Audiovisual integration and lipreading abilities of older adults with normal and impaired hearing

OBJECTIVE: The purpose of the current study was to examine how age-related hearing impairment affects lipreading and auditory-visual integration. The working hypothesis for the investigation was that presbycusic hearing loss would increase reliance on visual speech information, resulting in better lipreading and auditory-visual integration in older persons who have hearing impairment, compared with older persons who have normal hearing. DESIGN: This study compared the performance of 53 adults with normal hearing (above age 65) and 24 adults with mild-to-moderate hearing impairment (above age 65) on auditory-only (A), visual-only (V), and auditory-visual (AV) speech perception, using consonants, words, and sentences as stimuli. All testing was conducted in the presence of multi-talker background babble, set individually for each participant and each type of stimulus, to obtain approximately equivalent A performance across the groups. In addition, we compared the two groups of participants on measures of auditory enhancement, visual enhancement, and auditory-visual integration that were derived from the A, V and AV performance scores. RESULTS: In general, the two groups of participants performed similarly on measures of V and AV speech perception. The one exception to this finding was that the participants with hearing impairment performed significantly better than the participants with normal hearing on V identification of words. Measures of visual enhancement, auditory enhancement, and auditory-visual integration did not differ as a function of hearing status. CONCLUSIONS: Overall, the results of the current study suggest that despite increased reliance on visual speech information, older adults who have hearing impairment do not exhibit better V speech perception or auditory-visual integration than age-matched individuals who have normal hearing. These findings indicate that inclusion of V and AV speech perception measures can provide important information for designing maximally effective audiological rehabilitation strategies.