Biofeedback system
First Claim
1. A biofeedback system comprising, means for sensing electrical activity within a human body to generate a single source signal representing the sensed electrical activity, means for deriving from said source signal a first physiological signal normally indicative of the presence of a desired state of mind and a second physiological signal indicative of the absence of said desired state of mind, indicator means, and gate means for applying said first physiological signal to said indicator means to derive an indication in the absence of said second physiological signal and inhibiting said first physiological signal in the presence of said second physiological signal.
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Abstract
Mental activity of a human subject is indicated with electrodes placed on the head of the subject to respond to brain activity. The electrodes derive a signal including low and high frequency a.c. components respectively having frequency ranges in the same low frequency range as alpha waves derived by the brain and considerably higher than the highest frequency of the alpha waves. The high and low frequency amplitude components are supplied to an indicator arranged so the mental state activity is indicated only in response to the detected high frequency component having an amplitude less than a level indicative of the subject not being in a state of relaxation and the detected low frequency component having an amplitude greater than a first predetermined value and less than a second predetermined value. The low frequency amplitude between the first and second predetermined values is associated with the alpha waves.
74 Citations
22 Claims
- 1. A biofeedback system comprising, means for sensing electrical activity within a human body to generate a single source signal representing the sensed electrical activity, means for deriving from said source signal a first physiological signal normally indicative of the presence of a desired state of mind and a second physiological signal indicative of the absence of said desired state of mind, indicator means, and gate means for applying said first physiological signal to said indicator means to derive an indication in the absence of said second physiological signal and inhibiting said first physiological signal in the presence of said second physiological signal.
- 4. A biofeedback system comprising, electrode means for deriving a single source signal from the scalp of a human subject, means for deriving a first physiological signal from a first frequency range of said source signal, means for deriving a second physiological signal from a second frequency range of said source signal, first detecting means for detecting when the amplitude of said first physiological signal is in a predetermined range, second detecting means for detecting when the amplitude of said second physiological signal exceeds a predetermined value, indicator means, and gate means for applying the output of said first detecting means to said indicator means to derive an indication in the absence of the output of said second detecting means and inhibiting the output of said first detecting means in the presence of the output of said second detecting means.
- 12. A method of indicating the state of mental activity of a human subject comprising placing electrodes on the head of the subject, said electrodes responding to brain activity of the subject to derive a signal including low frequency a.c. components having a maximum frequency of approximately 14 Hertz and high frequency a.c. components having a minimum frequency of approximately 80 Hertz, detecting the amplitudes of the high and low frequency components, and activating an indicator for the mental state activity only in response to the detected high frequency component having an amplitude less than a first predetermined level and the detected low frequency component having an amplitude greater than a first predetermined value and less than a second predetermined value.
- 15. Apparatus for indicating the state of mental activity of a human subject comprising electrode means adapted to be placed on the head of the subject, said electrode means adapted to respond to brain activity of the subject to derive a signal including low frequency a.c. components having a maximum frequency of approximately 14 Hertz and high frequency a.c. components having a minimum frequency of approximately 80 Hertz, indicator means for detecting the amplitudes of the high and low frequency components, and means for activating the indicator means for the mental state activity only in response to the detected high frequency component having an amplitude less than a first predetermined level and the detected low frequency component having an amplitude greater than a first predetermined value and less than a second predetermined value.
- 18. A method of indicating the state of mental activity of a human subject comprising placing electrodes on the head of the subject, said electrodes responding to brain activity of the subject to derive a signal including a low frequency a.c. components having a frequency range in the same low frequency range as alpha waves derived by the brain and high frequency a.c. components having a minimum frequency considerably higher than the highest frequency of the alpha waves, detecting the amplitudes of the high and low frequency components, and activating an indicator for the mental state activity only in response to the detected high frequency component having an amplitude less than a first predetermined level indicative of the subject not being in a state of relaxation and the detected low frequency component having an amplitude greater than a first predetermined value and less than a second predetermined value, the amplitude of the low frequency component between the first and second predetermined values being associated with the alpha waves.
- 20. Apparatus for indicating the state of mental activity of a human subject comprising electrode means adapted to be placed on the head of the subject, said electrode means adapted to respond to brain activity of the subject to derive a signal including low frequency a.c. components having a frequency range in the same low frequency range as alpha waves derived by the brain and high frequency a.c. components having a minimum frequency considerably high than the highest frequency of the alpha waves, indicator means for detecting the amplitudes of the high and low frequency components, and means for activating the indicator means for the mental state activity only in response to the detected high frequency component having an amplitude less than a first predetermined level indicative of the subject not being in a state of relaxation and the detected low frequency component having an amplitude greater than a first predetermined value and less than a second predetermined value, the amplitude of the low frequency component between the first and second predetermined values being associated with the alpha waves.
Specification