Karen Iler Kirk

The present study examined how prelingually deafened children and postlingually deafened adults with cochlear implants (CIs) combine visual speech information with auditory cues. Performance was assessed under auditory-alone (A), visual- alone (V), and combined audiovisual (AV) presentation formats. A measure of visual enhancement, RA, was used to assess the gain in performance provided in the AV condition relative to the maximum possible performance in the auditory-alone format. Word recogniton was highest for AV presentation followed by A and V, respectively. Children who received more visual enhancement also produced more intelligible speech. Adults with CIs made better use of visual information in more difficult listening conditions (e.g., when mutiple talkers or phonemically similar words were used). The findings are discussed in terms of the complementary nature of auditory and visual sources of information that specify the same underlying gestures and articulatory events in speech

With broadening candidacy criteria for cochlear implantation, a greater number of pediatric candidates have usable residual hearing in their nonimplanted ears. This population potentially stands to benefit from continued use of conventional amplification in their nonimplanted ears. The purposes of this investigation were to examine the speech and language development of pediatric cochlear implant recipients with either profound or severe hearing loss in their nonimplanted ears, including a subset with severe hearing loss who continued wearing hearing aids in their nonimplanted ears; to evaluate whether children benefit from binaural use of cochlear implants and hearing aids; and to investigate the time course of adaptation to combined use of the devices together. Children were tested on a battery of speech recognition measures in quiet and background noise and language measures in quiet. The results suggest that, although children with different degrees of residual hearing have improved speech recognition and language skills after cochlear implantation, the developmental time course differs for the two groups. Children with severe hearing loss required more than 1 year of cochlear implant experience to demonstrate spoken word recognition gains, whereas children with profound hearing loss showed more benefit during the first year after cochlear implantation. For measures in which group performance differed, children with severe hearing loss had better speech recognition and language skills than the children with profound hearing loss. Furthermore, children with severe hearing loss who continued using hearing aids in their nonimplanted ears benefited from combining the acoustic input received from a hearing aid with the input received from a cochlear implant, particularly in background noise. However, this benefit emerged with experience. Our findings suggest that it is appropriate to encourage pediatric cochlear implant recipients with severe hearing loss to continue wearing an appropriately fitted hearing aid in the nonimplanted ear to maximally benefit from bilateral stimulation. They also suggest that speech and language gains for children with nonimplanted-ear residual hearing occur after children have at least one year of cochlear implant listening experience.

In the early days of pediatric cochlear implantation, only children thought to be ‘‘ideal’’candidates were eligible to receive an implant. Today, this technology is the accepted treatment for profound deafness. As a consequence, more families are seeking implants for children with medical complicating conditions or other factors that affect the rate and extent of progress in the development of postimplant skills including language, literacy, spatial hearing, and music perception. Understanding the range of cochlear implant outcomes in children in general, as well as in those children with complicating conditions or factors is of great importance.

Probabilistic phonotactics refers to the frequency with which segments and sequences of segments occur in syllables and words. Knowledge of phonotactics has been shown to be an important source of information in segmenting and recognizing speech in normal hearing listeners. A post-perceptual task (nonword rating) and two on-line tasks (an auditory same-different and an auditory lexical decision task) were used in the present set of experiments to examine the use of phonotactic information by postlingually deafened adults who have received a cochlear implant. The results of all three experiments showed that both normal-hearing and hearing-impaired listeners are sensitive to differences in phonotactic information to varying degrees. Furthermore, cochlear implant patients with better word recognition abilities (as measured by the NU6) tended to be more sensitive to phonotactic information than cochlear implant patients with poorer word recognition abilities. The implications of these results for outcome assessments and clinical interventions are discussed.

This study examined lexical effects on word recognition by children with multichannel cochlear implants. Based on computational analyses, word lists were constructed to allow systematic examination of the effects of word frequency, lexical density (i.e., the number of phonemically similar words, or neighbors), mean neighborhood word frequency, and word length. The percent of words correctly identified was significantly higher for lexically ‘‘easy’’ words (high frequency words with few neighbors) than for ‘‘hard’’ words (low frequency words with many neighbors). The percent of phonemes correctly identified did not differ between the ‘‘easy’’ and ‘‘hard’’ words, suggesting that phoneme scores do not accurately reflect word recognition. Word recognition scores were also better for multisyllabic than for monosyllabic words. These results demonstrate that children with multichannel cochlear implants systematically …