Biomedical subjects

Teresa A Zwolan

Publications and source records attributed to Teresa A Zwolan.

7 recordsLinked to original sources

PubMed2006

The age at which young deaf children receive cochlear implants and their vocabulary and speech-production growth: is there an added value for early implantation?

OBJECTIVE: The age at which a child receives a cochlear implant seems to be one of the more important predictors of his or her speech and language outcomes. However, understanding the association between age at implantation and child outcomes is complex because a child's age, length of device use, and age at implantation are highly related. In this study, we investigate whether there is an added value to earlier implantation or whether advantages observed in child outcomes are primarily attributable to longer device use at any given age. DESIGN: Using hierarchical linear modeling, we examined latent-growth curves for 100 children who had received their implants when they were between 1 and 10 yr of age, had used oral communication, and had used their devices for between 1 and 12 yr. Children were divided into four groups based on age at implantation: between 1 and 2.5 yr, between 2.6 and 3.5 yr, between 3.6 and 7 yr, and between 7.1 and 10 yr. RESULTS: Investigation of growth curves and rates of growth over time revealed an additional value for earlier implantation over and above advantages attributable to longer length of use at any given age. Children who had received their implants before the age of 2.5 yr had exhibited early bursts of growth in consonant-production accuracy and vocabulary and also had significantly stronger outcomes compared with age peers who had received their implants at later ages. The magnitude of the early burst diminished systematically with increasing age at implantation and was not observed for children who were older than 7 yr at implantation for consonant-production accuracy or for children who were over 3.5 yr old at implantation for vocabulary. The impact of age at implantation on children's growth curves differed for speech production and vocabulary. CONCLUSIONS: There seems to be a substantial benefit for both speech and vocabulary outcomes when children receive their implant before the age of 2.5 yr. This benefit may combine a burst of growth after implantation with the impact of increased length of use at any given age. The added advantage (i.e., burst of growth) diminishes systematically with increasing age at implantation.

Age Factors↗

PubMed2005

Cochlear implant failures and revision.

OBJECTIVE: To review cases involving implant failure and revision surgery in a large cochlear implant program. STUDY DESIGN: Retrospective case series. SETTING: Cochlear implant program in an academic medical center. PATIENTS: Adults and children who underwent revision cochlear implantation (n = 58). INTERVENTION: Diagnosis and explantation of failed cochlear implants, with subsequent reimplantation. Assessment of implant function and speech perception. MAIN OUTCOME MEASURES: Device type, time from implantation to revision, cause of failure, performance with original implant versus revision, number of electrodes placed, and surgical challenges related to reimplantation. RESULTS: Forty-five patients initially implanted at this program and 13 patients implanted elsewhere underwent revision surgery. The institutional device failure rate was 3.7% and the overall revision rate was 5.1%. Reasons for implant revision included documented internal device failure (46%), scalp flap complications (17%), optimization of electrode placement (13%), unexplained deterioration of performance (12%), technology upgrade (10%), and intratemporal pathology (3%). Revision surgery typically involved only minor anatomic challenges, but five patients required circumodiolar drillout procedures to improve electrode position. Electrode insertion was equal or deeper in 53 of 58 cases. Speech perception ability decreased in only three patients. CONCLUSIONS: Management of implant failures and performance of revision surgery are becoming increasingly important in cochlear implant programs. Outcomes are generally excellent. Revision implantation is a safe and appropriate procedure that should be pursued in a timely fashion when patients experience cochlear implant failure.

Adult↗

PubMed2005

Efficacy of a cochlear implant simultaneous analog stimulation strategy coupled with a monopolar electrode configuration.

OBJECTIVES: The present study was performed to evaluate the efficacy and clinical feasibility of using monopolar stimulation with the Clarion Simultaneous Analog Stimulation (SAS) strategy in patients with cochlear implants. METHODS: Speech recognition by 10 Clarion cochlear implant users was evaluated by means of 4 different speech processing strategy/electrode configuration combinations; ie, SAS and Continuous Interleaved Sampling (CIS) strategies were each used with monopolar (MP) and bipolar (BP) electrode configurations. The test measures included consonants, vowels, consonant-nucleus-consonant words, and Hearing in Noise Test sentences with a +10 dB signal-to-noise ratio. Additionally, subjective judgments of sound quality were obtained for each strategy/configuration combination. RESULTS: All subjects but 1 demonstrated open-set speech recognition with the SAS/MP combination. The group mean Hearing in Noise Test sentence score for the SAS/MP combination was 31.6% (range, 0% to 92%) correct, as compared to 25.0%, 46.7%, and 37.8% correct for the CIS/BP, CIS/MP, and SAS/BP combinations, respectively. Intersubject variability was high, and there were no significant differences in mean speech recognition scores or mean preference ratings among the 4 strategy/configuration combinations tested. Individually, the best speech recognition performance was with the subject's everyday strategy/configuration combination in 72% of the applicable cases. If the everyday strategy was excluded from the analysis, the subjects performed best with the SAS/MP combination in 37.5% of the remaining cases. CONCLUSIONS: The SAS processing strategy with an MP electrode configuration gave reasonable speech recognition in most subjects, even though subjects had minimal previous experience with this strategy/configuration combination. The SAS/MP combination might be particularly appropriate for patients for whom a full dynamic range of electrical hearing could not be achieved with a BP configuration.

Adult↗

PubMed2004

Measuring progress in children with autism spectrum disorder who have cochlear implants.

OBJECTIVE: To quantify progress after cochlear implantation for children with autism spectrum disorder (ASD). STUDY DESIGN: Retrospective review of speech and language and speech perception test scores of children with autism who have received a cochlear implant at our center. SETTING: University of Michigan Medical Center, Cochlear Implant Program. PATIENTS: Six children, ages 3 to 16 years, who received cochlear implants at the our center. All children were diagnosed as having ASD by a neuropsychologist, either before or after receiving a cochlear implant. MAIN OUTCOME MEASURES: Children participated in preoperative and postoperative speech and language and speech perception testing. A survey was administered to parents to evaluate subjective impressions of cochlear implant benefit and quality of life before and after implantation. RESULTS: Improved scores were recorded for children on whom standardized expressive and receptive vocabulary testing was possible. Children who could not complete standardized tests demonstrated improvement in raw scores. Improvement on the Meaningful Auditory Integration Scale was noted for the 4 of 7 children who completed the scale preoperatively and postoperatively. Survey results suggested changes in responsiveness to sound, interest in music, vocalization, and eye contact following implantation. Five of the 6 families indicated that they would recommend a cochlear implant to another family in a similar situation. CONCLUSIONS: Gains made by children in our study were small compared with the general implant population; however, when compared with themselves preoperatively, these children did demonstrate progress. Improvements in behaviors and interaction point to a quality of life benefit following implantation that is difficult to quantify.

Autistic Disorder↗

PubMed2004

Examining multiple sources of influence on the reading comprehension skills of children who use cochlear implants.

Children with profound deafness are at risk for serious reading difficulties. Multiple factors affect their development of reading skills, including use of cochlear implants. Further, multiple factors influence the overall success that children experience with their cochlear implants. These factors include the age at which they receive an implant, method of communication, vocabulary skills, preoperative residual hearing, and socioeconomic status. Ninety-one children with prelingual and profound hearing impairments who received cochlear implants at varying ages participated in the study. Structural equation modeling confirmed that multiple factors affected young cochlear implant users' reading comprehension skills and that there were significant associations between the predictors of reading comprehension. Pre-implant vocabulary had an indirect positive effect on reading through postimplant vocabulary, which had a direct positive effect on reading. Overall, children with stronger language skills demonstrated stronger reading outcomes. Age at implantation both directly and indirectly, through postimplant vocabulary, affected reading outcomes, and the total effect was large. Children who were younger when they received their implants tended to have higher reading comprehension scores. Socioeconomic status negatively affected reading. Children who used total communication prior to implantation tended to have stronger pre-implant vocabulary scores, but the total effect of pre-implant communication method on children's reading skills was negligible. Research and educational implications are discussed.

Chi-Square Distribution↗

PubMed2004

Pre-perioperative, transtympanic electrically evoked auditory brainstem response in children.

The purpose of this study was to characterize the transtympanically evoked, perioperative electrically evoked auditory brainstem response (EABR) and define its relationship with preoperative hearing, age and hearing loss etiology in 59 children (10-60 months of age) who had received cochlear implants. The results indicate that there was no difference between wave V latency obtained from the younger (10-36 months) and the older (37-60 months) children. There was a statistically significant difference in the preoperative pure-tone average between the higher-EABR threshold group (650 microA and above) and the lower-EABR threshold group (600 microA or less). Patients with post-meningitic deafness exhibited the longest EABR wave V latencies. Perioperative, transtympanic, promontory EABR is an effective clinical procedure which can decrease the likelihood of placing a cochlear implant in a non-stimulable ear, and may provide the clinician with a valuable tool for selecting the most appropriate ear for implantation.

Age Factors↗

PubMed2002

Cochlear implants in young children.

The past 20 years have seen the cochlear implant evolve from an innovative but radical concept to the standard of care in the management of children with severe to profound hearing loss. All children receiving the cochlear implant achieve substantial benefit; however, performance gains are optimized by a team approach to the evaluation and management of these children. The critical elements of this team include audiologists, speech pathologists, and surgeons with specific interest, expertise, and dedication to the management of children with cochlear implants. Children are not well served by practitioners who delegate follow-up to educational programs not experienced in children with implants. Long-term involvement and dedication on the part of teachers, speech pathologists, audiologists, surgeons, and family are critical to maximizing the benefit the child receives.

Adolescent↗