Bilingualism has been shown to have numerous cognitive benefits, ranging from improved executive function to possible protection against neurodegenerative diseases. Structurally, early childhood bilingualism correlates with expanded subcortical regions, specifically the basal ganglia (BG), an area most famously involved in functions such as motor control. In this project, we explore possible domain-general effects of infant and early childhood bilingualism. Specifically, we investigate the effect of early childhood language environments on motor skills in the form of rhythmically controlled babbling. Audio recordings were made in infants’ natural environments using the LENA system. Infants’ own utterances were captured and preprocessed. From these data, I first calculated the ratios of language use in the environment (English versus Spanish), and from these ratios, I categorized infants into monolingual English, monolingual Spanish, and bilingual groups. To determine the rhythmicity of babbling, I isolated subjects’ utterances from the audio data based on criteria that define canonical babbling (e.g., CV syllable structure where C is supraglottal, 4 or more syllables, and so on). For the purposes of this project, we defined the perceptual center as the peak intensity of each syllable and used it to determine the duration between syllables, or inter-syllable duration. The variation of syllable duration was subsequently calculated. We anticipate more rhythmic (i.e. lower variability across inter-syllable duration) babbling in bilingual subjects than in monolingual English and Spanish subjects. However, in accordance with previous findings on early childhood language development, we do not necessarily expect to see differences in whether or not infants are in the canonical babbling stage based on language group. We expect these findings to contribute to the theory of domain-general benefits of early life bilingualism through the quantification of language development milestones.

Vocabulary acquisition in children involves many cognitive processes, with semantic descriptions playing a potentially crucial role in word learning. Broader literature points to a positive impact of metacognitive strategies early in children’s learning. Additionally, studies have highlighted semantic descriptors in facilitating word acquisition. However, there is a lack of literature regarding the direct correlation between children's productions of semantic descriptions and success in word learning, which is the current focus. We examined the number of semantic descriptions produced by children alongside their corresponding word-learning performance to determine whether a relationship exists. We analyzed data from 33 participants ages 2.7 - 6.7 years (mean = 4.6 years, SD = 1.2) with an average Expressive Vocabulary Test-3 standard score of 120. Our team coded a total of 165 word-learning assessments from videos of participants engaging in a storybook listening activity where participants were exposed to novel words paired with objects, assessing their receptive and expressive word learning. Participants were asked to look at the objects, imitate the novel words in real-time, and both point to and label the associated objects after a delay. We recorded the number of times children made semantic descriptions (ex. “The gek is spiky”), total correct identifications (receptive performance), and total phonemes correctly imitated and labeled (expressive performance). For analysis, we tested the correlation between semantic descriptions and both receptive and expressive word learning scores. I hypothesize that a positive correlation between these scores will indicate that children who produce semantic descriptions find more success in word learning. I anticipate that our study will contribute to a better understanding of how semantic descriptions play a role in receptive and expressive word learning outcomes. Also, study findings could serve as a foundation for future research on how parents and educators might better support children’s vocabulary acquisition.

Loudness is a major component of how comfortable someone is with the sounds they hear, and looking at how people perceive the loudness of sounds around them is a crucial part of understanding how people process sound. Previous research by Dr. Yi Shen's laboratory has created an application that allows rapid measurement of loudness across frequencies and levels. The purpose of my project is to expand upon what was found using the previous application. To do so, I am measuring people’s perceptions of loudness across multiple bandwidths. In this project, I guide participants to listen to a sound stimulus in a specific condition, and then select what they perceive the loudness of said sound stimulus to be on an application. Multiple bandwidths of sound stimuli are presented (examples of bandwidths being presented include "Puretone", "1/2 Octave", etc.) and participants then rate how they perceive the loudness of each sound on a scale from "Not Heard" to "Too Loud". By utilizing the application to look at said stimulus bandwidths and performing computer modeling of the results, we gain a greater understanding of how a person’s loudness preferences from one ear can differ across frequency, level, and stimulus bandwidth. We can then analyze these interactions and create a more comprehensive model of the auditory system. I anticipate that results will show participants' bandwidths are consistent with the proposed bandwidths of prior models. This project has future implications regarding rapid identification of issues within a person’s auditory system, how comfortable they are with the loudness of what they hear, and the ability to deliver personalized interventions in assistive hearing devices accordingly.

DLD is a highly common yet underdiagnosed neurodevelopmental disorder which impacts receptive and/or expressive language and cannot be attributed to another etiology such as hearing loss or lack of early language exposure. There is a lack of research into the brain differences that characterize DLD, especially in adult populations. The purpose of this project was to explore whether there are brain differences that underlie reading ability in adults with DLD. I specifically focused on the white-matter integrity of reading-related tracts using diffusion magnetic resource imaging (MRI). Participants included a group of adults identified as having DLD, as well as a group of typically developed adults. To measure reading ability, we used the Test of Integrated Language & Literacy Skills (TILLS) and focused on the Nonword Reading and Reading Comprehension subtests. For brain analysis, I first used data-driven hypothesis-free analysis of white matter across the whole brain with tract-based spatial statistics (TBSS). Next, I used probabilistic tractography to evaluate white-matter microstructure in tracts in the dorsal language stream, and in particular, the bilateral SLF. I hypothesized that lower reading scores would be associated with white-matter tract differences in the bilateral SLF. This research matters because reading ability is something that impacts all aspects of modern life, including learning, navigating directions in the world, and succeeding in the workplace. Adults with DLD are often undiagnosed in childhood, and this can carry lifelong social, emotional, and career effects. It is essential to understand whether brain differences underlie DLD and reading, particularly in adulthood, in order to better understand how to ultimately understand, support, and treat this disorder.

Cleft palate is a prevalant congenital anomaly in the United States, often creating differences in speech and communicative efficacy among affected children. When acquiring speech with a cleft palate, children use compensatory misarticulations to help force air through the mouth instead of the nasal passages. When the cleft is surgically repaired, children continue to use these marticulations. In my undergraduate research, I helped develop a study to assess these misarticulations. Our question was whether the velopharyngeal port (the opening between the oral and nasal passages) was open or closed during these compensatory articulations following palatal repair. I determined a list of words to have children repeat in order to elicit these misarticulations. The data used to answer our research question are novel -- vocal tract MRI (vtMRI). These data show the whole vocal tract moving while a participant is in a standard MRI scanner, reading aloud or repeating phrases. I am thus able to tell for each speaker and for each type of misarticulation, whether the velopharyngeal port is open or closed during misarticulations. This research presents some of the first quantitative data indicating whether misarticulations following palatal repair are habitual or structural in nature, and may indicate pathways for speech therapy to address the misarticulations. 

Autism spectrum disorder (ASD) is defined as a complex developmental condition involving persistent challenges with social communication, restricted interests, and repetitive behavior. The development of autism spectrum disorder (ASD) has been associated with altered brain development in infants with high familial likelihood for developing the disorder. Some of the same subcortical regions associated with altered brain development in ASD are also associated with sleep problems, including the hippocampus. Healthy sleep is an integral contributor to brain development during childhood and there is increasing evidence that chronic sleep loss can lead to neuronal loss and impaired functioning. Additionally, the multi-site, NIH-funded Infant Brain Imaging Study (IBIS) has previously reported sleep problems are associated with hippocampal alterations in infants who developed ASD. However, the relationship between sleep problems and altered brain development in autistic school-age children is not well understood, even though clinically significant sleep problems affect 75-80% of this population. Based on prior findings from the IBIS network, this project will examine the relationship between hippocampal volume and sleep problems in 137 school-age children with high familial likelihood of ASD (HL-ASD), no diagnosis of ASD (HL- noASD) and low familial likelihood of developing ASD (LL). Our prior findings suggest there will be differences across the three school aged groups in hippocampal volume, sleep duration, and sleep quality. We also expect that hippocampal volume in the HL-ASD children is differentially affected by sleep quality and sleep duration compared to the HL-noASD and LL children. Understanding the connections between sleep patterns and autism will help steer future research endeavors examining a largely understudied but significant issue. Additionally, this project will provide new insights into the negative consequences associated with chronic sleep loss in autistic children, affecting both their daily functioning and their quality of life.