Cochlear Nerve eCAP Phase Coherence for Speech-in-Noise Assessment
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Solution Overview
Problem
There is no direct method to evaluate the functioning of the cochlear nerve in cochlear implant users, and existing systems fail to assess neural synchrony, leading to challenges in speech recognition in noisy environments.
Innovation Solution
A noninvasive system and method to quantify neural synchrony in the cochlear nerve by analyzing the trial-to-trial phase coherence of electrically evoked compound action potentials (eCAP) using electrophysiological measures, correlating this with temporal resolution acuity and speech perception outcomes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If eCAP measurements are used to assess neural function, then neural activity can be measured, but neural synchrony cannot be evaluated
Solution Approach 1:
The patent transforms the eCAP measurement approach by introducing phase coherence analysis as an additional parameter dimension. Instead of merely measuring amplitude or presence of eCAP responses, the system analyzes the phase relationship across multiple trials and electrodes, converting standard electrophysiological measurements into synchrony quantification data through mathematical transformation of the recorded signals.
Solution Approach 2:
The patent introduces phase coherence as an intermediary metric that bridges eCAP measurements and neural synchrony assessment. By calculating the consistency of phase angles across multiple recordings, the system uses this intermediate mathematical construct to infer neural synchrony without directly observing neural firing patterns, thus resolving the information loss problem.
2Reliability
If traditional eCAP recording methods are used, then neural response can be detected, but trial-to-trial phase coherence cannot be analyzed
Solution Approach 1:
The patent employs periodic stimulation through repeated presentation of auditory stimuli across multiple trials. By systematically repeating the stimulation protocol and recording eCAP responses across many trials, the system accumulates sufficient data to calculate stable phase coherence values, transforming a single-shot measurement approach into a repeated measures design that enables precision phase analysis.
Solution Approach 2:
The patent performs preliminary processing of eCAP signals by extracting phase information from individual trials before aggregating across trials. This preliminary action of phase extraction and alignment prepares the data structure necessary for subsequent coherence calculation, enabling precise phase measurements that would be impossible with raw, unprocessed eCAP recordings.
3Ease of operation
If speech perception is assessed in noise, then real-world listening ability can be evaluated, but the underlying neural mechanism (synchrony) remains unmeasured
Solution Approach 1:
The patent creates a multi-functional assessment system where the same eCAP recording protocol serves dual purposes: evaluating speech perception in noise and quantifying neural synchrony. By using the cochlear implant device itself to deliver both speech-in-noise stimuli and record eCAP responses, the system eliminates the need for separate measurement protocols, making neural synchrony assessment as routine as speech testing.
Solution Approach 2:
The patent establishes a feedback loop where behavioral speech perception data and electrophysiological synchrony data are correlated. The system uses the known relationship between neural synchrony and speech-in-noise performance to validate that eCAP phase coherence measurements accurately reflect the neural mechanisms underlying observed behavioral deficits, creating a validated feedback system for assessing both levels simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate assessment of neural synchrony, allowing for improved understanding of speech in noise by correlating eCAP measurements with speech perception outcomes, thereby enhancing the effectiveness of cochlear implants.
Implementation Method 1
user defined stimuli can be sent through one electrode of a cochlear implant to stimulate the surrounding neurons
Implementation Method 2
The neurons then respond, and the electrical response can be recorded by a neighboring electrode. The neural response is called the electrically-evoked compound action potential (eCAP)
Data Source
AI summary
Disclosed herein are of systems, methods, and computer-program products of determining a peripheral neural synchrony value based on eCAPS and correlating the peripheral neural synchrony value with temporal resolution acuity and speech perception outcomes measured in quiet and in noise in the patient.