US3910258A
Expired / Lapsed
US
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Cerebral activity monitor
Assignee: Humetrics Corp
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Filing: 1974-04-18
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Granted: 1975-10-07
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Expires: 1994-04-18
Abstract
Abstract A brain wave signal monitor with a warning device actuated by failure of the signals to be present at a preselected minimal level for a specific period of time. The warning device is actuated by a circuit that remains locked in the actuating condition until reset by an attendant. A delay circuit controls the minimum rate by preventing actuation of the warning device until a predetermined time has elapsed since the last brain wave signal. A circuit tuned to the local power line frequency receives signals from electrodes on the patient and provides a second type of warning signal if an electrode becomes dislodged. A third signal circuit is actuated if the power supply voltage drops too low. The second and third warning signals are generated by selectively pulsing a calibration signal generator. The latter also supplies signals of known amplitude to the input circuit. An electrically controlled switching circuit can switch selected electrodes or the calibration signal to the input amplifier.
Inventors
- 👤 Lech Pisarski
- 👤 Adelbert W Valiensi
- 👤 Lee R Baessler
- 👤 Harvey F Glassner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:20
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/24; A61B5/30; A61B5/307; A61B5/31; A61B5/25; A61B5/276; A61B5/304; A61B5/316; A61B5/369
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
209 words
A cerebral activity monitor comprising: A. means to derive electroencephalographic signals from a patient; B. rectifier means connected to receive selected ones of said signals and to transform the selected signals into a unipotential signal of varying magnitude impulses; C. integrator means connected to said rectifier means to generate a voltage that tends to change in one direction between successive ones of said impulses and tends to return to an initial value at the occurrence of each of said impulses that has at least a certain magnitude; D. a level detector circuit connected to said integrator means to be actuated when said output signal of said integrator changes in said one direction beyond a predetermined level, said level detector circuit returning to a predetermined output voltage value each time said voltage returns to said initial value; E. a switching circuit connected to said level detector to be actuated by the output signal from said level detector anD comprising a time constant circuit to start a change of charge level from the same predetermined initial level each time said switching circuit is actuated; and F. warning means connected to said time constant circuit to be actuated when the charge level of said time constant circuit reaches a predetermined actuating value.
Claim 2
Dependent Claim
209 words
A cerebral activity monitor comprising: A. means to derive electroencephalographic signals from a patient; B. rectifier means connected to receive selected ones of said signals and to transform the selected signals into a unipotential signal of varying magnitude impulses; C. integrator means connected to said rectifier means to generate a voltage that tends to change in one direction between successive ones of said impulses and tends to return to an initial value at the occurrence of each of said impulses that has at least a certain magnitude; D. a level detector circuit connected to said integrator means to be actuated when said output signal of said integrator changes in said one direction beyond a predetermined level, said level detector circuit returning to a predetermined output voltage value each time said voltage returns to said initial value; E. a switching circuit connected to said level detector to be actuated by the output signal from said level detector anD comprising a time constant circuit to start a change of charge level from the same predetermined initial level each time said switching circuit is actuated; and F. warning means connected to said time constant circuit to be actuated when the charge level of said time constant circuit reaches a predetermined actuating value.
Claim 3
Dependent Claim
30 words
The cerebral activity monitor of claim 1 in which said integrator means comprises a second time constant circuit of substantially lower time constant value than said first-named time constant circuit.
Claim 4
Dependent Claim
35 words
The cerebral activity monitor of claim 2 in which said time constant value of said first-named time constant is approximately 25 times as high as said time constant value of said second time constant circuit.
Claim 5
Dependent Claim
36 words
The cerebral activity monitor of claim 2 in which said level detector comprises level determining means to cause said level detector circuit to be actuated approximately 1 second after the last one of said selected signals.
Claim 6
Dependent Claim
32 words
The cerebral activity monitor of claim 4 in which said first-named time constant circuit allows said warning means to be actuated approximately 5 seconds after the last one of said selected signals.
Claim 7
Dependent Claim
74 words
The cerebral activity monitor of claim 1 in which said warning means comprises: A. a flip-flop having first and second conductivity conditions and connected to said level detector to be shifted from said first conductivity condition to said second conductivity condition when said warning means is actuated; and B. a warning device connected to said flip-flop to be placed in a continuous warning condition until said flip-flop is reset to said first conductivity condition.
Claim 8
Dependent Claim
112 words
The cerebral activity monitor of claim 1 in which said warning means is actuated to emit a first warning signal when the charge level of said time constant circuit reaches a predetermined actuating value, and said monitor comprises, in addition, a loose electrode detecting circuit connected to the output of said amplifier and tuned to respond to alternating current power line signals picked up by said input means if one of said electrodes becomes disengaged from said patient, said detecting circuit being connected to said warning device to actuate said warning device to emit a second warning signal noticeably different from the first warning signal as long as said electrode remains disengaged.
Claim 9
Dependent Claim
58 words
The cerebral activity monitor of claim 7 in which said loose electrode circuit comprises: A. a rectifying circuit connected to said electrodes to rectify said alternating current power line signals from said electrodes; and B. means connecting said rectifying curcuit to said warning device to actuate said warning device in response to rectified signals from said rectifying circuit.
Claim 10
Dependent Claim
46 words
The cerebral activity monitor of claim 8 in which said means connecting said rectifying circuit to said warning device comprises a pulsating circuit actuated in response to rectified signals from said rectifying circuit and connected to said warning device to actuate said warning device in pulsations.
Claim 11
Dependent Claim
68 words
The cerebral activity monitor of claim 9 in which said pulsating circuit comprises: A. a pulse generator connected to said rectifying circuit to be actuated in response to rectified signals therefrom; and B. a flip-flop circuit connected to said pulse generator to provide a pulsating signal, said flip-flop circuit being connected to said warning device to supply said pulsating signal thereto to actuate said warning device in pulsations.
Claim 12
Dependent Claim
70 words
The cerebral activity monitor of claim 10 in which said flip-flop circuit comprises a power supply input terminal and said monitor comprises, in addition, a transistor comprising an output circuit connecting said power supply input terminal to a power supply source terminal, said transistor also comprising an input circuit connected to be actuated in response to rectified signals from said rectifying circuit to cause said output circuIt to be conductive.
Claim 13
Dependent Claim
73 words
The cerebral activity monitor of claim 7 comprising, in addition: A. a power supply; B. measuring means connected to said power supply to measure the output voltage thereof; C. a second warning device; and D. warning device connection means connecting said measuring means to said second warning device to supply a low-voltage warning signal to actuate said second warning device when the output voltage of said power supply is below a predetermined level.
Claim 14
Dependent Claim
43 words
The cerebral activity monitor of claim 12 in which said second warning device is a light-emitting diode, said monitor comprising, in addition, means connecting said measuring means to said first-named warning device to actuate said first-named warning device simultaneously with said light-emitting diode.
Claim 15
Dependent Claim
55 words
The cerebral activity monitor of claim 12 in which said warning device connection means comprises: A. a pulse generator connected to said measuring means to be activated thereby; and B. a flip-flop circuit connected to said pulse generator to produce a pulsating signal to actuate both said first-named warning device and said second warning device.
Claim 16
Dependent Claim
63 words
The cerebral activity monitor of claim 14 in which said warning device connection means further comprises: A. unidirectionally conductive means connected between said measuring means and said pulse generator to supply operating voltage to said pulse generator for the duration of said low-voltage signal; and B. pulse frequency modifying means to modify the natural frequency of said pulse generator to a second frequency.
Claim 17
Dependent Claim
72 words
The cerebral activity monitor of claim 15 in which said flip-flop circuit comprises a power supply input terminal and said monitor comprises, in addition a transistor comprising an output circuit connecting said power supply input terminal to a terminal of said power supply, said transistor also comprising an input circuit connected to said unidirectionally conductive means to cause said output circuit to be conductive for the duration of said low-voltage warning signal.
Claim 18
Dependent Claim
114 words
The cerebral activity monitor of claim 16 in which said loose electrode circuit comprises a rectifying circuit to rectify said alternating power line signals, said monitor further comprising: A. second unidirectionally conductive means connected between said rectifying circuit and said pulse generator to supply operating voltage to said pulse generator for the duration of rectified signals from said rectifying circuit; B. second pulse frequency modifying means to modify the natural frequency of said pulse generator to a third frequency; and C. disabling means connected to said rectifying circuit to be actuated thereby and connected to said second warning device to disable it from operating for the duration of rectified signals from said rectifying circuit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-10-06 | 1979-04-07 | 1979-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-06 | 1983-04-07 | 1983-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-06 | 1987-04-07 | 1987-10-07 | $7700.00 | Window Closed / Lapsed |