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Biomedical subjects

S Zimmerman-Phillips

Publications and source records attributed to S Zimmerman-Phillips.

8 recordsLinked to original sources

A comparison of round-window and transtympanic promontory electric stimulation in cochlear implant candidates.

We compared within-subjects electrical thresholds and dynamic ranges obtained with direct round-window and transtympanic promontory stimulation carried out preoperatively in 12 patients who were candidates for a cochlear implant. Square waves with frequencies of 50, 100, 200, and 400 Hz were delivered in a 50% duty cycle to both sites in each patient. With the exception of threshold at 50 Hz (promontory thresholds were lower than round-window thresholds), there were no statistically significant differences for either thresholds or dynamic ranges between the two sites of stimulation. There was a general trend for round-window thresholds to be lower and dynamic ranges larger, especially for the higher frequencies of stimulation. Mean threshold slopes for the two sites of stimulation were nearly identical.

Adult

Auditory performance of children with cochlear ossification and partial implant insertion.

The management of the profoundly deaf child with a cochlear implant poses a special challenge, particularly when total ossification of the cochlea is present. In this setting, insertion of an electrode array into a child's cochlea is often difficult. Our experience supports the feasibility of partial insertion of a multichannel implant into the basal turn of an ossified cochlea. Five children with ossified cochleae who had undergone partial implantation of a multichannel electrode were compared with the performance of matched controls who had full insertion of multichannel implants. No dramatic differences were detected during a 6- to 18-month follow-up period on selected test measures. These preliminary results suggest that active electrode number may exert a limited effect on performance with a cochlear implant. Drilling out the basal turn of an ossified cochlea in conjunction with partial insertion of a multichannel implant appears to be an acceptable surgical and rehabilitational alternative for placement of a cochlear implant prosthesis in children with complete cochlear ossification.

Adolescent

Effects of channel number and place of stimulation on performance with the Cochlear Corporation multichannel implant.

The effects of active channel number and place of stimulation on auditory-only performance with the Cochlear Corporation multichannel cochlear implant were investigated in seven subjects. A balanced crossover design was employed; subjects were initially programmed with either 10 basal or the full complement of 20 to 21 active electrodes. Following a 6-month period with the initial coding strategy, subjects were programmed with the alternate configuration, which they used for an additional 6 months. Auditory-only performance on suprasegmental, phoneme (vowel and consonant) open- and closed-set speech recognition was compared between the two electrode configurations. Additionally, performance with the first configuration and performance with the second configuration 3 days following programming were also compared. While a trend for increased scores was noted with 20 electrodes, especially with open-set speech recognition tasks, none of the differences between the two configurations reached statistical significance, as indicated by a Wilcoxon test. A comparison of performance at the end of the first 6-month period and 3 days following programming with the second configuration revealed a trend for reduced scores, especially on vowel tests. Overall, our results indicate that the feature extraction coding strategy associated with the Cochlear Corporation device allows patients to function well with only 10 basal electrodes and that speech recognition is only mildly affected initially when patients are programmed with a different encoding strategy.

Acoustic Stimulation

Independent evaluation of the speech perception abilities of children with the Nucleus 22-channel cochlear implant system.

The performance of 28 children with the Nucleus multi-channel cochlear implant, who had used the device an average of 1.7 yr, was examined on a battery of speech perception measures. All children demonstrated better speech perception skills with the implant than they had in the preimplant condition with hearing aids. With the Nucleus implant, 61% of the children demonstrated some open-set speech recognition and another 14% demonstrated closed-set speech recognition. Scores on the tests were corrected for guessing and a hierarchy of test difficulty was developed. The results revealed systematic differences in performance as a function of perception task and test format. The results of regression analyses, which were performed to identify predictors of success, showed that communication mode made a significant unique contribution to the variance in performance among subjects on an open-set word recognition test. When the scores of the children who used oral or total communication were compared on the full battery of tests, however, there were few significant group differences.

Adolescent

Effects of preoperative electrical stimulability and historical factors on performance with multichannel cochlear implant.

We investigated the relationship between results of preoperative transtympanic electrical promontory stimulation, duration of deafness, postoperative implanted psychophysical results, and postoperative speech and speech sound recognition as indicated by a battery of five tests. Our subjects were 10 patients implanted with the Cochlear Corporation multielectrode implant, 1 year postimplantation, with a minimum of 17 active electrodes programmed in the bipolar + 1 mode. The results indicated that preoperative promontory thresholds, the slope of the threshold function, and the duration of auditory deprivation are excellent predictors of postoperative speech and speech sound recognition in the auditory (processor alone) mode. These results have significant implications for patient selection and counseling.

Adolescent

Cochlear implants in children.

The resources and areas of expertise necessary to establish and maintain a successful children's cochlear implant program is discussed. Insights based on experience with a pediatric patient population are presented.

Adolescent

Pediatric cochlear implant candidacy issues.

Children with progressive sensorineural hearing impairment represent a special challenge to the audiologist and the otologist. These are patients with some residual auditory abilities that deteriorate with time as the hearing loss progresses. No doubt, the unnecessary implantation of an ear that significantly benefits from amplification needs to be avoided at all costs. By the same token however, there appears to be no advantage to waiting an inordinate amount of time after the loss of functional auditory abilities before recommending implantation. At times when a complete loss is predictable, implantation may be advantageous before the onset of complete auditory deprivation. Steps the clinicians should take to manage these patients effectively are briefly summarized below: Implementation of rigorous and frequent audiologic monitoring. If, for instance, a significant progressive loss of hearing has occurred over a 6-month period, resulting in a complete absence of open-set speech recognition abilities in the auditory-alone mode with appropriate hearing aids, it is probably counterproductive to wait to the point of a complete absence of aided speech detection. Implantation at a critical point in time will prevent complete auditory deprivation. Parental counseling concerning various management strategies, such as use of vibrotactile devices, changing communication skills, and issues involving cochlear implants need to be undertaken early. Parents need to be involved in every phase of the evaluation process because they are the ones who make the final decision concerning the implantation of their child. Relatively early implantation should be considered in light of what is known concerning the effects of disruption in a child's linguistic, cognitive, and emotional development resulting from complete auditory deprivation.(ABSTRACT TRUNCATED AT 250 WORDS)

Auditory Threshold