Susan J Norton

Seattle Children's Hospital, Seattle, Washington, United States

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Publications (6)10 Total impact

  • Otolaryngology Head and Neck Surgery 01/2013; · 1.73 Impact Factor
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    ABSTRACT: The number of pediatric cochlear implant (CI) recipients has increased substantially over the past 10 years, and it has become more important to understand the underlying mechanisms of the variable outcomes in this population. In this study, psychoacoustic measures of spectral-ripple and Schroeder-phase discrimination, the Clinical Assessment of Music Perception, and consonant-nucleus-consonant (CNC) word recognition in quiet and spondee reception threshold (SRT) in noise tests have been presented to 11 prelingually deafened CI users, aged 8-16 years with at least 5 years of CI experience. The children's performance was compared to the previously reported results of postlingually deafened adult CI users. The average spectral-ripple threshold (n = 10) was 2.08 ripples/octave. The average Schroeder-phase discrimination was 67.3% for 50 Hz and 56.5% for 200 Hz (n = 9). The Clinical Assessment of Music Perception test showed that the average complex pitch direction discrimination was 2.98 semitones. The mean melody score was at a chance level, and the mean timbre score was 34.1% correct. The mean CNC word recognition score was 68.6%, and the mean SRT in steady noise was -8.5 dB SNR. The children's spectral-ripple resolution, CNC word recognition, and SRT in noise performances were, within statistical bounds, the same as in a population of postlingually deafened adult CI users. However, Schroeder-phase discrimination and music perception were generally poorer than in the adults. It is possible then that this poorer performance seen in the children might be partly accounted for by the delayed maturation in their temporal processing ability, and because of this, the children's performance may have been driven more by their spectral sensitivity.
    Audiology and Neurotology 03/2012; 17(3):189-97. · 2.32 Impact Factor
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    ABSTRACT: To compare the prevalence of congenital cytomegalovirus (CMV) infection in Washington State in children with hearing loss (HL) and the general population and to compare the characteristics of HL in children with and without congenital CMV infection. Matched case-control; case cohort. Regional pediatric hospital, Washington State Department of Health (WSDOH). Cases were children 4 years and older with HL born in Washington State. Control individuals matched for demographic characteristics were identified at random through the WSDOH. Congenital CMV status determined using quantitative polymerase chain reaction testing on newborn heel stick blood spots archived by the WSDOH. Audiologic data were used to characterize HL. Congenital CMV testing was performed for 222 matched cases and controls. Congenital CMV infection was detected in 1.4% of controls and in 9.9% of cases (odds ratio, 10.5; 95% confidence interval, 2.6-92.4). An estimated 8.9% of HL in children in Washington can be attributed to CMV infection. After inclusion of an additional 132 children with HL (for a total of 354 cases in the case cohort), we observed that children with congenital CMV had more severe HL (P < .001) and higher proportions of progressive (P = .02) and unilateral (P = .002) HL compared with children without congenital CMV infection. In the 35 children with congenital CMV infection, there was no relationship between neonatal CMV load and severity of HL. In Washington State, children with HL had a far higher prevalence of congenital CMV viremia than did the general pediatric population, and CMV infection seems to be responsible for an appreciable fraction of pediatric HL in Washington State.
    Archives of otolaryngology--head & neck surgery 01/2011; 137(1):47-53. · 1.92 Impact Factor
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    ABSTRACT: First, to establish the feasibility of the observer-based psychophysical procedure (OPP) in measuring sound detection in infant and toddler cochlear implant (CI) recipients. Second, to measure the psychometric function for detection (PFD) from individual subjects. Third, to determine whether reaction time (RT) provides information about the auditory sensitivity of young CI users. Twelve CI recipients, 11 to 32 mo old, participated in our study. Initially, tones were presented in sound field, and children learned to respond when they heard tones but not at other times. Once an 80% correct criterion was met in sound field, a novel stimulation paradigm was used to present stimuli to a single electrode while the child listened to acoustic input on most other electrodes using their usual map. The PFD and RT were measured using this single-electrode stimulation paradigm. Eleven subjects met criterion, 6 within the minimum possible number of trials. For eight subjects, the asymptotic level of detecting single-electrode stimuli averaged 86% correct, similar to levels achieved by normal-hearing infants and toddlers detecting pure tones. The PFD slope of infant and toddler CI recipients was less than or equal to the slope for adult CI users reported in previous studies. RT decreased significantly with stimulus level in four children. These preliminary results suggest that psychophysical detection data can be obtained from infant and toddler CI recipients using OPP. The PFD of young CI users may be shallower than that of adult CI users. Relatively good asymptotic detection performance implies that young CI users are more attentive to sound than has been suggested in previous studies. RT tended to be a less reliable measure of detection, but methodological changes could improve its utility.
    Ear and hearing 03/2009; 30(2):250-61. · 2.06 Impact Factor
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    ABSTRACT: Congenital severe to profound sensorineural hearing loss (SNHL) is found in higher proportions of children with minority and/or lower socioeconomic status (SES). Cochlear implants were approved by the U.S. Food and Drug Administration for use in children with bilateral severe to profound SNHL in 1990. The objectives of the study were as follows: 1) to study the epidemiology of pediatric cochlear implantation, assessing whether cochlear implant technology is provided to children with severe to profound SNHL in proportion to their racial/ethnic or SES, and 2) to compare data provided by a national health care database with data provided by cochlear implant manufacturers. Patients aged 0 to 18 years who underwent cochlear implantation in 1997 using a cross-sectional study design. Analyses were made of pediatric cochlear implant patients, using data from the 1997 Health Care and Utilization Project/Kids' Inpatient Database. Relative rates of implantation compared with rates of severe to profound SNHL were calculated using national estimates generated from census and Galludet Research Institution data. Logistic regression analysis was carried out to compare implanted children of different racial/ethnic backgrounds. A surrogate measure of socioeconomic status was used based on the median household income of the patient's home ZIP code. Information was also obtained from the two companies producing U.S. Food and Drug Administration-approved cochlear implants in 1997 and used to determine whether the data obtained from the Health Care and Utilization Project/Kids' Inpatient Database were representative of the national cohort of implanted children. The Health Care and Utilization Project/Kids' Inpatient Database identified 124 children who underwent cochlear implant surgery in 1997. White and Asian children were implanted at higher rates than Hispanic and black children. Furthermore, white and Asian children received implants at greater rates than would be expected based on prevalence of severe to profound SNHL. The relative rate (RR) of implantation, defined as the proportion of children who received cochlear implants divided by the proportion of children with severe to profound SNHL (in each race/ethnicity group compared with the same ratio in white children), was similar in white (RR = 1.00) and Asian (RR = 0.93) children but markedly different in Hispanic (RR = 0.28) and black (RR = 0.10) children. Comparison of SES information from the Health Care and Utilization Project/Kids' Inpatient Database population with the manufacturers' database suggested that the Health Care and Utilization Project/Kids' Inpatient Database is representative of all implanted children in the United States. Both sources of information suggested that children receiving cochlear implants in the United States in 1997 resided in above-average SES areas. White and Asian children with severe to profound SNHL had higher proportionate rates of cochlear implantation than black and Hispanic children in 1997. Implanted children were more likely to live in areas (represented by ZIP codes) with higher median incomes. Although there was a disparity in rate of cochlear implantation based on race/ethnicity and surrogate measures of SES, these data did not allow the authors to determine the causes for these differences.
    The Laryngoscope 02/2005; 115(1):125-31. · 1.98 Impact Factor
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    ABSTRACT: Problem: Pediatric cochlear implant recipients have been historically assessed postoperatively with audiometric testing in a soundproof booth by trained audiologists. Assessment of functional outcome after cochlear implantation must also consider a number of other factors including speech perception, speech intelligibility, mode of communication, educational placement, as well as the social and psychological factors that affect one’s ability to function in the mainstream environment. No uniform tool for assessing effective functional outcome in the daily life of pediatric cochlear implant recipients has been developed.Methods: Using a cross-sectional design, the COCHLEA (Children’s Outcome for Cochlear Implant Hearing, Language, and Environmental Assessment) questionnaire, designed to measure functional outcomes in the pediatric cochlear implant population, was administered. The questionnaire was tested for reliability and validity, while investigating for any possible respondent or administrative burden. The parents of children with cochlear implants completed the questionnaire. The subjects were individuals with nonsyndromic sensorineural hearing loss (SNHL) implanted at Children’s Hospital and Regional Medical Center before 12/31/2001, aged 3–12 years. Implantation must have occurred before age 7. Non-English-speaking children/families were excluded secondary to a lack of resources.Results: Thirty-one patients were enrolled in the study. Preliminary results indicate that absolute scores of this outcome measure correlate with higher global health measures, including the Child Health Questionnaire (CHQ), and predict better audiometric scores.Conclusion: The COCHLEA functional outcome measure appears to be a reliable and valid method for assessing effective cochlear implantation. More research is necessary to determine this questionnaire’s sensitivity to longitudinal change.Significance: The COCHLEA questionnaire represents the first disease-specific functional outcome measure for the pediatric cochlear implant patient population. Ultimately it may be used to compare the effectiveness of cochlear implants and rehabilitation strategies.Support: None reported.
    Otolaryngology-head and Neck Surgery - OTOLARYNGOL HEAD NECK SURG. 01/2004; 131(2).