Wolfe et al. (2007) Results for Sequentially Implanted CIs

Wolfe, J., Baker, S., Caraway, T., Kasulis, H., Mears, A., Smith, J., Swim, L., & Wood, M. (2007). 1-year postactivation results for sequentially implanted bilateral cochlear implant users. Otology & Neurotology.

Objective: Evaluate speech recognition in quiet and in noise for
a group of 12 children, all of whom underwent sequential bilateral cochlear implantation at various ages (range, 1 yr, 8 mo to 9 yr, 6 mo at time of second implant).
Main Outcome Measures: Speech recognition in quiet was evaluated for each ear separately using single-word speech recognition assessments (Multisyllabic Lexical Neighborhood Test and Early Speech Perception Test) via recorded presentation. Speech recognition in noise was assessed for each ear separately and in the bilateral condition by obtaining a spondee recognition threshold in the presence of speech-weighted noise presented at 45 dB hearing level. The primary outcome measure for speech recognition in noise assessment was the signal-to-noise ratio for 50% performance, which was calculated by determining the difference between the presentation level of the noise and the presentation level at which the speech recognition threshold was obtained. The results of these assessments were contrasted between children receiving their second cochlear implant before 4 years of age and children receiving their second cochlear implant after 4 years of age.
Results: A statistically significant difference for speech recognition scores in quiet was obtained between the early implanted ear and the late-implanted ears for children receiving their second cochlear implant after 4 years of age. There was not a statistically significant difference in speech recognition scores in quiet between the early-implanted and late-implanted ears of children receiving their second cochlear before 4 years of age. Both groups of children possessed better speech recognition scores in noise (statistically significant at an > = 0.05) in the bilateral condition relative to either unilateral condition. However, there was not a statistically significant relationship between speech recognition performance in noise and the duration of deafness of the later implanted ear.
Conclusion: Bilateral cochlear implantation allowed for better speech recognition in noise relative to unilateral performance for a group of 12 children who underwent sequential bilateral cochlear implantation at various ages. There was not a statistically significant relationship between speech recognition in noise benefit, which was defined as the difference in performance between the first implanted ear and the bilateral condition and the age at which the second implant was received. Children receiving bilateral cochlear implants younger than 4 years of age achieved better speech recognition in quiet performance for the later implanted ear as compared with children receiving their second cochlear implant after 4 year of age.

Mitchell, R. E. & Karchmer, M. A. (2004) parental hearing status for deaf and hard of hearing students

Mitchell, R.E. & Karchmer, M.A. (2004). Chasing the mythical ten percent: Parental hearing status of deaf and hard of hearing students in the United States. Sign Language Studies, 4(2), 138-163.

Deaf children born to deaf parents are likely to grow up in a social, cultural, and linguistic milieu different from that in which children of hearing parents grow up. The goal of this article was to determine the prevalence of "deaf-of-deaf" children within the overall group of deaf and hard of hearing children and youth. Based largely on the Annual Survey conducted by Gallaudet University, the authors concluded that about 4 percent of deaf children are born to deaf parents, instead of the often-cited ten percent. The Annual Survey collects demographic, program, and service data for each child using voluntary and confidential information provided by schools and programs serving deaf and hard of hearing pre-K through grade 12 and youth in the United States. The authors concluded that estimating the prevalence of deaf-of-deaf students is difficult and parental hearing status information is unavailable for a large number of students.