This study examined the average and individual performance over time of 49 adult cochlear implant subjects. Subjects were randomly assigned to receive either the Ineraid cochlear implant, with analog processing, or the Nucleus cochlear implant, with feature-extraction processing. All subjects had postlingual profound bilateral sensorineural hearing loss and received no significant benefit from hearing aids before implantation. Group data were examined in two ways. First, only subjects who had complete data over the test period were examined. Second, an analysis of all available data was carried out by mixed linear-model analysis. In this analysis, to account for missed follow-ups at the planned intervals, data consisting of the observations closest in time to the planned test times were modeled by natural splines with knots at the planned follow-up times. Contrasts between all pairs of planned follow-up times for each device were tested, as were contrasts between devices at each planned follow-up time. Results indicated little difference between the performance of the Ineraid and Nucleus subjects in their level of performance or their rate of learning. Postimplantation performance was typically superior to preimplantation performance within 9 months, and continued to improve up to 18-30 months depending on the speech perception measure. In some subjects, improvements in speech perception measures were observed up to four or five years postimplantation. There was also evidence that three subjects had a decrement in overall speech perception performance, although their postimplantation scores were always higher than their preimplantation scores. In at least one subjects this was likely a result of age-related cognition decrements.
[1]
N. Stafford,et al.
Double Pharyngeal Pouch
,
1987,
The Annals of otology, rhinology, and laryngology.
[2]
A. Thornton,et al.
Speech-discrimination scores modeled as a binomial variable.
,
1978,
Journal of speech and hearing research.
[3]
G M Clark,et al.
Speech recognition for 40 patients receiving multichannel cochlear implants.
,
1986,
Archives of otolaryngology--head & neck surgery.
[4]
S. Waltzman,et al.
Performance of cochlear implant patients as a function of time.
,
1990,
Journal of speech and hearing research.
[5]
A within-subject comparison of adult patients using the Nucleus F0F1F2 and F0F1F2B3B4B5 speech processing strategies.
,
1996,
Journal of speech and hearing research.
[6]
M F Dorman,et al.
Long-term measures of electrode impedance and auditory thresholds for the Ineraid cochlear implant.
,
1992,
Journal of speech and hearing research.
[7]
J K Shallop,et al.
Evaluation of a new spectral peak coding strategy for the Nucleus 22 Channel Cochlear Implant System.
,
1994,
The American journal of otology.
[8]
D. Eddington.
Speech discrimination in deaf subjects with cochlear implants.
,
1979,
The Journal of the Acoustical Society of America.