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An objective measure, not requiring a behavioral response, of speech recognition performance in individuals with cochlear implants (CIs) would be beneficial in directing clinical recommendations. Neuroimaging can be such a measure but is difficult in the CI population. Functional near-infrared spectroscopy (fNIRS) is a non-invasive neuroimaging technique that is viable for CI recipients. This dissertation began to examine the potential of fNIRS in this population by determining the effects of speech recognition performance and stimulus intensity level on fNIRS recorded cortical activation. We hypothesized that fNIRS responses would be correlated with both intensity level and speech recognition performance. Thirteen adults with bilateral CIs and 16 adults with normal hearing were included in the study. Experiment one used signal-correlated noise to determine the effect of intensity level in the range of soft to loud speech (45-75 dB SPL). Experiment two used both signal-correlated noise and sentences presented in background babble at three different signal-to-noise ratios to determine the effect of speech recognition performance on cortical activity. fNIRS data were recorded in the left hemisphere. The experiment one showed a positive correlation of auditory cortical activation with stimulus intensity level in both groups. In contrast, experiment two revealed a difference between the groups. The adults with normal hearing had stronger activation in the auditory cortex, inferior frontal gyrus, and the inferior parietal lobe with higher speech recognition. In contrast, the CI group had the opposite effect with stronger activation in those same areas with lower speech recognition. The stimulus level results are consistent with the literature and out hypothesis. The results of the second experiment are consistent with our hypothesis and the literature in only the normal hearing group. This is the first study to use neuroimaging for speech recognition in noise in individuals with CIs. Research is needed to further examine cortical activation patterns for speech recognition in noise in these two groups. These results support the potential of fNIRS as a measure of speech recognition performance at a group level. The individual variability was large, however, and might limit the potential of fNIRS at an individual level.

Tense marking at the point of school entry, that is, kindergarten, has been hypothesized to follow a bimodal distribution. Under this hypothesis, it is predicted that most children exhibit tense marking skills at or near the upper end of proficiency whereas some children demonstrate notably reduced proficiency. Due to this separation of skill level, kindergarten tense marking is considered a clinical marker for language impairment. The purpose of this study was to test the validity of a bimodal distribution of tense marking in a population-based sample of kindergarten students. The Test of Early Grammatical Impairment (TEGI) Screening Test was administered to three-quarters of the kindergarten students attending a school district of Mainstream American English speakers. Results revealed a distribution of TEGI Screening Test Scores that deviated significantly from normality. Cluster analysis indicated a best-fitting two-cluster solution that, upon inspection, generally aligned with bimodal-distribution expectations for typical and language-impaired classification prevalence rates and threshold values. Cross validation of child cluster membership to a reference standard for a subsample of participants offered further, albeit preliminary, evidence in support of the discriminant validity of assessing tense marking for the purpose of identifying language impairment in the general kindergarten population.

The purpose of this study was to describe return to school after sports-related concussion, including absences, academic performance, receipt of accommodations, and satisfaction of the parent/child with classroom accommodations and the return-to-school experience. We conducted telephone surveys of 83 families (78 parent-child dyads, 5 parents) a median of 276 days following concussion. Students missed a median of 2 days of school following concussion. There was a positive relationship between number of reported school-related problems and absences in the child-reported data only. There was a positive relationship between number of absences and symptom severity in both the parent and child-reported data. Return to academic baseline was reported by 86.7% of parents and 92.3% of children. Return to academic baseline was more likely in children with fewer school-related problems per parent report, and more likely in younger students and those with a lower symptom severity scores per child report. Academic accommodations were provided to 73.5% of children per parent report and 76.9% of children per child report. Receipt of accommodations was related to parent communication with the school, physician recommendation for accommodations, number of post-concussion school-related problems, and increased absences per parent report. No relationships were found between receipt of accommodations and investigated variables in the child-reported data. The majority of parents (81.9%) and children (82.1%) reported being satisfied with the schoolâs response to accommodating the childâs needs following concussion. Satisfaction with receipt of accommodations was higher for children who received accommodations and/or who returned to academic baseline, according to both parent and child-reported data. Parent income was positively associated with satisfaction with accommodations in the parent-reported data only. Similarly, 89.2% of parents and 85.9% of children reported being satisfied with the overall return-to-school experience. Satisfaction with the overall return-to-school experience was related to receipt of accommodations in both the parent and child-reported data, but was related to return to academic baseline only in the child-reported data. There was no significant relationship between other investigated variables and satisfaction outcomes. Findings highlight the continued need for policies and education of stakeholders to insure appropriate academic management of concussions in students.

Vocal fold paralysis (VFP) that results from injury to motor axons in the recurrent laryngeal nerve (RLN) is a common clinical problem. In the majority of these patients, misdirected regeneration of neural fibers in the RLN leads to a synkinetic larynx. Evidence has indicated that electrical stimulation (ES) of the denervated posterior cricoarytenoid (PCA) muscle with a low frequency may reduce synkinetic vocal fold motion. The current study was designed to investigate the mechanism of selective reinnervation promoted by ES (Specific aim 1), and to find out the best stimulation frequency to avoid synkinesis (Specific aim 2). To achieve the first specific aim, an implantable system was developed to obtain chronological EMG recordings from both abductor (PCA) and adductor (thyroarytenoid, TA) muscles in canineâs larynx. The system was implanted in 8 canines for up to 41 weeks. It showed good compatibility and consistent EMG signals were recorded. The reinnervation process was better understood with this system. For the second specific aim, eleven canines were implanted with a stimulation system to condition the denervated PCA muscles with different stimulation frequencies. Spontaneous vocal fold movement and rectified integrated EMG potentials were recorded in anesthetized animals. Exercise tolerance was measured on a treadmill in the awake animals. Results showed that ES of the denervated PCA muscle with a frequency of 10Hz, characteristic of the intrinsic activity of PCA inspiratory motoneurons, inhibited synkinetic reinnervation by RGC motoneurons, promoted selective reinnervation by its original inspiratory motoneurons, and improved functional recovery.

This is a linguistic analysis of elicited responses obtained in a language proficiency test of hearing impaired children (Grammatical Analysis of Elicited Language). The analysis focuses on the language, the social situation and setting of the test activity to describe the characteristics that are observable in the elicited responses--specifically the deviations from the target responses of the test, and on discovering the underlying rules that function to guide some of the systematic deviations in the participants' language in the test. The study examines the following features of the deviated responses: the grammatical structure, the syntactic/semantic acceptance and contextual appropriateness of the responses. The study develops procedures for analysis along each of these dimensions, called the Observed Response Analysis based on miscue analysis (Goodman: 1987) and error analysis (Corder: 1981). Some of the deviations were shown to be significantly systematic throughout the test. These systematic grammatical structures in children's underlying system were validated by the developed methodology. There were also many cases where the deviations were inconsistent, the grammatical structures were used 'correctly' at one place and 'incorrectly' at another. This inconsistency in language stems from the transitional nature of grammar which the learners are using. It has puzzled some teachers for a long time how a speaker can know something in one context and not know it in another context. Such uncertainties arise from the belief that speaking is word recall. The imitative responses were also inconsistent sometimes, implying thereby that speaking is more than simply imitating, memorizing or recalling. Children's language took precedence over the language of the test. This understanding of the psycholinguistic processes involved in deviations from the expected language of the test has pedagogical implications for the teachers, testers, or any educators who would like to use tests for diagnostic or prescriptive purpose and adds to the knowledge of not only 'what' children do on the language tests but 'why' they show specific linguistic deviations and what these deviations reflect about children's developing language competencies.

There is an ongoing need for public health information in pediatric speech-language pathology and newly adopted electronic health record procedures in clinics provide an opportunity to address this need. One-year outcomes of 198 children first seen for speech-language evaluation between 18-30 months in an outpatient clinic at the Vanderbilt Bill Wilkerson Center were examined in this project. The following predictors of initial enrollment and discharge or retention in treatment are considered: receptive language, medical history, and access to resources. The results indicated that children with lower receptive and expressive language were more likely to be referred to treatment (n=154). Children who lived closer to the clinic were more likely to enroll in treatment (n=67). Of the children whose medical record include both treatment and outcome, 13% demonstrated positive outcomes as defined by discharged from treatment due to meeting goals or reaching normal limits. Positive outcomes could be predicted by high receptive language, lack of comorbid medical history, and high income based on zip code data. 60% of the cases remained in treatment either at Vanderbilt or in the local school system. Retention after the first year could be significantly predicted by low receptive language. In addition, attrition from treatment as defined by discharged due to non-attendance accounted for 16% of the sample. The remaining 10% are children who were discharged by parent request, often due to the family relocating outside the Nashville region. Moreover, the project illustrates how electronic medical records can yield interpretable and useful public health data. The clinical and public health significance of these results are discussed.

Interaural time (ITD) and level differences (ILD) are susceptible to distortion by multipath acoustics due to reverberation, echoes, and potentially with open-fit, behind-the-ear (BTE) hearing aids, which pose an additional delay between acoustic and processed sound (~2-5ms). Here, ten young, normal hearing listeners localized broadband and narrowband (500, 4000, 500+4000 Hz) noise. Listeners were fit with linear amplification and evaluated in three aided conditions: unaided, open-fit, and occluded BTE coupling. Sounds were presented from 64 loudspeakers covering 360º azimuth in an anechoic chamber. Twenty-three target locations were evaluated, spanning ±61º. Sounds were presented in three virtual acoustic environments: anechoic, single virtual wall, and simulated 10m X 10m room. The virtual wall was 80% reflective (α=0.2) and oriented parallel to the listenerâs forward gaze, at a distance of 5m to the right. The room condition simulated four virtual walls (α=0.5), 5m to the left and right, 6.67m in front, and 3.33m behind the listening position. Performance was assessed across conditions by measuring localization gain (slope), localization variance, localization error, and front-back confusion rate. Results showed greater variability in the simulated room than anechoic conditions, particularly for aided conditions (occluded > open > unaided). Aided listening compressed localization gain at 4000 Hz and expanded gain at 500 Hz. Errors were generally reduced when 500 and 4000 Hz were played simultaneously. Additionally, in-ear acoustic recordings of broadband noise were made in all aided and room conditions. Binaural cross-correlation and intensity-difference calculation were used to estimate frequency-specific ITD and ILD, respectively, from the recordings. Consistent with previous research, ITD became erratic and ILD diminished in simulated rooms compared to anechoic. Effects of hearing aid venting were less noticeable. Finally, results were quantified in the form of binaural-cue weighting (ITD/ILD âtrading ratioâ) on the basis of measured interaural cue values extracted from in-ear recordings obtained for each listener and condition.

published_or_final_version / abstract / toc / Educational Psychology / Master / Master of Social Sciences

Introduction: This study investigated hearing aid (HA) satisfaction among adult with hearing impairment (HI) in New Zealand. This study aimed to answer three questions: 1) What are the current HA satisfaction levels amongst adult HA users in New Zealand? 2) How do the satisfaction findings of this study compare with other HA satisfaction data? 3) What client factors are related to HA satisfaction? Method: Participants were recruited prospectively. They completed a questionnaire prior to HA fitting and a questionnaire three months post-fitting. Information was collected on: age, gender, HA experience, HI severity, hearing ability, change in hearing ability, hearing handicap, communication self-efficacy, change in communication self-efficacy, HA self-efficacy, HA usage, and number of appointments. HA satisfaction was measured via the Satisfaction with Amplification in Daily Life questionnaire (SADL; Cox & Alexander, 1999). Results: Data were collected for 47 participants. Of these, 91.5% fell within or above the normative range for global satisfaction established by Cox & Alexander (1999). The mean SADL scores were predominantly high compared to previous research. Satisfaction with negative features of HAs was especially high in this study. However satisfaction with the service and cost of HAs was low compared to other research. SADL scores were found to significantly relate to age, gender, change in hearing ability, hearing handicap, communication self-efficacy, change in communication self-efficacy, and HA self-efficacy. Conclusions: Results differed from previous research indicating that HA satisfaction may differ over time and across countries. Assessing HA satisfaction in a comprehensive standardised way, as opposed to with a single-item measure, can help identify important related factors. Targeting identified variables such as communication and HA self-efficacy may lead to improved treatment efficacy.