Effects on intelligibility of television speech slowdown in disadvantaged populations

The role of communication by means of television is increasing in the last decades and now has gain a fundamental role above all for hearing impaired population. One of the principal parameters the influence intelligibility is speech velocity. Optimal speech velocity should be about 160 word/minute but frequently the velocity is higher than 200 word/minute. The aim of our study was to evaluate the benefits of audiovisual slowdown in people affected by with auditory disabilities. The study was based on an audiovisual speech recognizing test presented at different speech velocities in subjects older than 65 years with and without hearing loss and in cochlear implanted patients. A normal hearing group was also considered. The test consisted in the presentation a video with a speaker who says common Italian bi and trisyllabic words and sentences composed by 10 names, 10 verbs, 10 common names, 10 adjectives. The material was presented at a normal velocity and with a slowdown of 10 and 20%. All groups except cochlear implanted patients showed significant improvement when comparing results at normal speed and speed slowed to 20% less. The study confirms that slowdown of speech at video listening assure a significant improvement of intelligibility in older patients above all if affected by hearing loss. This procedure can assure a better quality of life in case of hearing loss, that is frequently represented in older people.