Sound source localization patterns and bilateral cochlear implants: Age at onset of deafness effects

Area of Science:

• Audiology
• Neuroscience
• Biomedical Engineering

Background:

• Sound source localization is vital for daily functioning but impaired in patients with bilateral cochlear implants (BiCIs).
• Patient factors such as auditory deprivation, experience, and age influence localization performance in BiCI users.
• Characteristic localization errors are observed in BiCI patients, with limited investigation into their relationship with patient-specific factors.

Purpose of the Study:

• To investigate the relationship between patient-dependent factors and sound localization errors in individuals with BiCIs.
• To characterize specific error types using a novel machine learning approach.
• To determine the impact of early bilateral hearing on sound localization outcomes.

Main Methods:

• Sound localization performance was assessed in 48 participants with BiCIs using free-field pink noise trains.
• Multiple analysis types were employed to understand localization errors and their correlation with patient factors.
• A machine learning approach was utilized to categorize and interpret localization error patterns.

Main Results:

• Older age at testing and earlier onset of deafness correlated with increased average localization error, especially for sounds near the head's center.
• Machine learning analysis indicated greater response variability in individuals with earlier deafness onset compared to later onset.
• Results align with previous research linking age and deafness duration to auditory processing deficits.

Conclusions:

• Early bilateral hearing is essential for optimal sound source localization abilities in individuals with BiCIs.
• Auditory deprivation and age significantly affect localization acuity and response consistency.
• The findings highlight the importance of early intervention and rehabilitation for improving spatial hearing in BiCI users.