Audiovisual Speech Perception in People with Hearing Loss across Languages: A Systematic Review of English and Mandarin

8 Introduction . 9 Comparison of English and Mandarin Phonemic Inventories . 10 Comparison of English and Mandarin Visemes . 11 Purpose . 15 Methods. 16 Information Sources . 16 Eligibility Criteria . 16 Populations. 16 Intervention. 16 Comparison. 16 Outcomes. 16 Time frame. 17 Language. 17 Data management . 17 Data extraction . 17 Assessment of level of evidence and quality of individual studies . 20 Data analysis . 20 AV SPEECH PERCEPTION IN PEOPLE WITH HEARING LOSS 5 Assessment of confidence in cumulative evidence . 20 Results . 20 Assessment of level of evidence and quality of individual studies . 29 Audiovisual effects in English-speaking cochlear implant users. 29 Audiovisual effects in English-speaking hearing aid users. 29 Audiovisual effects in unaided English-speaking people with hearing loss. 30 Audiovisual effects in Mandarin-speaking people with cochlear implants. 31 Audiovisual benefits in Mandarin-speaking people with hearing aids. 31 Data synthesis . 31 Audiovisual effects in English-speaking cochlear implant users. 37 Audiovisual effects in English-speaking hearing aid users. 42 Audiovisual effects in unaided English-speaking people with hearing loss. 46 Audiovisual effects in Mandarin-speaking people with hearing loss. 52 Assessment of confidence in cumulative evidence . 55 Audiovisual effects in English-speaking cochlear implant users. 55 Audiovisual effects in English-speaking hearing aid users. 55 Audiovisual effects in unaided English-speaking people with hearing loss. 55 Audiovisual effects in Mandarin-speaking people with hearing loss. 55 Discussion . 56 Clinical Implications . 58 AV SPEECH PERCEPTION IN PEOPLE WITH HEARING LOSS 6 Conclusion . 59 Appendix A – Search Strategies . 60 Appendix B – Level of Evidence Hierarchy and System of Quality Rating (Cox, 2005) . 66 Appendix C – System for Grading a Recommendation (Cox, 2005) . 67 References . 68 AV SPEECH PERCEPTION IN PEOPLE WITH HEARING LOSS 7 List of Figures and Tables List of Figures Figure 1 PRISMA Flow Diagram . 22 List of Tables Table 1 English Phonemic Inventory . 13 Table 2 Mandarin Phonemic Inventory . 14 Table 3 Table Shell . 19 Table 4 Study Design and Characteristics of Included Articles . 24 Table 5 Results of Included Studies. 32 Table 6 Audiovisual Benefits in English-Speaking Cochlear Implant Users . 41 Table 7 Audiovisual Benefits in English-Speaking Hearing Aid Users . 45 Table 8 Audiovisual Benefits in unaided English-Speaking People with Hearing Loss . 51 Table 9 Audiovisual Benefits in Mandarin-Speaking People with Hearing Loss . 54 AV SPEECH PERCEPTION IN PEOPLE WITH HEARING LOSS 8 Abstract Audiovisual (AV) information has been reported to facilitate speech understanding among the English-speaking population. However, it is not clear whether audiovisual benefits also exist among people who speak languages other than English. A systematic review was conducted to investigate the audiovisual effects on speech perception among people with hearing loss who speak English and people with hearing loss who speak Mandarin. The results of the review demonstrated audiovisual benefits in the English-speaking population with hearing loss regardless of age, degree of hearing loss, use and type of hearing technology, and acoustic environment. By contrast, significant audiovisual benefits were only found for Mandarin phoneme and word recognition but not for tone recognition in pre-lingually deafened adults with cochlear implants and for phoneme recognition in children with hearing aids. No significant audiovisual benefits were revealed in Mandarin-speaking post-lingually deafened adults with cochlear implants and for speech perception at higher intensity levels. Heterogeneity in the results across studies and limitations of the included studies were discussed.