Dexamethasone eluting electrodes for cochlear implantation: Effect on residual hearing

Area of Science:

• Otolaryngology
• Biomedical Engineering
• Pharmacology

Background:

• Cochlear implantation is a common treatment for severe to profound hearing loss.
• Preservation of residual hearing is a critical factor for cochlear implant success.
• Drug-eluting electrode arrays offer a potential method to mitigate surgical trauma and improve hearing outcomes.

Purpose of the Study:

• To compare the efficacy of a dexamethasone (DXM)-loaded cochlear implant electrode array with a conventional passive electrode array.
• To evaluate the preservation of residual hearing in gerbils following implantation with these arrays.

Main Methods:

• Thirty Mongolian gerbils were bilaterally implanted with either a DXM-eluting electrode (1% and 10% concentrations) or a conventional passive electrode.
• Hearing thresholds were assessed using auditory brainstem responses (ABRs) at 4-6 weeks and 1 year post-implantation.

Main Results:

• DXM-loaded electrode arrays demonstrated statistically significant preservation of residual hearing at 4-6 weeks across multiple frequencies (500-16,000 Hz).
• At 1 year, significant hearing preservation was observed at 16,000 Hz with DXM arrays.
• However, DXM arrays showed statistically significant hearing *loss* at 500 Hz and 1000 Hz at the 1-year mark.

Conclusions:

• Prolonged release of dexamethasone from cochlear implant electrodes enhances short-term residual hearing preservation in gerbils.
• While high-frequency hearing benefits persist at 1 year, the long-term effects on low frequencies require further investigation and validation.