Asynchronous Stochastic Neural Stimulation for Cochlear Implants
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Solution Overview
Problem
Conventional cochlear implants using fixed-rate stimulation strategies fail to mimic biological acoustic stimulation, leading to unnatural neural spiking patterns, synchronization issues, and inefficiencies in conveying sound information, particularly for patients with sensorineural hearing loss.
Innovation Solution
An asynchronous stochastic stimulation strategy is employed, where the channel selection unit dynamically adjusts stimulation rates and channel selection based on sound environment signals, incorporating inhibition signals to reduce repetition and enhance biological plausibility, and encodes amplitude and phase information for more accurate neural stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fixed-rate stimulation strategy is used, then stimulation delivery is simplified, but neural spiking patterns become unnatural and synchronization issues occur
Solution Approach 1:
The patent applies dynamics by transitioning from fixed-rate stimulation to variable-rate stimulation where the stimulation rate adapts dynamically based on the instantaneous amplitude of the acoustic signal. The stimulation rate is modulated to match the temporal envelope of the sound, creating naturalistic neural spiking patterns that mimic biological acoustic stimulation while maintaining operational simplicity through automated rate adjustment.
2Ease of operation
If fixed-rate stimulation is used, then device operation is simplified, but power consumption increases due to unnecessary stimulation
Solution Approach 1:
The patent implements periodic action by delivering stimulation pulses only during specific phases of the acoustic signal envelope, rather than continuously at a fixed rate. The stimulation is synchronized to the periodic structure of natural sound, delivering pulses during high-amplitude regions and reducing or suspending stimulation during low-amplitude regions, thereby reducing overall power consumption while maintaining operational simplicity through envelope-following modulation.
3Ease of manufacture
If conventional frequency-to-location mapping is used, then electrode array implementation is straightforward, but phase information is lost
Solution Approach 1:
The patent recovers phase information by introducing a temporal dimension to the stimulation encoding. Instead of relying solely on the spatial frequency-to-location mapping, the invention uses the timing of stimulation pulses within each cycle to encode phase information. The phase of the acoustic signal is represented by the temporal position of the stimulation pulse relative to the carrier frequency cycle, thereby adding a temporal dimension that preserves phase information while maintaining the straightforward spatial mapping.
Data Source
AI summary
The present invention provides methods and systems for selecting one or more channels of a neural implant to stimulate. A channel selection unit is configured to asynchronously and stochastically select the winning channel or channels based, in part, on the richness of the input sensory environment. Thereafter, the channel selection unit reduces the likelihood that the selected channel or channels will be selected again for a period of time.