Apparatus and method for beneficial modification of biorhythmic activity

• US 20040116784A1
• Filed: 12/13/2002
• Published: 06/17/2004
• Est. Priority Date: 12/13/2002
• Status: Active Grant

• Current Assignee: 2breathe Technologies Ltd
• Original Assignee: InterCure Ltd.
• Inventors: Gavish, Benjamin
• Granted Patent: US 8,672,852 B2
• Time in Patent Office: Days
• US Class Current: 600/300
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/02007 Evaluating blood vessel condition, e.g. elasticity, compliance
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/1118 Determining activity level
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/389 Electromyography [EMG]
• CPC Class Codes: A61B 5/4857 Indicating the phase of biorhythm clocks or watches with indicators for biological cycles G04B19/264
• CPC Class Codes: A61B 5/486 Bio-feedback A61B5/375 takes precedence
• CPC Class Codes: A61B 5/6831 Straps, bands or harnesses
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/7405 using sound
• CPC Class Codes: A61B 5/743 Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: A61B 7/003 Detecting lung or respiration noise

Abstract

Apparatus is provided, including a sensor, adapted to generate a sensor signal indicative of biorhythmic activity of a user of the apparatus, the sensor signal having a first characteristic, indicative of a voluntary action of the user, and a second characteristic, indicative of a benefit-related variable of the user. The apparatus also includes a control unit, adapted to receive the sensor signal, and, responsive to the second characteristics generate an output signal which directs the user to modify a parameter of the voluntary action indicated by the first characteristic.

Claims

1. Apparatus comprising:

a sensor, adapted to generate a sensor signal indicative of biorhythmic activity of a user of the apparatus, the sensor signal having a first characteristic, indicative of a voluntary action of the user, and a second characteristic, indicative of a benefit-related variable of the user; and

a control unit, adapted to receive the sensor signal, and, responsive to the second characteristic, generate an output signal which directs the user to modify a parameter of the voluntary action indicated by the first characteristic.

2. Apparatus according to claim 1, wherein the control unit is adapted to identify the first and the second characteristics in the sensor signal.

3. Apparatus according to claim 1, wherein the control unit is adapted to generate the output signal responsive to the first characteristic and the second characteristic.

4. Apparatus according to claim 1, wherein the control unit is adapted to:

identify an aspect of the first characteristic indicative of the user having modified the parameter to a desired extent, and

responsive to identifying the aspect of the first sensor signal, generate a new output signal, to direct the user to further modify the parameter of the voluntary action.

5. Apparatus according to claim 1, wherein the first characteristic is selected from the list consisting of:

a period of an aspect of the sensor signal, a rate of an aspect of the sensor signal, a rise time of an aspect of the sensor signal, a fall time of an aspect of the sensor signal, a time derivative at a point of an aspect of the sensor signal, a maximum of the time derivative, a minimum of the time derivative, an amplitude of a maximum of an aspect of the sensor signal averaged over two or more biorhythmic cycles of the aspect, and an amplitude of a minimum of an aspect of the sensor signal averaged over two or more cycles of the aspect, and wherein the sensor is adapted to generate the sensor signal having the first characteristic.

6. Apparatus according to claim 1, wherein the first characteristic includes a time difference between two points of an aspect of the sensor signal, the points characterizing a single cycle of the biorhythmic activity.

7. Apparatus according to claim 1, wherein the first characteristic includes a signal value difference between two points of an aspect of the sensor signal, the points characterizing a single cycle of the biorhythmic activity.

8. Apparatus according to claim 1, wherein the second characteristic includes a variability of an aspect of the biorhythmic activity, the aspect selected from the list consisting of:

an envelope of the biorhythmic activity, an amplitude of the biorhythmic activity, a period of the biorhythmic activity, a standard deviation (SD) of the envelope, an SD of the amplitude, and an SD of the period, and wherein the control unit is adapted to generate the output signal responsive to the variability of the aspect.

9. Apparatus according to claim 1, comprising a health status sensor, adapted to generate a health status signal indicative of a health status parameter of the user, which health status parameter is indicative of a state of health of the user, and wherein the control unit is adapted to receive the health status signal, and to determine whether the health status parameter passes a threshold value.

10. Apparatus according to claim 1, wherein the control unit comprises a memory, and wherein the control unit is adapted to:

store, in the memory, values of the second characteristic generated over a first period of time, during which first period the control unit withholds generating the output signal, and

during a second period of time after the conclusion of the first period, generate the output signal responsive to the stored values of the second characteristic.

11. Apparatus according to claim 1, wherein the control unit is adapted to generate the output signal in the form of a game, and to alter parameters of the game so as to induce the user to modify the parameter of the voluntary action.

12. Apparatus according to claim 1, wherein the biorhythmic activity includes muscle activity of the user, and wherein the sensor is adapted to generate the sensor signal indicative of the muscle activity.

13. Apparatus according to claim 1, wherein the biorhythmic activity includes cardiac activity, and wherein the sensor is adapted to generate the sensor signal indicative of the cardiac activity.

14. Apparatus according to claim 1, wherein the sensor is adapted to be coupled to a belt, which belt is adapted to be placed around a torso of the user.

15. Apparatus according to claim 1, wherein the sensor is selected from the list consisting of:

a fast-responding temperature sensor, an electrocardiogram (ECG) monitor, at least one electromyography (EMG) electrode, a electroencephalogram (EEG) monitor, a blood gas concentration sensor, a photoelectric sensor, a photoplethysmographic sensor, a pulse oximeter, and a laser Doppler sensor.

16. Apparatus according to claim 1, wherein the sensor is adapted to sense a concentration of a gas emitted from a tissue of the user.

17. Apparatus according to claim 1, wherein the sensor comprises an electrical impedance sensor, adapted to sense an electrical impedance of at least one organ of the user.

18. Apparatus according to claim 1, wherein the sensor is adapted to sense a microvascular property of the user.

19. Apparatus according to claim 1, wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause an improvement in the benefit-related variable.

20. Apparatus according to claim 19, wherein the benefit-related variable is an amplitude of respiration of the user, and wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the amplitude of the respiration.

21. Apparatus according to claim 19, wherein the benefit-related variable is a measure of baroreflex sensitivity of the user, and wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the measure of baroreflex sensitivity.

22. Apparatus according to claim 19, wherein the benefit-related variable is selected from the list consisting of:

a frequency of respiration of the user, a blood pressure of the user, a blood oxygenation saturation of the user, an end-tidal CO2 level of the user, a tissue oxygenation level of the user, a pulse-wave velocity of the user, variations in a skin blood volume of the user, a measure of peak air flow of the user, an amplitude of a skin pulse volume of the user, an arterial compliance of the user, and a parameter of an electrocardiogram of the user, and wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the benefit-related variable.

23. Apparatus according to claim 19, wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the benefit-related variable, so as to treat a cardiovascular disease of the user.

24. Apparatus according to claim 19, wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the benefit-related variable, so as to treat a pulmonary disease of the user.

25. Apparatus according to claim 19, wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the benefit-related variable, so as to treat a condition of the user selected from the list consisting of:

a neurological disease, hypertension, and hyperactivity.

26. Apparatus according to claim 1, wherein the output signal includes an intelligible stimulus, and wherein the control unit is adapted to generate the intelligible stimulus, so as to direct the user to modify the parameter of the voluntary action.

27. Apparatus according to claim 26, wherein the intelligible stimulus includes at least one stimulus selected from the list consisting of:

an image, alpha-numeric text, a sound, a sound pattern, and a dynamic graphical pattern, and wherein the control unit is adapted to generate the stimulus, so as to direct the user to modify the parameter of the voluntary action.

28. Apparatus according to claim 26, comprising a speaker, and wherein the intelligible stimulus includes music, and wherein the control unit is adapted to drive the speaker to generate the music, so as to direct the user to modify the parameter of the voluntary action.

29. Apparatus according to claim 1, wherein the sensor is adapted to generate the sensor signal having a third characteristic indicative of a health status parameter of the user, which health status parameter is indicative of a state of health of the user, and wherein the control unit is adapted to determine whether the health status parameter passes a threshold value.

30. Apparatus according to claim 29, wherein the control unit is adapted to withhold generating the output signal responsive to determining that the third characteristic passes the threshold value.

31. Apparatus according to claim 29, wherein the control unit is adapted to generate an alarm signal responsive to determining that the third characteristic passes the threshold value.

32. Apparatus according to claim 1, wherein the biorhythmic activity includes respiration, and wherein the sensor is adapted to generate the sensor signal indicative of the respiration.

33. Apparatus according to claim 32, wherein the sensor is selected from the list consisting of:

a flow meter, adapted to sense respiration by sensing respiratory air flow of the user;

a microphone, adapted to sense respiration by sensing breath sounds of the user; and

a heated wire, adapted to sense respiration by sensing respiratory air flow of the user.

34. Apparatus according to claim 32, wherein the voluntary action includes the respiration, and wherein the control unit is adapted to generate the output signal to direct the user to modify a parameter of the respiration.

35. Apparatus according to claim 34, wherein the first characteristic includes at least one breathing parameter selected from:

inspiration time and expiration time, and wherein the sensor is adapted to generate the sensor signal having the first characteristic.

36. Apparatus according to claim 34, wherein the first characteristic includes an average frequency of a skin pulse volume of the user, and wherein the sensor is adapted to generate the sensor signal having the first characteristic.

37. Apparatus according to claim 34, wherein the first characteristic includes an end-tidal CO2 level of the user, and wherein the sensor is adapted to generate the sensor signal having the first characteristic.

38. Apparatus according to claim 34, wherein the parameter of the respiration includes one or more timing parameters of the respiration, and wherein the control unit is adapted to generate the output signal to direct the user to modify the timing parameters of the respiration.

39. Apparatus according to claim 38, wherein the timing parameters include a pattern of inspiration and expiration of the user, and wherein the control unit is adapted to generate the output signal to direct the user to modify the pattern.

40. Apparatus according to claim 39, wherein the control unit is adapted to generate the output signal to direct the user to modify the pattern so as to reduce a ratio of a time period of the inspiration to a time period of the expiration.

41. Apparatus according to claim 1, wherein the sensor is adapted to sense a change in a property of an organ of the user, the property selected from the list consisting of:

a circumference of the organ, a volume of the organ, and a pressure of the organ.

42. Apparatus according to claim 41, wherein the sensor is selected from the list consisting of:

a finger plethysmograph, a pressure cuff, and a strain gauge.

43. Apparatus according to claim 1, wherein the first characteristic includes a plurality of first characteristics indicative of the voluntary action of the user, and wherein the control unit is adapted to generate the output signal responsive to at least one relationship among the plurality of first characteristics.

44. Apparatus according to claim 43, wherein the control unit is adapted to determine the relationship using an analysis technique selected from:

cross-correlation analysis in a frequency domain and cross-correlation analysis in a time domain.

45. Apparatus according to claim 1, wherein the first characteristic includes a relationship among two or more spectral components that are defined by points in the sensor signal.

46. Apparatus according to claim 1, wherein the first characteristic includes at least one spectral component that is defined by points in the sensor signal.

47. Apparatus according to claim 46, wherein the spectral component is defined by a first subset of points in the sensor signal, the first subset of points being located among a second subset of points in the sensor signal different from the first subset of points, the first subset of points sharing a common property.

48. Apparatus according to claim 47, wherein the common property is selected from the list consisting of:

local maxima and local minima of the sensor signal.

49. Apparatus comprising:

a first sensor, adapted to measure a voluntary physiological variable, which is indicative of a voluntary action of a user of the apparatus, and to generate a voluntary sensor signal responsive thereto;

a second sensor, adapted to measure a benefit-related physiological variable, indicative of an amplitude of respiration of the user, and to generate a benefit-related sensor signal responsive thereto; and

a control unit, adapted to receive the voluntary and benefit-related sensor signals, and, responsive thereto, to generate an output signal which directs the user to modify a parameter of the voluntary action.

50. Apparatus according to claim 49, wherein the voluntary action includes respiration of the user, and wherein the control unit is adapted to generate the output signal to direct the user the modify a parameter of the respiration.

51. Apparatus according to claim 49, wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause an improvement in the benefit-related physiological variable.

52. Apparatus comprising:

a first sensor, adapted to generate a first sensor signal;

a second sensor, adapted to generate a second sensor signal; and

a control unit, adapted to;

receive the first and second sensor signals,

identify a first characteristic in at least one of the first sensor signal and the second sensor signal, the first characteristic indicative of a voluntary action of a user of the apparatus;

derive a second characteristic from the first and second sensor signals in combination, and

responsive to the second characteristic, generate an output signal which directs the user to modify a parameter of the voluntary action.

53. Apparatus according to claim 52, wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the voluntary action so as to cause an improvement in a physiological variable of the user of which the second characteristic is indicative.

54. Apparatus according to claim 52, wherein the control unit is adapted to generate the output signal responsive to the first characteristic and the second characteristic.

55. Apparatus comprising:

a first sensor, adapted to measure abdominal breathing of a user of the apparatus, and to generate an abdominal breathing sensor signal;

a second sensor, adapted to measure thoracic breathing of the user, and to generate a thoracic breathing sensor signal; and

a control unit, adapted to receive the abdominal and thoracic breathing sensor signals, and, responsive thereto, to generate an output signal which directs the user to modify a parameter of respiration of the user.

56. Apparatus according to claim 55, wherein the parameter of the respiration includes a timing parameter of the respiration, and wherein the control unit is adapted to generate the output so as to direct the user to modify the timing parameter of the respiration.

57. Apparatus according to claim 55, wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the respiration so as to cause an improvement in a physiological variable of the user of which the abdominal and thoracic breathing sensor signals are indicative.

58. Apparatus according to claim 57, wherein the physiological variable includes a phase difference between the abdominal breathing and the thoracic breathing, and wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the respiration so as to cause a change in the phase difference.

59. Apparatus according to claim 57, wherein the physiological variable includes a ratio of abdominal breathing amplitude to thoracic breathing amplitude, and wherein the control unit is adapted to configure the output signal to direct the user to modify the parameter of the respiration so as to cause an increase in the ratio.

60. Apparatus according to claim 57, wherein the control unit is adapted to configure the output signal to treat a condition of the user selected from the list consisting of:

congestive heart failure and chronic obstructive pulmonary disease.

61. Apparatus comprising:

a sensor, adapted to generate a sensor signal indicative of respiration of a subject whose autonomic control of breathing is impaired; and

a control unit, adapted to receive the sensor signal, and, responsive thereto, to generate an output signal which causes the subject to involuntarily modify a parameter of the respiration.

62. Apparatus according to claim 61, wherein the control unit is adapted to generate the output signal slightly out of phase with the respiration.

63. Apparatus according to claim 61, wherein the sensor is adapted to be applied to the subject when the subject is sleeping.

64. Apparatus according to claim 63, wherein the control unit is adapted to generate the output signal so as to treat sleep apnea of the subject.

65. Apparatus according to claim 61, wherein the sensor is adapted to be applied to the subject when the subject is unconscious.

66. Apparatus according to claim 65, wherein the sensor is adapted to be applied to the subject when the subject is in a coma.

67. Apparatus according to claim 65, wherein the sensor is adapted to be applied to the subject when the subject is anesthetized.

68. Diagnostic apparatus, comprising:

a sensor, adapted to measure a voluntary physiological variable, which is indicative of a voluntary biorhythmic action of a user of the apparatus, and to generate a sensor signal responsive thereto; and

a control unit, adapted to receive the sensor signal, to determine a level of a variation over time of the voluntary action, and, responsive thereto, to generate an output signal.

69. Apparatus according to claim 68, wherein the control unit is adapted to determine the level of the variation so as to facilitate a diagnosis.

70. Apparatus according to claim 68, wherein the sensor comprises a respiration sensor.

71. Apparatus according to claim 68, wherein the control unit is adapted to determine a level of variation over time of an envelope of the signal.

72. Apparatus according to claim 68, wherein the control unit is adapted to determine a level of variation over time of an amplitude of the signal.

73. Apparatus according to claim 68, wherein the control unit is adapted to determine a level of variation over time of at least one of:

a period of the signal and a rate of the signal.

74. Diagnostic apparatus, comprising:

a plethysmography sensor, adapted to generate a sensor signal; and

a control unit, adapted to receive the sensor signal, to determine a level of a variation over time of the signal, and, responsive thereto, to generate an output signal.

75. Apparatus according to claim 74, wherein the control unit is adapted to determine the level of variation so as to facilitate a diagnosis.

76. Apparatus according to claim 74, wherein the control unit is adapted to determine a level of variation over time of an envelope of the signal.

77. Apparatus according to claim 74, wherein the control unit is adapted to determine a level of variation over time of an amplitude of the signal.

78. Apparatus according to claim 74, wherein the control unit is adapted to determine a level of variation over time of at least one of:

a period of the signal and a rate of the signal.

79. A method for facilitating improving health of a user, comprising:

receiving a sensor signal indicative of biorhythmic activity of the user, the sensor signal having a first characteristic, indicative of a voluntary action of the user, and a second characteristic, indicative of a benefit-related variable of the user; and

responsive to the second characteristic, generating an output signal which directs the user to modify a parameter of the voluntary action indicated by the first characteristic.

80. A method according to claim 79, wherein generating the output signal comprises generating the output signal responsive to the first characteristic and the second characteristic.

81. A method according to claim 79, wherein generating the output signal comprises:

identifying an aspect of the first characteristic indicative of the user having modified the parameter to a desired extent; and

responsive to identifying the aspect of the first sensor signal, generating a new output signal, to direct the user to further modify the parameter of the voluntary action.

82. A method according to claim 79, wherein the first characteristic is selected from the list consisting of:

a period of an aspect of the sensor signal, a rate of an aspect of the sensor signal, a rise time of an aspect of the sensor signal, a fall time of an aspect of the sensor signal, a time derivative at a point of an aspect of the sensor signal, a maximum of the time derivative, a minimum of the time derivative, an amplitude of a maximum of an aspect of the sensor signal averaged over two or more biorhythmic cycles of the aspect, and an amplitude of a minimum of an aspect of the sensor signal averaged over two or more cycles of the aspect, and wherein receiving the sensor signal comprises receiving the sensor signal having the first characteristic.

83. A method according to claim 79, wherein the first characteristic includes a time difference between two points of an aspect of the sensor signal, the points characterizing a single cycle of the biorhythmic activity.

84. A method according to claim 79, wherein the first characteristic includes a signal value difference between two points of an aspect of the sensor signal, the points characterizing a single cycle of the biorhythmic activity.

85. A method according to claim 79, wherein the second characteristic includes a variability of an aspect of the biorhythmic activity, the aspect selected from the list consisting of:

an envelope of the biorhythmic activity, an amplitude of the biorhythmic activity, a period of the biorhythmic activity, a standard deviation (SD) of the envelope, an SD of the amplitude, and an SD of the period, and wherein generating the output signal comprises generating the output signal responsive to the variability of the aspect.

86. A method according to claim 79, comprising receiving a health status signal indicative of a health status parameter of the user, which health status parameter is indicative of a state of health of the user, and wherein generating the output signal comprises determining whether the health status parameter passes a threshold value.

87. A method according to claim 79, wherein generating the output signal comprises:

storing values of the second characteristic generated over a first period of time,

withholding generating the output signal during the first period, and

during a second period of time after the conclusion of the first period, generating the output signal responsive to the stored values of the second characteristic.

88. A method according to claim 79, wherein generating the output signal comprises:

generating the output signal in the form of a game, and

altering parameters of the game so as to induce the user to modify the parameter of the voluntary action.

89. A method according to claim 79, wherein the biorhythmic activity includes muscle activity of the user, and wherein receiving the sensor signal comprises receiving the sensor signal indicative of the muscle activity.

90. A method according to claim 79, wherein the biorhythmic activity includes cardiac activity, and wherein receiving the sensor signal comprises receiving the sensor signal indicative of the cardiac activity.

91. A method according to claim 79, wherein receiving the sensor signal comprises monitoring breathing movements of the user via changes in a circumference of a portion of a torso of the user.

92. A method according to claim 79, wherein receiving the sensor signal comprises making a measurement selected from the list consisting of:

a fast temperature measurement, an electrocardiographic measurement, an electromyographic measurement, an electroencephalographic measurement, a blood gas concentration measurement, a measurement made photoelectrically, a photoplethysmographic measurement, a pulse oximeter measurement, a measurement of a concentration of a gas emitted from a tissue, a measurement of an electrical impedance of at least one organ of the user, a measurement of a microvascular property of the user, and a laser Doppler measurement.

93. A method according to claim 79, wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause an improvement in the benefit-related variable.

94. A method according to claim 93, wherein the benefit-related variable is an amplitude of respiration of the user, and wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the amplitude of the respiration.

95. A method according to claim 93, wherein the benefit-related variable is a measure of baroreflex sensitivity of the user, and wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the measure of baroreflex sensitivity.

96. A method according to claim 93, wherein the benefit-related variable is selected from the list consisting of:

a frequency of respiration of the user, a blood pressure of the user, a blood oxygenation saturation of the user, an end-tidal CO2 level of the user, a tissue oxygenation level of the user, a pulse-wave velocity of the user, variations in a skin blood volume of the user, a measure of peak air flow of the user, an amplitude of a skin pulse volume of the user, an arterial compliance of the user, and a parameter of an electrocardiogram of the user, and wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the benefit-related variable.

97. A method according to claim 93, wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the benefit-related variable, so as to treat a cardiovascular disease of the user.

98. A method according to claim 93, wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the benefit-related variable, so as to treat a pulmonary disease of the user.

99. A method according to claim 93, wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause the improvement in the benefit-related variable, so as to treat a condition of the user selected from the list consisting of:

a neurological disease, hypertension, and hyperactivity.

100. A method according to claim 79, wherein generating the output signal comprises generating an intelligible stimulus, so as to direct the user to modify the parameter of the voluntary action.

101. A method according to claim 100, wherein generating the intelligible stimulus comprises generating at least one stimulus selected from the list consisting of:

an image, alpha-numeric text, a sound, a sound pattern, and a dynamic graphical pattern, so as to direct the user to modify the parameter of the voluntary action.

102. A method according to claim 100, wherein generating the intelligible stimulus comprises generating music, so as to direct the user to modify the parameter of the voluntary action.

103. A method according to claim 79, wherein receiving the sensor signal comprises receiving the sensor signal having a third characteristic indicative of a health status parameter of the user, which health status parameter is indicative of a state of health of the user, and wherein generating the output signal comprises determining whether the health status parameter passes a threshold value.

104. A method according to claim 103, wherein generating the output signal comprises withholding generating the output signal responsive to determining that the third characteristic passes the threshold value.

105. A method according to claim 103, wherein generating the output signal comprises generating an alarm signal responsive to determining that the third characteristic passes the threshold value.

106. A method according to claim 79, wherein the biorhythmic activity includes respiration, and wherein receiving the sensor signal comprises receiving the sensor signal indicative of the respiration.

107. A method according to claim 106, wherein receiving the sensor signal comprises sensing respiration by sensing respiratory air flow of the user.

108. A method according to claim 106, wherein receiving the sensor signal comprises sensing respiration by sensing breath sounds of the user.

109. A method according to claim 106, wherein the voluntary action includes the respiration, and wherein generating the output signal comprises generating the output signal to direct the user to modify a parameter of the respiration.

110. A method according to claim 109, wherein the first characteristic includes at least one breathing parameter selected from:

inspiration time and expiration time, and wherein receiving the sensor signal comprises receiving the sensor signal having the first characteristic.

111. A method according to claim 109, wherein the first characteristic includes an average frequency of a skin pulse volume of the user, and wherein receiving the sensor signal comprises receiving the sensor signal having the first characteristic.

112. A method according to claim 109, wherein the first characteristic includes an end-tidal CO2 level of the user, and wherein receiving the sensor signal comprises receiving the sensor signal having the first characteristic.

113. A method according to claim 109, wherein the parameter of the respiration includes one or more timing parameters of the respiration, and wherein generating the output signal comprises generating the output signal to direct the user to modify the timing parameters of the respiration.

114. A method according to claim 113, wherein the timing parameters include a pattern of inspiration and expiration of the user, and wherein generating the output signal comprises generating the output signal to direct the user to modify the pattern.

115. A method according to claim 114, wherein generating the output signal comprises generating the output signal to direct the user to modify the pattern so as to reduce a ratio of a time period of the inspiration to a time period of the expiration.

116. A method according to claim 79, wherein receiving the sensor signal comprises sensing a change in a property of an organ of the user, the property selected from the list consisting of:

a circumference of the organ, a volume of the organ, and a pressure of the organ.

117. A method according to claim 79, wherein the first characteristic includes a plurality of first characteristics indicative of the voluntary action of the user, and wherein generating the output signal comprises:

determining at least one relationship among the plurality of first characteristics, and

generating the output signal responsive to the at least one relationship.

118. A method according to claim 117, wherein determining the relationship comprises using an analysis technique selected from:

cross-correlation analysis in a frequency domain and cross-correlation analysis in a time domain.

119. A method according to claim 79, wherein the first characteristic includes a relationship among two or more spectral components that are defined by points in the sensor signal.

120. A method according to claim 79, wherein the first characteristic includes at least one spectral component that is defined by points in the sensor signal.

121. A method according to claim 120, wherein the spectral component is defined by a first subset of points in the sensor signal, the first subset of points being located among a second subset of points in the sensor signal different from the first subset of points, the first subset of points sharing a common property.

122. A method according to claim 121, wherein the common property is selected from the list consisting of:

local maxima and local minima of the sensor signal.

123. A method for facilitating improving health of a user, comprising:

receiving a voluntary sensor signal indicative of a voluntary physiological variable, which voluntary physiological variable is indicative of a voluntary action of the user;

receiving a benefit-related sensor signal indicative of a benefit-related physiological variable, which benefit-related physiological variable is indicative of an amplitude of respiration of the user; and

responsive to the voluntary sensor signal and the benefit-related sensor signal, generating an output signal which directs the user to modify a parameter of the voluntary action.

124. A method according to claim 123, wherein the voluntary action includes respiration of the user, and wherein generating the output signal comprises generating the output signal to direct the user the modify a parameter of the respiration.

125. A method according to claim 123, wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause an improvement in the benefit-related physiological variable.

126. A method for facilitating improving health of a user, comprising:

receiving a first sensor signal and a second sensor signal;

identifying a first characteristic in at least one of the first sensor signal and the second sensor signal, the first characteristic indicative of a voluntary action of the user;

deriving a second characteristic from the first and second sensor signals in combination; and

responsive to the second characteristic, generating an output signal which directs the user to modify a parameter of the voluntary action.

127. A method according to claim 126, wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the voluntary action so as to cause an improvement in a physiological variable of the user of which the second characteristic is indicative.

128. A method according to claim 126, wherein generating the output signal comprises generating the output signal responsive to the first characteristic and the second characteristic.

129. A method for facilitating improving health of a user, comprising:

receiving an abdominal breathing sensor signal indicative of abdominal breathing of the user;

receiving a thoracic breathing sensor signal indicative of thoracic breathing of the user;

responsive to the abdominal and thoracic breathing sensor signals, generating an output signal which directs the user to modify a parameter of respiration of the user.

130. A method according to claim 129, wherein the parameter of the respiration includes a timing parameter of the respiration, and wherein generating the output signal comprises generating the output so as to direct the user to modify the timing parameter of the respiration.

131. A method according to claim 129, wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the respiration so as to cause an improvement in a physiological variable of the user of which the abdominal and thoracic breathing sensor signals are indicative.

132. A method according to claim 131, wherein the physiological variable includes a phase difference between the abdominal breathing and the thoracic breathing, and wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the respiration so as to cause a change in the phase difference.

133. A method according to claim 131, wherein the physiological variable includes a ratio of abdominal breathing amplitude to thoracic breathing amplitude, and wherein generating the output signal comprises configuring the output signal to direct the user to modify the parameter of the respiration so as to cause an increase in the ratio.

134. A method according to claim 131, wherein generating the output signal comprises configuring the output signal to treat a condition of the user selected from the list consisting of:

congestive heart failure and chronic obstructive pulmonary disease.

135. A method comprising:

receiving a sensor signal indicative of respiration of a subject whose autonomic control of breathing is impaired; and

responsive to the sensor signal, generating an output signal which causes the subject to involuntarily modify a parameter of the respiration.

136. A method according to claim 135, wherein generating the output signal comprises generating the output signal slightly out of phase with the respiration.

137. A method according to claim 135, wherein receiving the sensor signal comprises receiving the sensor signal when the subject is sleeping.

138. A method according to claim 137, wherein generating the output signal comprises generating the output signal so as to treat sleep apnea of the subject.

139. A method according to claim 135, wherein receiving the sensor signal comprises receiving the sensor signal when the subject is unconscious.

140. A method according to claim 139, wherein receiving the sensor signal comprises receiving the sensor signal when the subject is in a coma.

141. A method according to claim 135, wherein receiving the sensor signal comprises receiving the sensor signal when the subject is anesthetized.

142. A method for facilitating a diagnosis of a user, comprising:

measuring a voluntary physiological variable, which is indicative of a voluntary biorhythmic action of the user, and generating a sensor signal responsive thereto;

receiving the sensor signal;

determining a level of a variation over time of the voluntary action; and

responsive to the level of the variation, generating an output signal.

143. A method according to claim 142, wherein determining the level of the variation comprises determining the level of the variation so as to facilitate a diagnosis.

144. A method according to claim 142, wherein measuring the voluntary physiological variable comprises measuring respiration of the user.

145. A method according to claim 142, wherein determining the level of the variation over time comprises determining a level of variation over time of an envelope of the signal.

146. A method according to claim 142, wherein determining the level of the variation over time comprises determining a level of variation over time of an amplitude of the signal.

147. A method according to claim 142, wherein determining the level of the variation over time comprises determining a level of variation over time of at least one of:

a period of the signal and a rate of the signal.

148. A method for facilitating a diagnosis of a user, comprising:

generating a sensor signal using plethysmography;

receiving the sensor signal;

determining a level of a variation over time of the signal; and

responsive to the level of the variation, generating an output signal.

149. A method according to claim 148, wherein determining the level of the variation comprises determining the level of variation so as to facilitate a diagnosis.

150. A method according to claim 148, wherein determining the level of the variation over time comprises determining a level of variation over time of an envelope of the signal.

151. A method according to claim 148, wherein determining the level of the variation over time comprises determining a level of variation over time of an amplitude of the signal.

152. A method according to claim 148, wherein determining the level of the variation over time comprises determining a level of variation over time of at least one of:

a period of the signal and a rate of the signal.