The Spatial Selective Auditory Attention of Cochlear Implant Users in Different Conversational Sound Levels.

Sara Akbarzadeh,Sungmin Lee,Chin-Tuan Tan

doi:10.3390/jcm10143078

Abstract

In multi-speaker environments, cochlear implant (CI) users may attend to a target sound source in a different manner from normal hearing (NH) individuals during a conversation. This study attempted to investigate the effect of conversational sound levels on the mechanisms adopted by CI and NH listeners in selective auditory attention and how it affects their daily conversation. Nine CI users (five bilateral, three unilateral, and one bimodal) and eight NH listeners participated in this study. The behavioral speech recognition scores were collected using a matrix sentences test, and neural tracking to speech envelope was recorded using electroencephalography (EEG). Speech stimuli were presented at three different levels (75, 65, and 55 dB SPL) in the presence of two maskers from three spatially separated speakers. Different combinations of assisted/impaired hearing modes were evaluated for CI users, and the outcomes were analyzed in three categories: electric hearing only, acoustic hearing only, and electric + acoustic hearing. Our results showed that increasing the conversational sound level degraded the selective auditory attention in electrical hearing. On the other hand, increasing the sound level improved the selective auditory attention for the acoustic hearing group. In the NH listeners, however, increasing the sound level did not cause a significant change in the auditory attention. Our result implies that the effect of the sound level on selective auditory attention varies depending on the hearing modes, and the loudness control is necessary for the ease of attending to the conversation by CI users.

Highlights

Selective auditory attention is the ability of the auditory system to attend to a target sound source and ignore the competing sounds in multi-speaker environments, known as the cocktail party scenario
Among nine cochlear implant (CI) subjects, six subjects were in the electrical hearing only (EH) group, but three subjects were in the EH and electric + acoustic hearing (EAH) group
The scores are represented in percentage for the EH, AH, and EAH CI users in Figure 3a–c, respectively

Summary

Introduction

Selective auditory attention is the ability of the auditory system to attend to a target sound source and ignore the competing sounds in multi-speaker environments, known as the cocktail party scenario. Temporal, and frequency cues help to identify and separate the speech streams If these cues are not accessible in the auditory pathway, this may result in decreased spatial selective auditory attention and speech intelligibility [1,2]. Most hearing-impaired (HI) listeners suffer from poor spatial hearing, especially when they encounter social settings where multiple people talk in a group. This is the case for cochlear implant (CI) listeners who have severe hearing loss, and their performance falls much below that of the normal hearing (NH) listeners in spatial hearing tasks [7,8,9,10]. Poor temporal resolution typically experienced by CI users [11]

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