Multichannel cochlear prosthesis with flexible control of stimulus waveforms

• US 5,601,617 A
• Filed: 04/26/1995
• Issued: 02/11/1997
• Est. Priority Date: 04/26/1995
• Status: Expired due to Term

• Current Assignee: Advanced Bionics AG (Sonova Holding AG)
• Original Assignee: Advanced Bionics Corporation (Sonova Holding AG)
• Inventors: Faltys, Michael A., Loeb, Gerald E.
• Primary Examiner(s): Kamm, William E.
• Assistant Examiner(s): LAYNO, CARL HERNANDZ
• Application Number:
  US08/429,749
• Time in Patent Office: 657 Days
• Field of Search: 607/55, 607/56, 607/57, 607/60
• US Class Current: 607/56
• CPC Class Codes: A61N 1/36038 Cochlear stimulation

Abstract

A method and system of readily specifying a wide range of temporospatial patterns of electrical stimulation waveforms that can be used by an implantable cochlear prosthesis. Such stimulation patterns and waveforms can thus be readily tested by an audiologist in the process of fitting the cochlear prosthesis, allowing desirable patterns of pulsatile stimuli of almost arbitrary complexity to be modulated in real-time by the acoustic signal to produce useful perceptions of sound in otherwise deaf patients. The cochlear prosthesis includes two main components: (1) an external system, and (2) an implantable system. The external system includes electronic circuitry, typically including a microprocessor, that converts sensed acoustical signals to electrical signals and processes the electrical signals in accordance with a desired speech processing strategy. The present invention facilitates the definition of complex stimulation waveforms to be used as part of the selected speech processing strategy. In a preferred embodiment, the stimulation patterns and waveforms are specified in a template table, the rows and columns of which define time intervals and stimulation sites. Alternatively, the stimulation patterns and waveforms may be specified in a list of spatial/temporal events.

Claims

1. A cochlear prosthesis system comprising:

an implantable cochlear stimulator (ICS) having a multiplicity of electrode pairs, means for receiving power and control signals, and means responsive to receiving the power and control signals for generating a multiplicity of temporospatial patterns of stimulus waveforms that are applied to said electrode pairs;

a wearable processor (WP) including means for generating the power and control signals, means for transmitting the power and control signals to the ICS, and means for specifying within the control signals a particular temporospatial pattern of stimulus waveforms for application to each of the multiplicity of electrode pairs, whereby a first electrode pair may be stimulated with a first temporospatial pattern of stimulus waveforms, a second electrode pair may be stimulated with a second temporospatial pattern of stimulus waveforms, and so on, with each of the multiplicity of electrode pairs being stimulated with a temporospatial pattern of stimulus waveforms that has been individually specified for that electrode pair;

the WP including template means for specifying a template of a temporospatial pattern of stimulus waveforms to be applied to each of the multiplicity of electrode pairs, said template means comprising means for generating a table having rows and columns, with each one of the rows or columns being associated with one of the multiplicity of electrode pairs, and with each one of the other of the columns or rows being associated with an increment of time such that a consecutive sequence of the other of the columns or rows represents increasing time, and wherein the intersection of each row and column comprises a table cell, and wherein said template means further includes means for inserting a data value in any cell of said table, said data value defining the amplitude and polarity of the stimulus waveform for the electrode pair and time represented by the table cell wherein the data value is inserted, whereby the template of the temporospatial pattern of stimulus waveforms specified for a given electrode pair is defined by the sequence of data values inserted in the column or row of said table corresponding to said given electrode pair.

2. The cohlear prosthesis system of claim 1 wherein said template means further includes means for interpreting a blank table cell as specifying a zero stimulus waveform for the electrode pair corresponding to the column of the blank table cell at the time corresponding to the row of the blank table cell.

3. The cochlear prosthesis system of claim 2 wherein the rows of the table are associated with an increment of time such that a sequence of consecutive rows represents increasing time, and wherein each column of the table is associated with one of the multiplicity of electrode pairs.

4. The cochlear prosthesis system of claim 2 wherein the columns of the table are associated with an increment of time such that a sequence of consecutive columns represents increasing time, and wherein each row of the table is associated with one of the multiplicity of electrode pairs.

5. The cochlear prosthesis system of claim 2 wherein the WP further includes means for displaying the table generated by said template means, including displaying the data values and blanks which may be inserted into the individual cells of said table.

6. The cochlear prosthesis system of claim 2 wherein the length of the row or column used to represent increasing time defines a data frame having a specified duration, which specified duration in turn defines a minimum pulse width that may be utilized in the stimulus waveform.

7. The cochlear prosthesis system of claim 6 wherein said template means includes means for shortening selected rows of said table to reduce the number of blank cells in the row, thereby reducing the minimum pulse width that may be utilized in the stimulus waveform, thereby allowing a more rapid rate of pulses in the stimulus waveform.

8. The cochlear prosthesis system of claim 7 wherein the WP includes mapping means for specifying that the pulses of the stimulus waveform having the minimum pulse width and most rapid rate are directed within the ICS to a first electrode pair positioned within the cochlea to best provide high frequency information to the cochlea.

9. The cochlear prosthesis system of claim 8 wherein the first electrode pair is positioned near a basal end of the cochlea.

10. The cochlear prosthesis system of claim 1, wherein the template means includes means for specifying a multiplicity of temporaspatial patterns of stimulus waveforms, said multiplicity of temporospatial patterns of stimulus waveforms including biphasic pulses, biphasic pulses with delays, asymmetrical pulses, and triphasic pulses.

11. The cochlear prosthesis system of claim 10 wherein the multiplicity of temporospatial patterns of stimulus waveforms further includes alterphasic pulses.

12. The cochlear prosthesis system of claim 1 further including means for stimulating a first electrode pair with a first temporospatial pattern of stimulus waveforms at the same time that a second electrode pair is stimulated with a second temporospatial pattern of stimulus waveforms.

13. The cochlear prosthesis system of claim 12 wherein the stimulation means further includes means for stimulating other electrode pairs besides the first electrode pair and the second electrode pair simultaneously at a time when the first and second electrode pairs are not stimulated.

14. The cochlear prosthesis system of claim 1 wherein the temporospatial pattern of stimulus waveforms comprises a double-speed continuous interleaved sampling (CIS) strategy wherein simultaneous pulses are applied on at least two pairs of electrodes each time a stimulus waveform is generated.

15. The cochlear prosthesis system of claim 14 wherein the simultaneous pulses that are applied on at least two pairs of electrodes each time a stimulus waveform is generated comprise biphasic stimulation pulses.

16. The cochlear prosthesis system of claim 1 wherein the temporospatial pattern of stimulus waveforms comprises a continuous interleaved sampling (CIS) strategy wherein short pulses are applied at a rapid rate to a first electrode pair, and longer pulses are applied at a less frequent rate to a second electrode pair.

17. The cochlear prosthesis system of claim 16 wherein a short pulse is applied to the first electrode pair for every two pulses included in the stimulus waveform.

18. The cochlear prosthesis system of claim 1 wherein the template means of the WP comprises means for mathematically defining the table which specifies the temporaspatial pattern of stimulus waveforms to be applied to each of the multiplicity of electrode pairs.

19. The cochlear prosthesis system of claim 1 wherein the template means of the WP comprises means for logically defining the table which specifies the temporaspatial pattern of stimulus waveforms to be applied to each of the multiplicity of electrode pairs.

20. A method of controlling an implantable cochlear stimulator (ICS), said ICS including a multiplicity of channels, each channel having a pair of stimulation electrodes associated therewith and means for generating and applying a stimulation pulse thereto;

and means for defining a data frame that defines a time period during which the multiplicity of channels are stimulated in accordance with a prescribed pattern;

said method comprising the steps of;

(a) specifying external to the ICS a particular type of stimulation waveform that is desired for each channel of the ICS during each data frame, said type of stimulation waveform including a specification of a stimulation pulse polarity, magnitude, duration, and time of occurrence within the data frame, the type of stimulation waveform specified for one channel being completely independent of the type of stimulation waveforms specified for others of the channels, whereby each channel has its own stimulation waveform specified therefor, which stimulation waveform need not be the same as the stimulation waveform specified for another channel, but can be when desired, said specifying comprising;

generating a table having rows and columns, each column or row being associated with one of the multiplicity of channels, and each row or column being associated with an increment of time equal to the duration of the narrowest pulse width to be included within the stimulation waveform, such that the channels and increments of time form the two ordinates of the table, with the sum of the time increments from all of the rows/columns of the table equaling the time period of a data frame, and wherein the intersection of each row and column comprises a table cell, and

inserting an alphanumerical value in the cell of the table that defines the desired amplitude and polarity of the stimulus waveform for the channel and frame time corresponding to the table cell, whereby the temporospatial pattern of stimulus waveforms specified for a given channel is defined by the sequence of alphanumerical values inserted in the column/row of said table corresponding to said given channel;

(b) generating and transmitting a control signal to the ICS that defines the particular type of stimulation waveform desired for each channel of the ICS;

(c) receiving the control signal at the ICS; and

(d) generating the stimulation waveform specified by the control signal for each channel of the ICS during each data frame.

21. The method of claim 20 further including interpreting a null value (blank) table cell as specifying a zero stimulus waveform for the channel corresponding to the column/row of the null value table cell at the frame time corresponding to the row/column of the null value table cell.

22. The method of claim 21 further including shortening the frame time by an amount equal to the number of cells in a given row/column of the table that contain nothing but null values.

23. A multichannel cochlear prosthesis comprising:

a speech processor;

a cochlear stimulator; and

means for coupling the speech processor and the cochlear stimulator together so that data signals and control signals may be passed therebetween;

said speech processor including;

template storage means for storing a set of coefficients that represent a particular temporospatial pattern of stimulus waveforms,

means responsive to the set of coefficients stored in the template storage means for generating data and control signals that specify a particular temporospatial pattern of controlled stimulus waveforms to be generated by respective channels within the cochlear stimulator; and

said cochlear stimulator including;

means for receiving said data and control signals from the speech processor,

a multiplicity of channels, each having at least one pair of electrodes associated therewith,

means for generating a controlled stimulus waveform for each of the multiplicity of channels as a function of said data and control signals received from the speech processor, and

means for applying the controlled stimulus waveform to at least two of the multiplicity of channels so that the specified controlled stimulus waveform appears across the paired electrodes of at least two channels.

24. The multichannel cochlear prosthesis of claim 23 wherein the controlled stimulus waveform applied to at least two of the multiplicity of channels comprises a waveform selected from the group comprising biphasic pulses, triphasic pulses, asymmetrical pulses, and alterphasic pulses.

25. The multichannel cochlear prosthesis of claim 23 wherein the means for applying the controlled stimulus waveform to at least two of the multiplicity of channels includes means for grouping the multiplicity of channels into a plurality of groups of channels, wherein each group includes at least two channels;

and means for simultaneously applying the controlled stimulus to each of the plurality of channels in each group in sequence so that all of the channels in a first group receive the controlled stimulus at a first time, all of the channels in a second group receive a controlled stimulus at a second time, and so on, until all of the groups have received the controlled stimulus in sequence.