Method of nerve stimulation and a stimulator for the application of the method
First Claim
1. A method for electric excitation of living cells by means of an electromagnetically inductive receiver implanted in a living body and equipped with output electrodes, comprising the steps of:
- producing an alternating electromagnetic induction field at the location of said receiver of a frequency variable about a reference frequency f0 by means of a transmitter external to said body operated at a frequency f so set and for a period so selected that the requency difference f -f0 corresponds to a desired amplitude of a cell excitation pulse and the selected period corresponds to a desired cell excitation pulse duration, and repeating said field producing step at predetermined intervals to the extent further cell excitation is desired;
detecting said induction field in said receiver to collect energy therefrom for operating said receiver, anddetecting in said receiver the extent of said frequency difference f -f0 of said induction field and producing in response thereto at said output electrodes a cell excitation signal of an amplitude corresponding to said frequency difference f -f0 and of a duration determined by said selected period.
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Accused Products
Abstract
In order to excite living cells, a FM transmitter transmits for a period t at a frequency f such that the difference between f and a reference frequency fO sets the amplitude of a desired nerve stimulation pulse. A receiver implanted in the living body is inductively coupled to the transmitter and processes the signal so as to obtain an output signal having an amplitude which is proportional to the frequency deviation. The duration of the stimulation pulse is adjustable independently of the amplitude. The output signal is applied between two electrodes which are implanted in the vicinity of the cells to be excited and can be multiplexed to excite several pairs of electrodes in succession by an electronic circuit advanced by signal segments at a frequency at one end of the deviation range.
60 Citations
8 Claims
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1. A method for electric excitation of living cells by means of an electromagnetically inductive receiver implanted in a living body and equipped with output electrodes, comprising the steps of:
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producing an alternating electromagnetic induction field at the location of said receiver of a frequency variable about a reference frequency f0 by means of a transmitter external to said body operated at a frequency f so set and for a period so selected that the requency difference f -f0 corresponds to a desired amplitude of a cell excitation pulse and the selected period corresponds to a desired cell excitation pulse duration, and repeating said field producing step at predetermined intervals to the extent further cell excitation is desired; detecting said induction field in said receiver to collect energy therefrom for operating said receiver, and detecting in said receiver the extent of said frequency difference f -f0 of said induction field and producing in response thereto at said output electrodes a cell excitation signal of an amplitude corresponding to said frequency difference f -f0 and of a duration determined by said selected period. - View Dependent Claims (2)
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3. A method for electric excitation of living cells by means of an electromagnetically inductive receiver implanted in a living body and equipped with output electrodes, comprising the steps of:
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producing an alternating electromagnetic induction field at the location of said receiver by means of a variable frequency transmitter external to said body successively at frequencies f1,f2 fi 2 fi respectively for durations t1 t2 . . . ti ; detecting said induction field in said receiver to collect energy therefrom for operating said receiver, and detecting in said receiver the several frequencies f1, f2 . . . fi and in response to at least one of them switching the output of said receiver from one to another pair of cell excitation electrodes among a set of a plurality of pair of cell excitation electrodes implanted in said living body, and in response to others of said frequencies f1, f2 . . . fi producing at one pair of said electrodes a cell excitation signal of an amplitude and polarity determined by the difference between the particular frequency and a reference frequency f0 and of a duration determined by the corresponding of the period durations t1, t2 . . . ti.
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4. A stimulator for implantation in a living body and there delivering, by means of electrodes, pulses which are capable of electrically exciting living cells in response to a frequency modulated electromagnetic transmitter external to said living body, said stimulator comprising, in combination:
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a receiving coil tuned to a predetermined reference frequency f0 ; first detecting means responsive to the output of the receiving coil for delivering a continuous d.c. signal having a duration equal to the duration of an alternating current signal obtained at the output of the receiving coil; stabilizing circuit means responsive to said first detecting means for providing a continuous d.c. output signal having a constant as well as a duration equal to the duration of said alternating current signal; frequency detection means, having a first input connected for response to the output of said receiving coil and having a second input connected to the output of said stabilizing circuit, for delivering an output signal having a magnitude which is proportional to the difference between the detected frequency f and said reference frequency f0 during a time interval t equal to the duration of said alternating current signal obtained at the output of the receiving coil and for delivering no significant output at other times; pulse shaping circuit means for producing a cell stimulating pulse in response to the output of said frequency detection means, having a control input connected to the output of said frequency detection means, said pulse having an amplitude which is proportional to said frequency difference f -f0 and a duration determined by said time interval t, and output means, including electrodes implanted in said living body, responsive to the output of said pulse shaping circuit means for providing cell stimulating pulses to living cells adjacent to said electrodes. - View Dependent Claims (5, 6, 7, 8)
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Specification