Sentence Recognition Performance in Visual-Only and Auditory-Visual Conditions by Normal and Hearing Impaired Adults

Objectives: This study aimed to investigate the list equivalency of the Korean Standard-Sentence List for Adults (KS-SL-A) in visual-only (VO) presentation conditions and to measure sentence recognition abilities for normal and hearing impaired individuals in VO and auditory-visual (AV) conditions. Methods: Sentences from the KS-SL-A, spoken by both males and females, were filmed and subsequently presented to 32 normal-hearing subjects in VO conditions, and to 21 normal subjects and 11 hearing-impaired subjects in VO and AV (+5, +10, +15 dB SL) conditions. Subjects were asked to identify sentences in VO and AV conditions. KS sentence lists of 10 everyday sentences were determined based on keyword accuracy. Auditory and visual enhancements were also calculated. Results: ANOVA revealed significant differences in sentence lists, and post hoc tests indicated that the following four lists were determined to be equivalent: List 1, 3, 4, and 6. Subjects with hearing impairment showed significantly higher scores in VO and +5 dB AV conditions, while subjects with normal hearing had significantly better performance in +15 dB AV condition. Conclusion: These findings suggest that individuals with hearing impaired are more reliant on visual speech information than individuals with normal hearing, but have been shown to develop their speech-reading ability along with auditory information. Therefore, speech recognition should be obtained in AV conditions as well as in AO conditions for clinical use in order to provide the best recommendation and rehabilitation.