Abstract:
A portable light delivery device for delivering light to the blood supply of a human body through a non-ocular area of skin on the body includes an attachment member, a portable light delivery unit connected to the attachment and a portable power supply. The portable light delivery provides one or more wavelengths of light within a specifically-determined range of intensity and a specifically determined angle of illumination. A portable control unit may be included on the light delivery device for selectively controlling the light delivery unit. A programming device associated with the control unit selectively changes the programming of the controller. The light delivery device is portably secured to a region of the body having a substantial amount of blood vessels near the surface thereof to deliver light to the blood supply of the body for treating mood disorders, seasonal affective disorder and disorders involving circadian rhythm and sleep.

Description:
GOVERNMENT RIGHTS  
       [0001] This invention was made with Government support under Contract Nos. N43-NS82393 and MH61043-01, both awarded by the National Institute of Health. The Government has certain rights in this invention. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    This invention relates to means for delivering light to the blood supply of a human body to treat mood disorders, sleep and body cycle problems in humans. More particularly, the present invention concerns a portable and wearable light source apparatus, and methods related thereto, for delivering light to the blood supply by exposing a non-ocular portion of the body to light in pre-selected wavelengths, for pre-selected periods of time at optimal times of the day.  
           [0004]    2. The Related Art  
           [0005]    Seasonal affective disorder (SAD) is a form of recurrent depressive or bipolar disorder, that seems to occur at times in the year when the natural amount of light decreases, such as in the winter. Symptoms of SAD include hypersomnia, carbohydrate-craving and weight gain, as well as panic disorders and other ailments. In such cases, it has been found to be effective to apply light therapy, that is to introduce the body to artificial light of varying intensities and wavelengths and at different times of the day, in order to increase the amount of light provided to the body. See, e.g. “Winter Depression and Phototherapy,” Gysin F; Gross F Acta Med Port (Portugal) December 1997, 10 (12) p 887-93.  
           [0006]    Other types of non-seasonal, major depressive disorders, such as bulimia, have also been found to respond favorably to the application of various types of artificial light to supplement the natural light to the body of the subject. See, e.g., “Light Therapy in Bulimia Nervosa” Blouin A G et al, Department of Psychiatry, Ottawa Civic Hospital, Ontario, Canada. Psychiatry Res (Ireland) Feb. 28, 1996, 60 (1) p 1-9.  
           [0007]    Humans have an intrinsic body clock that responds to light cues to aid in synchronizing activities to the rising and setting of the sun. This phenomenon is referred to as the circadian cycle or circadian clock and is known to control a variety of physiological processes, including daily fluctuations in body temperature hormone production, and even sleep itself.  
           [0008]    The circadian cycle may become disoriented or confused, so that sleep-related disorders develop. For example, a person traveling through various time zones often has difficulty acclimating the circadian cycle to a new time zone that may be hours different than the previous time zone. This problem is commonly referred to as “jet lag” and usually is resolved in a few days. Other sleep-related disorders may be more chronic and very difficult to cure or overcome.  
           [0009]    In such sleep disorder cases, it has also been determined that light therapy can be quite effective in helping the circadian cycle to adapt. In particular, research has indicated that light can be provided not only to the retina but to extraocular portions of the body to create a circadian response. U.S. Pat. No. 6,135,117 (Campbell et al.) discloses methods for providing non-ocular light to the body to treat circadian rhythm problems and various sleep disorders. Campbell indicates that the delivery of extraocular light stimulus to certain regions, such as the popliteal region, can mediate and shift the phase of a circadian cycle. U.S. Pat. No. 6,164,787 (Seki) discloses an apparatus positioned beneath an airplane seat for administering light to the popliteal region to affect the circadian cycle during extended flights.  
           [0010]    In the Campbell et al. patent light was delivered using large fiber-optic light pads designed to treat jaundice in newborns. These pads were attached to a bulky power supply. In the Seki patent, light was administered by fixed apparatus disposed beneath the airplane seat connected to a halogen lamp in a vented metal housing having a fan attached thereto. Neither system lends itself to portability.  
           [0011]    Seasonal affective disorders (SAD) and other mood disorders, as well as circadian disorders and other sleep problems, require periodic timed treatment given at precise times over a period of several days or weeks. During and between treatment times, the subject needs to be free to move about and take care of normal activities. In particular, the treatment of circadian problems presupposes that the subject is treated before, during or after sleep and/or travel.  
           [0012]    Accordingly, it is important that the treating device be easily portable and, optionally, wearable so that the subject is able to carry out normal activities during treatment. Moreover, the nature of the treatment requires that a power supply be included which must also be portable and wearable. In addition, the time intervals and intensity of treatment may vary widely, depending on the subject and the type and severity of disorder. Accordingly, a portable control device may also be needed for effective treatment. A wearable unit may be useful for providing periodic treatment of varying times and intensities while not causing substantial discomfort or interfering with the mobility of the subject.  
           [0013]    It has also been determined that some wavelengths of light are more effective in treating certain disorders than others. Thus, treatment using light with a single wavelength or a plurality of wavelengths within a fairly small range is often preferred. Accordingly, a means for light delivery is needed that can provide monochromatic light focused on the desired light wavelength or range of light wavelengths needed to treat a particular disorder.  
         SUMMARY OF THE INVENTION  
         [0014]    The present invention involves providing light to areas of the body where there are substantial blood vessels near the surface of the skin, so that the light can interact with photoactive substances in the blood to correct various problems. An effective area for the administration of light has been found to be the popliteal region, the area directly behind the knee joint, because there are many blood vessels close to the surface of the skin. Other effective regions for contacting blood vessels are the chest, neck, arm and abdominal area.  
           [0015]    The present invention comprises novel apparatus and methods for delivering light to regions of the body having substantial blood vessels near the surface of the skin. The apparatus is a portable, wearable device having a light source and a battery pack. The light source is a plurality of light emitting diodes (LEDs) capable of emitting light having a single wavelength or range of wavelengths within a desired wavelength range. A controller may be included to activate the light source for pre-selected times and durations.  
           [0016]    In one embodiment, a portable light-emitting device is provided for delivering light to the blood supply of a human body through an exposed non-ocular area of skin on the body. The device includes an attachment for wearing the device on a portion of the human body. A portable light delivery unit is connected to the attachment for providing light to the blood supply through the skin of the portion of the human body. A portable power supply is connected to the light emitting device for powering the light-emitting unit.  
           [0017]    In another embodiment, the portable light delivery unit is an LED array having a single wavelength or range of wavelengths. The LED array is also preferably selected to deliver light within a predetermined circular angle over a specific portion of the skin of the human body.  
           [0018]    In another embodiment of the present invention, a portable controller is associated with the light delivery unit to control the times and durations of light delivery to the blood supply of the human body. The controller is also preferably programmable to vary the light delivery to the body. A portable programming device is preferably also attached to the controller to change the programming in the controller.  
           [0019]    In another embodiment of the present invention, the portable light delivery unit includes a plurality of small light strips, each strip having a plurality of LEDs thereon for delivering light through the skin to the blood supply of the body. Preferably, the LEDs of each strip are electrically connected together to coordinate the light delivery to the body.  
           [0020]    In another embodiment, a method is provided for delivering light to the blood supply of a human body through an exposed non-ocular area of skin on the body. The method includes attaching a portable light delivery unit to a portion of the human body, providing light to the blood supply through the skin of the portion of the human body by means of the portable light delivery unit, and providing power to the portable light delivery unit by means of a portable power supply connected to the portable light delivery unit. The method includes delivery of the light by means of a portable LED array.  
           [0021]    Another method of the present invention involves delivery of light to a portion of the body having a substantial amount of blood vessels near the surface of the skin, such as the popliteal area of the knee or the abdominal area of the body. The method may include selection of the angle at which the light is provided to the exposed area of the skin and/or the intensity of the light provided to the exposed area of the skin. The method may further involve controlling the timing and duration of the light delivery to the exposed area of skin. The methods of the present invention may be used to treat various bodily problems, including seasonal affective disorders, depression and mood disorders, circadian rhythm problems and various types of sleep disorders.  
           [0022]    Accordingly, the present invention has many features, including providing a portable light delivery system using a monochromatic LED array. This system of the present invention has the advantages of delivering desirable wavelengths and intensities of light, wearability because the unit is portable and compact, battery-powered which assists in portability, low heat output adding to comfort of use, and long life. The LED unit may be flexible to conform to the shape of the body part, so as to enhance the wearability of the device.  
           [0023]    Moreover, the portability and wearability of the device of the present invention enables applying light to areas that have many blood vessels near the surface of the skin, such as the backside of the knee, where there is optimal contact with the bloodstream to receive the light rays. These advantages and improvements and others will be shown by reference to the following detailed description of preferred embodiments of the invention with reference to the attached drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    [0024]FIG. 1 is a perspective, schematic view of one embodiment of the light delivery apparatus of the present invention;  
         [0025]    [0025]FIG. 2 is a block diagram of the components of the light delivery apparatus of FIG. 1.  
         [0026]    [0026]FIGS. 3 and 4 are schematic views showing different angles of illumination for LED arrays according to preferred embodiments of the present invention;  
         [0027]    [0027]FIG. 5 is a schematic view showing an embodiment having padding around the LED array of the present invention;  
         [0028]    [0028]FIG. 6 is a schematic view showing an embodiment having waterproof sealing around the LED array of the present invention;  
         [0029]    [0029]FIGS. 7 and 8 are schematic views showing another embodiment of the light pad for the light delivery apparatus of the present invention;  
         [0030]    [0030]FIG. 9 is a block diagram showing an embodiment of the controller shown in FIG. 1; and  
         [0031]    [0031]FIG. 10 is a block diagram showing an alternate embodiment of the controller shown in FIG. 1. 
     
    
     DETAILED DESCRIPTION  
       [0032]    The novel light delivery apparatus of the present invention has a number of features and advantages, including a light delivery apparatus that is portable, wearable, programmable and has the capability of delivering light energy at wavelengths within a preselected wavelength range and at or above a preselected light intensity. It is important that the device be portable and wearable for the reasons previously stated—namely that the subject needs treatment over an extended period for multiple time periods and preferably while the subject is mobile and able to accomplish necessary tasks. The wearability of the apparatus is also enhanced by the use of thin substrates connected together to form a flexible light treatment apparatus.  
         [0033]    Wearability is particularly important in delivering light to the popliteal region or other suitable regions of the body, since the patient is likely to be mobile and involved in numerous activities. In addition, light is intended to be delivered to the subject at certain pre-selected periods during sleep or daily activities, so it may be securable to the body. In addition, the light delivery apparatus may be comfortable and non-obtrusive to allow the subject to sleep and move comfortably during treatment.  
         [0034]    In some instances, it may be important that the light delivery device be programmable, so that the subject can receive treatment while asleep or while preoccupied with other matters. Obviously, one cannot expect the subject to be awakened for treatment when a critical element of that treatment involves administering light during a specific period of the sleep cycle.  
         [0035]    The Apparatus  
         [0036]    Referring now to FIGS. 1 and 2, one embodiment of the light treatment apparatus of the present invention is shown generally at  10 . The apparatus includes a battery pack  12 , a controller  14 , and a light pad  16 . Light treatment apparatus  10  may be secured to the subject&#39;s leg just above and/or below the knee  18  and, more particularly, with light pad  16  in juxtaposition to the popliteal region  20 . Alternately, the light pad may be applied to other body regions discussed earlier where numerous blood vessels are near the surface of the skin.  
         [0037]    A strap  22  having strap ends  22   a  and  22   b  with VELCRO pads  24   a  and  24   b  or other attachment or connection elements thereon may be used to adjustably and releasably mount light treatment apparatus  10  to knee  18  with light pad  16  placed against popliteal region  20 . Alternatively, a light treatment apparatus  10  according to the present invention may include a single-piece strap, which may be expandable and/or contractible (e.g., elastic).  
         [0038]    Battery pack  12  is preferably any suitable conventional battery pack having sufficient electrical energy storage capacity to support illumination of light pad  16  for the treatment times selected on controller  14 . A wire  26 , which may be embedded in strap  22 , otherwise carried thereby, or separate from strap  22 , delivers this electrical energy from battery pack  12  to light pad  16 . In the present embodiment, battery pack  12  is shown separate from light pad  16 , although both elements could be integrated into a single structural unit and provide the same benefits.  
         [0039]    In the present embodiment, with the battery pack  12  and light pad  16  as separate elements, controller  14  is mounted on the battery pack  12  (as shown) so that it is readily accessible to the operator while the light pad  16  is in position on the popliteal region  20  behind knee  18 . The separation of battery pack  12  and light pad  16  is also advantageous, in that only the light pad  16  needs to be positioned behind the knee for extended light delivery treatment (up to three hours), particularly during sleep times. Therefore, the bulk behind the knee is minimized and the comfort of the subject is enhanced.  
         [0040]    In one embodiment, controller  14  is a conventional device that activates the light pad  16  at a given intensity for as long as it is turned on by connecting the battery  12  or by a simple on-off switch. Another embodiment of the controller, discussed later, includes a conventional programming device (not shown), such as input keys, to provide the desired program for the controller to follow. Alternately, the programming device may be separated from the light delivery apparatus to minimize the weight and bulk to be carried by the patient. In such case, the programmer could be a separate device that would only be attached at certain rest periods so as change the programming of the controller, as desired.  
         [0041]    In another embodiment, the controller may be replaced by an on-off switch or entirely omitted from the system, so that the light pad  16  is operational for as long as it is engaged with the battery pack  12 . In this usage, the subject follows a program of his own choosing or as prescribed by a professional to apply light to the desired area.  
         [0042]    Light pad  16  is shown having a recess  25  with a plurality of LEDs  30  mounted therein. The depth of recess  25  is coordinated with the height of LEDs  30 , so that the upper ends of LEDs  30  are essentially flush with or slightly recessed relative to the upper surface of light pad  16 . In this manner, light pad  16  and more particularly LEDs  30  are all placed in direct contact with popliteal region  20 . Since none of the LEDs  30  extends above the upper surface of light pad  16 , no undue pressure points are provided that could otherwise interfere with the circulatory integrity and comfort of popliteal region  20 .  
         [0043]    [0043]FIGS. 3 and 4 show different preferred embodiments using LEDs with different angles of illumination. In FIG. 3, an array of LEDs  32  provides an angle of illumination of about 30°, considered a relatively broad diffusion of light. Using this type of LED array, the light delivery will be more diffuse to cover a greater area, but is not likely to have as much intensity as more focused light delivery. The light delivery system is likely to function better where there are an abundance of blood vessels relatively close to the surface of the skin. In that situation it would be advantageous to deliver light to a broad area with less need for light penetration.  
         [0044]    Conversely, in FIG. 4, an array of LEDs  34  provide an angle of illumination of about 15°. This approach results in greater intensity and less diffusion of the light delivery system. Thus, this type of LED is most effective where there are not as many blood vessels near the surface of the skin, and greater light penetration is needed.  
         [0045]    In one example, 15° LEDs  34  shown in FIG. 4 were used driven by a current of about 20 milliamps. The LEDs  34  each provided monochromatic light having a wavelength of about 465 nanometers and an intensity of about three milliwatts per square centimeter at a temperature of about 104° Fahrenheit. This provided more heat than acceptable to be worn for any extended period. Accordingly, the forward current was reduced to about five milliamps. The resulting intensity was reduced to about two milliwatts per square centimeter at a temperature of about 93° Fahrenheit, which provided acceptable penetration and comfort level.  
         [0046]    In a second example, 30° LEDs  32  shown in FIG. 3 were used having monochromatic light at a wavelength of about 465 nanometers. Again the forward voltage provided a current of about 20 milliamps. The resulting intensity was about three milliwatts per square centimeter at a temperature of about 103° Fahrenheit. Again, this heat was beyond the comfort zone. The forward current was reduced to about 10 milliamps. The resulting intensity was about two milliwatts per square centimeter at a temperature of about 94° Fahrenheit, which provided acceptable penetration and comfort level. This adjustment brought the temperature down to a comfortable level for the wearer.  
         [0047]    For light delivery to the popliteal region, the 30° LEDs  32  were found to be preferable because they covered a greater area with the same intensity and about the same temperature. In delivering light to other non-ocular regions, the 15° LEDs  34  may be more suitable, because of the possibility of greater light penetration.  
         [0048]    Another advantage of using an LED array is that a specific light frequency and wavelength can be selected that is advantageous for each application. In the present preferred embodiment for delivering light to the popliteal region, it was found that light having a wavelength of about 490 nanometers was effective in shifting circadian cycles. In applying light to the popliteal region for the treatment of seasonal affective disorder and mood disorders, light having a wavelength of about 474 nanometers was found to be effective. In treating jaundice, light having a wavelength of about 460 nanometers was found to be effective. All wavelengths mentioned above include a wavelength range of plus or minus fifteen percent (15%).  
         [0049]    Referring now to FIG. 5, padding  40  is shown secured around LED array  42 . The padding  40  extends around the periphery of the array  42 . Preferably the padding  40  also extends over the surface of LED array  42 , with openings  46  to enable the LEDs  42  to direct light to the skin surface.  
         [0050]    [0050]FIG. 6 shows an embodiment of the light delivery apparatus of the present invention, in which the LED array is completely encapsulated in a waterproof material  52 . This waterproof material may be of any suitable material, such as plastic, and is likely to be thicker for light delivery to the popliteal region at the back of the knee than for devices where light delivery is provided to some other regions of the body.  
         [0051]    The portable battery  12  may be of any suitable size and power. The size may be minimized to enhance portability, while still being large enough to delivery the necessary power for the LED array. In the present invention, conventional nickel cadmium rechargeable battery units having an output of about 12 volts and a capacity of either about 300 milliamps*hours or about 700 milliamps*hours may be used, depending on the desired results.  
         [0052]    Referring now to FIGS. 7 and 8, an alternate embodiment is shown for the light pad  16  shown in FIG. 1 for the light delivery system of the present invention. As shown in FIG. 7, each of a plurality of light strips  62  has several LED units  64  spaced from each other in a row on each strip. The LED units  64  on each strip  62  are electrically connected together. Wires  66  connect the LED units  64  of each strip  62  to the LED units  64  of the adjoining strips. Strips  62  are preferably made of suitable short and narrow strips of substrate material, such as a fabric, plastic, rubber, or foam rubber material, so that the pad can easily bend to conform to the surface of the body portion, such as the underside of the knee, the neck or other suitable body part.  
         [0053]    [0053]FIG. 8 shows the back side of a pad  68  with the strips  62  mounted therein. Preferably, spaced-apart cavities  70  are formed in the pad  68  and sized to accept the strips  62 . The cavities include holes on the front side (not shown) for the LED units  64  to direct light out of the front of the pad, similar to the padding  40  around LED array  42 , shown in FIG. 5.  
         [0054]    With reference now to FIG. 9, the components of one preferred embodiment of a system  80  according to the present invention are shown. In this embodiment, system  80  includes a microcontroller unit  82  connected to programming devices, such as keypad  84  and display  86 , which may be used to control and communicate with microcontroller  82  which, in turn, operates LED pad  89  in a desired manner. Selected data are periodically input via keypad  84  to program microcontroller  82  in the operation of LED pad  89 .  
         [0055]    An alternative system  90  is shown in FIG. 10, in which the programming function is provided by a microcontroller  92  that is separate from a second microcontroller  93  that operates the LED light pad  99 . As shown, the programming devices, keypad  94  and display  96  are connected to a microcontroller  92  that is separate from the LED pad  99  and battery  98 , in order to reduce the bulk of the light delivery device worn by the subject. Microcontroller  92  may, for example, be linked to a second microcontroller  93  via a data cable  95  and socket and plug link  97 . Microcontroller  93  receives the programming via data cable  95  and operates the LED pad  99  accordingly.  
         [0056]    In this embodiment, the microcontroller  92 , keypad  94  and display  96  do not have to be portable, so the size and weight of the portable device worn by the subject are minimized. Instead, microcontroller  92  may be connected periodically to the microcontroller  93  at any convenient time, such as during bedtime, to input new programming. Microcontrollers  82 ,  92  and  93  are conventional microcontrollers that can be readily obtained in the industry. One example is microcontroller, model number PIC 16F873, made by Microchip Technology in Chandler, Ariz.  
         [0057]    Operation of the Apparatus  
         [0058]    An example of the operation of the embodiment of the present invention shown in FIG. 2 is as follows. The light treatment apparatus  10  is positioned so that light pad  16  is placed against popliteal region  20  in a manner that LEDs  30  deliver light directly against the tissue of popliteal region  20 . Battery pack  12  with controller  14  mounted thereon, as well as light pad  16 , are secured to the knee  18  by strap  22 . Strap ends  22   a  and  22   b  are secured together by joining Velcro piece  24   a  to Velcro piece  24   b.    
         [0059]    Apparatus  10  is used by simply activating the controller  14  with power from the battery pack  12 , which in turn enables the light pad  16  to provide light to the subject as long as the system is operational. Alternately, if the controller  14  is not present, the subject activates the light pad  16  by simply connecting it to the battery pack  12  for the prescribed periods of time. The entire system is portable and is worn by the subject who can go about his or her activities during the time that light is applied to the blood supply of the subject. The subject may be instructed to wear the unit for selected times over one or more days to achieve the desired result.  
         [0060]    Similarly, the embodiment shown in FIG. 9 which is entirely portable and wearable by the subject including a microcontroller  82  that may be programmed at will by keypad  84  and display  86  to activate the LED pad  89 . Alternately, as shown in FIG. 10, the microcontroller  92 , key pad  94  and display  96  may be left in the subject&#39;s room or elsewhere for periodically updating the portable microcontroller  93 . Data cable  95  may also include battery wires (not shown) for recharging battery  98  at the same time that microcontroller  93  is receiving new programming.  
         [0061]    In one example of operation, keypad  84  and display  86  may be used to set the current time in microcontroller  82 . The same input means may also be used to provide microcontroller  82  with the time that the LED pad  89  is to be turned off and the duration of time the LED pad  89  should remain on. Several such cycles of on and off time can also be input to microcontroller  82 .  
         [0062]    With the system  90  shown in FIG. 10, the same data may be input to microcontroller  92 , which then calculates the appropriate on and off times. This information is then fed to microcontroller  93  at a convenient time so that microcontroller  93  can operate the on and off time of LED pad  99  accordingly.  
         [0063]    One example of a light delivery treatment schedule for a flight from New York City to Paris is as follows: (1) the day before travel, light is provided from 5:00 am to 6:00 am New York City time; (2) on the day of travel, light is provided from 3:00 am to 4:00 am New York City time; and (3) on the first day in Paris, light is provided from 8:00 am to 9:00 am Paris time.  
         [0064]    As a further embodiment of the present invention, microcontroller  82  or the combination of microcontrollers  92  and  93  may be programmed to process the corresponding LED light pads through duty cycles, in which the light pads are switched repeatedly on and off. Such duty cycles may have any combination of on and off times and may be set to operate at low frequencies or at higher frequencies of hundreds or thousands of cycles per second. This duty cycle operation enables the use of light of higher intensity than would ordinary be used without causing the buildup of heat that would be uncomfortable to the wearer. The use of more intense light enables deeper penetration of light to the body so that more effective treatment may be achieved in certain cases where greater light intensity is needed.  
         [0065]    For instance, in the preceding example, if a higher intensity of light is desired to achieve deeper penetration, one may apply the more intense light in a duty cycle with equal on and off times, so that the light is effectively applied to the body only half of the time that the light pad is turned on. The periods during which the light is applied may be the same as in the above example, namely, one hour the day before travel, on hour during the day of travel and one hour the day after travel, each at the indicated times. In this application, since the light intensity has been substantially increased the use of a duty cycle lessens the total application of light so that there is no uncomfortable heat buildup. However, the reduction in the amount of light applied is compensated for by the increased intensity of light, enabling the desired treatment through deeper penetration.  
         [0066]    Although the above embodiments are representative of the present invention, other embodiments will be apparent to those skilled in the art from a consideration of this specification and the appended claims, or from a practice of the embodiments of the disclosed invention. It is intended that the specification and embodiments therein be considered as exemplary only, with the present invention being defined by the claims and their equivalents.