Round window stimulation for conductive and mixed hearing loss

Area of Science:

• Otolaryngology
• Biomedical Engineering
• Auditory Neuroscience

Background:

• Conductive and mixed hearing loss often limit the effectiveness of conventional hearing aids.
• Middle ear implants offer an alternative for patients who do not benefit from traditional amplification.

Purpose of the Study:

• To evaluate surgical complications, residual hearing, and speech perception outcomes after round window placement of a middle ear implant.
• To assess the efficacy of vibratory stimulation via a floating mass transducer (FMT) in patients with conductive and mixed hearing loss.

Main Methods:

• A single-subject, repeated-measures design was employed in a tertiary referral setting.
• Eighteen subjects with conductive or mixed hearing loss received a floating mass transducer (FMT) implanted in the round window niche.
• Hearing thresholds and speech perception were assessed preoperatively and at multiple intervals post-activation.

Main Results:

• Six subjects experienced manageable or self-resolving surgical complications.
• No significant changes were observed in residual bone conduction thresholds or unaided word discrimination.
• All subjects demonstrated significant improvements in aided speech perception compared to their preoperative abilities.

Conclusions:

• Round window implantation of the FMT in patients with conductive and mixed hearing loss leads to enhanced sound field thresholds and speech perception without compromising residual hearing.
• Vibratory stimulation of the round window with a middle ear implant is a potential treatment for specific hearing loss types.
• Further research is recommended for optimal FMT placement, functional gain enhancement, and complication reduction.