Behavioral Measures of Temporal Processing and Speech Perception in Cochlear Implant Users

Area of Science:

• Audiology
• Neuroscience
• Speech and Hearing Sciences

Background:

• Cochlear implant (CI) users exhibit significant variability in speech perception outcomes.
• Individual differences in temporal processing are linked to speech perception performance in CI users.
• Existing gap detection threshold (GDT) measures often use non-clinical paradigms and direct electrical stimulation.

Purpose of the Study:

• To investigate the relationship between temporal processing abilities and speech perception performance in CI users.
• To determine if clinical measures of temporal processing, like the Randomized Gap Detection Test (RGDT), can explain speech perception variability.

Main Methods:

• A correlational study involving 12 postlingually deafened adult CI users and 10 normal-hearing (NH) adults.
• Behavioral GDTs were assessed using the RGDT or Expanded RGDT.
• Speech perception was measured using standardized tests including SRT, W-22, CNC, AzBio, and BKB-SIN.

Main Results:

• Most CI participants demonstrated temporal processing impairments (GDTs > 20 msec) and reduced speech perception compared to NH participants.
• Significant differences were found between CI and NH groups in GDTs and several speech perception tests (SRT, W-22, BKB-SIN).
• In CI users, GDTs significantly correlated with performance on CNC Phoneme, AzBio, and BKB-SIN tests.

Conclusions:

• Variability in temporal acuity among CI users contributes to the wide range of speech perception outcomes.
• The clinically administered RGDT is a suitable tool for identifying CI users with temporal processing deficits.
• Identifying these deficits can guide appropriate rehabilitation strategies for improved speech perception.