Delayed cochlear implantation endorsed for congenitally deaf children and adults
New findings suggest show overall improvement in communication skills in this population
Previous research has concluded that expanding the criteria for cochlear implantation is justifiable. Groups that have benefited from this research include children under age two, multiply handicapped children, and children and adults with increased amounts of residual hearing. This same research shows that the duration of deafness, especially in the congenitally deaf population, and age of implantation are important predictors of success for this device. Consequently, many believed that cochlear implantation for the congenitally deaf would not provide a significant impact in overall communication skills.
Little research has been done to assess the efficacy of cochlear implantation at a delayed age for the congenitally deaf child or adult. A new postoperative study addresses that issue. The authors of the study, Delayed Implantation of Congenitally Deaf Children and Adults, are Susan B. Waltzman, PhD, J. Thomas Roland, Jr., MD, and Noel Cohen, MD, all from the Department of Otolaryngology, New York University School of Medicine, New York, NY. Their findings were presented May 13, 2001, before the spring meeting of the American Neurotology Society, held in Palm Springs, CA.
Thirty five congenitally deaf children implanted above age eight and 14 congenitally deaf adults also implanted as adults participated in this study. The time of cochlear implant device usage ranged from six months to three years.
Preoperative and postoperative evaluation consisted of measuring routine pure tone as well as speech audiometry and open set speech perception tests designed to assess phoneme (the smallest sound unit which, in terms of the phonetic sequences of sound, controls meaning), word and sentence recognition in the auditory listening condition.
For the adults, a majority displayed varying degrees of improved performance with their cochlear implant. Seventy-one percent demonstrated improvement of four to 46 percent on monosyllabic word identification. Fifty percent of the subjects showed growth in open set sentence recognition ability, 64 percent improved their performance on the Hearing in Noise Test, and 62 percent of the test subjects improved their ability to understand sentences in the presence of competing noise. All used the device on a regular basis and believe their communication skills have been enhanced by the cochlear implant.
Children demonstrated statistically significant improvement on open set speech performance using audition (hearing) only following cochlear implantation. For all tests, average scores improved after they received the device. A significant and inverse linear correlation was established between duration of deafness, age at implantation, and postoperative performance. The results implied that younger, congenitally deaf children showed greater postoperative improvement than their older counterparts.
The researchers suggest that the findings reveal:
- Congenitally, long-termed profoundly hearing impaired children and adults can obtain substantial open set speech recognition, after implantation, using the currently available speech processing strategies.
- There is a correlation between the age at implantation (and age of deafness) and the length of time the device was used with post-implant improvement.
- A consistent increase in mean test scores demonstrates continued improvement in speech perceptual, skills but there is no evidence to assert that pre-implant performace predicts benefit from cochlear implantation.
Source: American Neurotology Society
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