Physioanatomical characteristics
Modality categories
Variability in binaural integration
Materials and methods
Patients
Cochlear coverage
Audiometric data
Statistical analysis
Results
Demographics
Etiology | n |
---|---|
Meniere’s disease | 6 |
Hearing loss | 3 |
Heredity | 3 |
Intracochlear schwannoma | 2 |
Large vestibular aqueduct syndrome with Mondini malformation | 1 |
Unknown | 24 |
Total | 39 |
Cochlear coverage
Morphology | CC500 (n = 14) | CC600 (n = 25) | p | Total cohort (n = 39) | |||
---|---|---|---|---|---|---|---|
CC (%) | 60.6 | ±3.6 | 73.1 | ± 5.4 | 0.000* | 68.6 | ±7.7 |
CDL (mm) | 37.2 | ±1.4 | 35.0 | ± 2.0 | 0.001* | 35.8 | ±2.1 |
A‑value (mm) | 9.6 | ±0.4 | 9.2 | ± 0.4 | 0.009* | 9.4 | ±0.4 |
B‑value (mm) | 7.3 | ±0.3 | 6.7 | ± 0.5 | 0.001* | 6.9 | ±0.5 |
Height (mm) | 4.3 | ±0.2 | 4.2 | ± 0.4 | 0.324 | 4.2 | ±0.3 |
AID (°) | 498.6 | ±29.5 | 591.1 | ±53.5 | 0.000* | 557.9 | ±64.2 |
Audiometric data
CC500 (n = 14) | CC600 (n = 25) | Total cohort (n = 39) | ||||
---|---|---|---|---|---|---|
Median | Range | Median | Range | Median | Range | |
PTA attended hearing threshold (dB HL) | 46.25 | 36.25–58.75 | 43.00 | 30.00–62.50 | 43.75 | 30.00–62.50 |
Speech intelligibility (%)a | 65 | 0–90 | 60 | 15–95 | 60 | 0–95 |
Correlation of cochlear coverage with speech perception
Discussion
The present study
Comparison with other studies
Practical conclusion
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We did not find a significant correlation between monaural monosyllabic speech perception with a cochlear implant (CI) and the cochlear coverage (CC) provided by the CI electrode in bimodally (CI and hearing aid [HA]) fitted patients.
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A trend was observed: speech perception increased with increasing CC, reaching a maximum at ca. 70–75% and then decreased with further increases in CC.
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The lack of a significant relationship may be due to the large variability in a small patient population, resulting in insufficient statistical power, as well as the possibility of a nonlinear relationship between CC and speech perception. Linear Pearson correlation analysis was not suitable for assessing the possibility of a nonlinear relationship, partly due to the covariance of the electrode array (FLEX28, FLEXSOFT).
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Patients with a greater insertion depth achieved faster learning success. Despite different CC500/CC600 mean values (59.2 ± 28.4%/47.1 ± 21.9%) and medians (65%/60%) of the CC, no significant difference in long-term speech perception was found.
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In clinical practice, preoperative measurement of the cochlea and individualized electrode selection are beneficial to determine the most suitable electrode length for every patient.
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A CC of 70–75% was identified as a good reference point for CC, but more research is needed in this area before a definitive recommendation can be made.