Stimulus timing for a stimulating medical device

• US 9,339,648 B2
• Filed: 01/28/2014
• Issued: 05/17/2016
• Est. Priority Date: 02/05/2009
• Status: Active Grant

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Smith, Zachary Mark
• Primary Examiner(s): VOORHEES, CATHERINE M
• Application Number:
  US14/165,936
• Publication Number:
  US 20140222104A1
• Time in Patent Office: 840 Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/36038 Cochlear stimulation
• CPC Class Codes: H04R 25/505 using digital signal processing

Abstract

Methods and systems are disclosed for determining the timing of stimulation applied using a medical device. In embodiments, the medical device filters a received signal to obtain a plurality of band-pass filtered signals, each corresponding to one or more stimulation channels. The medical device then determines the envelopes of these band-pass filtered signals. Next, the medical device determines the stimulation timing (i.e., the pulse times) for the corresponding stimulation channel based on the timing of a particular phase (e.g., a peak, a minimum, etc.) of the envelope. A pulse amplitude for the stimulation channel may then be determined, and stimulation applied using the determined amplitude and pulse time.

Claims

1. A method, comprising:

filtering a received signal to obtain a set of band-pass filtered signals;

determining one or more envelopes for at least one of the band-pass filtered signals;

determining, for at least one envelope of the one or more envelopes, a pulse rate for stimulation pulses at a corresponding stimulation channel of a stimulating medical device, wherein the pulse rate is based on when a detected value of a characteristic of the at least one envelope is equal to a specified value of the characteristic; and

delivering stimulation pulses via the corresponding stimulation channel using the pulse rate.

2. The method of claim 1, further comprising:

determining, based on at least one of the one or more envelopes, one or more pulse amplitudes for stimulation pulses at the corresponding stimulation channel; and

delivering stimulation pulses via the corresponding stimulation channel using the pulse rate and the one or more pulse amplitudes.

3. The method of claim 1, wherein each stimulation channel corresponds to one or more electrodes for use in delivering stimulation pulses.

4. The method of claim 1, wherein the set of band-pass filtered signals includes a plurality of band-pass filtered signals each corresponding to one of a plurality of stimulation channels of the stimulating medical device, and further comprising:

determining a plurality of envelopes, wherein each of the plurality of envelopes corresponds to one of the plurality of band-pass filtered signals;

determining pulse rates for stimulation pulses on stimulation channels corresponding to the plurality of band-pass filtered signals based on when a detected value of a characteristic of the corresponding envelope is equal to a specified value of the characteristic; and

delivering, via the stimulation channels corresponding to the plurality of band-pass filtered signals, stimulation pulses using the corresponding pulse rate.

5. The method of claim 1, further comprising:

determining, based on at least one of the one or more envelopes for each of the plurality of band-pass filtered signals, one or more pulse amplitudes for stimulation pulses at the corresponding stimulation channels; and

delivering, via the stimulation channels corresponding to the plurality of band-pass filtered signals, stimulation pulses using the corresponding pulse rate and one or more pulse amplitudes.

6. The method of claim 5, further comprising:

selecting a plurality of maxima from the pulse amplitudes; and

arbitrating between the selected maxima to determine a set of stimulation pulse rates and corresponding pulse amplitudes for use in delivery of stimulation pulses to the recipient.

7. The method of claim 6, wherein arbitrating between the selected maxima comprises:

selecting a set of stimulation pulses with the highest amplitude and at least one of delaying or dropping stimulating pulses having smaller amplitudes.

8. The method of claim 1, wherein the characteristic of the envelope is amplitude and the specified value is equal to a maximum value of the amplitude.

9. The method of claim 1, further comprising:

high-pass filtering the one or more envelopes to remove DC components of the one or more envelopes; and

detecting zero-crossings of the one or more high-pass filtered envelopes,

wherein the characteristic of the envelope is one or more of the detected zero crossings.

10. The method of claim 9, wherein the characteristic of the envelope is one of only positive going zero-crossings, only negative going zero-crossings, or a combination of positive going and negative going zero-crossings.

11. The method of claim 1, further comprising:

extracting an instantaneous phase of the one or more envelopes,

wherein the characteristic of the envelope is one or more selected instantaneous phases.

12. The method of claim 1, further comprising:

low-pass filtering each of the one or more envelopes, wherein the pulse rate of stimulation pulses is limited by a cutoff frequency of the corresponding low-pass-filtering.

13. The method of claim 12, wherein the low-pass filtering includes:

setting the cutoff frequency so as to limit low-pass filtered envelopes to a frequency range for which a parameter other than loudness can be perceived by a recipient of the stimulating medical device.

14. The method of claim 1, further comprising:

encoding the stimulation pulses using different speech coding strategies at different subsets of the stimulation channels.

15. The method of claim 14, wherein the different speech coding strategies are selected from a group comprising a Continuous Interleaved Sampling (CIS) strategy, a Spectral PEAK Extraction (SPEAK) strategy, and an Advanced Combination Encoders (ACE) strategy.