Effects of text supplementation on speech intelligibility for listeners with normal and impaired hearing: a systematic review with implications for telecommunication.

OBJECTIVE: Telecommunication can be difficult in the presence of noise or hearing loss. The purpose of this study was to systematically review evidence regarding the effects of text supplementation (e.g. captions, subtitles) of auditory or auditory-visual signals on speech intelligibility for listeners with normal or impaired hearing. DESIGN: Three databases were searched. Articles were evaluated for inclusion based on the Population Intervention Comparison Outcome framework. The Effective Public Health Practice Project instrument was used to evaluate the quality of the identified articles. STUDY SAMPLE: After duplicates were removed, the titles and abstracts of 2019 articles were screened. Forty-six full texts were reviewed; ten met inclusion criteria. RESULTS: The quality of all ten articles was moderate or strong. The articles demonstrated that text added to auditory (or auditory-visual) signals improved speech intelligibility and that the benefits were largest when auditory signal integrity was low, accuracy of the text was high, and the auditory signal and text were synchronous. Age and hearing loss did not affect benefits from the addition of text. CONCLUSIONS: Although only based on ten studies, these data support the use of text as a supplement during telecommunication, such as while watching television or during telehealth appointments.