Abstract:
A stress management device is formed in an integrated design that enables pulse measurement, display of results and a power supply gathered into a small finger clip device. The stress management device includes a non-invasive infrared sensor that identifies and measures pulse rate variability and utilizes that information to calculate the power spectrum distribution and create a curve of the results multiple times per second. The device incorporates a display screen on which a graphic image of a pair of lungs filling and emptying to encourage the user into a predetermined breathing pattern known to reduce stress levels during a training period. After the completion of the training period, the device presents a score reflecting the percentage of times the user achieved high, medium and low relaxation states, and a pie chart reflecting the distribution of the states of relaxation calculated during the training period.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to the management of stress through the inducement of relaxation and, more specifically, to an apparatus and a method of using that apparatus to guide the respiratory rate of the user of the apparatus to achieve a state of relaxation. 
     BACKGROUND OF THE INVENTION 
     Being subjected to stress has been shown to cause adverse mental and physical results in people. As a result, people have been trying to develop new methods and practices that will relieve stress and, as a consequence, induce a state of relaxation. Various stress-relieving practices have been developed over the years, from yoga techniques, to devices that massage various areas of the body, and to electronic devices that intend to control the breathing patterns of a user of the device, and thus indirectly revise the user&#39;s heart rate, to create a state of peaceful relaxation. Such electronic devices have been marketed under the brand names of emWave® Coherence Systems, emWave® Personal Stress Reliever and StressEraser® biofeedback system. 
     It has been found that the human body can achieve a state of relaxation by utilizing controlled breathing techniques, such as slow, steady and deep breathing, which in turn, slows and stabilizes the heart rate and induces a state of relaxation. One commonly utilized breathing rate for achieving relaxation has been six breathes per minute accomplished in a steady rhythm. However, breathing at the rate of six breaths per minute is not a normal breathing rate for many people. As a result, most people need to be trained and guided into such a breathing pattern. 
     The stationary condition of breathing and the trend of heart rate variation reflect the status of interaction between the sympathetic and parasympathetic neural system in the human body. When heart rate variation becomes regular and synchronized with the breathing rhythm, it is considered that the neural system tends to be in harmony with the body and mind, which means that the physical body becomes more effective, emotions are stabilized, and the mind is peaceful and perceptive, which is referred to as a highly physiological relaxed state. On the contrary, stressful emotions including anger, disappointment, and anxiety make the heart rate variation irregular and incoherent with breathing. In such cases, a stress management device can be utilized to guide the user to conduct slow and deep breaths, thus helping the user to focus his/her attention to enter into a relaxed state with body and mind harmony. 
     U.S. Pat. No. 6,358,201, issued on Mar. 19, 2002, to Doc L. Childre, et al, discloses a method of determining the state of entrainment between biological systems which undergo rhythmic functions, such as a breathing and heart rates, by determining a heart rate variability, and an apparatus for monitoring the heart beat of a user for application of that method. This Childre patent defines formulas to calculate a parameter of the frequency distribution and then outputs that parameter on the display of the apparatus to assist the user in attaining relaxation. Several divisional patents have also been granted from this U.S. Pat. No. 6,358,201, including U.S. Pat. No. 7,117,032, granted on Oct. 3, 2006; U.S. Pat. No. 7,163,512, granted on Jan. 16, 2007; and U.S. Pat. No. 7,462,151, granted on Dec. 9, 2008. 
     In U.S. Pat. No. 7,117,032, the apparatus defines one or more optimal breathing patterns for the user and then provides feedback to the user to reflect how closely the actual breathing pattern of the user matches the optimal breathing pattern defined by the apparatus. U.S. Pat. No. 7,163,512 defines the manner in which psychological coherence is indicated by the power spectrum distribution having a peak above a predetermined amplitude with the heart rate achieving a sine wave pattern, while U.S. Pat. No. 7,462,151 defines the indication of psychological coherence as when the power spectrum distribution is above a predetermined amplitude with total energy being above and below the peak, thus defining different aspects of the method of facilitating physiological coherence utilizing respiration training and autonomic balance. 
     An apparatus utilizing a method of presenting audible and visual cues to synchronize a user&#39;s breathing cycle with an external timing reference to synchronize heart rate variability with the user&#39;s breathing cycle is disclosed in U.S. Pat. No. 7,255,672, granted to Stephen B. Elliott on Aug. 14, 2007, and in U.S. Pat. No. 7,497,821, granted to Stephen B. Elliott on Mar. 3, 2009. A similar method and system for consciously synchronizing the breathing cycle with the natural heart rate cycle is disclosed in U.S. Pat. No. 7,713,212, issued to Stephen B. Elliott on May 11, 2010. 
     It would be desirable to provide a compact apparatus that can be mounted on the user&#39;s finger to measure heart rate, and sense breathing patterns, then display animation to guide the user into a breathing pattern that will induce a state of relaxation in the user. It would also be desirable that this apparatus evaluate the status of relaxation in the user and provide a respiratory feedback control to guide the user into the desired respiratory rate for achieving a state of relaxation. It would further be desirable to provide motivation to the user to continue utilizing the respiratory pattern for achieving a state of relaxation by providing the user with a visual display of the user&#39;s efforts in reaching a state of relaxation, as well as a score reflecting the success of the user&#39;s efforts. 
     SUMMARY OF THE INVENTION 
     It is an object of this invention to overcome the disadvantages of the prior art by providing a stress management device that is operable to measure stress through sensing pulse rates. 
     It is another object of this invention to provide a stress management apparatus that is housed within a casing having the general appearance of a pulse oximeter that mounts on the fingertip of the user. 
     It is still another object of this invention to provide a stress management device that measures the user&#39;s pulse via use of a non-invasive infrared sensor. 
     It is a feature of this invention that the stress management apparatus can be positioned on the end of a finger of the user to detect stress levels through measurements of the user&#39;s pulse rate. 
     It is another feature of this invention that the stress level of the user can be calculated from the heart rate variability in the user&#39;s pulse rate, as detected through the infrared sensor. 
     It is an advantage of this invention that the stress management device is compact and can be carried easily on the person of the user for utilization as desired. 
     It is another advantage of this invention that the stress management apparatus incorporates a training procedure to conform the breathing pattern of the user into a low stress breathing pattern. 
     It is still another feature of this invention that the stress level of the user can be reduced through utilization of the stress management device and conforming to the training protocol provided by the stress management device. 
     It is still another object of this invention to provide an algorithm to measure the stress level of the user and then to provide feedback via a display screen on the stress management device to allow the user an opportunity to recognize stress levels and to adopt a breathing pattern that will reduce stress levels. 
     It is still another feature of this invention that the results of the stress measurement algorithm are displayed to the user at the end of the training period to provide feedback to the user as to the effectiveness of the efforts to reduce stress levels. 
     It is still another advantage of this invention that the results of the stress measurement algorithm are displayed in a pie chart reflecting the calculations of low, medium and high stress levels, as measured through the repeated application of the algorithm. 
     It is yet another feature of this invention that the stress management device provides a graphic to aid the user in establishing a breathing pattern that will lower the user&#39;s stress level. 
     It is yet another advantage of this invention that the graphic image displayed to the user is a diagram of a pair of lungs filling and emptying to urge the inhalation and exhalation of the user into a stress reducing breathing pattern. 
     It is a further feature of this invention to provide an integrated design for a stress management device that enables the measurement, display and power supply all gathered in a small finger clip device. 
     It is a further advantage of this invention to manage the respiration biofeedback of the stress management device by using animation to guide and display the user&#39;s current relaxation status. 
     It is yet a further advantage of this invention to provide a scoring method corresponding to the percentages of high, medium and low stress level scores calculated during the training period to encourage continued use of the stress relaxation techniques promoted by the stress management apparatus. 
     It is a further object of this invention to provide a stress management apparatus that is provided in a small, compact housing to promote a reduction of stress levels of the user through suggested breathing techniques resulting in scores to encourage stress reduction that is durable in construction, carefree of maintenance, and simple and effective in use. 
     These and other objects, features and advantages are accomplished according to the instant invention by providing a stress management device having an integrated design that enables pulse measurement, display of results and a power supply gathered into a small finger clip device. The stress management device includes an infrared sensor that identifies and measures pulse rate variability and utilizes that information to calculate the power spectrum distribution. The device incorporates a display screen on which a graphic image of a pair of lungs filling and emptying to encourage the user into a predetermined breathing pattern known to reduce stress levels during a training period. After the completion of the training period, the device presents a score reflecting the percentage of times the user achieved high, medium and low relaxation states, and a pie chart reflecting the distribution of the states of relaxation calculated during the training period. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows, in conjunction with the accompanying sheets of drawings. It is to be expressly understood, however, that the drawings are for illustrative purposes and are not to be construed as defining the limits of the invention. 
         FIG. 1  is a schematic perspective view of a stress management device incorporating the principles of the instant invention; 
         FIG. 2  is another schematic perspective view of the stress management device shown in  FIG. 1  to show the opening in which the finger of the user is inserted to enable a reading and measurement of the pulse rate variability of the user; 
         FIG. 3  is another schematic perspective view of the stress management device of  FIGS. 1 and 2  to depict the application of the device onto a finger of the user; 
         FIG. 4  is a schematic diagram of the display screen depicting the graphic images utilized to encourage the user into a suggested predetermined breathing pattern known to reduce stress levels; 
         FIGS. 4A through 4E  reflect the animated graphic image for encouraging the user into the predetermined breathing pattern; 
         FIG. 5  is a logic flow diagram reflecting the algorithm for calculating the relaxation status of the user during the training period; 
         FIG. 6  is a representative graph of the heart rate variability curve measured through the infrared sensor in the upper portion of the device housing; 
         FIG. 7  is a representative graph of the power spectrum distribution developed from the heart rate variability graph; and 
         FIG. 8  is a schematic diagram of the display screen depicting the pie chart showing a representative distribution of the high, medium and low relaxation states of the user, along with an effort index score calculated from the percentages of the respective relaxation states. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1-3 , a stress management device, incorporating the principles of the instant invention, can best be seen. This stress management device  10  combines breath guiding and heart rate variability biofeedback technology, by analyzing the signal detected from a non-invasive sensor  17  positioned on the finger to extract heart rate variability information and identify the coherence between heart rate variability and respiratory rhythm. In this manner, the device  10  can, therefore, monitor the status and degree of relaxation of the user. The stress management device  10  can be used to guide the user to breathe by an intuitive graphic display, and to help the user to focus his/her attention, as well as adjust his/her emotion actively, aiding the user to enter into a highly relaxed state of body and mind. 
     The stress management device  10  includes a housing  12  that is formed similarly to a pulse oximeter, a device that is mounted on a user&#39;s fingertip to determine the pulse rate and oxygen content of the user&#39;s blood, such that there is an upper member  13  on which the display screen  15  is located and a lower member  14  pivotally hinged to the upper member  13  at the pivot  13   a  so that a user&#39;s finger F can be positioned within an opening  16  between the upper and lower members  13 ,  14 . A multifunction button  18  is provided on the upper member  13  to allow a selection of a menu function, as will be described in greater detail below. A non-invasive photoelectric sensor, such as an infrared sensor  17  located in the upper and lower members  13 ,  14 , detects the heart rate of the user through the user&#39;s fingernail N, in a similar manner as is accomplished through a pulse oximeter. Preferably, the infrared sensor  17  operates at a frequency of about one hundred times per second to identify and record the time interval between heart beats, as well as heart rate variability (HRV), which is re-sampled at a frequency of four times per second and corresponds to the time interval between the respective beats of the user&#39;s heart. The stress management device  10  then transforms the heart rate variability curve, such as is representatively depicted in  FIG. 6 , by utilizing the known process of the Fast Fourier Transform (FFT) algorithm to obtain a power spectrum distribution (PSD) curve  20 , as is shown in  FIG. 7 . 
     As is reflected in the logic flow diagram in  FIG. 5 , the PSD diagram  20  is then utilized by the processor  19  within the device  10  at step  31  to determine if the PSD curve  20  has a PSD peak  22  having a frequency falling between 0.04 and 0.4 cycles per second (Hz). If the PSD peak  22  is not in the designated range, the user is deemed to be in a low relaxed status at step  37 . If the PSD peak  22  is within the designated range of 0.04 to 0.4 Hz, the processor  19  next checks at step  32  the PSD value reading from the PSD curve  20  at zero (0) Hz and compares the zero Hz PSD value reading to the PSD peak  22  reading divided by the number 4. If the PSD value reading at zero Hz is greater than 25% of the PSD peak  22 , the user is deemed to be in a low relaxed status  37 . 
     If the value of the zero Hz PSD value reading is less than the PSD peak  22  reading divided by 4, then the processor  19  calculates at step  33  the area beneath the PSD curve between the 0.04 and 0.4 cycles per second (Hz) boundaries, referred to as PSDsum. Then at step  34 , the processor  19  calculates a ratio of the PSD peak  22  reading to PSDsum less the PSD peak  22  reading. At step  35 , if that ratio calculation is less than 1.0, the user is deemed to be in a low relaxed status  37 . At step  36 , if the calculated ratio is greater than 2.0, the user is deemed to be in a high relaxed status  39 , but if the calculated ratio is greater than 1.0, but less than 2.0, then the user is deemed to be in medium relaxed status  38 . When the user is deemed to be in a medium relaxed status  38  or a high relaxed status  39 , the respiration rate of the user can be calculated as being 60 times the frequency at the PSD peak  22 . 
     The average heart rate for normal people is considered to be at 72 beats per minute, which corresponds to 0.833 seconds (or 833 milliseconds) between heart beats. Further, most people have a variation in their heart rate corresponding to respiration. The heart rate for most people increases when inhaling and decreases when exhaling. This variation in the heart rate corresponding to respiration typically averages in the range of 50-60 milliseconds for adults, and about 20-25 milliseconds for elderly people. Some studies have shown that there can be as much as 10% variability in the heart rate for a normal adult person. This variability in the heart rate is typically referred to by the acronym HRV and is reflected in  FIG. 6 . Accordingly, the sampling of the heart rate at four times per second by the stress management device  10  can result in the identification of when the user is inhaling and exhaling. 
     As noted above, maintaining a respiratory rate in the range of 5 to 10 breaths per minute, and specifically at 6 breaths per minute can result in a continuation of a high relaxed state. Accordingly, the stress management device  10  provides animation on the display screen  15  to help guide the user into a respiratory pattern that will help the user maintain a high relaxed status. As is depicted in  FIG. 4 , the display screen  15  can show an animated device  25 , such as a graphic of a pair of lungs filling up and emptying at an interval corresponding to the preferred respiratory rate, such as at 6 breaths per minute with five seconds devoted to inhaling and five seconds devoted to exhaling, as is represented in  FIGS. 4A through 4E . By attuning the user&#39;s respiratory pattern to the animation device  25 , the user can achieve high relaxed status  39 . The animated device  25  is displayed on the display screen  15  during the training period during which the user is urged to breathe in the pattern suggested by the animated device  25 . 
     After the training period provided by the stress management device  10 , during which the processor  19  makes evaluations taken from the pulse readings twelve times each minute, the processor  19  makes a statistical evaluation of the fractions of high, medium and low related status corresponding to the determinations of low, medium and high relaxed status evaluations from the algorithm reflected in  FIG. 5 , and then derives an effort index score for the user from the fractions of high, medium and low relaxed status determinations. The computation of the effort index score  26 , as depicted in  FIG. 8 , being equal to the fraction of the high relaxed status readings multiplied by 4 added to the fraction of the medium relaxed status readings multiplied by 3 and to the fraction of the low relaxed status readings multiplied by zero, the sum of which is divided by 4 and then multiplied by 100, with the total of the fractions of the high, medium and low relaxed status readings equaling 1.0. This score is then presented to the user on the display screen  15  as a motivation to achieve a greater percentage of high relaxed status readings  39 . The fractions of the high, medium and low relaxed status readings can also be represented in a pie chart  27 , as depicted in  FIG. 8 , in which the percentage of high relaxed status  39 , medium relaxed status  38 , and low relaxed status  37  are displayed graphically, to provide additional information and motivation for the user to utilize the stress management device  10  to achieve a greater percentage of high relaxed status readings  39 . The greater the percentage of high relaxed state readings  39 , compared to the medium relaxed state readings  38  and the low relaxed state readings  37 , increases the effort index score  26 . 
     As is best seen in  FIG. 4 , the display screen  15  displays a graphic image  25 , preferably in the form of a pair of lungs filling and emptying with a color display, to guide the user in a suggested predetermined breathing pattern known to induce a high state of relaxation in the user. In addition, the display screen  15  can provide other important information to the user, including the heart rate  24 , a timer  28  identifying the length of the training period, a color-coded indicator (not shown) that provides an instantaneous image showing the most recent relaxation state calculation, and a bar graph  29  that exhibits the strength of the detected pulsation of the user&#39;s heart beat. Preferably, the timer  28  will alternate every two or three seconds as a display with the color-coded indicator (not shown) that could display the color green for a high relaxation state, yellow or blue for a medium relaxation state and red for a low relaxation state. The timer  28  will preferably countdown from 60 to zero for the first minute of the training period because the effort index score requires a training period having a duration of at least one minute to provide a displayed result. After the timer  28  has counted down the first minute, the additional time of the training period will preferably be shown in increasing numbers. The training period can be as long as the user desires, although a maximum of twenty minutes is recommended, provided that the training period lasts for at least one minute. 
     In operation, the user will power up the stress management device  10  by simply placing the device  10  on his/her finger so that the non-invasive infrared sensor  17  can sense the heart beat of the user and initiate operation of the device  10 . Preferably, the stress management device  10  will go through a training session in which the animated device  25  operates at a predetermined initial guided respiratory rate, such as a rate of six breaths per minute, to guide the user into a respiratory pattern that results in a high relaxed state  39 . Preferably, the display screen  15  will show the heart rate variability (HRV) curve  23  in the form of a wave pattern. The heart rate variability curve  23  is an important indicator of physiological compliance and emotional flexibility. When the HRV curve  23  looks like a sinusoidal waveform, the HRV is stabilized and the user is relaxed. When the user experiences stressful emotions, the curve  23  becomes irregular and incoherent with the respiration pace. 
     If the user is uncomfortable with the demonstrated respiratory rate of six breaths per minute, the stress management device  10  will preferably have a function by which the user can change the guided respiration rate to a different predetermined initial guided respiratory rate. If the user feels that the guided respiration rate demonstrated by the animated device  25  is too slow for relaxation, the user can select a lower training level for breathing more comfortably. Similarly, if the user feels that the guided respiration rate is too fast, the user can select a higher training level to slow down the operation of the animated device  25 . Optionally, the animated device  25  can also utilize an audible respiration guide to guide the respiratory pattern of the user rather than, or in addition to, the animated graphics. 
     After the user has followed the initial guided respiratory rate and the HRV is stabilized, which typically occurs in about 25 seconds, the stress management device  10  can adjust the guided respiration rate in response to the actual current respiration rate of the user. For example, if the current respiration rate of the user is greater than ten breaths per minute, the stress management device  10  can assist the user toward a higher state of relaxation by adjusting the guided respiration rate to equal the user&#39;s current respiration rate less a predetermined value, such as the number two. Once the respiration rate of the user has dropped below ten breaths per minute, the guided respiration rate can be adjusted to be equal to the user&#39;s actual current respiration rate. Meanwhile, the user is prompted to follow the guided respiratory rate displayed by the filing and emptying of the graphic lung image  25  on the display screen  15 . In the alternative, the guided respiratory rate can be retained at the initial guided respiratory rate, or manually adjusted to a higher or lower rate as desired by the user. 
     When the user wants to obtain a relaxation score, the user will remove his/her finger F from the stress management device  10 . If the training session has lasted for more than sixty seconds, the display screen  15  will preferably show a pie chart  27  indicating the percentages of the high, medium and low relaxed status readings  37 - 39 , as well as a numerical score  26 , calculated as defined above. 
     Preferably, the stress management device  10  will have a menu function stored and operated by the processor  19 . By manipulating the multifunction button  18 , the menu function can be selected to provide the user with a choice between high, mid or low training levels, with the mid-level training session corresponding to a respiratory rate of six breaths per minute. Also, the menu function can provide a selection for the use of the optional audible respiration guide. Alternatively, the multi-function button  18  can be configured to be used as a manual control for the on/off function of the device  10 . 
     The stationary condition of breath and the trend of heart rate variation reflect the status of interaction between the sympathetic and parasympathetic neural system in the human body. When heart rate variation turns to be regular and synchronized with the breathing rhythm, it is considered that the neural system tends to be in harmony with the body and mind, which means that the physical body becomes more effective, the emotion turns more stationary, and the mind is peaceful and perceptive, which is called a highly physiological relaxed state. On the contrary, stressful emotions including anger, disappointment, and anxiety make the heart rate variation irregular and incoherent with breath. In this case, the stress management device  10  can be used to guide the user to conduct the slow and deep breaths, and help the user to focus his/her attention to enter into a relaxed state with body and mind in harmony. 
     This stress management device  10  combines the breathing guiding  25  and heart rate variability biofeedback  23  technology, by analyzing the signal detected from the non-invasive infrared sensor  17  on the finger and extracting the heart rate variability information  23  and the coherence between heart rate variability and respiratory rhythm, therefore, monitoring the status and degree of relaxation. The device can guide the user to breathe by an intuitive animated graphic display  25 , and help the user to focus attention and adjust his/her emotion actively, aiding the user to enter into a highly relaxed state. 
     It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiments of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention. The invention is not otherwise limited, except for the recitation of the claims set forth below.