Jacob Oleson

Accuracy of cochlear implant recipients on pitch perception, melody recognition, and speech reception in noise.

Objective: The purposes of this study were to (a) examine the accuracy of cochlear implant recipients who use different types of devices and signal processing strategies on pitch ranking as a function of size of interval and frequency range and (b) to examine the relations between this pitch perception measure and demographic variables, melody recognition, and speech reception in background noise. Design: One hundred fourteen cochlear implant users and 21 normal-hearing adults were tested on a pitch discrimination task (pitch ranking) that required them to determine direction of pitch change as a function of base frequency and interval size. Three groups were tested: (a) long electrode cochlear implant users (N = 101); (b) short electrode users that received acoustic plus electrical stimulation (A+E) (N = 13); and (c) a normal-hearing (NH) comparison group (N = 21). Pitch ranking was tested at standard frequencies of 131 to 1048 Hz, and the size of the pitch-change intervals ranged from 1 to 4 semitones. A generalized linear mixed model (GLMM) was fit to predict pitch ranking and to determine if group differences exist as a function of base frequency and interval size. Overall significance effects were measured with Chi-square tests and individual effects were measured with t-tests. Pitch ranking accuracy was correlated with demographic measures (age at time of testing, length of profound deafness, months of implant use), frequency difference limens, familiar melody recognition, and two measures of speech reception in noise. Results: The long electrode recipients performed significantly poorer on pitch discrimination than the NH and A+E group. The A+E users performed similarly to the NH listeners as a function of interval size in the lower base frequency range, but their pitch discrimination scores deteriorated slightly in the higher frequency range. The long electrode recipients, although less accurate than participants in the NH and A+E groups, tended to perform with greater accuracy within the higher frequency range. There were statistically significant correlations between pitch ranking and familiar melody recognition as well as with pure-tone frequency difference limens at 200 and 400 Hz. Conclusions: Low-frequency acoustic hearing improves pitch discrimination as compared with traditional, electric-only cochlear implants. These findings have implications for musical tasks such as familiar melody recognition.

Hybrid 10 clinical trial: preliminary results.

Acoustic plus electric (electric-acoustic) speech processing has been successful in highlighting the important role of articulation information in consonant recognition in those adults that have profound high-frequency hearing loss at frequencies greater than 1500 Hz and less than 60% discrimination scores. Eighty-seven subjects were enrolled in an adult Hybrid multicenter Food and Drug Administration clinical trial. Immediate hearing preservation was accomplished in 85/87 subjects. Over time (3 months to 5 years), some hearing preservation was maintained in 91% of the group. Combined electric-acoustic processing enabled most of this group of volunteers to gain improved speech understanding, compared to their preoperative hearing, with bilateral hearing aids. Most have preservation of low-frequency acoustic hearing within 15 dB of their preoperative pure tone levels. Those with greater losses (>30 dB) also benefited from the combination of electric-acoustic speech processing. Postoperatively, in the electric-acoustic processing condition, loss of low-frequency hearing did not correlate with improvements in speech perception scores in quiet. Sixteen subjects were identified as poor performers in that they did not achieve a significant improvement through electric-acoustic processing. A multiple regression analysis determined that 91% of the variance in the poorly performing group can be explained by the preoperative speech recognition score and duration of deafness. Signal-to-noise ratios for speech understanding in noise improved more than 9 dB in some individuals in the electric-acoustic processing condition. The relation between speech understanding in noise thresholds and residual low-frequency acoustic hearing is significant (r = 0.62; p < 0.05). The data suggest that, in general, the advantages gained for speech recognition in noise by preserving residual hearing exist, unless the hearing loss approaches profound levels. Preservation of residual low-frequency hearing should be considered when expanding candidate selection criteria for standard cochlear implants. Duration of profound high-frequency hearing loss appears to be an important variable when determining selection criteria for the Hybrid implant.

Music Perception with Cochlear Implants and Residual Hearing

Aim: The aims of this study were to examine the music perception abilities of Cochlear Nucleus Hybrid (acoustic plus electric stimulation) cochlear implant (CI) recipients and to compare their performance with that of normal-hearing (NH) adults and CI recipients using conventional long-electrode (LE) devices (Advanced Bionics: 90K, Clarion, CIIHF; Cochlear Corporation: CI24M, CI22, Contour; Ineraid). Hybrid CI recipients were compared with NH adults and LE CI recipients on recognition of (a) real-world melodies and (b) musical instruments. Patients and Methods: We tested 4 Hybrid CI recipients, 17 NH adults, and 39 LE CI recipients on open-set recognition of real-world songs presented with and without lyrics. We also tested 14 Hybrid CI recipients, 21 NH adults, and 174 LE CI recipients on closed-set recognition of 8 musical instruments playing a 7-note phrase. Results: On recognition of real-world songs, both the Hybrid recipients and NH listeners were significantly more accurate (p < 0.0001) than the LE CI recipients in the no lyrics condition, which required reliance on musical cues only. The LE group was significantly less accurate than either the Hybrid or NH group (p < 0.0001) on instrument recognition for low and high frequency ranges. Conclusions: These results, while preliminary in nature, suggest that preservation of low-frequency acoustic hearing is important for perception of real-world musical stimuli.

Language Outcomes in Young Children with Mild to Severe Hearing Loss

Objectives: This study examined the language outcomes of children with mild to severe hearing loss during the preschool years. The longitudinal design was leveraged to test whether language growth trajectories were associated with degree of hearing loss and whether aided hearing influenced language growth in a systematic manner. The study also explored the influence of the timing of hearing aid fitting and extent of use on children’s language growth. Finally, the study tested the hypothesis that morphosyntax may be at particular risk due to the demands it places on the processing of fine details in the linguistic input. Design: The full cohort of children in this study comprised 290 children who were hard of hearing (CHH) and 112 children with normal hearing who participated in the Outcomes of Children with Hearing Loss (OCHL) study between the ages of 2 and 6 years. CHH had a mean better-ear pure-tone average of 47.66 dB HL (SD = 13.35). All children received a comprehensive battery of language measures at annual intervals, including standardized tests, parent-report measures, and spontaneous and elicited language samples. Principal components analysis supported the use of a single composite language score for each of the age levels (2, 3, 4, 5, and 6 years). Measures of unaided (better-ear pure-tone average, speech intelligibility index) and aided (residualized speech intelligibility index) hearing were collected, along with parent-report measures of daily hearing aid use time. Mixed modeling procedures were applied to examine the rate of change (227 CHH; 94 children with normal hearing) in language ability over time in relation to (1) degree of hearing loss, (2) aided hearing, (3) age of hearing aid fit and duration of use, and (4) daily hearing aid use. Principal components analysis was also employed to examine factor loadings from spontaneous language samples and to test their correspondence with standardized measures. Multiple regression analysis was used to test for differential effects of hearing loss on morphosyntax and lexical development. Results: Children with mild to severe hearing loss, on average, showed depressed language levels compared with peers with normal hearing who were matched on age and socioeconomic status. The degree to which CHH fell behind increased with greater severity of hearing loss. The amount of improved audibility with hearing aids was associated with differential rates of language growth; better audibility was associated with faster rates of language growth in the preschool years. Children fit early with hearing aids had better early language achievement than children fit later. However, children who were fit after 18 months of age improved in their language abilities as a function of the duration of hearing aid use. These results suggest that the language learning system remains open to experience provided by improved access to linguistic input. Performance in the domain of morphosyntax was found to be more delayed in CHH than their semantic abilities. Conclusion: The data obtained in this study largely support the predictions, suggesting that mild to severe hearing loss places children at risk for delays in language development. Risks are moderated by the provision of early and consistent access to well-fit hearing aids that provide optimized audibility.

Early Listening and Speaking Skills Predict Later Reading Proficiency in Pediatric Cochlear Implant Users

Objectives: Previous studies have reported that children who use cochlear implants (CIs) tend to achieve higher reading levels than their peers with profound hearing loss who use hearing aids. The purpose of this study was to investigate the influences of auditory information provided by the CI on the later reading skills of children born with profound deafness. The hypothesis was that there would be a positive and predictive relationship between earlier speech perception, production, and subsequent reading comprehension. Design: The speech perception and production skills at the vowel, consonant, phoneme, and word level of 72 children with prelingual, profound hearing loss were assessed after 48 mos of CI use. The childrens reading skills were subsequently assessed using word and passage comprehension measures after an average of 89.5 mos of CI use. A regression analysis determined the amount of variance in reading that could be explained by the variables of perception, production, and socioeconomic status. Results: Regression analysis revealed that it was possible to explain 59% of the variance of later reading skills by assessing the early speech perception and production performance. The results indicated that early speech perception and production skills of children with profound hearing loss who receive CIs predict future reading achievement skills. Furthermore, the study implies that better early speech perception and production skills result in higher reading achievement. It is speculated that the early access to sound helps to build better phonological processing skills, which is one of the likely contributors to eventual reading success.

The Influence of Hearing Aids on the Speech and Language Development of Children With Hearing Loss

IMPORTANCE Hearing loss (HL) in children can be deleterious to their speech and language development. The standard of practice has been early provision of hearing aids (HAs) to moderate these effects; however, there have been few empirical studies evaluating the effectiveness of this practice on speech and language development among children with mild-to-severe HL. OBJECTIVE To investigate the contributions of aided hearing and duration of HA use to speech and language outcomes in children with mild-to-severe HL. DESIGN, SETTING, AND PARTICIPANTS An observational cross-sectional design was used to examine the association of aided hearing levels and length of HA use with levels of speech and language outcomes. One hundred eighty 3- and 5-year-old children with HL were recruited through records of Universal Newborn Hearing Screening and referrals from clinical service providers in the general community in 6 US states. INTERVENTIONS All but 4 children had been fitted with HAs, and measures of aided hearing and the duration of HA use were obtained. MAIN OUTCOMES AND MEASURES Standardized measures of speech and language ability were obtained. RESULTS Measures of the gain in hearing ability for speech provided by the HA were significantly correlated with levels of speech (ρ179 = 0.20; P = .008) and language: ρ155 = 0.21; P = .01) ability. These correlations were indicative of modest levels of association between aided hearing and speech and language outcomes. These benefits were found for children with mild and moderate-to-severe HL. In addition, the amount of benefit from aided hearing interacted with the duration of HA experience (Speech: F4,161 = 4.98; P < .001; Language: F4,138 = 2.91; P < .02). Longer duration of HA experience was most beneficial for children who had the best aided hearing. CONCLUSIONS AND RELEVANCE The degree of improved hearing provided by HAs was associated with better speech and language development in children. In addition, the duration of HA experience interacted with the aided hearing to influence outcomes. These results provide support for the provision of well-fitted HAs to children with HL. In particular, the findings support early HA fitting and HA provision to children with mild HL.

Longitudinal speech perception and language performance in pediatric cochlear implant users: the effect of age at implantation.

Objectives: Few studies have examined the long-term effect of age at implantation on outcomes using multiple data points in children with cochlear implants. The goal of this study was to determine whether age at implantation has a significant, lasting impact on speech perception, language, and reading performance for children with prelingual hearing loss. Design: A linear mixed-model framework was used to determine the effect of age at implantation on speech perception, language, and reading abilities in 83 children with prelingual hearing loss who received cochlear implants by the age of 4 years. The children were divided into two groups based on their age at implantation: (1) under 2 years of age and (2) between 2 and 3.9 years of age. Differences in model-specified mean scores between groups were compared at annual intervals from 5 to 13 years of age for speech perception, and 7 to 11 years of age for language and reading. Results: After controlling for communication mode, device configuration, and preoperative pure-tone average, there was no significant effect of age at implantation for receptive language by 8 years of age, expressive language by 10 years of age, reading by 7 years of age. In terms of speech-perception outcomes, significance varied between 7 and 13 years of age, with no significant difference in speech-perception scores between groups at ages 7, 11, and 13 years. Children who used oral communication (OC) demonstrated significantly higher speech-perception scores than children who used total communication (TC). OC users tended to have higher expressive language scores than TC users, although this did not reach significance. There was no significant difference between OC and TC users for receptive language or reading scores. Conclusions: Speech perception, language, and reading performance continue to improve over time for children implanted before 4 years of age. The present results indicate that the effect of age at implantation diminishes with time, particularly for higher-order skills such as language and reading. Some children who receive cochlear implants after the age of 2 years have the capacity to approximate the language and reading skills of their earlier-implanted peers, suggesting that additional factors may moderate the influence of age at implantation on outcomes over time.

Clinical trials for tinnitus: study populations, designs, measurement variables, and data analysis.

We review a few issues related to clinical trials for treating patients with tinnitus, including the study population, design, choice of measurement variables, and some new approaches to data analysis. We emphasize the importance of being aware of different subgroups of tinnitus patients, and that patients who have had tinnitus for less than 6 months could be more amenable to treatment than patients who have had their tinnitus for a longer period. We distinguish the tinnitus itself, from the reactions to the tinnitus. When the treatment is intended to reduce the tinnitus, we recommend measuring the magnitude of the tinnitus. We provide arguments and data to support the use of the Tinnitus Handicap Questionnaire as a measure of the reaction to the tinnitus. We suggest that the current quality of life measures are not valid for measuring lifestyle effects of alleviating tinnitus. Because tinnitus likely has different subgroups, and because tinnitus affects people differently, we believe data analysis should emphasize individuals, not groups. A clinically meaningful effect should represent a valid and reliable statistical change for an individual.

Sexually abstinent adolescents: an 18-month follow-up.

This study was a longitudinal follow-up of 697 early adolescents from 20 schools in Missouri, investigating students who, in 1997, indicated on a survey of sexual attitudes and behaviors that they had not had sexual intercourse. They completed the Reasons for Abstinence Scale (RAS) by identifying those items that were reasons why they had not had sex. In 1999, 18 months later, 568 of the same students were available to complete the RAS again. When the adolescents who remained abstinent in 1999 ( n = 422) were compared with their peers who had become sexually active ( n = 146), the abstinent adolescents (a) were significantly less likely to report consuming alcohol on a regular basis, (b) were significantly more likely to be male, and (c) gave more reasons for being abstinent. However, the adolescents who remained abstinent had a significant drop in the number of reasons for being abstinent over the 18 months.

Spatial variation in soil inorganic nitrogen across an arid urban ecosystem

We explored variations in inorganic soil nitrogen (N) concentrations across metropolitan Phoenix, Arizona, and the surrounding desert using a probability-based synoptic survey. Data were examined using spatial statistics on the entire region, as well as for the desert and urban sites separately. Concentrations of both NO3-N and NH4-N were markedly higher and more heterogeneous amongst urban compared to desert soils. Regional variation in soil NO3-N concentration was best explained by latitude, land use history, population density, along with percent cover of impervious surfaces and lawn, whereas soil NH4-N concentrations were related to only latitude and population density. Within the urban area, patterns in both soil NO3-N and NH4-N were best predicted by elevation, population density and type of irrigation in the surrounding neighborhood. Spatial autocorrelation of soil NO3-N concentrations explained 49% of variation among desert sites but was absent between urban sites. We suggest that inorganic soil N concentrations are controlled by a number of ‘local’ or ‘neighborhood’ human-related drivers in the city, rather than factors related to an urban-rural gradient.