Temporal fine structure processing, pitch and speech perception in cochlear implant recipients

Cochlear implant (CI) recipients usually complain about poor speech understanding in the presence of noise. Indeed, they generally show ceiling effects for understanding sentences presented in quiet, but their scores decrease drastically when testing in the presence of competing noise. One important aspect that contributes to speech perception skills, especially when listening in a fluctuating background, has been described as Temporal Fine Structure (TFS) processing. TFS cues are more dominant in conveying Low Frequency (LF) signals linked in particular to Fundamental Frequency (F0), which is crucial for linguistic and musical perception. A§E Harmonic Intonation (HI) and Disharmonic Intonation (DI) are tests of pitch perception in the LF domain and their outcomes are believed to depend on the availability of TFS cues. Previous findings indicated that the DI test provided more differential LF pitch perception outcomes in that it reflected phase locking and TFS processing capacities of the ear, whereas the HI test provided information on its place coding capacity as well. Previous HI/DI studies were mainly done in adult population showing abnormal pitch perception outcomes in CI recipients and there was no or limited data in paediatric population as well as HI/DI outcomes in relation to speech perception outcomes in the presence of noise. One of the primary objectives of this thesis has been to investigate LF pitch perception skills in a group of pediatric CI recipients in comparison to normal hearing (NH) children. Another objective was to introduce a new assessment tool, the Italian STARR test which was based on measurement of speech perception using a roving-level adaptive method where the presentation level of both speech and noise signals varied across sentences. The STARR test attempts to reflect a better representation of real world listening conditions where background noise is usually present and speech intensity varies according to vocal capacity as well as the distance of the speaker. The Italian STARR outcomes in NH adults were studied to produce normative data, as well as to evaluate interlist variability and learning effects. Finally, LF pitch perception outcomes linked to availability of TFS were investigated in a group of adult CI recipients including bimodal users in relation to speech perception, in particular Italian STARR outcomes. Results were interesting: Although the majority of CI recipient children showed abnormal outcomes for A§E, their scores were considerably better than in the adult CI users. Age had a statistically significant effect on performance in both children and adults; younger children and older adults tended to show poorer performance. Similarly, CI recipient adults (even the better performers) showed abnormal STARR outcomes in comparison to NH subjects and group differences were statistically significant. The duration of profound deafness before implantation had a significant effect on STARR performance. On the other hand, the significant effect of CI thresholds re-emphasized the sensitivity of the test to lower level speech which a CI user can face very often during everyday life. Analysis revealed statistically significant correlations between HI/DI and STARR performance. Moreover, contralateral hearing aid users showed significant bimodal benefit for both HI/DI and STARR tests. Overall findings confirmed the usefulness of evaluating both LF pitch and speech perception in order to track changes in TFS sensitivity for CI recipients over time and across different listening conditions which might be provided by future technological advances as well as to study individual differences

Neuropsychological functions and audiological findings in elderly cochlear implant users: the role of attention in postoperative performance

Objectives: The present study aimed to investigate in a group of elderly CI users working memory and attention, conventionally considered as predictors of better CI performance and to try to disentangle the effects of these cognitive domains on speech perception, finding potential markers of cognitive decline related to audiometric findings. Methods Thirty postlingually deafened CI users aged >60 underwent an audiological evaluation followed by a cognitive assessment of attention and verbal working memory. A correlation analysis was performed to evaluate the associations between cognitive variables while a simple regression investigated the relationships between cognitive and audiological variables. Comparative analysis was performed to compare variables on the basis of subjects’ attention performance. Results: Attention was found to play a significant role in sound field and speech perception. Univariate analysis found a significant difference between poor and high attention performers, while regression analysis showed that attention significantly predicted recognition of words presented at Signal/Noise +10. Further, the high attention performers showed significantly higher scores than low attentional performers for all working memory tasks. Conclusion: Overall findings confirmed that a better cognitive performance may positively contribute to better speech perception outcomes, especially in complex listening situations. WM may play a crucial role in storage and processing of auditory-verbal stimuli and a robust attention may lead to better performance for speech perception in noise. Implementation of cognitive training in auditory rehabilitation of CI users should be investigated in order to improve cognitive and audiological performance in elderly CI users

Intonational cues for speech perception in noise by cochlear implant listeners

Purpose The objectives of this study are to evaluate cochlear implant (CI) listeners’ ability to infer low frequency (LF) pitch information from temporal fine structure (TFS) cues and to gain insight into its effects on speech perception, especially in the presence of a fluctuating background noise. Pitch perception assessment using linguistic stimuli is believed to better reflect the role of pitch in communicatively realistic situations. Methods The low-pass-filtered sentence intonation (SI-LPF) test based on linguistic stimuli marked by intonation changes is used to estimate a difference limen for discrimination of LF pitch changes in adult CI listeners (N = 17 ears). Speech perception in the presence of noise is assessed using the sentence test with adaptive randomized roving level (STARR), where everyday sentences are presented at low, medium, and high levels in a fluctuating background noise. SI-LPF correlations with STARR are compared to those with sentence recognition tests presented in quiet (SRQ) and in noise, using fixed signal-to-noise ratio (SNRs at +10 and +5 dB). Results SI-LPF findings show significant positive correlations with STARR performance (rs = 0.63, p = 0.007), whilst the associations with SRQ (rs = − 0.37, p = 0.149), SNR + 10 (rs = − 0.24, p = 0.345), and SNR + 5 (rs = − 0.14, p = 0.587) are not statistically significant. Conclusions Present findings reflecting considerably stronger correlations than previous studies using non-linguistic stimuli, in particular for speech perception with roving-level adaptive test method (STARR) highlight the effects of LF pitch perception and TFS sensitivity on challenging everyday situations, where CI users listen to speakers with varying levels in a fluctuating backgroun

An objective tool for cochlear implant electrode selection

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Music perception and speech intelligibility in noise performance by Italian-speaking cochlear implant users.

Funder: Università degli Studi di Roma La SapienzaOBJECTIVE: The goal of this study was to investigate the performance correlations between music perception and speech intelligibility in noise by Italian-speaking cochlear implant (CI) users. MATERIALS AND METHODS: Twenty postlingually deafened adults with unilateral CIs (mean age 65 years, range 46-92 years) were tested with a music quality questionnaire using three passages of music from Classical Music, Jazz, and Soul. Speech recognition in noise was assessed using two newly developed adaptive tests in Italian: The Sentence Test with Adaptive Randomized Roving levels (STARR) and Matrix tests. RESULTS: Median quality ratings for Classical, Jazz and Soul music were 63%, 58% and 58%, respectively. Median SRTs for the STARR and Matrix tests were 14.3 dB and 7.6 dB, respectively. STARR performance was significantly correlated with Classical music ratings (rs = - 0.49, p = 0.029), whereas Matrix performance was significantly correlated with both Classical (rs = - 0.48, p = 0.031) and Jazz music ratings (rs = - 0.56, p = 0.011). CONCLUSION: Speech with competitive noise and music are naturally present in everyday listening environments. Recent speech perception tests based on an adaptive paradigm and sentence materials in relation with music quality measures might be representative of everyday performance in CI users. The present data contribute to cross-language studies and suggest that improving music perception in CI users may yield everyday benefit in speech perception in noise and may hence enhance the quality of listening for CI users

Speech reception in noise using roving-adaptive test technique (Italian starr test) in adults with AB clearvoice technology

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Pitch perception in cochlear implant using children and adolescents

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Adaptation of the STARR test for adult Italian population: a speech test for a realistic estimate in real-life listening conditions

Objectives: To introduce the Italian adaptation of the STARR test based on a roving-level adaptive method to mimic challenging real-life listening conditions for use in people with auditory prostheses. Design: Normative data were collected and interlist-variability, as well as learning effects, were investigated using a within-subject design with repeated measures. Study sample: A group of 32 normal-hearing (NH) adults participated in the study. Results: The average speech reception threshold (SRT) for NH subjects was 8.4 dB SNR. The variability of mean SRTs across test lists was relatively small ( 1 dB for all test lists). The statistically significant differences between lists were eliminated after applying correction factors. On the basis of variability for the corrected SRTs within each subject, a difference of 2.8 dB in SRT was meaningful for outcome comparisons using one test list per condition and 2 dB using two lists per condition. Statistical analysis did not show any significant learning effects. Conclusions: Findings in NH listeners suggested that the Italian STARR test could be a promising supplement to existing speech assessment tools. Further studies in populations with hearing impairment could contribute to cross-language studies