# US 8,494,625 B2 · Methods and apparatus for electrical stimulation of tissues using signals that minimize the effects of tissue impedance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,494,625 B2 - Document ID: US8494625B2 - Status: Granted - Kind: B2 - Application number: 12/187,375 - Filed: 2008-08-06 - Published: 2009-01-29 - Granted: 2013-07-23 - Earliest claimed: 2002-02-04 - Assignees: Cerephex Corporation - Applicants: Jeffrey B. Hargrove - Inventors: Jeffrey B. Hargrove - Web page: https://patentgrep.com/patent/US8494625B2 ## CPC - A61B 5/374: Detecting the frequency distribution of signals, e.g. detecting delta, theta, alpha, beta or gamma waves - A61B 5/372: Analysis of electroencephalograms - A61B 5/378: Visual stimuli - A61B 5/383: Somatosensory stimuli, e.g. electric stimulation - A61B 5/6843: {Monitoring or controlling sensor contact pressure} - A61N 1/36025: {for treating a mental or cerebral condition} - A61N 1/36031: {using physiological parameters for adjustment} - A61N 1/36034: {specified by the stimulation parameters} - A61N 1/36082: {Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease} - A61N 1/37247: {User interfaces, e.g. input or presentation means} - G16H 50/70: for mining of medical data, e.g. analysing previous cases of other patients - A61B 5/053: Measuring electrical impedance or conductance of a portion of the body - A61B 5/145: Measuring characteristics of blood in vivo, e.g. gas concentration or pH-value {; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid or cerebral tissue} (non-radiation detecting or locating of foreign bodies in blood A61B5/06) - A61B 5/4519: {Muscles (measuring muscular strength A61B5/224; using electromyography [EMG] A61B5/389)} - A61B 5/7257: {using Fourier transforms} - A61N 1/37235: {Aspects of the external programmer} - G16H 40/63: for local operation - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) - G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA ## Abstract A tissue stimulation system that generates an electrical tissue stimulation signal configured to reduce tissue impedance and increase depth of signal penetration. The use of leads is dynamically controlled and altered between conducting biopotential voltages, conducting electrical tissue stimulation signals, and grounding, in response to a computational analysis of biopotential data acquired from a region of tissue to be stimulated. ## Claims ### Claim 1 A tissue stimulation apparatus comprising an electrical stimulation device that includes a stimulation signal generation circuit configured to generate an electrical tissue stimulation signal comprising a therapeutic signal component and a penetration signal component wherein the penetration signal component is configured to reduce tissue impedance and increase depth of stimulation signal penetration. ### Claim 2 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the stimulation signal generation circuit is configured to generate an amplitude modulated pulse width modulated (AMPWM) signal. ### Claim 3 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the stimulation signal generation circuit comprises a processor configured to control generation of electrical signals by the electrical stimulation device for tissue stimulation. ### Claim 4 (depends on 3) A tissue stimulation apparatus as set forth in claim 3 in which the tissue stimulation apparatus includes an external computing device electrically coupled to the processor and configured to provide a user interface. ### Claim 5 (depends on 4) A tissue stimulation apparatus as set forth in claim 4 in which the external computing device is configured to exchange data and control signals with the processor. ### Claim 6 (depends on 4) A tissue stimulation apparatus as set forth in claim 4 in which the external computing device is configured to allow a user to modify operational parameters of the electrical stimulation device. ### Claim 7 (depends on 4) A tissue stimulation apparatus as set forth in claim 4 in which the external computing device is configured to establish parameters of the electrical signals generated by the device. ### Claim 8 (depends on 4) A tissue stimulation apparatus as set forth in claim 4 in which the external computing device is configured to functionally interface with at least one other network computing device. ### Claim 9 (depends on 8) A tissue stimulation apparatus as set forth in claim 8 in which the external computing device is configured to functionally interface with at least one of the other network computing devices via the Internet. ### Claim 10 (depends on 9) A tissue stimulation apparatus as set forth in claim 9 in which the external computing device is configured to functionally interface with at least one of the other network computing devices to determine parametric values of an electrical tissue stimulation signal, and to receive subsequent corresponding control data from the other network computing device via the functional interfaces. ### Claim 11 (depends on 3) A tissue stimulation apparatus as set forth in claim 3 in which the stimulation signal generation circuit further comprises a digital-to-analog (D/A) converter configured to receive signal parameters from the processor and to generate a corresponding analog voltage representing an electrical signal for stimulating tissues. ### Claim 12 (depends on 11) A tissue stimulation apparatus as set forth in claim 11 in which the stimulation signal generation circuit further comprises a signal conditioning and amplification circuit configured to receive the analog voltage from the D/A converter and to generate a generally equivalent signal having one or more advantageous enhancements selected from the group of enhancements consisting of increased voltage amplitude, decreased signal-to-noise ratio, and increased current capability. ### Claim 13 (depends on 12) A tissue stimulation apparatus as set forth in claim 12 in which the tissue stimulation apparatus includes a plurality of stimulation leads and one or more ground leads configured to conduct electrical energy between tissues and the electrical stimulation device. ### Claim 14 (depends on 13) A tissue stimulation apparatus as set forth in claim 13 in which the stimulation signal generation circuit is configured to selectively control the delivery of stimulating electrical signals to tissues through one or more selected ones of the stimulation leads. ### Claim 15 (depends on 14) A tissue stimulation apparatus as set forth in claim 14 in which the stimulation signal generation circuit further includes a stimulation switching circuit electrically coupled to the processor, the processor and stimulation switching circuit being configured to switch signals from the signal conditioning and amplification circuit to independent electrical conduction paths that are electrically coupled with the respective stimulation leads. ### Claim 16 (depends on 15) A tissue stimulation apparatus as set forth in claim 15 in which the stimulation signal generation circuit further includes a first ground switching circuit electrically coupled with the independent electrical conduction paths and with the processor, the processor and ground switching circuit being configured to selectively switch the independent conduction paths to at least one system ground point. ### Claim 17 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the electrical stimulation device includes: a battery connected to other circuits of the apparatus and configured to provide electrical power to other circuits of the electrical stimulation device; a battery charger and switching circuit electrically coupled to the battery; and a processor electrically coupled to the battery charger and switching circuit, the processor being configured to command the battery charger and switching circuit to decouple the device from an external power source when isolation is desired and to couple the external power source to the battery to charge the battery when isolation is not desired. ### Claim 18 (depends on 17) A tissue stimulation apparatus as set forth in claim 17 in which the electrical stimulation device includes at least one auxiliary control I/O connector electrically coupled with an input-output (I/O) port of the processor, the processor and control I/O connector being configured to provide control signals between the processor and a peripheral device. ### Claim 19 (depends on 13) A tissue stimulation apparatus as set forth in claim 13 in which the apparatus includes at least one lead test port electrically coupled to the processor and configured to electrically couple a conduction interface of one of the leads to the processor, the processor being configured to test the electrical conducting integrity of the lead whose conduction interface has been coupled via the lead test port to the processor. ### Claim 20 (depends on 19) A tissue stimulation apparatus as set forth in claim 19 in which the processor is configured to output an electrical signal of known properties to the lead whose conduction interface has been coupled via the lead test port to the processor, and to acquire and test the resulting electrical signal conducted through that lead and returned to the processor through the lead test port. ### Claim 21 (depends on 20) A tissue stimulation apparatus as set forth in claim 20 in which processor is configured to determine the electrical conducting integrity of the lead whose conduction interface has been coupled via the lead test port to the processor, by comparing the electrical signal of known properties to the signal conducted through that lead. ### Claim 22 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the tissue stimulation apparatus includes one or more external stimulation devices electrically coupleable to the electrical stimulation device. ### Claim 23 (depends on 22) A tissue stimulation apparatus as set forth in claim 22 in which the one or more external stimulation devices include one or more devices selected from the group of devices consisting of an optical device, an electromagnetic device, and electromechanical device, and an audio device. ### Claim 24 (depends on 22) A tissue stimulation apparatus as set forth in claim 22 in which the one or more external stimulation devices include an optical device comprising eyeglasses adapted to carry illuminating devices. ### Claim 25 (depends on 22) A tissue stimulation apparatus as set forth in claim 22 in which the one or more external stimulation devices include an optical device comprising one or more displays for showing images. ### Claim 26 (depends on 22) A tissue stimulation apparatus as set forth in claim 22 in which the one or more external stimulation devices include an audio device adapted to play music. ### Claim 27 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the tissue stimulation apparatus includes data collection instruments configured to collect data on a subject during periods of therapy and electrically coupled to the electrical stimulation device. ### Claim 28 (depends on 13) A tissue stimulation apparatus as set forth in claim 13 in which the tissue stimulation apparatus includes a biopotential acquisition device configured to measure biopotential voltage of tissues to be stimulated. ### Claim 29 (depends on 28) A tissue stimulation apparatus as set forth in claim 28 in which the biopotential acquisition device includes an amplifier module comprising a biopotential amplifier. ### Claim 30 (depends on 29) A tissue stimulation apparatus as set forth in claim 29 in which the biopotential acquisition device includes at least one biopotential acquisition lead and at least one ground lead. ### Claim 31 (depends on 30) A tissue stimulation apparatus as set forth in claim 30 in which the biopotential amplifier module is electrically coupleable to the electrical stimulation device through anyone or more connectors selected from the group of connectors consisting of stimulation lead connectors, auxiliary power supply connector, control I/O connectors, and auxiliary I/O connectors of the electrical stimulation device. ### Claim 32 (depends on 31) A tissue stimulation apparatus as set forth in claim 31 in which the biopotential acquisition device is configured to measure anyone or more biopotential voltages selected from the group of biopotential voltages consisting of electroencephalographic (EEG) voltage, electromyographic (EMG) voltage, and electrocardiographic voltage. ### Claim 33 (depends on 30) A tissue stimulation apparatus as set forth in claim 30 in which the tissue stimulation apparatus is configured for the biopotential amplifier to measure biopotential voltage of tissue as the electrical stimulation device provides stimulation to the tissue. ### Claim 34 (depends on 33) A tissue stimulation apparatus as set forth in claim 33 in which the biopotential acquisition device includes at least one inductor electrically coupled to the electrical stimulation device and operatively coupleable to at least one biopotential acquisition lead, the electrical stimulation device and the at least one inductor being configured to deliver tissue stimulation signals through the at least one biopotential acquisition lead. ### Claim 35 (depends on 33) A tissue stimulation apparatus as set forth in claim 33 in which the biopotential acquisition device includes one or more inductors electrically coupled to the electrical stimulation device and operatively coupleable to one or more respective biopotential acquisition leads, the electrical stimulation device and inductors being configured to selectively deliver tissue stimulation signals through the one or more biopotential acquisition leads. ### Claim 36 (depends on 33) A tissue stimulation apparatus as set forth in claim 33 in which the biopotential acquisition device includes at least one adjunct switching circuit and an adjunct switching control electrically coupled to the electrical stimulation device, the adjunct switching circuit being operatively coupleable to at least one biopotential acquisition lead, the electrical stimulation device and an adjunct switching control being configured to selectively connect the electrical stimulation device to selected leads to transmit tissue stimulation signals to the selected leads and to connect selected leads to the biopotential amplifier to transmit biopotential voltages to the biopotential amplifier. ### Claim 37 (depends on 30) A tissue stimulation apparatus as set forth in claim 30 in which the electrical stimulation device is configured to use at least one biopotential acquisition lead for both acquiring biopotential voltage and delivering an electrical tissue stimulation signal. ### Claim 38 (depends on 37) A tissue stimulation apparatus as set forth in claim 37 in which the electrical stimulation device is configured to use at least one biopotential acquisition lead for simultaneously acquiring biopotential voltage and delivering an electrical tissue stimulation signal. ### Claim 39 (depends on 38) A tissue stimulation apparatus as set forth in claim 38 in which the electrical stimulation device is configured to selectively sample biopotential voltage data from the biopotential acquisition device at times of minimal electrical stimulation signal amplitude. ### Claim 40 (depends on 39) A tissue stimulation apparatus as set forth in claim 39 in which the electrical stimulation device is configured to selectively sample biopotential voltage data from the biopotential acquisition device over assessment periods of between about I second and about 60 seconds. ### Claim 41 (depends on 39) A tissue stimulation apparatus as set forth in claim 39 in which the electrical stimulation device is configured to selectively sample biopotential voltage data from the biopotential acquisition device at times of minimal electrical stimulation signal amplitude within the period of a high frequency signal component of an AMPWM signal. ### Claim 42 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the electrical stimulation device is configured to select the frequencies of a high frequency signal component of an AMPWM signal to be multiples of integral powers of two. ### Claim 43 (depends on 42) A tissue stimulation apparatus as set forth in claim 42 in which the electrical stimulation device is configured to select the frequencies of a high frequency signal component of an AMPWM signal to be integral multiples of 256. ### Claim 44 (depends on 42) A tissue stimulation apparatus as set forth in claim 42 in which the electrical stimulation device is configured to mathematically analyze acquired biopotential voltage data using a Fourier Transform analysis whereupon a number of samples per second is equal to an integral power of two. ### Claim 45 (depends on 30) A tissue stimulation apparatus as set forth in claim 30 in which the tissue stimulation apparatus is configured to use biopotential voltage data to determine parametric values of an electrical tissue stimulation signal. ### Claim 46 (depends on 45) A tissue stimulation apparatus as set forth in claim 45 in which an external computing device is configured to determine parametric value of an electrical tissue stimulation signal in response to biopotential voltage data obtained by the biopotential acquisition device and to send corresponding control data to the processor. ### Claim 47 (depends on 46) A tissue stimulation apparatus as set forth in claim 46 in which the biopotential acquisition device is an EEG acquisition device and the external computing device is configured to determine parametric value of an electrical tissue stimulation signal in response to EEG data obtained by the EEG acquisition device and to send corresponding control data to the processor. ### Claim 48 (depends on 46) A tissue stimulation apparatus as set forth in claim 46 in which the tissue stimulation apparatus is configured to use at least one biopotential acquisition lead as either a conduction path for an electrical tissue stimulation signal, a conduction path for carrying a biopotential voltage to the biopotential amplifier, or a ground. ### Claim 49 (depends on 48) A tissue stimulation apparatus as set forth in claim 48 in which the processor is configured to selectively switch a biopotential acquisition lead to an apparatus ground point by sending corresponding control signals to the second ground switching circuit. ### Claim 50 (depends on 46) A tissue stimulation apparatus as set forth in claim 46 in which the processor is configured to differentially compare biopotential voltages at more than one acquisition site on a tissue by selectively using biopotential acquisition leads as reference leads to the biopotential amplifier or as differential leads to the biopotential amplifier. ### Claim 51 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the tissue stimulation apparatus includes an impedance testing circuit configured to monitor the impedance of tissues, the apparatus being configured to determine parametric values of an electrical tissue stimulation signal in response to tissue impedance data acquired by the impedance testing circuit. ### Claim 52 (depends on 51) A tissue stimulation apparatus as set forth in claim 51 in which the impedance testing circuit is coupled to the electrical stimulation device and a biopotential amplifier of a biopotential acquisition device and is configured to monitor the impedance of tissues in contact with at least one ground lead and at least one biopotential acquisition lead of the biopotential acquisition device and to transfer such data to the processor. ### Claim 53 (depends on 51) A tissue stimulation apparatus as set forth in claim 51 further including an external computing device coupled to the processor and configured to analyze tissue impedance data and to send corresponding control data to the processor for altering parametric parameters of electrical tissue stimulation signals. ### Claim 54 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the tissue stimulation apparatus includes an impedance testing circuit that is coupled with the biopotential amplifier of a biopotential acquisition device and is configured to monitor biopotential voltage integrity. ### Claim 55 (depends on 54) A tissue stimulation apparatus as set forth in claim 54 in which the tissue stimulation apparatus is configured to indicate to a user when good biopotential voltage integrity is achieved. ### Claim 56 (depends on 54) A tissue stimulation apparatus as set forth in claim 54 in which the tissue stimulation apparatus is configured to generate an alert when biopotential voltage integrity is lost. ### Claim 57 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 in which the tissue stimulation apparatus comprises: a sensor set; an independent biopotential voltage measurement apparatus; and an adjunct electrical stimulation apparatus operatively connected between the sensor set and the independent biopotential voltage measurement apparatus, operatively coupled to the electrical stimulation device, and configured to transmit to the sensor set electrical tissue stimulation signals received from the electrical stimulation device, to transmit biopotential voltage from the sensor set to the independent biopotential voltage measurement apparatus, and to receive control signals from a processor of the electrical stimulation device. ### Claim 58 (depends on 57) A tissue stimulation apparatus as set forth in claim 57 in which the biopotential measurement apparatus is an EEG measurement apparatus and the sensor set is an EEG sensor set. ### Claim 59 (depends on 57) A tissue stimulation apparatus as set forth in claim 57 in which the sensor set comprises at least one electrode and a cap configured to position the at least one electrode and to be worn by a subject. ### Claim 60 (depends on 57) A tissue stimulation apparatus as set forth in claim 57 in which in which the adjunct electrical stimulation apparatus includes: an adjunct switching control operatively coupled to the processor of the electrical stimulation device; a plurality of adjunct switching circuits operatively coupled to the adjunct switching control, to the electrical stimulation device, to the independent biopotential measurement apparatus, and to respective electrodes of the sensor set; and the processor and adjunct switching control are configured to provide selectable conduction pathways for tissue stimulation signals between the electrical stimulation device and the electrodes of the sensor set, and for biopotential voltages between the electrodes of the sensor set and the biopotential voltage measurement apparatus. ### Claim 61 (depends on 60) A tissue stimulation apparatus as set forth in claim 60 in which in which the processor and adjunct switching circuits are configured to provide selectable conduction pathways between the electrodes of the sensor set and a ground. ### Claim 62 (depends on 57) A tissue stimulation apparatus as set forth in claim 57 in which the adjunct electrical stimulation apparatus includes: a ground switching circuit operatively coupled to the processor of the electrical stimulation device, to the biopotential amplifier, and by conduction paths to respective electrodes of the sensor set; a plurality of inductors operatively coupled to the electrical stimulation device and to the conduction paths; and the processor and ground switching circuit are configured to provide selectable conduction pathways for tissue stimulation signals between the electrical stimulation device and the electrodes of the sensor set, and for biopotential voltages between the electrodes of the sensor set and the biopotential voltage measurement apparatus. ### Claim 63 (depends on 62) A tissue stimulation apparatus as set forth in claim 62 in which the processor and ground switching circuit are configured to provide selectable conduction pathways between the electrodes of the sensor set and a ground. ### Claim 64 (depends on 60) A tissue stimulation apparatus as set forth in claim 60 in which the adjunct electrical stimulation apparatus includes at least one switching control conductor electrically coupled to an adjunct switching circuit and configured to determine the state of the adjunct switching circuit and a conduction path provided to a corresponding electrode of the sensor set. ### Claim 65 (depends on 57) A tissue stimulation apparatus as set forth in claim 57 in which the processor of the electrical stimulation device and the adjunct switching control are configured to: direct biopotential voltage from selected electrodes of the sensor set to the biopotential measurement apparatus by selective switching via the adjunct switching control operated by the processor when a biopotential voltage measurement is required; to direct a tissue stimulation signal from the electrical stimulation device to selected electrodes of the sensor set by selective switching via the adjunct switching control operated by the processor when tissue stimulation is required; and to couple an electrode of the sensor set to ground by selective switching via the adjunct switching control operated by the processor when grounding of an electrode is desired. ### Claim 66 (depends on 1) A tissue stimulation apparatus as set forth in claim 1 and further comprising: a mobile apparatus carrying the electrical stimulation device; and a material supplies storage and use apparatus carried by the mobile apparatus and configured to carry consumable supplies for use in administering tissue stimulation signals to a subject. ### Claim 67 (depends on 66) A tissue stimulation apparatus as set forth in claim 66 in which the material supplies storage and use apparatus is configured to carry any number of consumable supplies selected from the group of supplies consisting of conductive pastes, conductive gels, cleaning materials, cleaning agents, and supporting materials. ### Claim 68 (depends on 66) A tissue stimulation apparatus as set forth in claim 66 in which the material supplies storage and use apparatus comprises a plurality of receptacles configured to store any number of items selected from the group of items consisting of a waste, conductive gel, conductive paste, cleaning materials, alcohol, supporting materials, and electrodes. ### Claim 69 (depends on 66) A tissue stimulation apparatus as set forth in claim 66 in which the material supplies storage and use apparatus includes an electrode storage receptacle configured to store and block light from reaching lead electrodes comprising photosensitive materials. ### Claim 70 (depends on 66) A tissue stimulation apparatus as set forth in claim 66 in which the tissue stimulation apparatus includes one or more sensors carried by the material supplies and use apparatus and configured to sense the quantities of materials stored in receptacles of the material supplies storage and use apparatus. ### Claim 71 (depends on 66) A tissue stimulation apparatus as set forth in claim 66 in which the tissue stimulation apparatus includes an external computing device coupled to the one or more sensors and configured to manage inventory in response to signals acquired from the one or more sensors. ### Claim 72 (depends on 71) A tissue stimulation apparatus as set forth in claim 71 in which the tissue stimulation apparatus is configured to generate an alert when inventory of any material reaches a predetermined low point. ### Claim 73 (depends on 71) A tissue stimulation apparatus as set forth in claim 71 in which the tissue stimulation apparatus is configured to order materials necessary to replenish inventory when a predetermined low point is reached. ### Claim 74 (depends on 71) A tissue stimulation apparatus as set forth in claim 71 in which the tissue stimulation apparatus is configured to order materials by interfacing with a communications network. ### Claim 75 (depends on 66) A tissue stimulation apparatus as set forth in claim 66 in which the electrical stimulation apparatus is configured to provide stimulation through composite stimulation leads, the composite stimulation leads comprising a combination of stimulation leads and ground leads. ### Claim 76 (depends on 75) A tissue stimulation apparatus as set forth in claim 75 in which the composite stimulation leads include external stimulation device cables.