Visual Speech in hearing recovery with Cochlear Implant

Deafness and cochlear implants: According to the WHO estimates, 278 million people worldwide have moderate to profound hearing loss in both ears. In consequence hearing impairment and deafness have a strong social-economic impact on individuals families and communities. Children with hearing impairment often experience delayed in the development of speech, language and cognitive skills, which may result in slow learning and difficulty progressing in school. When hearing aids are ineffective to help profoundly deaf patients retaining speech-based communicative abilities, cochlear implantation has become the only efficient method (Deggouj et al., 2007). While hearing aids amplify sounds to be detected by damaged ears, cochlear implants bypass the damaged portions of the ear and directly stimulate the auditory nerve. Signals generated by the implant are sent by way of the auditory nerve to the brain, which recognizes the signals as sound. Modern cochlear implants allow deaf individuals to better understand spoken speech, environmental sounds and even in some cases to listen to music. However, auditory information delivered by the implant remains spectrally degraded (Shannon et al., 1995) and lacks some of the fine temporal acoustic structure important for speech comprehension (Lorenzi et al., 2006).