Measuring benefits from transformation of lost segregation cues in hearing devices with Acoustical Change Complex

Abstract

Can transformation of lost Temporal Fine Structure (TFS) cues help people with hearing impairment in situations that require TFS cues? Moreover, what does the Acoustical Change Complex (ACC) reveal about the efficiency of the transformation of TFS cues? Many recent studies have shown that age and sensorineural hearing loss limits the ability to perceive and utilize Temporal Fine Structure (TFS) cues. Moreover, the TFS cues seem to facilitate segregation of voices. Finally, until recently, cochlear implant users were also missing TFS cues, as most stimulation strategies discarded all TFS cues. The TFS1 listening test [1] is very difficult for people with mild-to- moderate hearing impairment. The present study investigates extraction of the unavailable TFS cues and transformation of TFS to envelope cues (TFS2ENV) and measures the benefit with the TFS1 test. The TFS2ENV transformation enables the people with hearing impairment to perform the TFS1 test with similar performance as people with normal hearing. The present study compares the behavioural TFS1 test results with the ACC responses to investigate to which extent TFS2ENV processing restores ACC amplitude and timing back to those of people with normal hearing. Moreover, the present study investigates the modification of the TFS1 stimuli to improve recording of the acoustical change complex. While TFS2ENV improves discrimination tasks in the TFS1 test, it remains to be seen if the benefit also carries over to segregation of voices. For cochlear implants, it also remains to be seen if TFS2ENV provide supplementary benefits together with stimulation strategies that convey TFS.