Abstract: An envelope based amplitude mapping achieves the signal compression required to provide a natural sound level without the high processor loading or waveform alteration. In one embodiment, the output of a family of parallel bandpass filters is processed by an envelope detector, followed by decimation. The resulting reduced data rate envelope is log mapped to produce a scaling factor for the original high data rate bandpass filter output sequence. The resulting scaled signal determines the current level for stimulation of the cochlea for each frequency band, which stimulation achieves a log mapping of the sound amplitude effect similar to natural hearing, while reducing processor load, and preserving waveform shape.

Abstract: Methods of selecting a number of channels for stimulation within a neural stimulation system include determining an amplitude of a multiplicity of stimulation signals each corresponding to a channel within a multiplicity of channels in the implantable stimulation system, using the amplitudes of the stimulation signals to determine a probability of each of the stimulation signals, and using the probabilities of one or more of the stimulation signals to randomly select a predetermined number of channels from the multiplicity of channels through which one or more of the stimulation signals are applied to a patient during a stimulation frame.

Abstract: Implantable neural stimulation systems include an array of electrodes configured to apply one or more stimulation signals to a patient via one or more channels out of a multiplicity of channels during a stimulation frame and a signal processor configured to select the one or more channels for stimulation. The selection of the one or more channels is based on a probability associated with each channel within the multiplicity of channels.

Abstract: An implantable neural stimulation system, such as a cochlear implant system, utilizes a Distributed Compression Amplitude Mapping (DCAM) system to distribute signal compression between a pre-bandpass linear mapping function, and a post-bandpass compressive mapping function. The pre-bandpass linear mapping function is implemented, in one exemplary embodiment, as a traditional audio compressor to prevent distortion that might result from a non-linear mapping function. The post-bandpass compressive mapping function is implemented, in another exemplary embodiment, as a logarithmic transform to reflect natural hearing. As a result of the DCAM processing, the differences in amplitudes of components of the acoustic spectrum are maintained. By maintaining these differences, spectral smearing between channels is reduced and speech clues are preserved.

Abstract: An implantable neural stimulation system, such as a cochlear implant system, utilizes a Distributed Compression Amplitude Mapping (DCAM) system to distribute signal compression between a pre-bandpass linear mapping function, and a post-bandpass compressive mapping function. The pre-bandpass linear mapping function is implemented, in one exemplary embodiment, as a traditional audio compressor to prevent distortion that might result from a non-linear mapping function. The post-bandpass compressive mapping function is implemented, in another exemplary embodiment, as a logarithmic transform to reflect natural hearing. As a result of the DCAM processing, the differences in amplitudes of components of the acoustic spectrum are maintained. By maintaining these differences, spectral smearing between channels is reduced and speech clues are preserved.

Abstract: Stimulation channel selection methods for an implantable neural stimulation system having a multiplicity of channels include computing a probability for each channel within the multiplicity of channels and selecting at least one of the channels for stimulation during a frame. The selecting of the at least one of the channels for stimulation during the frame includes selecting a channel, obtaining a random number, comparing the random number to the probability of the channel, and selecting the channel for stimulation if the probability of the channel is greater than the random number.

Abstract: Methods of selecting a number of channels out of a multiplicity of channels of an implantable neural stimulation system for stimulation during a stimulation frame include obtaining a threshold corresponding to the stimulation frame, using the threshold to determine an adjusted amplitude corresponding to one or more channels within the multiplicity of channels, using the adjusted amplitudes to determine a probability for each of the one or more channels within the multiplicity of channels, providing a random number for each of the one or more channels within the multiplicity of channels, and selecting a number of channels within the one or more channels for stimulation during the stimulation frame. Each of the selected number of channels has a probability that is greater than the random number.

Abstract: Methods of selecting a number of channels out of a multiplicity of channels of an implantable neural stimulation system for stimulation during a stimulation frame include obtaining a threshold corresponding to the stimulation frame, determining an amplitude corresponding to each channel within the multiplicity of channels, comparing the amplitude corresponding to each of the channels within the multiplicity of channels to the threshold, and selecting each of the channels having amplitudes that exceed the threshold for stimulation during the stimulation frame.

Abstract: An envelope based amplitude mapping achieves the signal compression required to provide a natural sound level without the high processor loading or waveform alteration. In one embodiment, the output of a family of parallel bandpass filters is processed by an envelope detector, followed by decimation. The resulting reduced data rate envelope is log mapped to produce a scaling factor for the original high data rate bandpass filter output sequence. The resulting scaled signal determines the current level for stimulation of the cochlea for each frequency band, which stimulation achieves a log mapping of the sound amplitude effect similar to natural hearing, while reducing processor load, and preserving waveform shape.

Abstract: An implantable neural stimulation system, such as a cochlear implant system, utilizes a Distributed Compression Amplitude Mapping (DCAM) system to distribute signal compression between a pre-bandpass linear mapping function, and a post-bandpass compressive mapping function. The pre-bandpass linear mapping function is implemented, in one embodiment, as a traditional fast audio compressor to prevent distortion that might result from a non-linear mapping. The post-bandpass compressive mapping function is implemented, in one embodiment, as a logarithmic transform to reflect natural hearing. As a result of the DCAM processing, the differences in amplitudes of components of the acoustic spectrum are maintained. By maintaining these differences, spectral smearing between channels is reduced and speech clues are preserved.

Abstract: Improved skipping strategies for cochlear or other multi-channel neural stimulation implants selects N out of M channels for stimulation during a given stimulation frame. A microphone transduces acoustic energy into an electrical signal. The electrical signal is processed by a family of bandpass filters, or the equivalent, to produce a number of frequency channels. In a first embodiment, a probability based channel selection strategy computes a probably for each of the M channels based on the strength of each channel. N channels are probabilistically selected for stimulation based on their individual probability. The result is a randomized “stochastic” stimulus presentation to the patient. Such randomized stimulation reduces under representation of weaker channels for steady state input conditions such as vowels. In second, third and fourth embodiments, a variable threshold is adjusted to obtain the selection of N channels per frame.

Abstract: An envelope based amplitude mapping achieves the signal compression required to provide a natural sound level without the high processor loading or waveform alteration. In a preferred embodiment, the output of a family of parallel bandpass filters is processed by an envelope detector, followed by decimation. The resulting reduced data rate envelope is log mapped to produce a scaling factor for the original high data rate bandpass filter output sequence. The resulting scaled signal determines the current level for stimulation of the cochlea for each frequency band, which stimulation achieves a log mapping of the sound amplitude effect similar to natural hearing, while reducing processor load, and preserving waveform shape.

Abstract: An envelope based amplitude mapping achieves the signal compression required to provide a natural sound level without the high processor loading or waveform alteration. In a preferred embodiment, the output of a family of parallel bandpass filters is processed by an envelope detector, followed by decimation. The resulting reduced data rate envelope is log mapped to produce a scaling factor for the original high data rate bandpass filter output sequence. The resulting scaled signal determines the current level for stimulation of the cochlea for each frequency band, which stimulation achieves a log mapping of the sound amplitude effect similar to natural hearing, while reducing processor load, and preserving waveform shape.

Abstract: A cochlear implant system includes an implant portion and an external portion. The external portion performs at least the function of sensing acoustic signals and converting such sensed signals to electrical signals. The implant portion performs at least the function of generating electrical stimuli, modulated and classified in response to the sensed acoustic signals, and intended for direct electrical stimulation of the auditory nerve in accordance with a selected speech processing strategy. Control data defines the selected speech processing strategy, i.e., the pulsatile stimulation pattern to be used by implantable portion. Such control data is transmitted to and stored within the implantable portion of the system only once, when a particular speech processing strategy is selected, thereby eliminating the need to continually resend such speech-processing-defining data over a bandwidth-limited link between the implantable and external portions of the system.