Loudness Adaptation Among Cochlear Implant Candidates to Inform Hearing Preservation During Awake Cochlear...

Area of Science:

• Audiology
• Neurosurgery
• Otolaryngology

Background:

• Cochlear implantation (CI) under local anesthesia allows intraoperative patient feedback for better hearing preservation.
• Loudness adaptation and intensity discrimination are critical for awake CI but are not well-studied in CI candidates.

Purpose of the Study:

• To systematically study loudness adaptation and intensity discrimination in adult CI candidates.
• To assess the reliability of audiometric testing in the presence of operating room (OR) noise.

Main Methods:

• Adult CI candidates underwent standard audiometry in quiet and in recorded OR noise.
• Loudness adaptation and intensity discrimination were tested using pure tones at various suprathreshold levels and frequencies.
• Pure tone average (PTA), proportion of loudness adaptation, and intensity discrimination reliability were measured.

Main Results:

• PTA was similar in quiet and OR noise.
• 55% of participants reported loudness adaptation at +10 dB suprathreshold, decreasing to 40% at +20 dB.
• Intensity discrimination was reliable at a 5 dB increment, even with background OR noise.

Conclusions:

• Intraoperative audiometric testing is reliable for CI candidates, as performance does not significantly differ in OR noise.
• Higher tone presentation levels (+20 dB) and lower frequencies reduce loudness adaptation.
• A 5 dB increment is reliable for intensity discrimination across tested conditions.