device 100. Likewise, while this method has primarily been described for a wearable device 100 incorporating primary temperature sensors 12 and secondary temperature sensors 14, it is equally applicable for any other type of primary sensor 12 and secondary sensor 14.

A system can be provided to carry out this method. Particularly, the system may be a heating system which can include a heating device 100 as discussed above. Again, while the description may refer to a heating system this is equally applicable to any type of system.

The system can include a processor which is arranged to carry out the method set out above. This processor may be arranged on the wearable device 100. Alternatively, or additionally, this processor may be located on a remote device such as a remote server or a user’s mobile phone which is in communication with the wearable device 100. For example, the wearable device 100 may include a transmitter for communication with the remote device.

An example of a remote device, such as a smartphone 200, which may be used with methods and wearable devices 100 described above is shown in Figure 3. While Figure 3 generally corresponds to the wearable device 100, such as a heating device 100, of Figure 2 in that the wearable device 100 shown is generally circular, the disclosure should not be limited to this wearable device 100. This remote device 200 can equally be used for the wearable device 100, such as a heating device 100, of Figure 1 or any other suitable wearable device 100.

The remote device 200 includes a display showing an interface with a representation 100a of the wearable device 100 and one or more indicia 12a, 14a. The representation 100a may be generally shaped to correspond to the shape of the wearable device 100 that the remote device 200 is operating and/or communicating with.

The indicia 12a, 14a may comprise primary indicia 12a and secondary indicia 14a corresponding respectively to the primary sensors 12 and secondary sensors 14. In this sense, sensor readings of the primary sensors 12 and secondary sensors 14 may be displayed to the user. The indicia 12a, 14a may be arranged on the representation 100a to correspond to the physical locations of the primary sensors 12 and secondary sensors 14 on the wearable device 100.

This interface may be used to generate and deliver the notifications to the user. For example, the display may indicate to the user which of the primary sensors 12 and/or secondary sensors 14 is causing the notification. This may be, for example, by highlighting the corresponding indicia 12a, 14a.

The user may interact with the remote device, for example to override the second method step for one or more of the secondary sensors 14.

Once the wearable device 100 has been correctly fitted as per the method above, operation of the wearable device 100 may begin. For example, where the wearable device 100 is a heating device 100, once the heating device 100 has been correctly fitted heat may be applied to the region of the user’s body via the heating device 100. For example, this could be by running a current through a resistive wire in the heating device 100.

In use, one or more of the primary sensors 12 and/or secondary sensors 14 may be used to determine an effectiveness of operation of the wearable device 100.

For example, where the wearable device 100 is a heating device 100 and the primary sensors 12 are primary temperature sensors 12 and/or the secondary sensors 14 are secondary temperature sensors 14, the primary temperature sensors 12 and/or the secondary temperature sensors 14 may be used to determine an effectiveness of the heating from the heating device 100. That is, one or more of the primary temperature sensors 12 and/or secondary temperature sensors 14 may compare a temperature of the user’s body adjacent the sensor to a target temperature for the region of the user’s body.

The one or more of the primary sensors 12 and/or secondary sensors 14 can be used as a part of a feedback loop for the wearable device 100.

For example, where the wearable device 100 is a heating device 100 and the primary sensors 12 are primary temperature sensors 12 and/or the secondary sensors 14 are secondary temperature sensors 14, if the one or more of the primary temperature sensors 12 and/or secondary temperature sensors 14 indicate that the temperature of the region of the user’s body is greater than the target temperature or less than the target temperature (or a threshold either side thereof), the heat source can be adjusted to decrease or increase the amount of heat provided (as appropriate).

GB 2580947 A discloses a heating device which includes sensors arranged to determine the blood flow in the region of the user’s body. One example of such blood flow sensors is those disclosed in Epidermal devices for noninvasive, precise, and continuous mapping of macrovascular and microvascular blood flow to Webb et aL, 2015. The sensors of Webb et al. comprise a local heat source and transmission of the local heat is detected as set out in the paper. This local heat source can effectively be superimposed upon the global heating of the main heat source of the heating device. That is, the local heat source may heat to a greater temperature than the main heat source of the heating device. Such an arrangement is equally applicable to the present wearable device 100, particularly when the wearable device 100 is a heating device 100 and the primary sensors 12 are primary temperature sensors 12 and/or the secondary sensors 14 are secondary temperature sensors 14. In such an arrangement, one or more of the primary temperature sensors 12 and/or the secondary temperature sensors 14 may be used to detect the effect of this local heat source and thereby determine the amount of blood flow in the region of the user’s body.

CLAUSES:

1 . A method for fitting a wearable device to a region of a user, the wearable device comprising one or more primary sensor(s) and one or more secondary sensor(s), wherein the method comprises the steps of:

(a) comparing a sensor reading from each of the one or more primary sensor(s) to a pre-determined range and generating a notification to the user indicating that the wearable device is incorrectly fitted if any of the sensor readings from the one or more primary sensor(s) are outside of the pre-determined range; and

(b) comparing a sensor reading from each of the one or more secondary sensor(s) to an average sensor reading from the one or more primary sensor(s) and generating a notification to the user indicating that the wearable device is incorrectly fitted if any of the sensor readings from the one or more secondary sensor(s) differ from the average sensor reading by more than a first pre-determined threshold.

2. The method of clause 1 , further comprising: repeating step (a) until each of the sensor readings from the one or more primary sensor(s) are within the pre-determined range, before proceeding to step (b).

3. The method of any preceding clause, wherein the one or more primary sensor(s) comprises two primary sensors.

4. The method of clause 3, further comprising the step of:

(a-i) comparing sensor readings from each of the primary sensors and generating a notification to the user indicating that the wearable device is incorrectly fitted if any of the sensor readings from the primary sensors differ from another of the sensor readings from the primary sensors by more than a second pre-determined threshold.

5. The method of clause 4, further comprising: repeating step (a-i) until none of the sensor readings from the primary sensors differs from another of the sensor readings by more than the second pre-determined threshold.

6. The method of any preceding clause, wherein the one or more secondary sensor(s) comprises two secondary sensors. 7. The method of clause 6, further comprising the steps of:

(b-i) discarding the sensor reading of or disabling each secondary sensor which has a sensor reading which differs from the average sensor reading by more than the first pre-determined threshold; and

(b-ii) operating the wearable device if the number of secondary sensors which are disabled or have their reading discarded is less than or equal to a threshold number.

8. The method of any preceding clause, wherein the pre-determined range is set based on one or more sensor readings from the primary sensor(s) and/or the secondary sensor(s).

9. The method of any preceding clause, wherein the primary sensor(s) and/or the secondary sensor(s) are skin-contact sensors.

10. The method of any preceding clause, wherein the primary sensor(s) are primary temperature sensor(s) and the secondary sensor(s) are secondary temperature sensor(s).

11 . The method of clause 10, wherein the pre-determined range corresponds to typical body skin temperature range for the region.

12. The method of clause 10 or 11 , wherein the pre-determined range is 30°C to 40°C, preferably 33°C to 37°C.

13. The method of any of clauses 10 to 12 when dependent on clause 4, wherein the second pre-determined threshold is ±3°C, preferably ±1°C.

14. The method of any preceding clause, wherein the wearable device is a heating device comprising a heat source for applying heat to the region of the user.

15. A system for fitting a wearable device to a region of a user, the system comprising: a wearable device comprising: one or more primary sensor(s) arranged to overlie in use a reference area corresponding to the region of the user; one or more secondary sensor(s) arranged to overlie in use a remaining area of the region spaced from the reference area; and a processor arranged to carry out the method of any preceding clause.

16. The system of clause 15, wherein the remaining area generally surrounds the reference area.

17. The system of any of clauses 15 to 16, wherein the processor is arranged on a remote device and the wearable device further comprises a transmitter for transmitting signals to the remote device.

18. The system of any of clauses 15 to 17, wherein the one or more primary sensor(s) comprises two primary sensors.

19. The system of any of clauses 15 to 18, wherein the one or more secondary sensor(s) comprises two secondary sensors.

20. The system of clause 19, wherein the one or more secondary sensor(s) comprises three secondary sensors, arranged in a circle generally centred on the reference area.

21 . The system of any of clauses 15 to 20, wherein the one or more primary sensor(s) are centrally arranged on or around a centre of the wearable device, with the one or more secondary sensor(s) arranged radially outward from the centre.

22. The system of any of clauses 15 to 21 , wherein the primary sensor(s) and/or the secondary sensor(s) are skin-contact sensors.

23. The system of any of clauses 15 to 22, wherein the primary sensor(s) are primary temperature sensor(s) and the secondary sensor(s) are secondary temperature sensor(s).

24. The system of any of clauses 15 to 23, wherein the wearable device is a heating device comprising a heat source for applying heat to the region of the user.

25. The system of clause 24, wherein the region is the user’s breast, and the reference area corresponds to the user’s nipple and areola.