Rapid Assessment of Non-Verbal Auditory Perception in Normal-Hearing Participants and Cochlear Implant Users

Abstract

In the case of hearing loss, cochlear implants (CI) allow for the restoration of hearing. Despite the advantages of CIs for speech perception, CI users still complain about their poor perception of their auditory environment. Aiming to assess non-verbal auditory perception in CI users, we developed five listening tests. These tests measure pitch change detection, pitch direction identification, pitch short-term memory, auditory stream segregation, and emotional prosody recognition, along with perceived intensity ratings. In order to test the potential benefit of visual cues for pitch processing, the three pitch tests included half of the trials with visual indications to perform the task. We tested 10 normal-hearing (NH) participants with material being presented as original and vocoded sounds, and 10 post-lingually deaf CI users. With the vocoded sounds, the NH participants had reduced scores for the detection of small pitch differences, and reduced emotion recognition and streaming abilities compared to the original sounds. Similarly, the CI users had deficits for small differences in the pitch change detection task and emotion recognition, as well as a decreased streaming capacity. Overall, this assessment allows for the rapid detection of specific patterns of non-verbal auditory perception deficits. The current findings also open new perspectives about how to enhance pitch perception capacities using visual cues.

Keywords: audiovisual integration; auditory scene analysis; hearing loss; pitch perception; prosody.

Figure 1

Schematics of the five listening tests of the battery. (A) In the PCD test, the participants have to determine whether the fourth note is identical to or different from the others. (B) In the DCI test, the participants have to determine if the second note is higher (“up”) or lower (“down”) than the first note. (C) In the STM test, the participants have to compare two melodies (sequence 1 and sequence 2) and determine if they are identical or different. The bottom panels of (A–C) present a visual representation of the tones played simultaneously with the visual information. Note that the visual stimuli (disks) appear one at a time, simultaneously with a tone, and remain on the screen during the rest of the stimulation (PCD, DCI, STM), as well as during the retention delay before S2 (STM). (D) In the AS test, the participants hear a sequence of notes with ABA triplet repetitions (see the schematic on the top row of the panel), the frequency of A is fixed, and the frequency of B changes across time (see the corresponding frequency difference, Df). The sequence can be perceived as one stream or two streams. (E) In the EMO test, the participants hear a sentence with one emotion, and have to choose the correct emotion (Joy, Sadness, Anger, Fear, or Neutral) and then rate the corresponding intensity of this emotion (except for Neutral stimuli).

Figure 2

Results of the NH participants with original (O) and vocoded sounds (16, 8, or four channels) in the five tasks (PCD, DCI, STM, AS, and EMO). For PCD, DCI, and STM, the percentage of correct responses for the auditory (white bars) and audiovisual (black bars) trials are reported (A). For STM, an additional analysis of the percentage of Hits minus the percentage of False Alarm (FA) was performed (B). For AS, the total time (in percentage) in the perception of one (in white) or two (in black) streams is reported (C), as well as the mean frequency of the difference between tone A and Bat the change of perception (in Hertz) (D). For EMO, the percentage of correct recognition (E) and mean intensity ratings (F) are reported for each emotion. The error bars represent the standard error of the mean. PCD: Pitch Change Detection; DCI: Direction Change Identification; STM: Short-Term Memory; AS: Auditory Streaming; EMO: Emotional prosody.

Figure 3

Results of the NH participants for original (O) and vocoded sounds (16, 8, and four channels) in the PCD (identical and different trials) and DCI, according to the size of the changes. The percentage of correct responses for auditory and audiovisual trials are reported for PCD (A) and DCI (B). For PCD, six size changes were used for the different trials: 1/16, 1/8, ¼, ½, 1 or 2 tones, and results for identical trials are also presented. For DCI, seven size changes were presented: 0.5, 1, 1.5, 2; 2.5, 3, or 3.5 tones. The error bars represent the standard error of the mean. PCD: Pitch Change Detection; DCI: Direction Change Identification; Id.: Identical trials.

Figure 4

Results of the NH participants (with original sounds) and CI users in the five tasks (PCD, DCI, STM, AS, and EMO). For PCD, DCI and STM, the percentage of correct responses for the auditory (white bars) and audiovisual (black bars) trials are reported (A). For STM, an additional analysis of the percentage of Hits minus the percentage of False Alarms (FA) was performed (B). For AS, the total time (in percentage) in the perception of 1 (in white) or 2 (in black) streams is reported (C), as well as the mean frequency at change of perception (in Hertz) of the difference between tone A and B (D). For EMO, the percentage of correct recognition (E) and mean intensity ratings (F) are reported for each emotion. The error bars represent the standard error of the mean. PCD: Pitch Change Detection; DCI: Direction Change Identification; STM: Short-Term Memory; AS: Auditory Streaming; EMO: Emotional prosody.

Figure 5

Results of the NH participants and CI users in the PCD and DCI, according to the size of the changes. The percentages of correct responses for auditory and audiovisual trials are reported for PCD (A) and DCI (B). For PCD, six size changes were present for the different trials: 1/16, 1/8, ¼, ½, 1, or 2 tones, and the results for identical trials are also presented. For DCI, seven size changes were presented: 0.5, 1, 1.5, 2; 2.5, 3, or 3.5 tones. The error bars represent the standard error of the mean. PCD: Pitch change Detection; DCI: Direction Change Identification; Id.: Identical trials.