Peak-derived timing stimulation strategy for a multi-channel cochlear implant

• US 20040172101A1
• Filed: 04/15/2004
• Published: 09/02/2004
• Est. Priority Date: 05/24/2001
• Status: Active Grant

• Current Assignee: Hearworks Pty., Ltd. (Cochlear Limited)
• Original Assignee: Hearworks Pty., Ltd. (Cochlear Limited)
• Inventors: Van Hoesel, Richard
• Granted Patent: US 7,310,558 B2
• Time in Patent Office: Days
• US Class Current: 607/57
• CPC Class Codes: A61N 1/36038 Cochlear stimulation

Abstract

A binaural cochlear implant system, including two intracochlear implants adapted for implantation in the cochleas of a user, each cochlear implant utilising a speech processing strategy wherein the electrical stimuli are matched to the relative timing of the relevant audio signals as detected at each ear, such that the interaural time delays between the audio signals at each ear are substantially preserved in electrical stimuli at each ear.

The processing strategy comprises band pass filtering the audio signal, determining the peaks in, and intensity of, each band, prioritising and placing each peak in a buffer in time slots corresponding to the relative timing of each peak. The buffer output forms the basis for stimulus instructions.

Claims

1. A process for generating stimuli for use in a cochlear implant, including the steps of:

receiving an audio signal and processing it so as to define signals within each of a set of frequency channels;

determining the peaks in each of said signals, including the time of each peak and its intensity;

prioritising each of said peaks according to a predetermined instruction set,

placing each peak, in order of priority, into a buffer in a time slot corresponding to the time of the peak in said channel; and

outputting a set of data for use in generating stimulus instructions from said buffer.

4. A process according to claim 1, wherein said predetermined instruction set includes an arbitration scheme to be applied when peaks occur on more than one channel within the same sampling period, said arbitration scheme being such that up to a predefined frequency channel, priority is given to low frequency channels over high frequency channels unless the higher frequency channel has an amplitude which is larger by a predefined amount than the lower channel, and wherein for channels higher than the predefined channel, priority is given only on the basis of low frequency channels over high frequency channels, and wherein if no appropriate time slot is available for lower priority channels, the peak on that channel is discarded.

5. A process according to claim 1, wherein said predetermined instruction set includes a rate limitation method, wherein a minimum time interval between peaks on each channel is specified, and peaks occurring within said interval are discarded.

6. A process according to claim 1, wherein the output data is such that stimuli are presented at electrodes in an order which corresponds to the order of the corresponding peaks in the audio signal.

7. A process according to claim 6, wherein the stimuli are further presented with a relative timing which substantially corresponds to the timing of the corresponding peaks in the audio spectrum.

9. A process according to claim 6, wherein said process further includes a rate limitation step applied after the peaks have been determined, wherein a minimum time -interval between peaks on a channel is specified, and peaks occurring within said interval are discarded.

2. An cochlear implant device, including

a filter for receiving an audio signal and processing it so as to define signals within each of a set of frequency channels;

processing means adapted to determine the peaks in each of said signals, including the time of each peak and its intensity, and to prioritise each of said channels in response to a predetermined instruction set;

said processing means further placing each peak, in order of priority, into a buffer, so that each peak is placed into a time slot corresponding to the time of the peak in said channel, the output of said buffer being used in generating stimulus instructions for said device.

3. A binaural cochlear implant system, including two intracochlear implants adapted for implantation in the cochleas of a user, each of said cochlear implants utilising a speech processing strategy wherein the electrical stimuli are matched to the relative timing of the relevant audio signals as detected at each ear, such that the interaural time delays between the audio signals at each ear are substantially preserved in electrical stimuli at each ear.

8. A process for generating stimuli for use in a cochlear implant, including the steps of:

receiving an audio signal and processing it so as to define signals within each of a set of frequency channels;

determining the peaks in each of said signals, including the time of each peak and its intensity;

applying an arbitration scheme when peaks occur in more than one channel within the same sampling period; and

outputting a set of data for use in generating stimulus instructions from said buffer,

characterised in that said arbitration scheme operates so that up to a predefined frequency channel, priority is given to low frequency channels over high frequency channels unless the higher frequency channel has an amplitude which is larger by a predefined amount than the lower channel, and wherein for channels higher than the predefined channel, priority is given only on the basis of low frequency channels over high frequency channels, and wherein if no appropriate time slot is available for lower priority channels, the peak on that channel is discarded.