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.

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.

Purpose: The purpose of the current study was to investigate cortical associates of emotional reactivity and emotion regulation (as indexed by the amplitude of evoked response potentials [ERP]) in young children who do and do not stutter during passive viewing of pleasant, unpleasant and neutral pictures. Method: Participants were 17 young children who stutter and 19 young children who do not stutter (between 4 years 0 months to 6 years 11 months). The dependent measures were (1) mean amplitude of late positive potential (LPP, an evoked response potential (ERP) sensitive to emotional stimuli) during passive (i.e., no response required) picture viewing and directed reappraisal tasks as well as (2) emotional reactivity and regulation related scores on caregiver reports of young childrenâs temperament (Childrenâs Behavior Questionnaire [CBQ] Rothbart, Ahdadi, Hershey & Fisher, 2001). Results: Main findings indicated that young CWS, when compared to their CWNS peers, exhibited significantly greater LPP amplitudes to the unpleasant pictures. Further, for only CWS, there were significant correlations between cortical measures of emotional reactivity and aspects of their temperament; also, only for CWS there were significant correlations between cortical measures of emotion regulation and temperamentally-related measures of emotion. Conclusions: Results were taken to suggest that CWS, when compared to CWNS, are more emotionally reactive to negatively-valenced stimuli (as indicated by cortical measures of emotional reactivity) and that CWSâs emotional reactivity and regulation (as indexed by cortical measures of emotional reactivity and regulation) are correlated with their caregiver reports of emotional reactivity and regulation, while such correlations were not observed for CWNS.

Children with hearing loss are at risk for vocabulary delays which can subsequently impact their language and literacy outcomes. Although direct vocabulary instruction can be effective, previous research indicates teachers can maximize young childrenâs vocabulary learning by incorporating linguistic input strategies throughout the school day. Linguistic input â the language children are exposed to â is especially effective when it occurs during adult-to-child speech. This exploratory study sampled five teachersâ use of three linguistic input strategies in a preschool for children with hearing loss who use spoken language: 1) instructional vocabulary during free play, 2) conversational turns, and 3) reading aloud. The results indicated teachersâ use of the target linguistic input strategies was highly variable across teachers. Relatively low use of the target strategies could indicate missed opportunities to support childrenâs vocabulary development. However, because all of the teachers provided linguistic support, the results show these strategies can feasibly be delivered in preschools for children with hearing loss.

The relationship between language and reading has been studied from several perspectives but is not fully understood. Studies of this relationship have examined the relative importance of decoding and basic reading skills versus broader language skills for reading comprehension, reporting that phonological awareness and decoding are more important for reading comprehension early in the process of literacy acquisition, whereas broader language skills become more important with decoding proficiency (e.g., Curtis, 1980; Perfetti, 1985; Vellutino, Scanlon, Small, & Tanzman, 1991). This study sought to explore these relationships in the context of Woodcock Johnson III Tests of Achievement (Woodcock, McGrew, & Mather, 2001), a single test battery that includes measures of each of these areas. A repeated multiple regression approach (as used in McGrew, 1993) in which Reading Fluency cluster and Reading Comprehension cluster served as criteria and Sound Awareness test, Basic Reading cluster, Listening Comprehension cluster, and Oral Expression cluster served as predictors was used to examine these issues. These analyses were computed for six age groups (age 6, 7, 8-9, 10-12, 13-16, and 17-18; n = 2,885) and six grade groups (grade 1, 2, 3, 4-6, 7-9, and 10-12; n = 2,748) in a cross-sectional design to allow for consideration of relationships across the school years. Standardized regression coefficients were utilized as measures of relative importance, and were plotted to reveal trends in these relationships. The results indicated that the strength of the relationships of Reading Fluency and Reading Comprehension with Basic Reading (particularly Letter-Word Identification) decreased across age and grade groups. This decrease was accompanied by an increased association between Reading Fluency and Listening Comprehension across age and grade groups, and an increased association of all predictors other than Basic Reading with Reading Comprehension across age and grade groups. These findings support those of previous studies, as well as the hypothesis that broader language skills become more strongly associated with reading comprehension as decoding proficiency increases.

This project investigated speech recognition in rooms of different size with similar average reverberation times. A comparative analysis of existing literature has provided evidence to support that speech recognition in small rooms may be poorer than in larger rooms when the two spaces have a similar amount of reverberation. This study evaluated speech recognition using sentences binaurally recorded using an acoustic manikin in three rooms of different volume and/or dimension. The three rooms included a small reverberation chamber (48 m3), a university lecture hall (479 m3), and a high school band practice room (474 m3). Speech recognition was tested using bilateral insert earphones in two groups with 13 participants in each group. One group consisted of individuals with normal-hearing and the second group consisted of participants with mild-to-severe hearing impairment. Testing was completed at five signal-to-noise ratios (SNRs) for each group. Several measures, designed to quantify the acoustic characteristics of each room, were made and included mean free path, frequency-specific reverberation time and the Speech Transmission Index (STI). This investigation determined that listeners in both groups showed a significant decrease in speech recognition performance as SNRs decreased and a significant effect of room size. The poorest speech recognition was measured in the smallest room. There was no interaction between SNR and room type for either of the two participant groups. The effect of both change in room size and SNR correlated well with changes in Speech Transmission Index. A rationale was proposed as the source of the room size-specific reverberation effects. This idea speculates that the period during which early reflections are beneficial to speech understanding may decrease as room size increases. This is consistent with measures of decreased mean free path in smaller rooms. In addition, the reverberant field of a small room will contain more reflections than a larger room when the two are matched for reverberation time. It is proposed that the increased number of overlapping reflections also contributes to decreases in speech recognition ability.