WO2015049108A1

WO2015049108A1 - Body illumination system and method

Info

Publication number: WO2015049108A1
Application number: PCT/EP2014/069846
Authority: WO
Inventors: Jacobus Petrus Johannes VAN OS; Kunigunde Hadelinde CHERENACK; Guofu Zhuo; Eliav Itzhak Haskal; Wouter Hendrik Cornelis SPOORENDONK
Original assignee: Koninklijke Philips N.V.
Priority date: 2013-10-02
Filing date: 2014-09-18
Publication date: 2015-04-09

Abstract

A method of operating a body illumination system for illuminating a body portion of a subject comprising at least one light source configured for illuminating a target area of the body portion is disclosed. The method comprises: during operation of the body illumination system according to first and second predetermined settings, while disposed with respect to the target area for operably illuminating the target area,receiving user input and receiving data measured by at least one sensor configured for measuring one or more of biophysical and/or biochemical parameters associated with at least part of said body portion including at least part of the target area; recording the user input and the measurement data as a function of the first and second settings; determining a third predetermined setting for operation of the system as a function of the recorded user input and data; and changing operation of the system so that the system is operated according to the third predetermined setting.

Description

Body illumination system and method

TECHNICAL FIELD OF THE INVENTION

The present disclosure relates to body illumination systems and methods of operation of said body illumination systems. BACKGROUND OF THE INVENTION

People can suffer from different types of physical pain, which can be classified as acute pain or chronic pain. Acute pain is a biological response to disease, inflammation and/or factors that (threaten to) damage the body. Acute pain can be continuous or repetitive, and it is considered to serve for alerting to one or more causes of (potential) harm to the body. Chronic pain is pain that lasts for prolonged periods, generally several months or longer, that appears unrelated to a direct cause, e.g. after healing of a condition, and/or that is caused by a chronic affliction. Chronic pain may be continuous or intermittent, and it is often considered not to have a useful biological function.

Somatogenic pain is caused by the body itself and comprises neuropathic pain and nociceptive pain. Neuropathic pain is a consequence of damage to and/or malfunction of the nervous system. Nociceptive pain is a consequence of triggering particular nerves, the nociceptors, of a normally functioning central or peripheric nervous system.

Several forms of pain, in particular nociceptive pain such as muscular pain and joint pain are known to be reduced or removed by applying heat and/or other extracorporeal signals to the painful location, which may comprise "drowning" the pain in one or more other sensations that may comprise (acute) pain (just as when scratching oneself). Heat may be applied e.g. via a hot bath or shower, a heat pad such as a chemical or physical heat pad and/or via illumination with infrared light (IR light). Heat may improve blood circulation and warm muscles. As the muscles are soothed by the heat, they automatically loosen up and relax. At the same time, improved blood circulation helps the irradiated body part get rid of impurities and quickly sends oxygen-rich blood to stressed or aching muscles, bringing effective pain relief. In joints, heat may assist in restoring the right viscosity of the synovial fluid to improve its lubricating and nourishing properties for the joint, thus reducing joint pain. Heat may further stimulate production of endorphins. Illuminating an afflicted body part with suitable light, has proven to be an effective manner of realizing pain relief. E.g., WO 2011/135502 discloses an effective device and method for relieving nociceptive pain.

However, since pain as well as perception and suffering from pain come in many forms, further improvements in pain relief are desired.

SUMMARY OF THE INVENTION

Herewith, a body illumination system for illuminating a body portion of a subject with light according to the appended claims is provided. The body illumination system comprising;

at least one light source configured for illuminating a body portion of a subject with light,

a user interface (23) for receiving user input (A), wherein the user input is a value perceived by said user, wherein the value relates to a psychophysiological measure related to at least the portion of the body receiving the illumination,

at least one sensor (15) configured for measuring one or more of biophysical and/or biochemical signals (A, B) associated with at least part of the illuminated portion; and a processing unit (19) configured to receive;

- the user input (A), and

- the data measured by the at least one sensor;

said processing unit adapted for operating the body illumination system in dependence on,

- the received user input (A),

- the received data measured by the said at least one sensor (15).

Thus, the body illumination system is disposed with respect to the body portion for operably illuminating the target area, e.g. with the light source close to or against a skin portion of the target area, the user input is a value perceived by the user wherein the value relates to a psychophysiological measure related to at least the portion of the body receiving the illumination and the physical reaction of the subject are measured as a function of operation of the system and used to determine a further operational setting of the system according to which the system is subsequently operated. The system is therefore operated for providing body illumination in dependence of both subjective and objective data, which interact; the user-provided information reflects a psychophysiological measure, these can include measures of brain activity such as Event Related Potential (ERP), brain waves ( electroencephalography, EEG) functional Magnetic Resonance Imaging (fMRI), measures of skin conductance (Skin Conductance response SCR; Galvanic Skin Response GSR), cardiovascular measures (Heart Rate HR, Beats Per Minute BPM, Heart rate variability HRV; vasomotor activity), muscle activity (Electromyography EMG), Electrogastrogram (EGG), changes in pupil diameter with thought and emotion (pupillometry), eye movements recorded using the techniques of Electro-oculogram (EOG) and direction of gaze methods and cardiodynamics, recorded via impedence cardiography.

The International Association for the Study of Pain defines pain as an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. Different people have different pain thresholds and pain tolerance levels as pain is a subjective experience. The pain threshold is the minimum intensity of a stimulus that is perceived as painful and the pain tolerance level is the maximum intensity of a pain producing stimulus that a subject is willing to accept in a given situation.

The amount of pain experienced by the subject may be measured using a pain scale, these pain scales are based on self-report, observational, physiological or

psychophysiological data. Numerous scales have been developed but the central tenet of all scales is a measurement of the pain perceived by the subject. The Visual Analogue Scale (VAS) and the Verbal Rating Scale (VRS) are commonly used, the VAS can comprise a single straight horizontal line with no pain at the left end and pain as bad as it could be at the right hand end, it can also comprise a series of faces (this can also be called the Faces Pain Scale) with a happy face at the left end passing through a series of declining happiness faces until a distressed face is reached on the right. The subject simply indicates whereabouts on the scale they perceive the pain to be using the visual clues as a reference. The VRS consists of a series of words that are commonly used to describe pain such as no pain, mild pain, moderate pain, severe pain etc, the subject reads the words and chooses which they feel best describes the perceived level of pain they are experiencing. To manage pain, both sensory and emotional factors must be considered.

Psychophysiological perception of pain and the objective measurable physiological data reflects not only the body's response to the body illumination, but also to the subject's emotional state which may be unrelated to the pain and/or the body illumination per se. For example, it has been found that general anxiety or happiness of a subject can significantly increase or decrease the subject's perceived level of suffering from pain with little or no measurable biophysical and/or biochemical changes in the painful body portion. The comfort level or conversely, discomfort level of the subject can also increase or decrease the perceived level of pain as comfort can be described as a sense of physical or

psychological ease, that is to say if a subject was asked to provide a measure of the perceived level of pain in a "comfortable" environment such as a soft bed or in an "uncomfortable" environment such as laying on a hard floor it is to be expected that the pain scale will show more perceived pain when the subject is uncomfortable than the perceived level of pain shown by the pain scale when in a comfortable environment. Utilizing a combination of user perception and measurable physiological data facilitates both assessing the status of the painful portion and of the subject's body and mind and optimizing the illumination

conditions.

The user input may be provided by the subject, which is preferred as the subject is the one perceiving the pain and undergoing the body illumination, as this facilitates self-administration of the system and domestic use. However, it is conceivable that the body illumination is administered by or in collaboration with another user providing the input such as a therapist and/or other care giver, a relative, etc. Input of the subject into the operation of the system and subsequent body illumination provides a sense of autonomy and control over the body illumination that reduces a reactive and passive stance the subject may have (or have had) with respect to the perceived level of pain, increases acceptance of any residual perceived pain and/or reduces anxiety. This is particularly relevant with respect to chronic pain. Thus the method facilitates both bio-feedback and psychological-feedback for improving system adaptation, system efficiency, subject acceptance of the illumination, illumination regimen adherence and/or general subject well-being. It is noted that operating the system according to further settings and recording further user input and biochemical and/or biophysical data with respect to each further setting facilitates building a database and detecting patterns in the physical and/or psychological behavior in response to different settings. This allows increasing accuracy in determining the third setting and any further setting used or considered useful for the body illumination.

Suitable biophysical and biochemical parameters may comprise local and/or more systemic parameters such as an NO level in the target area, possibly relative to one or more body portions outside the target area; blood flow; blood perfusion; tissue (dis-) coloration such as bleaching, erythema, jaundice, hematoma, tanning, etc.; blood oxygenation; muscle tension; skin conductivity; heart rate; breathing rate; breathing volume; breathing efficiency, e.g. 0₂ uptake, CO/C0₂ balance in exhaled air; perspiration; etc. Local temperatures and/or temperature distributions with respect to extension along the target area, e.g. extension in lateral direction along the skin, and/or into the tissue may also provide useful information, indicative of absorption and/or of the illumination energy and/or other causes such as vasodilation, inflammation etc. Different sensors for measuring different biophysical and/or biochemical parameters may be provided, e.g. local parameters of the target area and systemic parameters measured remotely from the target area. Sensors may be optical sensors and/or contact sensors.

Note that operation of the body illumination system according to the first, second and third setting need not be subsequent to each other in one session, but may be performed in individual subsequent sessions. However the former is preferred over the latter as this provides more direct and therefore clearer and more reliable feedback.

An embodiment of a method of operating a body illumination system according to a second aspect of the appended claims is provided. The method comprises the steps of: during operation of the system according to a first predetermined setting and a second predetermined setting while at least the light source of the system is disposed with respect to the body portion for operably illuminating the target area, receiving user input and receiving data measured by at least one sensor configured for measuring one or more of biophysical and/or biochemical parameters associated with at least part of said body portion including at least part of the target area; the step of recording the user input and the measurement data as a function of the first and second settings; the step of determining a third setting for operation of the system as a function of the subject input and the data measured by the at least one sensor at the first and second settings; and the step of changing operation of the system so that the system is operated according to the third predetermined setting.

In an embodiment, the first predetermined setting may comprise a first spatial illumination intensity distribution for illuminating the target area by the at least one light source and the second predetermined setting may comprise a second spatial illumination intensity distribution for illuminating the target area by the at least one light source, the second spatial illumination intensity distribution being different from the first spatial illumination intensity distribution in at least one of a spatially- varying, intensity varying, spectrally varying, and a temporally- varying pattern. Thus, psychological and physical response of the subject to different illumination patterns may be received and recorded.

Further, the third setting may comprise a third spatial illumination intensity distribution for illuminating the target area by the at least one light source, being different from at least one of the first and second spatial illumination intensity distributions in at least one of a spatially- varying, intensity varying, spectrally- varying and a temporally- varying pattern. Thus, the illumination pattern may be adjusted between the different settings and a suitable illumination pattern may be provided, which may - and generally should and will - differ from that of the first and/or second setting.

In an embodiment, at least one of the first, second and third settings may comprise a spatial illumination intensity distribution for the illumination provided by the at least one light source and wherein changing operation of the system operation of the body illumination system between operating according to the first, second and third setting to another one of the first, second and third settings comprises providing one of the first, second and third spatial illumination intensity distributions for the illumination provided by the at least one light source while providing a predetermined user indication of operation according to a different setting, in particular a different one of the first, second and third settings. The user indication may comprise a visual, acoustic and/or tactile signal. In such case a more or less pronounced placebo effect may be provided that predominantly acts on the psychological aspects of pain perception, rather than on physical aspects. In such case, illumination may be significantly more or less powerful than indicated, or of a different nature, e.g. with a different wavelength and/or illumination pattern, since the user suffers less or more from perceived pain than expected based on the measurable parameters indicative of physical pain indicia. It is noted that changing operation in this embodiment, or any other embodiment, may comprise adjusting the at least one light source and/or adjusting possible secondary actuators comprised in the system, like additional light sources, thermal actuators such as a heater or chiller and/or other non-optical actuators.

The method may comprise recording the measurement data for at least one of the biophysical and/or biochemical parameters of the body portion as a function of at least one of the illumination pattern, the user input, measurement data for a further biophysical and/or biochemical parameter, the setting of the system according to which the system is operated and time.

The method may also or alternatively comprise recording the user input as a function of the measurement data for at least one of the biophysical and/or biochemical parameter of the body portion, the illumination pattern, the setting of the system according to which the system is operated and time.

In such cases, the biophysical and/or biochemical parameter(s) and/or the user input can be related accurately with respect to different aspects of the system settings, the illumination per se and/or other aspects, for example, illumination regimen adherence and/or user satisfaction. This facilitates further optimization of the body illumination system, tailored to the (re)actions of the individual subject. Moreover, it is considered that individuals tend to have recurrent individual patterns in their physical and emotional states over a day which may result in time-dependent pain perception and associated suffering, e.g. as a result of muscular and/or emotional relaxation due to sleep, or rather increased feelings of pain and sleep deprivation such as due to particular postures when lying down. Further, (perception of) pain in women may follow their hormonal cycle. Such patterns may be detected and accounted for in further body illumination, e.g. by adjusting the operational setting of the system as a function of time.

Recording data facilitates building a feedback system for a doctor/therapist, the subject and/or another data collector, as well as for (a program for) the processing unit itself, e.g. to adapt itself according to a predetermined, possibly average, pattern.

In accordance with the preceding, in an aspect, a body illumination system is provided comprising;

at least one light source configured for illuminating a target area of a body portion of a subject with light; a user interface for receiving user input; at least one sensor configured for measuring one or more of biophysical and/or biochemical signals associated with at least part of said body portion including at least part of the target area; and a processing unit configured for performing the steps of the method provided herewith or any embodiment thereof. With the system, improved body illumination may be provided to the subject. The at least one light source may be monochromic, polychromic and/or have one or more controllable wavelengths. The at least one light source may have any suitable shape, e.g. a luminaire, a hand-held device such as a torch, etc.

A particular embodiment may comprise a human wearable device for wearing close to and/or in contact with the body portion and being formed for conforming to a least part of the body portion, which comprises the at least one light source and which is arranged for illuminating at least part of the body portion with light from the at least one light source. E.g., the device may comprise a flexible, pliable or generally deformable portion such as a patch, plaster and/or bandage. The device being formed for conforming to at least part of the body portion to be illuminated facilitates donning and wearing the patch without hindrance to the subject and its movements, improves user comfort and facilitates prolonged illumination. Such device, in particular in the form of a patch or bandage, may be worn inconspicuously under clothing. Such device allows improved and predictable illumination of the body portion since shifted illumination portions and/or shadows caused by relative movement of the device and the body portion are prevented. The device may be flexible, textile-like and may be provided with means for attaching the patch to a body part, e.g. one or more straps, elastic portions, sticky portions and/or cuffs, preferably allowing fixation of the position of the patch with respect to (the target area of) the body portion.

In an embodiment, the at least one light source and the at least one sensor, possibly also the user interface and/or a processing unit may be integrated in the wearable device. Thus, the positions of the at least one light source and the sensor may be determined with respect to each other and, in use, with respect to the target area. Such embodiment may facilitate application and use.

The system may comprise a controller for operating the at least one light source as a function of one or more signals from the processing unit and wherein the processing unit and the controller may be provided, at least partly, in different devices, in particular being configured for communicating via wireless communication. Such a system may facilitate operation when illuminating a body portion that is difficult to access (e.g. a back) and it may facilitate optimization of either device. The processing unit may serve further tasks, e.g. for processing method steps for further devices such as for illumination of plural body portions and/or different subjects with different devices. The controller may control further features of the system, e.g. a further light source, a chiller for cooling a surface layer of the target area etc. It is also conceivable that the processing unit may be provided in a more general purpose computing device, possibly a portable device, such as a suitably programmed tablet computer or mobile phone, e.g. via a suitable computer program product, such as provided as a loaded application.

In an aspect, a computer program product may be provided comprising software code portions configured for, when executed on a processing unit, performing the steps of the method provided herewith or any embodiment thereof. Such computer program product facilitates programming a programmable body illumination system to obtain a system providing one or more of the benefits described herein. The computer program product may be provided as an application for a mobile consumer device such as a mobile phone and/or a tablet computer.

The user input may be received via a user interface connected with the body illumination system. The user interface may be provided in a separate device configured to communicate with the processing unit contained in a different device. In an embodiment, the user interface may provide a user indication of operation of a setting of operation of the system and/or a user indication of an illumination effect, e.g. reflecting one or more measured biophysical and/or biochemical signals. In an embodiment, the user interface and possibly the user indication and the processing unit may be provided by one device e.g.

forming aspects of one program executed on the processing unit such as forming aspects of an application running on a mobile phone or tablet computer.

In the present context, "light" means electromagnetic radiation with a wavelength in the range of about 0.4 - 11 micrometers, ultraviolet (UV) through visible (VIS) to near- and far-infrared (IR) light, for which various light sources are commonly available. In an embodiment, the wavelength may comprise light in a wavelength range of 400-500 nm. Blue light of such wavelength range is predominantly absorbed by the epidermis and dermis of a human. Absorption and reflection of light at such wavelengths depends on the skin color of the subject; fair skin reflects more than dark skin. However, it has been found that light at such wavelengths is perceived as a pleasant temperature by human skin heat sensors, better than InfraRed light, and provides a sensation of warmth which may be very comfortable to the subject. Further, it has been found that the optical energy deposited in the skin is transformed to heat which will warm up the target area with the above-described curative effects and pleasant sensations. This in-depth thermal effect of blue-violet light has been found to appear slower than what can be achieved by IR illumination but, once in a steady state, to be substantially equal to the thermal effect of IR irradiation. It has further been found that light at such wavelengths promotes the formation of nitric oxide (NO) in the tissue. Nitric oxide tends to incite vasodilation, thus improving blood flow, and reducing

inflammation.

Efficient light sources, in particular at blue wavelengths, are Light Emitting Diodes (LEDs), which may be organic LEDs and/or may further comprise a luminescent material for adapting an emitted wavelength. Thus, in an efficient body illumination system the at least one light source may comprise at least one LED. A system comprising a plurality of LEDs may facilitate uniform illumination of a significantly larger target area than when comprising a single LED. LEDs may generate little heat relative to emitted optical energy compared to other types of light sources. Any heat that is, after all, generated by a body illumination system comprising LEDs may be used to benefit system efficacy. Presently, relatively powerful LEDs with an emission peak at approx. 450 nm and a full-width-at-half- maximum spectral bandwidth of approx. 20 nm are readily available and have proven particularly suitable. Moreover, LEDs may have one or more controllable wavelengths allowing a change to the spectral intensity distribution of the emitted light. In an embodiment, the system, in particular a wearable body illumination system, where applicable, may comprise one or more devices for manipulating a temperature of the target area with non-optical means, e.g. a heater for contact heating, a fan or chiller for reducing a surface temperature while increasing a temperature deeper into the body portion etc. This may facilitate providing a body illumination with a particular wavelength without overheating a surface layer of the target area.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

Fig. 1 illustrates a subject, a system for illuminating a body portion of the subject and aspects of a method of operation of said system;

Fig. 2 illustrates an embodiment of a body illumination system according to

Fig. 1,

Fig. 3 illustrates an embodiment of a wearable body illumination system according to Fig. 1;

Fig. 4 illustrates an embodiment of the method of operating a body illumination system;

Fig. 5 is a graph with exemplary results of an embodiment of the disclosed body illumination.

DETAILED DESCRIPTION OF EMBODIMENTS

It is noted that in the drawings, like features may be identified with like reference signs. It is further noted that the drawings are schematic, not necessarily to scale and that details that are not required for understanding the present invention may have been omitted. The terms "upward", "downward", "below", "above", and the like relate to the embodiments as oriented in the drawings. Further, elements that are at least substantially identical or that perform an at least substantially identical function are denoted by the same numeral.

Fig. 1 indicates a subject 1 perceiving pain in a body portion, here a portion of an arm 3. A body illumination system 5 for illuminating a target area is further indicated. An embodiment of the system 5 is shown in Fig. 2 in more detail.

The body illumination system 5 is configured for illuminating a target area 6 of the body portion 3 by means of a body illumination device 7 for wearing in contact with the body portion 3, and a mobile device 8 comprising a processing unit and a user interface configured for performing steps of the method disclosed herein by executing a suitable program.

The body illumination device 7 comprises at least one light source 9 for providing light L at a bio-stimulating wavelength to the body portion 3 and illuminating the target area 6. Here, the at least one light source 9 comprises a plurality of sub-light sources 11 mounted to a carrier 13, in the form of LEDs. The body illumination device 7 further comprises at least one sensor 15 for measuring biophysical parameters B and biochemical parameters C associated with at least part of said body portion 3 including at least part of target area 6, e.g. a skin portion of the subject 1. The body illumination device 7 is arranged for illuminating the subject's body portion, in particular the skin thereof, with light L emitted by the at least one light source 9. The body illumination device 7 further comprises a controller 17 for controlling operation of the at least one light source 9 as a function of one or more signals from the processing unit 19. The body illumination device 7 may be powered from any suitable power source 21, e.g. an electrical mains outlet, but for portability and convenience, powering from a (possibly rechargeable) battery 21 is preferred as indicated. The controller 17 is configured for communication with the processing unit 19, e.g. via a wireless communication connection and -protocol, as indicated here. The processing unit 19 is connected with a user interface 23 for receiving user input A, here being both realized in the mobile device 8 by execution of a suitable program in the form of a mobile application or "app" suitably addressing and controlling respective hardware portions of the mobile device 8. Also or alternatively, the controller 17 and/or processing unit 19 may be configured to take additional input, e.g. for determining parameters of an illumination regimen, user settings, timing, driving schemes for different skin colors etc. Portions of the program may be stored on or in a memory comprised in the apparatus. Note that the program may itself comprise and/or call on other programs for effecting particular functions.

Fig. 3 shows that the body illumination device 7 may be a human wearable device being formed for at least partly conforming to the body portion 3, such as an apparatus conforming to human physique, preferably being deformable or even pliable, as indicated in Fig. 3. The body illumination device 7 may be maintained in position with any suitable means such as one or more adhesive portions, hook-and- loop-type fasteners and/or a strap 25 closable around the body portion. Here, the LEDs 11 and the at least one sensor 15 are embedded in an optional padding layer 27.

Alternatively (not shown) the body illumination system may comprise an assembly further comprising the at least one light source and the at least one sensor 15 as separate objects, which may be interconnected for communicating with each other, e.g. with cables or via wireless communication. In another embodiment all elements are integrated in a single body illumination device.

To further increase system efficiency, in particular when commencing a body illumination session, the body illumination system may comprise a second light source which is arranged for illuminating the body part with near-infrared light (near-IR) having a wavelength in the range of approx. 800-2500 nm, in particular 800-1500 nm (IR-A), and with the body illumination system being arranged for, when in use, illuminating at least a portion of the body part with light from the second light source. Such near IR light is reflected by human skin more than violet or blue light, up till approximately 1200nm, but, once transmitted, it is absorbed predominantly in the dermis, and the subcutis. The penetration depth of near-IR light into human tissue through the skin has a global maximum absorption for near-IR light at approx. 1500 nm, and a local maximum at approx. 2200 nm, with a local minimum in between at approx. 1950 nm. Further, most consumers know that IR radiation is thermal radiation. Acceptance of (the use of) a body illumination system may thus be improved when the body illumination system comprises an IR light source. IR-A light may efficiently be provided with one or more LEDs. Powerful LEDs in the range 800-1500 nm are commercially available at moderate cost.

A body illumination system may comprise plural sensors for determining biophysical parameters B and/or biochemical parameters C of the subject's body portion, e.g. to detect local variations in the body portion and/or for measuring distinct parameters, for example, one or more of the following; measuring a heart rate, measuring blood oxygenation, a breathing characteristic and/or a measurement device for taking electro-encephalogram (EEG) data.

The at least one light source 9 may be pixelated, e.g. as shown here, comprising plural LEDs as sub-light sources 11, which are available for numerous suitable wavelengths, they can provide significant optical output power per watt input power and generate little heat. Incoherent LEDs are considered particularly advantageous, since lasers require additional control, increasing complexity and cost of the system and relatively narrowband radiation poses a high risk of overheating skin. Lasers may also present a danger to a user's eyes.

A pixelated light source may be used to provide particular spatial illumination intensity distributions over relatively large surface areas at close distances to the illuminated (surface of the) body part. Further, different pixels may provide light with different characteristics, for example, with respect to power, wavelength, spatial and/or temporal intensity distribution etc. In particular when at least some or preferably all of the pixels are individually addressable, different illumination patterns may be provided, for example, for a massaging effect.

Similarly, a pixelated sensor (not shown) can detect local variations in the measured parameters, this information may be employed to provide local light intensity variations, for example, reducing light intensity for delicate body portions.

A suitable sensor 15 may comprise at least one light source and at least one detector for detecting light, the sensor being configured to illuminate at least a portion of a subject's body portion and to detect the amount of reflected light , wherein the sensor is configured for determining a reflectivity of the subject's illuminated body portion at one or more wavelengths. This allows accurate determination of the reflectance of the illuminated body portion, in particular the skin thereof, and thus of determining its coloration, e.g. for determining melanin content, erythema, (ageing) hematoma dryness and/or other conditions. More, different and/or differently arranged types of sensors may also be provided.

Fig. 4 illustrates an embodiment of the method of operating a system for illumination of a body portion 3 of a subject 1. The method comprises in step 31 providing a body illumination system 5 having;

at least one light source 9 for illuminating a target area 6 of the body portion 3, - a user interface 23,

at least one sensor 15 configured for measuring one or more of biophysical and/or biochemical parameters of the subject, and

a processing unit 19.

Said body illumination system 5 being operable according to a plurality of settings.

The method comprises in step 33 arranging the body illumination system with respect to (the target area 6 of) the body portion 3 for operably illuminating the target area 6 by the body illumination system 5 with light from the at least one light source 9 and thus operating the system in a plurality of settings SI, S2.

The method comprises in steps 35 and 37 receiving user input A in particular from the subject, via the user interface 23 with respect to each of the plurality of settings SI, S2 and recording the user input A as a function of the settings SI, S2.

The method comprises in steps 39 and 41 measuring one or more biophysical and/or biochemical parameters B, C of (the target area 6 of) the subject 1 in each of the plurality of settings SI, S2 and recording the measured parameters B, C as a function of the settings SI, S2, concurrent with and/or independent from other input signals A, B, C, respectively.

In any method embodiment, in one or more of settings SI or S2 more than one user input A data point, biophysical and/or biochemical measurements Band/or C data points may be received and recorded, for example, for monitoring and/or indicating a temporal evolution of the respective data.

The method comprises in step 43 determining a further setting S3 of operation of the body illumination system 5 as a function of the recorded user input A and at least one of the recorded measured parameters B, C with respect to the respective settings SI, S2. The method comprises in step 45 changing operation of the system 5 so that the system 5 is subsequently operated according to the third setting S3.

Fig. 5 shows an example of how results of a typical illumination regimen according to the present method and with the present system 5 may look. In a first illumination session a subject suffering from pain, e.g. lower back pain or head ache, operates the system 5 at a particular setting SI and determines a subjective level of his pain, i.e. his perception of the pain at that moment, and enters this level into the body illumination system 5 via the user interface 23 (user input data Al). One or more scales such as the Verbal Rating Scale (VRS) or Visual Analog Scale (VAS) and/or other options may be provided for quantifying the pain perception, for example, graduation systems with a number of continuous or discretely selectable levels, for example, as in a menu-selection, via buttons, a slide bar and/or a dial. Also, one or more biophysical and/or biochemical signals from the subject's body and in particular from the painful body portion and/or the target area, for example, the lower back or in the neck and shoulders, are measured. Said measurements may consist of one or more of the following; skin temperature, skin color, blood oxygenation, muscle tension, electrical conductivity of the tissue, at or near the target area and heart rate at another position of the subject's body (data Bl, CI). The data is recorded in the system together with data indicative of the actual system setting SI, e.g. indicative of a particular spatial illumination intensity distribution. Recorded data may be encrypted and/or otherwise protected against unauthorized access. The resulting dataset dl is recorded. The total pain level P, in particular as determined by the subject's perception, may be plotted, as indicated in Fig. 5. Similarly, for each subsequent session a further dataset d2-d... is recorded.

Fig. 5 indicates that, although behaving at first glance somewhat erratic (long dash) the illumination is in fact successful on average and a circadian pattern in the total pain level P becomes apparent. The body illumination system 5 adapts to the detected pattern and for each subsequent session changes operating settings according to the previous settings and detected long-term pattern.

It is noted that during one session plural data Ai, Bi, Ci and/or settings Si may be recorded at instances i, for example, variations in the biophysical and/or biochemical signals B, C and/or if the subject adjusts a power setting and/or changes his perceived pain level A. This may lead to recording of individual data sets i in one session and possibly performing the method within the session and/or to an overall data set i indicative of the entire illumination session, e.g. an average over the session or a difference in one or more recorded data (A, B, C, S) over the session.

This can easily be shown on a mobile application and may clarify patterns in pain perception and/or physical causes, for example, due to the "body clock" with a circadian temperature rhythm, environmental effects (daytime temperature) etc. This can give feedback to the user about diagnosing pain factors and/or progress in long term pain relief.

The recorded information can be used for automated adjustment of the operation of the body illumination device, by action of the processing unit.

User perception data and feedback can be used to provide and use a "placebo" effect, for example, by reporting data from the system to the user that the device 7 is "on", and receiving and interpreting the user input. In this way, the illumination dose, for example, illumination power and/or pulse lengths can be regularly reduced, eventually leading to a reduction of illumination requirements.

Such optimization may allow a reduction in the long term dependence of a subject on the system. A goal of the optimization may be to facilitate the subject to be independent of the device within a predetermined time period, for example within 6 months, or more preferably within a period of two months. An issue may be that after this initial time period a psychological habit may be formed thus the subject may subconsciously over-apply the body illumination possibly leading to a reduction of efficacy of the body illumination system due to the system having to operate below safety threshold limits of the illumination dose.

A possible way of increasing the effectiveness of the body illumination system in reducing the subject's perceived level of pain may include utilizing a different wavelength for a proportion of the operating time. An example may be that blue light in a range of 400 - 500nm is applied for a proportion of the total time and for the rest of the operating time period red light in a range of 600 - 750 nm may be provided. Another example may be that a pulsed higher intensity illumination is replaced for a proportion of the operating time by a non-pulsed, lower intensity illumination.

This may mean that effectiveness of the illumination may be restored for when the subject next wishes to reduce their perceived level of pain.

Another optimization may be achieved by reducing the time period of the illumination received per day whilst increasing the intensity or pulsing effect of the illumination to provide the same illumination dose. This may allow the subject to predetermine at the start of the illumination procedure how long they wish to utilize the system, for example, one week, 2 weeks, one month etc.

Further, the user feedback (A) linked to the physical measured parameters (B,

C) can be mined, so as to attain optimum system operation- and dosage times, based on a desired result such as weaning the person from the system, or achieving a certain state of relief, or maximizing battery lifetime, etc.

Predictive and/or repetitive illumination settings may be provided, e.g., for ensuring that the physical parameters such as NO-creation occur at the same level over time. For instance, if NO-reduction is observed at the same light dose, i.e. the system is collecting data that indicate that the subject becomes less sensitive to the system, and where the perception of pain is increasing, then it is clear that higher dosages can be automatically given to stop this acclimatization before it spirals out of the range of operation of the system.

By measuring physiological signals related to emotional stress such as heart- rate in the system, an understanding of relations between stress and physiological pain indicators, e.g. NO levels, for the same illumination dose and how this affects perceived levels of pain. Therefore, stress sensing can be used to optimize provided illumination based on creating a link between stress and perceived pain.

It is conceivable that operation according to at least one of the first, second, and in particular the third setting comprises providing one or more suggested settings to the user for operation of the system and operating the system according to a setting selected by a user, possibly including in fact indicating operation according to one setting and providing an illumination intensity pattern corresponding to a different setting.

In an embodiment with a pixelated sensor, results of local measurement data may be provided to the user, and possibly the user may provide individual input for individual portions, e.g. in the form of dividing the target area into individually assessed and or operated pixels. A suitable form of providing and receiving such pixelated data is by projecting an image (schematic, possibly) of the target area on a touch screen or other suitable interface device and allowing the user to select one or more pixels to be considered. For each such pixel or group of pixels, the method disclosed herein may be employed individually so as to provide locally optimized settings.

Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

Various embodiments may be implemented as a program product for use with a computer system, where the program(s) of the program product define functions of the embodiments (including the methods described herein). In one embodiment, the program(s) can be contained on a variety of non-transitory computer-readable storage media, where, as used herein, the expression "non-transitory computer readable storage media" comprises all computer-readable media, with the sole exception being a transitory, propagating signal. In another embodiment, the program(s) can be contained on a variety of transitory computer- readable storage media. Illustrative computer-readable storage media include, but are not limited to: (i) non-writable storage media (e.g., read-only memory systems within a computer such as CD-ROM disks readable by a CD-ROM drive, ROM chips or any type of solid-state non- volatile semiconductor memory) on which information is permanently stored; and (ii) writable storage media (e.g., flash memory, floppy disks within a diskette drive or hard-disk drive or any type of solid-state random-access semiconductor memory) on which alterable information is stored.

Claims

CLAIMS:

1. A body illumination system (5) comprising;

at least one light source (9) configured for illuminating a body portion (3) of a subject (1) with light (L)

- the user input (A), and

- the data measured by the at least one sensor;

- said processing unit adapted for operating the body illumination system in dependence on,

- the received user input (A),

- the received data measured by the said at least one sensor (15).

2. The system (5) according to claim 1, comprising a human wearable device (7) for wearing close to and/or in contact with the body portion (3) and being formed for conforming to a least part of the body portion, comprising the at least one light source (9) and being arranged for illuminating at least part of the body portion with light (L) from the at least one light source.

3. The system (5) according to claim 2, wherein the at least one light source (9) and the at least one sensor (15) are integrated in the wearable device.

4. The system (5) according to any preceding claim, comprising a controller (17) for operating the at least one light source (9) as a function of one or more signals from the processing unit (19) and wherein the processing unit and the controller are provided, at least partly, in different devices (7, 8), in particular being configured for communicating with each other via wireless communication.

5. The system (5) according to any preceding claim, wherein the at least one light source (9) comprises one or more Light Emitting Diodes (LEDs) (11), said one or more Light

Emitting Diodes are individually controllable and/or comprise plural light sources (11) providing light with different wavelength ranges.

6. The system (5) according to any preceding claim, wherein the system comprises one or more devices for manipulating a temperature of the illuminated portion with non-optical means, said means may include one of the following;

a heater,

a chiller.

7. The system (5) according to any proceeding claim, wherein at least one of the at least one light source (9) and the at least one sensor (15) is pixelated.

8. The system (5) according to any preceding claim wherein the user input is a value perceived by the user, said perceived value may be one or more of;

- a perceived temperature of the body,

a perceived pain intensity,

a perceived frequency of pain,

a perceived location of pain,

a perceived area of illumination.

9. A method of operating a body illumination system (5), the method comprising:

receiving user input (A), wherein the user input is a value perceived by a user, wherein the value relates to a psychophysiological measure related to at least a portion of the body receiving the illumination,

- receiving data measured by at least one sensor (15) configured for measuring one or more of biophysical and/or biochemical parameters (B, C) associated with the portion of the body receiving the illumination, and

controlling the body illumination system in dependence on; the received user input (A), and

the received data measured by the at least one sensor (15).

10. The method according to claim 9, wherein the method further comprises;

- during operation of the system (5) according to a first predetermined setting

(SI) and a second predetermined setting (S2),

receiving user input (A), wherein the user input is a value perceived by said user, wherein the value relates to a psychophysiological measure related to at least a portion of the body receiving the illumination,

- receiving data measured by the at least one sensor (15) configured for measuring one or more of biophysical and/or biochemical parameters (B, C);

recording the user input and the measurement data as a function of the first and second settings, and

determining a third setting (S3) for operation of the system as a function of the user input and the data measured by the at least one sensor (15)at the first and second settings; and

changing operation of the system (5) so that the system is operated according to the third setting.

11. The method according to claim 10, wherein the first predetermined setting (SI) comprises a first spatial illumination intensity distribution for illuminating a target area (6) by the at least one light source (9), the second predetermined setting (S2) comprises a second spatial illumination intensity distribution for illuminating the target area (6) by the at least one light source, wherein the second spatial illumination intensity distribution is different from the first spatial illumination intensity distribution in at least one of a spatially- varying, intensity varying, spectrally- varying and a temporally- varying pattern.

12. The method according to claim 10 or 11, wherein the third setting (S3) comprises a third spatial illumination intensity distribution for illuminating the target area (6) by the at least one light source (9), being different from at least one of the first and second spatial illumination intensity distributions in at least one of a spatially- varying intensity varying, spectrally- varying and a temporally- varying pattern.

13. The method according to any one of claims 9-12, wherein at least one of the predetermined first or second settings or third determined setting (SI, S2, S3) comprise a spatial illumination intensity distribution for the illumination provided by the at least one light source (9) and wherein changing operation of the system (5) between operating according to the predetermined first or second settings or third determined setting to another one of the predetermined first or second settings or third determined setting comprises providing one of the predetermined first or second spatial illumination intensity distributions or third determined spatial illumination intensity distribution for the illumination provided by the at least one light source while providing a user indication of operation according to a different one of the first, second or third settings.

14. The method according to any one of claims 9-13, wherein the method comprises recording the measurement data for at least one of the biophysical and/or biochemical parameters (B, C) of the body portion as a function of at least one of;

- the illumination pattern,

the user input (A),

measurement data for a further biophysical and/or biochemical parameter (B,

C),

the setting of the system (5) according to which said system is operated, and - time.

15. The method according to any one of claims 9-14, wherein the method comprises recording the user input (A) as a function of the measurement data for at least one of;

- the biophysical and/or biochemical parameter (B, C) of the body portion (3), the illumination pattern,

the setting of the system (5) according to which said system is operated, and time.