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Browsing by Author "Stephens, Jaclyn A., committee member"

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    Associations between neuroanatomy and neurophysiology with turning performance in people with multiple sclerosis
    (Colorado State University. Libraries, 2021) Swanson, Clayton Winford, author; Fling, Brett W., advisor; Leach, Heather J., committee member; Stephens, Jaclyn A., committee member; Mancini, Martina, committee member; Miravalle, Augusto A., committee member
    Neurodegenerative diseases such as multiple sclerosis (MS) are associated with decreased mobility and a variety of changes affecting neural structure and function. Due to the cortical influence on various aspects of mobility, it is likely that these neural adaptations negatively affect mobility, and therefore, increase the potential for falls. Additionally, the progression of MS has been associated with cortical grey matter atrophy, and adaptions to neurophysiological activity. While previous research has demonstrated associations between levels of inhibition and a variety of turning characteristics in neurotypical young and older adults, it remains unclear if associations exist between cortical structure and function for dynamic lower limb control for daily tasks such as turning. Therefore, purpose of this project was to understand how sensorimotor cortical thickness and corticospinal excitation and inhibition contribute to turning performance in both people with MS (PwMS) and age-matched neurotypical control (HC) participants. Participants were asked to conduct a series of 360Ëš in-place turns at two self-selected speeds and 180Ëš turns during a self-selected pace two-minute walk test. Quantification of turning was assessed using wireless inertial sensors placed on each foot, around the waist, on the sternum, and on the forehead. Grey matter (GM) thickness of the sensorimotor cortex (i.e., pre-, para-, and postcentral gyri) was measured via magnetic resonance imaging (MRI) and processed using FreeSurfer 6.0.0 (http://surfer.nmr.mgh.harvard.edu/, Harvard University, Boston, MA, USA). To measure corticospinal excitation and inhibition single-pulse transcranial magnetic stimulation (TMS) was performed. The leg region of both motor cortices was identified by acquiring the resting motor threshold (RMT) of the tibialis anterior. To assess neurophysiology, participants sustained an isometric contraction in dorsiflexion at 15% of their maximal voluntary contraction for three-minutes. Simultaneously, a TMS stimulation was delivered at 120% of RMT every 7-10 seconds. This procedure was conducted for both cortical hemispheres. A total of forty-nine individuals (23 HC, 26 MS) participated in the study. PwMS demonstrated reduced turning performance for a variety of 360Ëš turning variables, although only one variable was significant between groups for the 180Ëš turns. GM thickness revealed significant cortical thinning of the pre- and paracentral gyri in the MS group, while the postcentral gyrus did not demonstrate between group differences. For TMS measures, PwMS demonstrated reductions in excitation and inhibitory capacity compared to neurotypical controls. All significant correlations were primarily observed in the MS group and demonstrated lateralization, such that they were limited to the left hemisphere. The current results showed that both cortical thickness and inhibitory activity were associated with turning performance in PwMS, but not in the HC group. The associations between inhibitory activity and turning performance were stronger than the associations between cortical thickness and turning performance. These results may indicate that inhibitory activity is more associated with dynamic lower limb movements compared to GM thickness. Furthermore, these results suggest that PwMS may rely on different neural resources to perform dynamic movements typically associated with fall risk.
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    Influence of prosody and emotional congruence in emotion perception
    (Colorado State University. Libraries, 2020) Becker, Katherine M., author; Rojas, Donald C., advisor; Davalos, Deana B., committee member; Graham, Dan J., committee member; Stephens, Jaclyn A., committee member
    Vocal emotion, or emotional prosody, is conveyed via suprasegmental changes to the acoustic qualities of a speaker's voice. Prosody is essential to affect perception as it can independently and instantaneously convey emotion. Prosody normally coincides with affective facial expressions and other non-verbal cues to form holistic emotional percepts. Prior research pairing emotional voices with affective faces found that emotion perception may be biased by emotional prosody, as affective faces presented with a happy voice were rated 'happier' than faces presented with an angry or neutral voice. While these findings indicate that emotion perception is biased by voice prosody, the precise mechanism of this bias remains unclear. Since vision predominates perception, much like in the more well-known McGurk effect, it is likely that visual cues in the speaker influence the prosodic bias. Visual modality cues in the face may moderate this bias via increased fixations to the mouth or eyes, potentially changing the influence of prosody as the perceiver is or is not directed to visual cues associated with auditory information. Thus, increased visual attention to moving mouths may increase the perceptual bias created by prosodic voices. Visual attention patterns will be directed to fixate on either the mouth or eyes of speaking faces paired with either emotionally congruent or incongruent voices. The current study will use behavioral measures, electroencephalography, and magnetoencephalography to assess the neural and behavioral correlates underlying the effects of emotional congruency and visual attention on prosodic perceptual biases.
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    The effects of personality and social determinants of health on sports-related concussion risk: an examination of symptom reporting, concussion incidence, and return to play
    (Colorado State University. Libraries, 2024) Weishaar, Megan Gardner, author; Conner, Bradley T., advisor; Prince, Mark A., committee member; Davalos, Deana B., committee member; Stephens, Jaclyn A., committee member
    Sports-related concussion (SRC), a form of mild traumatic brain injury (TBI) that occurs during sport participation or recreation, has emerged as a public health concern among adolescent athletes in the United States in recent decades due to increasing knowledge of high incidence rates. Important factors such as return to play (RTP) timeline and symptom reporting behaviors have been shown to contribute to SRC incidence. As a result, recent research has called for work that identifies a parsimonious group of variables that are salient in identifying athletes most at risk of outcomes such as early RTP, higher SRC incidence, and symptom nondisclosure. A small body of work has established that certain personality characteristics and social determinants of health are associated with these SRC outcomes. However, few specific personality and social determinants of health factors have been examined, few studies have investigated predictors of SRC incidence and RTP outcomes specifically, and a small number of these studies have investigated these research questions among adolescent athletes despite high rates of athletic participation and SRC incidence. The current study sought to expand previous work to further elucidate relations between a myriad of personality and social determinants of health predictors, and time to RTP, diagnosed SRC, and symptom reporting outcomes among adolescent athletes (N = 317, ages 14-19). The ultimate goal of the study was to identify personality and social determinants of health factors most salient in SRC outcomes to inform practical tailoring of prevention and intervention strategies. Participants were adolescents who were currently enrolled in high school or college or were enrolled in high school within the past calendar year, participated in a high school or club sport in the past year, and either denied sustaining a diagnosed SRC in the past year (N = 156) or endorsed sustaining a diagnosed SRC in the past year (N = 161). Data were collected through a one-time online survey that took participants 20-30 minutes to complete. Participants were compensated via an online gift card or course credit. Recruitment methods included outpatient medical clinics, high school athletic trainers, sports gyms and tournaments, Twitter, and university research pools. Analyses included a series of Cox proportional hazards and logistic regression models investigating associations between personality and social determinants of health predictors and time to RTP, diagnosed SRC incidence, and symptom reporting outcomes (i.e., honesty and comfort in symptom reporting). Overall, study results bolstered the conclusion that 1. Personality and social determinants of health factors are important in predicting SRC outcomes and 2. The relations between personality and SRC outcomes are highly nuanced, depending upon specific personality facets, outcome, and sample characteristics. Study results inform athletes, peers and family of athletes, coaches, athletic trainers, and other medical professionals about which personality and social determinants of health variables are most salient in SRC risk, thus informing prevention and intervention efforts for SRC such that they can be more personalized and tailored at the individual, environmental, and systems levels.