Theses and Dissertations from UMD
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New submissions to the thesis/dissertation collections are added automatically as they are received from the Graduate School. Currently, the Graduate School deposits all theses and dissertations from a given semester after the official graduation date. This means that there may be up to a 4 month delay in the appearance of a give thesis/dissertation in DRUM
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Item EXPLORING THE RELATIONSHIP BETWEEN VERB RETRIEVAL, AGRAMMATISM AND PAUSES(2024) Campbell, Lauren; Faroqi-Shah, Yasmeen; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Persons with agrammatic aphasia (a symptom of Broca’s aphasia) tend to speak at a slow rate compared to neurotypical adults and to other aphasia subtypes (Kertesz, 2007). This connection between slow rate and agrammatic aphasia is underexplored. This study examines three key variables impacting speech rate in agrammatic narratives: syntactic impairment (i.e., diagnosis of agrammatism), verb retrieval, and pauses. Specifically, forty-five narrative (Cinderella) samples (15 agrammatic aphasia, 15 anomic aphasia, and 15 controls) from AphasiaBank database (MacWinney et al., 2011) were converted into Praat TextGrids (Boersma & Weenink, 2023) with sound files, and the first five qualifying pre-verb pause durations were recorded. Additionally, the first five qualifiying pre-noun pauses were logged for comparison as well as the overall grammaticality of each targeted utterance. The results were that the number of pauses and pause duration differentiated persons with agrammatic aphasia from persons with anomic aphasia and neurotypical controls, yet verb retrieval and the syntactic well-formedness of an utterance did not significantly vary by aphasia type in utterances where verbs were successfully retrieved. Overall, this study did not lend support to the Synergistic Processing Bottleneck model for agrammatic aphasia (Faroqi-Shah, 2023).Item SYNTACTIC AND LEXICAL ALIGNMENT DURING NATURALISTIC CONVERSATIONS AMONGST AFRICAN AMERICAN PARENTS OF 4-YEAR-OLD CHILDREN FROM PROFESSIONAL- AND WORKING-CLASS FAMILIES(2023) Ogbonna, Chidinma; Bernstein Ratner, Nan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Parents play an important role when it comes to child language development. This study examines differences in lexical and syntactic alignment, in child-directed speech (CDS), between African American mothers and fathers from the professional- and working-class. The Hall (1984) corpus from the Child Language Data Exchange System (CHILDES; MacWhinney, 1991) was used to analyze syntactic and lexical alignment in African American professional- and working-class parent-child dyads (children aged 4;6). We investigated the proportion of overlapping nouns shared between mother-child and father-child dyads, as well as differences between parent-child syntactic complexity scores (i.e., Mean Length of Utterance-words (MLU-w), and Verbs per Utterance (Verbs/utt). Results revealed there to be no significant differences regarding lexical and syntactic alignment between the professional- and working-class families; however, fathers were found to produce a significantly higher average proportion of overlapping nouns compared to mothers.Item The Effect Of Language Mixing on Word Retrieval in Bilingual Adults with Aphasia(2022) Nichols, Meghan; Faroqi-Shah, Yasmeen; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Lexical retrieval deficits are a common feature in aphasia, and while much research has been done on bilingual aphasia and on the processes involved in language mixing by healthy bilingual adults, it is not clear whether it may be beneficial for bilingual people with aphasia to change languages in moments of lexical retrieval or if it is more effective to continue the lexical search in one language. The primary aim of this project was to determine whether bilingual people with aphasia demonstrate global and local effects of language mixing. Grammatical categories (i.e., nouns and verbs) were examined separately, and participant- and stimulus-related factors were considered. Based on preliminary analyses of participants’ accuracy and response onset latencies, it appears that participants tended to benefit from mixing in terms of speed and accuracy and that their results may be related to their language proficiency and dominance.Item Examining Narrative Language in Early Stage Parkinson's Disease and Intermediate Farsi-English Bilingual Speakers(2022) Lohrasbi, Bushra; Faroqi-Shah, Yasmeen; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study aimed to examine procedural aspects of language (grammaticality, syntactic complexity, regular past tense verb production), verb use, and the association between motor-speech, language abilities, and intelligibility in Early Stage Parkinson's Disease (PD) and Intermediate Farsi-English Bilingual Speakers (L2). Ullman’s Declarative-Procedural Model (2001) provided this study with a dual-mechanism model that justified a theoretical comparison between these two populations. Twenty-four neurologically healthy native speakers of English, twenty-three Parkinson’s Disease participants, and thirteen bilingual Farsi-English speakers completed three narrative picture description tasks and read the first three sentences of the Rainbow Passage. Language samples were transcribed and analyzed to derive measures of morphosyntax and verb use, including grammatical accuracy, grammatical complexity, and proportions of regular past tense, action verbs and light verbs. The results did not show any evidence of morphosyntactic or action verb deficit in PD. Neither was there any evidence of a trade-off between morphosyntactic performance and severity of speech motor impairment in PD. L2 speakers had lower scores on grammatical accuracy and a measure of morphosyntactic complexity, but did not differ from monolingual speakers on measures of verb use. Overall, these results show that language abilities (morphosyntax and verb use) are preserved in early stage PD. This study replicates the well-documented finding that morphosyntax is particularly challenging for late bilingual speakers. The results did not support Ullman’s Declarative-Procedural (2001) hypothesis of language production in Parkinson’s Disease or L2 speakers.Item The Impact of Maternal Negative Language on Children’s Language Development(2022) Lee, Hae Ri; Bernstein Ratner, Nan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Various features of infant- and child-directed speech (IDS/CDS) are known to have a positive impact on children’s language development. Some, such as directive language, appear to be less facilitating. We investigated whether mothers’ usage of negative language impacts children’s language development. Thirty-three mothers’ language samples at 30 months and children’s conversational language samples at 66 months were analyzed to locate operationally defined negative language and imperatives. Five language sample analysis measures were utilized to assess children’s expressive language abilities. Inverse relationships between maternal use of negative language and children’s language outcome measures were found. This preliminary result suggests that the more children hear negative language at an earlier age, the lower their language outcomes are at a later age. This study was exploratory in nature, and various limitations and implications for future studies are outlined in the paper.Item SPECTRAL CONTRASTS PRODUCED BY CHILDREN WITH COCHLEAR IMPLANTS: INVESTIGATING THE IMPACT OF SIGNAL DEGRADATION ON SPEECH ACQUISITION(2022) Johnson, Allison Ann; Edwards, Jan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The primary objective of this dissertation was to assess four consonants, /t/, /k/, /s/, and /ʃ/, produced by young children with cochlear implants (CIs). These consonants were chosen because they comprise two place-of-articulation contrasts, which are cued auditorily by spectral information in English, and they cover both early-acquired (/t/, /k/) and late-acquired (/s/, /ʃ/) manners of articulation. Thus, the auditory-perceptual limitations imposed by CIs is likely to impact acquisition of these sounds: because spectral information is particularly distorted, children have limited access to the cues that differentiate these sounds.Twenty-eight children with CIs and a group of peers with normal hearing (NH) who were matched in terms of age, sex, and maternal education levels participated in this project. The experiment required children to repeat familiar words with initial /t/, /k/, /s/, or /ʃ/ following an auditory model and picture prompt. To create in-depth speech profiles and examine variability both within and across children, target consonants were elicited many times in front-vowel and back-vowel contexts. Patterns of accuracy and errors were analyzed based on transcriptions. Acoustic robustness of contrast was analyzed based on correct productions. Centroid frequencies were calculated from the release-burst spectra for /t/ and /k/ and the fricative noise spectra for /s/ and /ʃ/. Results showed that children with CIs demonstrated patterns not observed in children with NH. Findings provide evidence that for children with CIs, speech acquisition is not simply delayed due to a period of auditory deprivation prior to implantation. Idiosyncratic patterns in speech production are explained in-part by the limitations of CI’s speech-processing algorithms. The first chapter of this dissertation provides a general introduction. The second chapter includes a validation study for a measure to differentiate /t/ and /k/ in adults’ productions. The third chapter analyzes accuracy, errors, and spectral features of /t/ and /k/ across groups of children with and without CIs. The fourth chapter analyzes /s/ and /ʃ/ across groups of children, as well as the spectral robustness of both the /t/-/k/ and the /s/-/ʃ/ contrasts across adults and children. The final chapter discusses future directions for research and clinical applications for speech-language pathologists.Item THE RELATIONSHIP BETWEEN LANGUAGE EXPERIENCE AND PERFORMANCE ON LANGUAGE ASSESSMENT MEASURES IN TYPICALLY-DEVELOPING SPANISH-ENGLISH BILINGUAL CHILDREN(2021) Otarola-Seravalli, Daniella; Bernstein Ratner, Nan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study aimed to better understand the factors that affect bilingual children’s assessment performance and compare the effects of language experience on different types of measures. English language sample measures (i.e., Index of Productive Syntax, Mean Length of Utterance in morphemes, number of Brown’s morphemes, and Vocabulary Diversity) and English/Spanish nonword repetition (NWR) from 29 children with varying degrees of English and Spanish language experience were analyzed. Language experience, age, and baseline language abilities were identified as factors that influence and predict performance on language samples. Additionally, it was determined that NWR ability was not influenced by language-specific knowledge, due to the lack of significant correlation between nonword repetition accuracy and language experience. These preliminary findings suggest that NWR, even in a child’s second language, is a relatively unbiased tool. Future studies should compare the role of language experience on different measures in other languages.Item Utterance-level predictors of stuttering-like, stall, and revision disfluencies in the speech of young children who do and do not stutter(2021) Garbarino, Julianne; Bernstein Ratner, Nan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Disfluencies are generally divided into two types: stuttering-like disfluencies (SLDs), which are characteristic of the speech of people who stutter, and typical disfluencies (TDs), which are produced by nearly all speakers. In several studies, TDs have been further divided into stalls and revisions; stalls (fillers, repetitions) are thought to be prospective, occurring due to glitches in planning upcoming words and structures, while revisions (word and phrase repetitions, word fragments) are thought to be retrospective, occurring when a speaker corrects language produced in error.This dissertation involved the analysis of 15,782 utterances produced by 32 preschool-age children who stutter (CWS) and 32 matched children who do not stutter (CWNS). The first portion of this dissertation focused on how syntactic factors relate to disfluency. Disfluencies (of all three types) were more likely to occur when utterances were ungrammatical. The disfluency types thought a priori to relate to planning (SLDs and stalls) occurred significantly more often before errors, which is consistent with these disfluencies occurring, in part, due to difficulty planning the error-containing portion of the utterance. Previous findings of a distributional dichotomy between stalls and revisions were not replicated. Both stalls and revisions increased in likelihood in ungrammatical utterances, as the length of the utterance increased, and as the language level of the child who produced the utterance increased. This unexpected result suggests that both stalls and revisions are more likely to occur in utterances that are harder to plan (those that are ungrammatical and/or longer), and that as children’s language develops, so do the skills they need to produce both stalls and revisions. The second part of this dissertation assessed the evidence base for the widespread recommendation that caregivers of young CWS should avoid asking them questions, as CWS have been thought to stutter more often when answering questions. CWS were, in fact, less likely to stutter when answering questions than in other utterance types. Given this finding, the absence of previous evidence connecting question-answering to stuttering, and the potential benefits of asking children questions, clinicians should reconsider the recommendation for caregivers of CWS to reduce their question-asking.Item The Role of Age and Bilingualism on Perception of Vocoded Speech(2020) Waked, Arifi Noman; Goupell, Matthew J; Ratner, Nan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation examines the role of age and bilingualism on perception of vocoded speech in order to determine whether bilingual individuals, children, and bilingual individuals with later ages of second language acquisition show greater difficulties in vocoded speech perception. Measures of language skill and verbal inhibition were also examined in relation to vocoded speech perception. Two studies were conducted, each of which had two participant language groups: Monolingual English speakers and bilingual Spanish-English speakers. The first study also explored the role of age at the time of testing by including both monolingual and bilingual children (8-10 years), and monolingual and bilingual adults (18+ years). As such, this study included four total groups of adult and child language pairs. Participants were tested on vocoded stimuli simulating speech as perceived through an 8-channel CI in conditions of both deep (0-mm shift) and shallow (6-mm shift) insertion of the electrode array. Between testing trials, participants were trained on the more difficult, 6-mm shift condition. The second study explored the role of age of second language acquisition in native speakers of Spanish (18+ years) first exposed to English at ages ranging from 0 to 12 years. This study also included a control group of monolingual English speakers (18+ years). This study examined perception of target lexical items presented either in isolation or at the end of sentences. Stimuli in this study were either unaltered or vocoded to simulate speech as heard through an 8-channel CI at 0-mm shift. Items presented in isolation were divided into differing levels of difficulty based on frequency and neighborhood density. Target items presented at the ends of sentences were divided into differing levels of difficulty based on the degree of semantic context provided by the sentence. No effects of age at testing or age of acquisition were found. In the first study, there was also no effect of language group. All groups improved with training and showed significant improvement between pre- and post-test speech perception scores in both conditions of shift. In the second study, all participants were significantly negatively impacted by vocoding; however, bilingual participants showed greater difficulty in perception of vocoded lexical items presented in isolation relative to their monolingual peers. This group difference was not found in sentence conditions, where all participants significantly benefited from greater semantic context. From this, we can conclude that bilingual individuals can make use of semantic context to perceive vocoded speech similarly to their monolingual peers. Neither language skills nor verbal inhibition, as measured in these studies, were found to significantly impact speech perception scores in any of the tested conditions across groups.Item USE OF MULTIMODAL COMMUNICATION IN PLAY INTERACTIONS WITH CHILDREN WITH AUTISM(2020) Rain, Avery; Bernstein Ratner, Nan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)In typical adult-child interaction, adults tend to coordinate gesture and other nonverbal modes of communication with their verbalizations (multimodal communication). This study explored the effectiveness of multimodal communication with young children with autism spectrum disorders (ASD) to encourage child responses. The maternal use of verbal, nonverbal, and multimodal initiations and the subsequent response or lack of response of their child was examined in fifty mother/child video-recorded play interactions. Results indicated that mothers initiated multimodally at similar rates with children with lower and higher expressive language levels. Child response rates to multimodal communication initiations were higher than response rates to verbal-only or nonverbal-only initiations; this finding was consistent across low and high expressive language groups. Additionally, a significant positive correlation was found between maternal wait time after initiation and overall child response rate. These findings have important ramifications for clinical practice and parent training.