State-of-the-Art on the Impact of Bimodal Acoustic Stimulation on Speech Perception in Noise in Adults: A Systematic Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This review paper gives a summary of the outcomes of bimodal stimulation (BS) vs. unilateral CI. The results are well-known in the research community. I don't think it adds any new views or values. In addition, the review is superficial, without providing an in-depth discussion of different studies. The Discussion section is not well organized in terms of the advantages and issues of BS stimulation.  

Here are some specific comments. There are many typos and grammar errors.

Line 59: Authors demonstrated that the control the device delay mismatch affects. Please rewrite this sentence.

Line 63: Addressing following results, it is necessary to define the concept of Electric and Acoustic Stimulation (EAS). It needs a transitional sentence here. 

Line 76: The The systematic review. remove "the"

Line 206: In addition, in a 206 large multicentred study by Gifford et al., was demonstrated an improvement. It is not a complete sentence.

Line 208: BS than IC unilateral.  CI

Line 225: Firstly, the findings are controversial, with significant 225 variability in patient outcomes and study methodologies, Proper papers should be discussed.

Line 328: 12. [17] Dourado and afterwards. Double numbers.

 

Comments on the Quality of English Language

Suggest "reject" due to the low quality of this manuscript. 

Author Response

REVIEWER 1

1. This review paper gives a summary of the outcomes of bimodal stimulation (BS) vs. unilateral CI. The results are well-known in the research community. I don't think it adds any new views or values. In addition, the review is superficial, without providing an in-depth discussion of different studies. The Discussion section is not well organized in terms of the advantages and issues of BS stimulation.

[Reply]: Thank you for your comment.

The aim of our systematic review is to examine in detail the advantages and disadvantages of bimodal stimulation in adult patient on speech perception in noisy environments and to provide a comprehensive overview of the current evidence and to suggest possible future directions for research and clinical practice. Particularly, we evaluated the improvements made in the coupling systems between CI/HA devices, showing a reduction of the temporal gap in the interpretation of acoustic information between the two sides.

The authors are aware that the results about advantages and disadvantages of bimodal stimulation have already been described in the scientific literature. In this systematic review we include only recent study because the new advances in inter-device coupling systems and evaluations to reduce the time gap between devices are bringing better quality of life to patients using BS than few years ago. Particularly, some review studies that include articles published more than 10 years ago do not provide a scenario of the current situation, while in our study we showed the advantages and disadvantages of the BS refer to the last 5 years.

To highlight our results, in Discussion section we compare our study with the recent review articles publishes (lines 305-325)

Finally, we found not clear guidelines in the literature regarding the selection criteria for choosing patients who are candidates for a BS stimulation system, which is a prerequisite for more advantageous and reliable results and outcomes

 

2. Here are some specific comments. There are many typos and grammar errors.

[Reply]: Thank you for your comment. A native speaker has proofread the article

 

3. Line 59: Authors demonstrated that the control the device delay mismatch affects. Please rewrite this sentence.

[Reply]: Thank you for your comment. We changed the sentence

 

4. Line 63: Addressing following results, it is necessary to define the concept of Electric and Acoustic Stimulation (EAS). It needs a transitional sentence here.

            [Reply]: Thank you for your comment. We changed

 

5. Line 76: The The systematic review. remove "the"

[Reply]: Thank you for your comment. We corrected

 

6. Line 206: In addition, in a 206 large multicentred study by Gifford et al., was demonstrated an improvement. It is not a complete sentence.

[Reply]: Thank you for your comment. We changed the sentence

 

7. Line 208: BS than IC unilateral. CI

[Reply]: Thank you for your comment. We corrected

 

8. Line 225: Firstly, the findings are controversial, with significant 225 variability in patient outcomes and study methodologies, Proper papers should be discussed.

[Reply]: Thank you for your comment. This aspect was reported in many papers, we have cited some of them at line 271

1. Payne J, Au A, Dowell RC. An overview of factors affecting bimodal and electric-acoustic stimulation (EAS) speech understanding outcomes. Hear Res. 2023 Apr;431:108736. doi: 10.1016/j.heares.2023.108736. Epub 2023 Mar 5. PMID: 36931019.
2. Sturm, J. J., Kuhlmey, M., Alexiades, G., Hoffman, R., & Kim, A. H. (2021). Comparison of speech performance in bimodal versus bilateral cochlear implant users. The Laryngoscope, 131(4), E1322-E1327.
3. Laria, C., Auletta, G., Riccardi, P., Papa, C., Malesci, R., Franzé, A., & Marciano, E. (2014). Very good performance with bimodal stimulation in a like-hybrid modality in a patient with profound bilateral sensorineural hearing loss with low-frequencies preservation. American Journal of Otolaryngology, 35(1), 70-72.

 

 

9. Line 328: 12. [17] Dourado and afterwards. Double numbers.

[Reply]: Thank you for your comment. We corrected

Reviewer 2 Report

Comments and Suggestions for Authors

This is a systematic review of the last four years on bimodal stimulation after cochlear implantation (2020-2024). Even if many previous literature on the subject was published before 2020, given the advancements in cochlear implantation criteria for candidacy, it makes sense to focus on recent studies.

It would enhance the paper to include a discussion on the concept of asymmetric hearing loss in cochlear implant candidacy, especially since the outcomes of bimodal stimulation may differ between patients with bilateral severe-to-profound hearing loss and those with asymmetric hearing loss who receive a cochlear implant in the worse ear (see for reference: https://doi.org/10.1017/S0022215121004333).

The methodology is sound, adhering to PRISMA guidelines, and the discussion effectively links the results to practical conclusions. The review of technological advancements, such as directional microphones and programming software, is relevant and well-discussed.

Overall, the manuscript is well-written, and despite minor language imperfections, the English is sufficiently clear.

I suggest to accept it after minor revisions.

Specific comments:

line 19 - I suggest replacing "emerging" with "established" (or equivalent) as bimodal stimulation has been widely studied and applied in clinical practice for some time

line 236 - I suggest replacing "study" with "systematic review".

Author Response

REVIEWER 2

This is a systematic review of the last four years on bimodal stimulation after cochlear implantation (2020-2024). Even if many previous literature on the subject was published before 2020, given the advancements in cochlear implantation criteria for candidacy, it makes sense to focus on recent studies.

1. It would enhance the paper to include a discussion on the concept of asymmetric hearing loss in cochlear implant candidacy, especially since the outcomes of bimodal stimulation may differ between patients with bilateral severe-to-profound hearing loss and those with asymmetric hearing loss who receive a cochlear implant in the worse ear (see for reference: https://doi.org/10.1017/S0022215121004333).
   [Reply]: Thank you for your suggestion. Currently, the FDA has approved CI candidacy for subjects with asymmetric hearing loss also if guidelines are not been well established. We have improved the discussion describing the significant CI and bimodal benefit for asymmetric hearing loss and the recommendations for the expansion of the current FDA criteria according to the recent literature.

 

2. The methodology is sound, adhering to PRISMA guidelines, and the discussion effectively links the results to practical conclusions. The review of technological advancements, such as directional microphones and programming software, is relevant and well-discussed.

[Reply]: Thank you very much for your comment.

 

3. Overall, the manuscript is well-written, and despite minor language imperfections, the English is sufficiently clear.

[Reply]: Thank you for your comment.

 

4. I suggest to accept it after minor revisions.

[Reply]: Thank you.

 

5. Specific comments:

line 19 - I suggest replacing "emerging" with "established" (or equivalent) as bimodal stimulation has been widely studied and applied in clinical practice for some time

[Reply]: Thank you for your comment. We replaced it

 

Reviewer 3 Report

Comments and Suggestions for Authors

This study reviews the literature on the benefits and drawbacks of bimodal acoustic stimulation for adults' speech perception in noisy environments. The last four years will be the scope of the authors' research. They give the impact of updated programming software growth in this industry as justification for their choice. However, a significant number of publications from the last ten years are excluded by this restriction, and the authors can not guarantee that the articles from the previous years are based on a specifically updated program of fitting. In this instance, it would have been wiser to add the program type in the selection criteria. This study's drawback, in my opinion, is that it does not provide readers with an evolution of the findings over time .

In the selection criteria it is better to specify  the "other reasons" of exclusion of 2 articles.

On the other hand, a table of the overall results effectively presents the results. The benefits and drawbacks of bimodal stimulation are thoroughly discussed, and evidence is provided to support the superior performance of bimodal hearing over a cochlear implant alone in terms of speech perception in noisy environments.

There are several grammatical problems in the text; the English has to be revised. (line 59 "the control the... line 76 The the...and so on).

The argument is relevant and for this reason the article, in my opinion, has several design flaws that should be better specified in the selection criteria for the articles (e.g., the use of an outdated fitting software in the exclusion criteria; indicate which) 

Comments on the Quality of English Language

There are several grammatical problems in the text; the English has to be revised. (line 59 "the control the... line 76 The the...and so on).

Author Response

REVIEWER 3

 

1. This study reviews the literature on the benefits and drawbacks of bimodal acoustic stimulation for adults' speech perception in noisy environments. The last four years will be the scope of the authors' research. They give the impact of updated programming software growth in this industry as justification for their choice. However, a significant number of publications from the last ten years are excluded by this restriction, and the authors can not guarantee that the articles from the previous years are based on a specifically updated program of fitting. In this instance, it would have been wiser to add the program type in the selection criteria. This study's drawback, in my opinion, is that it does not provide readers with an evolution of the findings over time.

[Reply]: Thank you for your comment.

             Our selection criteria were not based on the evolution of programming software, which in some cases appeared earlier, e.g. APDB, but on the different approach that all the manufacturers had towards bimodal stimulation, which was no longer considered as the simple summation of the use of two hearing devices but as a therapeutic unicum of certain types and degrees of hearing loss. Therefore, companies with different approaches have intervened both on the HA/CI hardware and on the management software of specific devices, e.g. attack and release time of AGC, as well as on the programming software with very different strategic paths and above all not very confrontable between the various companies.

 

2. In the selection criteria it is better to specify the "other reasons" of exclusion of 2 articles.

[Reply]: Thank you for your comment. One of the articles was excluded because it was in the German language and only cited in the main text. about the other article, we included it in the review by optimising the PRISMA 2020.

 

3. On the other hand, a table of the overall results effectively presents the results. The benefits and drawbacks of bimodal stimulation are thoroughly discussed, and evidence is provided to support the superior performance of bimodal hearing over a cochlear implant alone in terms of speech perception in noisy environments.

[Reply]: Thank you for your comment.

 

4. There are several grammatical problems in the text; the English has to be revised. (line 59 "the control the... line 76 The the...and so on).

[Reply]: Thank you for your comment. We corrected.

 

5. The argument is relevant and for this reason the article, in my opinion, has several design flaws that should be better specified in the selection criteria for the articles (e.g., the use of an outdated fitting software in the exclusion criteria; indicate which) 

[Reply]: Thank you for your comment. As mentioned in comment 1, our selection or exclusion criteria were not based on the evolution of programming software, but on the different approaches of the companies that intervened on both HA/CI hardware and management software for specific devices, as well as on the use of very different and not very comparable strategies between programming software.

Reviewer 4 Report

Comments and Suggestions for Authors

This review examined clinical studies regarding bimodal stimulation (BS), in which patients use both a cochlear implant and a hearing aid and found that BS provide significant benefits in speech perception when residual hearing is available. The contents of this review will provide valuable information for clinicians and audiologists engaging in patients with hearing loss.

In practice, BS is rarely applied intentionally, as most people are first fitted with hearing aids and then transitioned to cochlear implants

Author Response

REVIEWER 4

 

This review examined clinical studies regarding bimodal stimulation (BS), in which patients use both a cochlear implant and a hearing aid and found that BS provide significant benefits in speech perception when residual hearing is available. The contents of this review will provide valuable information for clinicians and audiologists engaging in patients with hearing loss.

In practice, BS is rarely applied intentionally, as most people are first fitted with hearing aids and then transitioned to cochlear implants

[Reply] We thank the Reviewer for the positive comment on our study.

 

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

Every important point that I raised has been addressed by the authors. The paper might now qualify for publication.

Author Response

Dear Reviewer,

Thank you for your positive feedback on the publication and your constructive comments.

Best regards,

Nicola Serra