Early Gap Detection Threshold Predicts Late Speech Perception in Cochlear Implant Users.

Abstract

ObjectiveTo study whether the ability to detect frequency changes or temporal gaps at the early phase postactivation can predict speech perception performance at the late phase postactivation in postlingually deafened cochlear implant (CI) users.MethodPsychophysical tests and event-related potential (ERP) tests were conducted at the third-month postactivation (early phase postactivation, T1) and after 1-year postactivation (late phase postactivation, T2) in 27 postlingually deafened CI users. CI hearing thresholds and speech perception performance were measured at T1 and T2. The frequency change detection threshold (FCDT) and gap detection threshold (GDT) were obtained through psychophysical tests. The evoked threshold, amplitude, and latency of auditory change complex response, evoked by frequency change or temporal gap stimuli, were investigated using ERP tests.ResultsCompared with T1, speech perception performance was significantly better at T2, but there was no significant difference in the psychophysical or ERP test results. Speech perception performance at T2 could be predicted by GDT at T1, but not by FCDT or ERP indicators at T1. Receiver-operating characteristic curve analysis suggested that the GDT at T1 may be moderately accurate in discriminating between good and poor speech perception groups at T2.ConclusionCompared to early phase postactivation, CI users' ability to detect frequency changes or temporal gaps did not change significantly at the late phase postactivation, but speech perception performance improved significantly. The early GDT can predict later speech perception performance of CI users.Level of EvidenceIII.