The relationships between cochlear nerve health and AzBio sentence scores in quiet and noise in postlingually deafened adult cochlear implant users
Bibliographic record
Abstract
ABSTRACT Objectives This study investigated the relationships between the cochlear nerve (CN) health and sentence-level speech perception outcomes measured in quiet and noise in postlingually deafened adult cochlear implant (CI) users. Design Study participants included 28 postlingually deafened adult CI users with a Cochlear® Nucleus™ device. For each participant, only one ear was tested. Neural health of the CN was assessed at three or four electrode locations across the electrode array using two parameters derived from results of the electrically evoked compound action potential (eCAP). One parameter was the phase locking value (PLV) which estimated neural synchrony in the CN. The other parameter was the sensitivity of the eCAP amplitude growth function (AGF) slope to changes in the interphase gap (IPG) of biphasic electrical pulses (i.e., the IPGE slope ). Speech perception was tested using AzBio sentences in both quiet and a ten-talker babble background noise with +5 dB and +10 dB signal-to-noise ratios (SNR). IPGE slope and PLV values were averaged across electrodes for each subject, both with and without weighting by the frequency importance function (FIF) of the AzBio sentences. Pearson and Spearman correlations were used to assess the pairwise relationships between the IPGE slope , the PLV, and age. Multiple linear regression models with AzBio score as the outcome and the PLV and the IPGE slope as predictors were used to evaluate the associations between the three variables while controlling for age. Results The IPGE slope and the PLV demonstrated different patterns with regards to their relationships with electrode location, age, and speech perception. The PLV, but not the IPGE slope , differed significantly across electrodes, where the apical electrodes had larger PLVs (better neural synchrony) than the basal electrodes. The IPGE slope , but not the PLV, was significantly correlated with participant’s age, where smaller IPGE slope values (poorer spiral ganglion neuron density) were associated with more advanced age. The PLV, but not the IPGE slope , was significantly associated with AzBio scores in the +5 dB SNR condition, where larger PLVs predicted better speech perception. Neither the PLV nor the IPGE slope was significantly associated with AzBio score in quiet or in the +10 dB SNR condition. The result patterns remained the same regardless of whether the mean values of the IPGE slope and the PLV were weighted by the AzBio FIF. The result patterns generally did not change with fitting methods or input/output scales of the AGF slopes. Conclusions The IPGE slope and the PLV quantify different aspects of CN health. The positive association between the PLV and AzBio scores in the +5 dB SNR condition suggests that neural synchrony is important for speech perception in adult CI users in challenging listening conditions with a relatively high noise level. The lack of association between age and the PLV indicates that reduced neural synchrony in the CN is unlikely the primary factor accounting for the greater deficits in understanding speech in noise observed in older CI users, as compared to middle-aged CI users.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".