Theses and Dissertations
This collection includes both ASU Theses and Dissertations, submitted by graduate students, and the Barrett, Honors College theses submitted by undergraduate students.
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- Creators: Braden, B. Blair
Description
Adults with autism spectrum disorder (ASD) face heightened risk of co-occurring psychiatric conditions, especially depression and anxiety disorders, which contribute to seven-fold higher suicide rates than the general population. Mindfulness-based stress reduction (MBSR) is an 8-week meditation intervention centered around training continuous redirection of attention toward present moment experience, and has been shown to improve mental health in autistic adults. However, the underlying therapeutic neural mechanisms and whether behavioral and brain changes are mindfulness-specific have yet to be elucidated. In this randomized clinical trial, I utilized functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) to characterize fMRI functional activity (Study 1) and connectivity (Study 2) and EEG neurophysiological (Study 3) changes between MBSR and a social support/relaxation education (SE) active control group. Study 1 revealed an MBSR-specific increase in the midcingulate cortex fMRI blood oxygen level dependent signal which was associated with reduced depression. Study 2 identified nonspecific intervention improvements in depression, anxiety, and autistic, and MBSR-specific improvements in the mindfulness trait ‘nonjudgment toward experience’ and in the executive functioning domain of working memory. MBSR-specific decreases in insula-thalamus and frontal pole-posterior cingulate functional connectivity was associated with improvements in anxiety, mindfulness traits, and working memory abilities. Both MBSR and SE groups showed decreased amygdala-sensorimotor and frontal pole-insula connectivity which correlated with reduced depression. Study 3 consisted of an EEG spectral power analysis at high-frequency brainwaves associated with default mode network (DMN) activity. Results showed MBSR-specific and nonspecific decreases in beta- and gamma-band power, with effects being generally more robust in the MBSR group; additionally, MBSR-specific decreases in posterior gamma correlated with anxiolytic effects. Collectively, these studies suggest: 1) social support is sufficient for improvements in depression, anxiety, and autistic traits; 2) MBSR provides additional benefits related to mindfulness traits and working memory; and 3) distinct and shared neural mechanisms of mindfulness training in adults with ASD, implicating the salience and default mode networks and high-frequency neurophysiology. Findings bear relevance to the development of personalized medicine approaches for psychiatric co-morbidity in ASD, provide putative targets for neurostimulation research, and warrant replication and extension using advanced multimodal imaging approaches.
ContributorsPagni, Broc (Author) / Braden, B. Blair (Thesis advisor) / Newbern, Jason (Thesis advisor) / Davis, Mary (Committee member) / Brewer, Gene (Committee member) / Arizona State University (Publisher)
Created2022
Description
Autistic adults face heightened risk of psychiatric disorders, with depression occurrence estimated at quadruple the rate of the general population. Mindfulness Based Stress Reduction (MBSR), an intensive 8-week in-person intervention, reduces depressive symptoms in adults with autism spectrum disorder (ASD). However, access to these programs is restricted due to financial, geographic, and scheduling limitations. Additionally, lapses in practice post-intervention cause these effects to be short-lived. This study examines antidepressant effects of an 8-week app-delivered mindfulness meditation intervention using Ten Percent Happier in adults with ASD and explores whether anchoring meditation practice to a preexisting behavior will improve therapy compliance and depression-related efficacy. Ninety-seven participants were randomly assigned to either App Only (n=30), App + Habit training (n=27) or Waitlist Control (n=40). App Only and App + Habit groups were requested to meditate a minimum of 10 minutes per day, 5 days per week for 8 consecutive weeks using the mobile application. The App + Habit group received additional instruction to anchor leaving the bathroom each morning with meditation; The App Only group was only provided with education on habit formation. Participants completed the Beck Depression Inventory-II (BDI-II) at pre- and post-intervention. All groups received weekly ecological momentary assessments (EMAs) to assess frequency and length of practice. The App + Habit group was additionally assessed for cue-initiated meditation frequency. Data were analyzed using repeated measures analysis of variance (ANOVA). Pre-to-post changes on BDI-II scores indicated a group by time interaction (p=0.04) and a main effect of time (p <0.001). Post-hoc analysis revealed the App + Habit group exclusively showed significant decline in depressive symptoms (p<0.001). The App + Habit group showed greater number of days meditated, average minutes per day of meditating, and continuation of meditation practice 8-weeks after the intervention period, compared to the App Only group.
Findings support app-delivered mindfulness interventions as an accessible and cost-effective alternative to traditional in-person mindfulness training for Autistic adults. However, results suggest app-based mindfulness tools may only be effective when delivered with specific habit formation instruction. Additionally, habit formation instruction led to greater adherence to meditation practice after the study period ended.
ContributorsVink, Schuyler Rae (Author) / Braden, B. Blair (Thesis advisor) / Stecher, Chad (Committee member) / Dixon, Maria (Committee member) / Rogalsky, Corriane (Committee member) / Arizona State University (Publisher)
Created2022