Restoring Sound Localization in Single-Sided Deafness Through Cochlear Implantation: A Meta-Analysis

Area of Science:

• Audiology
• Neurosurgery
• Rehabilitation Medicine

Background:

• Single-sided deafness (SSD) negatively impacts sound localization, spatial awareness, and quality of life.
• Cochlear implantation (CI) is a potential intervention for SSD, but its effectiveness and influencing factors require clarification.

Purpose of the Study:

• To systematically review and meta-analyze localization outcomes in patients with SSD following cochlear implantation.
• To assess the influence of patient demographics and rehabilitation factors on CI outcomes in SSD.

Main Methods:

• A systematic search of multiple databases was conducted up to February 2025 for studies on CI in SSD.
• Quantitative localization error (RMS error) was the primary outcome measure.
• Random-effects meta-analysis and subgroup analyses (age, etiology, rehabilitation) were performed.

Main Results:

• Cochlear implantation significantly reduced localization error by 20.8 degrees (P<0.001).
• Younger patients (≤50 years) and those with sudden sensorineural hearing loss showed greater improvements.
• Structured rehabilitation, earlier activation (≤21 days), and high daily device use (≥10 hours) correlated with better outcomes.

Conclusions:

• Cochlear implantation offers meaningful improvements in sound localization for SSD, though not to normal hearing levels.
• Outcomes are enhanced by structured rehabilitation, early activation, and consistent device usage.
• CI is an effective treatment for SSD, supporting evidence-based rehabilitation strategies.