Residual Cochlear Function in Adults and Children Receiving Cochlear Implants: Correlations With Speech Perception...

Area of Science:

• Audiology
• Neurosurgery
• Biomedical Engineering

Background:

• Variability in speech perception after cochlear implantation is not fully understood.
• Electrocochleography (ECoG) measures cochlear potentials to assess residual cochlear function.
• ECoG is increasingly used preoperatively to predict cochlear implant outcomes.

Purpose of the Study:

• To characterize preimplantation electrocochleography responses across all age groups.
• To evaluate the relationship between these responses and speech perception outcomes.
• To determine if neural activity measures improve predictive accuracy over cochlear function alone.

Main Methods:

• Prospective cohort study of 284 cochlear implant candidates (10 months to 88 years).
• Electrocochleography recorded to measure the "total response" (TR), reflecting residual cochlear function.
• TR correlated with age-appropriate monosyllabic word scores; neural activity (compound action potential, auditory nerve neurophonic) also assessed.

Main Results:

• The "total response" (TR) magnitude varied widely (0.02 µV to >100 µV).
• TR explained 46% of speech perception variability in adults and 36% in older children (p < 0.001).
• TR explained less variability in younger children (15%, p = 0.012); the elderly showed poorer performance for a given TR.

Conclusions:

• Auditory periphery status, particularly hair cell function, significantly predicts speech perception variability in adults and older children.
• The predictive relationship is weaker in younger children, and the elderly exhibit distinct patterns.
• High-throughput ECoG can guide patient expectations, personalize treatment, and identify individuals with unexpected outcomes.