Incremental stimulation sound processor
In one aspect of the invention, a cochlear implant constructed and arranged to successively generate stimulation signals each comprising at least one stimulus pulse such that said successive stimulation signals incrementally build a neural excitation pattern that accurately reflects a received sound. In one embodiment, each said successive stimulation signal is generated based on the cumulative effect of all previous stimulus pulses, thereby compensating for finite spatial spreading of individual stimulus pulses as well as for the temporal integration of the neural excitation pattern along the neural pathways.
1. A cochlear implant having a speech processor configured to convert a received electrical signal representing received ambient sound into instructions defining stimulation signals to deliver an excitation pattern to a recipient's auditory nerve, the cochlear implant comprising:
a modeler configured to calculate a model of an excitation pattern currently existing on the auditory nerve;
an increment generator configured to determine a difference between an ideal excitation pattern representing the received ambient sound and said existing excitation pattern in order to generate an incremental excitation pattern; and
apparatus for generating stimulation signals for delivery to the auditory nerve based on said incremental excitation pattern.
2. The cochlear implant of claim 1 , wherein said apparatus comprises:
an error reducer configured to modify said incremental excitation pattern to minimize selected error criterion based on an implemented optimization strategy to thereby generate an optimized incremental excitation pattern.
3. The cochlear implant of claim 2 , wherein said error reducer is further configured to select stimulation channels and associated pulse amplitudes of the stimulation signal to deliver said optimized incremental excitation pattern.
4. The cochlear implant of claim 2 , wherein the apparatus comprising:
a level mapper configured to convert said optimized incremental excitation pattern into electrical stimulation levels used to generate the stimulation signals.
5. The cochlear implant of claim 1 , wherein the apparatus comprising:
a level mapper configured to convert said incremental excitation pattern into electrical stimulation levels used to generate the stimulation signals.
6. The cochlear implant of claim 1 , further comprising:
a programmable memory configured to store said existing excitation pattern.
7. The cochlear implant of claim 6 , where said programmable memory is further configured to store at least one recipient-specific parameter.
8. The cochlear implant of claim 1 , further comprising:
an analyzer configured to generate said ideal excitation pattern based on said electrical signal.
9. The cochlear implant of claim 1 , wherein said modeler is further configured to calculate said model based on a spatial effect in the auditory nerve.
10. The cochlear implant of claim 9 , wherein said model based on the spatial effect is calculated using calculations that approximate a proximity effect from one or more previously generated instructions.
11. The cochlear implant of claim 1 , wherein said modeler is further configured to calculate said model based on a temporal effect in the auditory nerve.
12. The cochlear implant of claim 11 , wherein said model based on the temporal effect is calculated using calculations that approximate an accumulation effect from one or more previously generated instructions.
13. The cochlear implant of claim 11 , wherein said model based on the temporal effect is further calculated using calculations that approximate a decay effect from one or more previously generated instructions.
14. The cochlear implant of claim 1 , wherein the cochlear implant is configured to be at least partially implantable.
15. The cochlear implant of claim 1 , wherein said modeler is further configured to update said existing excitation pattern.
16. A method for converting a received electrical signal representing received ambient sound into instructions defining stimulation signals to deliver an excitation pattern to a recipient's auditory nerve, the method comprising:
calculating a model of an excitation pattern currently existing on the auditory nerve;
determining a difference between an ideal excitation pattern representing the received ambient sound and said existing excitation pattern in order to generate an incremental excitation pattern; and
generating stimulation signals for delivery to the auditory nerve based on said incremental excitation pattern.
17. The method of claim 16 , further comprising:
modifying said incremental excitation pattern to minimize selected error criterion based on an implemented optimization strategy to thereby generate an optimized incremental excitation pattern.
18. The method of claim 17 , further comprising:
selecting stimulation channels and associated pulse amplitudes of the stimulation signal to deliver said optimized incremental excitation pattern.
19. The method of claim 17 , further comprising:
converting said incremental excitation pattern into electrical stimulation levels used to generate the stimulation signals.
20. The method of claim 16 , further comprising:
converting said incremental excitation pattern into electrical stimulation levels used to generate the stimulation signals.
21. The method of claim 16 , further comprising:
storing said existing excitation pattern.
22. The method of claim 21 , where the step of storing further comprises:
storing at least one recipient-specific parameter.
23. The method of claim 16 , further comprising:
generating said ideal excitation pattern based on said electrical signal.
24. The method of claim 16 , wherein the step of calculating a model further comprises:
calculating said model based on a spatial effect in the auditory nerve.
25. The method of claim 24 , wherein said step of calculating a model further comprises:
calculating using calculations that approximate a proximity effect from one or more previously generated instructions.
26. The method of claim 16 , wherein the step of calculating a model further comprises:
calculating said model based on a temporal effect in the auditory nerve.
27. The method of claim 26 , wherein said step of calculating a model further comprises:
calculating using calculations that approximate an accumulation effect from one or more previously generated instructions.
28. The method of claim 26 , wherein said step of calculating a model further comprises:
calculating using calculations that approximate a decay effect from one or more previously generated instructions.
29. A system for converting a received electrical signal representing received ambient sound into instructions defining stimulation signals to deliver an excitation pattern to a recipient's auditory nerve, the system comprising:
means for calculating a model of an excitation pattern currently existing on the auditory nerve;
means for determining a difference between an ideal excitation pattern representing the received ambient sound and said existing excitation pattern in order to generate an incremental excitation pattern; and
means for generating stimulation signals for delivery to the auditory nerve based on said incremental excitation pattern.
30. The system of claim 29 , further comprising:
means for modifying said incremental excitation pattern to minimize selected error criterion based on an implemented optimization strategy to thereby generate an optimized incremental excitation pattern.
31. The system of claim 29 , further comprising:
means for storing said existing excitation pattern.
32. The system of claim 29 , further comprising:
means for generating said ideal excitation pattern based on said electrical signals.