Browsing by Subject "Sleep"

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Associations between sleep and memory in aging
(2016-05) Sherman, Stephanie Michelle; Schnyer, David M.; Beevers, Christopher G; Haley, Andreana P; Westerberg, Carmen E
The goal of this dissertation was to understand how changes in sleep influence memory performance in healthy older adults. Previous research suggests that older individuals experience parallel declines in sleep and episodic memory. These age-related changes appear to be linked such that sleep disruptions contribute to deficits in memory performance. We examined the components of episodic memory that changed following sleep loss and correlated with aspects of sleep physiology. Healthy older adults completed two overnight sessions: an in-lab sleep recording session and a 24-hour sleep deprivation session. The morning after each sleep manipulation, participants completed both episodic memory and sustained attention tasks. We applied computational models, specifically drift-diffusion models, to the episodic memory tasks to examine whether sleep loss affected memory indirectly through lapses in sustained attention (vigilance hypothesis) or specifically through declines in the strategic processes associated with memory (neuropsychological hypothesis). Our results showed that memory functions that depend on processes associated with the prefrontal cortex were impaired following sleep deprivation. In addition, sleep loss caused a small but robust impairment in sustained attention. Since multiple cognitive processes were impaired by sleep loss in older adults, these findings do not provide unequivocal support for either the neuropsychological hypothesis or the vigilance hypothesis. In addition, we explored which aspects of sleep physiology (recorded during the sleep session) optimized components of memory performance. Our results illustrated that more slow wave power during sleep was correlated with higher next-day source memory strength. Additionally, individuals who spent more time in slow wave sleep had better memory retention. These results support further efforts to investigate sleep as a general indicator of cognitive function across the lifespan and highlight the importance of reinforcing healthy sleep behaviors as a method to preserve cognitive functioning in older adults.
Cancer-symptom burden and health-related quality of life associated with sleep disturbance and hypnotic use
(2016-12) Scalo, Julieta Frances; Rascati, Karen L.; Barner, Jamie C; Carter, Patricia A; Keith, Timothy Z; Lichtenstein, Michael J; Madhavan, Suresh; Wilson, James P
Objectives: To assess prevalence and correlates of cancer-related sleep disturbance (SD) and hypnotic use, and evaluate changes in cancer symptom burden and health-related quality of life (HRQoL) associated with sleep disturbance change and hypnotic use. Methods: Secondary analysis of the Symptom Outcomes and Practice Patterns (SOAPP) survey of 3,106 adult (aged ≥ 18 years) outpatients receiving treatment for breast, lung, prostate, or colorectal cancer between March 3, 2006 and May 19, 2008. At baseline and approximately four weeks later, patients scored severity of nineteen cancer symptoms from 0='Not present' to 10='As bad as you can imagine'. Both patients and clinicians scored symptom-burden interference for six HRQoL items (from 0='Did not interfere' to 10='interfered completely'). Correlates of SD and hypnotic use were identified using linear and logistic regression, respectively. Multivariate analyses tested whether hypnotic use (Hotelling's T²) or change in SD severity (multivariate linear regression) were associated with changes in symptom burden and HRQoL. Cancer-specific subgroups were evaluated when sample size permitted. Results: SD scores were available for 2,748 participants: 71% female, 86% white, mean age 61 years (range, 23-93 years). Primary cancer sites: breast (51%), colorectal (24%), lung (15%), and prostate (10%). The majority (62.8%) reported SD and 23.5% used hypnotics. The most important SD correlates were other cancer symptoms, regardless of their severity. Distress was the strongest and only universal correlate; cognitive difficulty, drowsiness, and fatigue were also common across cancer-specific subgroups. Hypnotic use was two to three times higher among whites, versus blacks. Several sedating medications correlated positively with hypnotic use, including opioid analgesics and promethazine. Hypnotic use correlated positively with clinician-identified distress, but not with clinician-identified sleep disturbance. Reduced sleep disturbance severity (SDS) correlated with improvement in nearly all symptoms (most notably: distress, dry mouth, and fatigue), and with improved HRQoL (possibly mediated by other symptoms). Hypnotic use correlated modestly with lower overall symptom burden, but not HRQoL change. Conclusions: Relationships observed between SD and many other cancer symptoms argue in favor of therapies that target multiple symptoms. Patterns of hypnotic use raise questions about whether cancer-related SD is being treated adequately, equitably, and effectively.
Daily worry, rumination, and sleep in late life
(2023-12) Zhou, Zexi, M.A.; Fingerman, Karen L.
Perseverative thinking (e.g., worry/rumination) is a common response to stress, and can be detrimental to well-being in late life. Sleep may represent an important mechanism by which perseverative thinking is disrupted or amplified from day to day. Yet, limited research has investigated the implications of worry and rumination for sleep, and vice versa, in late life. This study examined the associations between older adults’ everyday worry, rumination, and sleep. Older adults (N = 270) aged 65–89 completed a baseline interview and two daily dairies each day (i.e., one morning assessment and one evening assessment) for five to six days. Every morning, they indicated how worried they were about something that might happen that day, and rated qualities of their sleep the prior night (e.g., duration, subjective perceptions of quality, disturbances). Every evening, older adults rated worry and rumination they had experienced that day. Multilevel models showed that daytime worry and rumination reported before bed were associated with self-reported sleep disturbances and hours of sleep that night. More hours of sleep, higher sleep quality, and fewer sleep disturbances were associated with less worry the next morning. Prior night’s worry predicted greater next morning’s worry, but this association was significant only when older adults reported fewer hours of sleep, not when they reported more hours of sleep. Findings suggest that worry and rumination may tend to persist in older adults’ daily life, and highlight the protective role that better sleep may play in reducing older adults’ everyday perseverative thinking.
Memory processing of novel experiences in the hippocampus
(2019-08) Hwaun, Ernie; Colgin, Laura; Mauk, Michael; Priebe, Nicholas J; Johnston, Daniel; Brumback, Audrey
The hippocampus is a brain structure critical for learning and memory. With limited resources, memory processing in the hippocampus must involve extraction of useful information from daily experiences. A potential factor in this selection may be novelty of incoming information. To avoid redundancy in memory storage, the hippocampus may prefer to process novel stimuli. In this dissertation, I used extracellular tetrode recording techniques in freely behaving rats to demonstrate selective reactivation of novel experiences in the hippocampus. The principle neurons of the hippocampus, known as ‘place cells’, exhibit place-selective activity that is thought to reflect spatial aspects of a memory. In addition, during sleep and rest, ensembles of hippocampal neurons periodically engage in coordinated firing that results in signature patterns in local field potential recordings, called ‘sharp wave-ripples’. I show that during sharp wave-ripples, which are believed to reflect a retrieval mode of the hippocampal network, the place cells that were active in a novel environment fired more often than other place cells that were active in a familiar environment. In addition, firing sequences during sharp wave-ripples primarily reflected trajectories in the novel environment. To investigate how hippocampal representations of a familiar experience incorporate novel information, rats were trained to learn a new goal location within a familiar environment. I found selective modification of spatial representations near a newly-learnt goal in the familiar environment. Moreover, firing sequences during sharp wave-ripples preferentially terminated near the goal location after learning, suggesting preferential memory retrieval of the goal. Together, these results support the hypothesis that novel experiences are preferentially processed in the hippocampus.
Perceived stress, sleep, and psychosocial health among Mexican-origin adolescents from immigrant families
(2020-08-24) Zhang, Minyu; Kim, Su Yeong; Benner, Aprile D.; Zeiders, Katharine H.; Lorenzo-Blanco, Elma I.; Anderson, Edward R.
Mexican-origin adolescents face multiple stressors in their daily lives. They also struggle with insufficient sleep, poor quality sleep (Guglielmo, Gazmararian, Chung, Rogers, & Hale, 2018), and high risk of mental health problems (American Psychiatric Association, 2017). Sleep is a restorative process essential to health and development: it can be seen either as a downstream outcome (an important health indicator) that may be influenced by stress directly, or mediated by psychosocial health indirectly; or as an upstream indicator that mediates the process of stress impacting psychosocial health. The current dissertation aims to depict sleep patterns (Study I) and understand the mechanism behind cumulative stress, sleep, and psychosocial health from both a daily perspective (Study I) and a chronic perspective (Study II) among a sample of low-income Mexican-origin adolescents. Data were retrieved from a three-wave longitudinal project (W1: N = 604, Mage = 12.41, SD = 0.97; W2: N = 483, Mage = 13.22, SD = 0.95; W3: N = 334, Mage = 17.10, SD = 1.12) that measured stress, sleep, and psychosocial outcomes among Mexican-origin adolescents in central Texas from 2014 to early 2020. At W3, the project also initiated a four-day diary study with a sub-sample (N = 277, Mage = 16.93, SD = 1.00) to record adolescents’ daily sleep with actigraphy-based measures. Study I, the daily study, found that the sample displays a sleep pattern with insufficient time but good quality. Study I found evidence to support sleep duration only as a downstream outcome that is being directly impacted by average cumulative stress; marginal trends were found for latency as a downstream outcome directly influenced by daily/average cumulative stress. From a longitudinal perspective, Study II found support for sleep quality as both a downstream outcome impacted by perceived contextual stress directly, or indirectly via depressive symptoms, and an upstream indicator that mediates the links between stress and psychosocial health outcomes. Altogether, the current dissertation provides initial empirical evidence that sleep may be conceptualized as a downstream outcome of daily stress; whereas chronically, sleep can be considered as both a downstream and an upstream indicator in the stress-health model.
Rest-activity rhythms and white matter microstructure across the lifespan
(2020-08-07) McMahon, Megan Catherine; Schnyer, David M.
The purpose of this study was to examine how rest-activity (RA) rhythm stability may be associated with white matter microstructure across the lifespan in healthy adults free of significant cardiovascular risk. We analyzed multi-shell diffusion tensor images from 103 healthy young and older adults using tract-based spatial statistics (TBSS) to examine relationships between white matter microstructure and RA rhythm stability. RA measures were computed using both cosinor and non-parametric methods derived from seven days of actigraphy data. Fractional anisotropy (FA) and mean diffusivity (MD) were examined in this analysis. Because prior studies have suggested that the corpus callosum (CC) is sensitive to sleep physiology and RA rhythms, we also conducted a focused region of interest analysis on the CC. Results indicated that greater rest-activity rhythm stability was associated with greater FA across both young and older adults, primarily in the corpus callosum and anterior corona radiata. This effect was not moderated by age group. Further, while RA measures were associated with sleep metrics, RA rhythm measures uniquely accounted for the variance in white matter integrity. This study strengthens existing evidence for a relationship between brain white matter structure and RA rhythm stability in the absence of confounding health risk factors. While there are differences in RA stability between young and older adults, the relationship with brain white matter appears to be stable across the lifespan. RA rhythms may be a useful biomarker of brain health across adult development
Sleep paralysis
(2013-05) Jackfert, Matthew Damous; Pinkston, Russell
Sleep Paralysis was written to be performed by a chamber orchestra of 17 performers total. The piece runs between 11 and 12 minutes and has a distinct programmatic approach. This piece attempts to convey the emotions and feelings one might experience when he or she is stricken with sleep paralysis—a condition where one wakes up during sleep but cannot move. Thus, this piece is set up as a dream gone badly. Harmonic and rhythmic tension increase throughout the piece until it reaches a moment of “paralysis” where the harmonies are static and melodies and themes appear in a dream-like fashion. Eventually, the ever-mounting tension resolves to free the listener of the paralysis; however, one should not assume that the paralysis is gone forever.
Sleep-wake characteristics of children with pervasive developmental disorders (PDD) : a survey study
(2012-12) Chiang, Chia-Jung; Schaller, James L., active 2013; Carter, Patricia A; Lopez, Martitia A; O'Reilly, Mark F; Rieth, Herbert J
A higher prevalence of sleep problems and a few specific sleep-wake characteristics have been preliminarily found to be associated with pervasive developmental disorders (PDD). However, there is limited research that has examined multiple variables associated with sleep-wake characteristics and problems of children with PDD. This dissertation study assessed and examined the sleep-wake characteristics, sleep problems, and daytime problem behaviors of children with PDD aged three to fifteen years, and their caregivers’ sleep as well as contextual variables using data from the primary caregivers’ reports and recordings. This study confirmed several findings in the literature related to sleep-wake characteristics and sleep problems in children with both PDD and sleep problems. Although the relationship between sleep and daytime problem behaviors of the children was not found to be statistically correlated, the descriptive data indicated that some conditions such as illness or anxiety of the children negatively impacted their sleep and behaviors. In addition, the children participants with PDD and sleep problems tended to watch TV or to use computer/play video games before bedtime, in comparison to those with PDD but without sleep problems in this study. Moreover, a significant correlation between sleep of the caregivers and of their children was found in the group of children with PDD and sleep problems, but not in the other group of children with PDD but without sleep problems. Lastly, the results of this study showed that the children with diagnoses of PDD were 3.84 times more likely to have sleep problems than those with diagnoses of Asperger’s Disorder (AD) or PDD not otherwise specified (PDD-NOS). These findings are discussed in light of the similarities and differences between the current study and previous literature, and with respect to the implications for practice and research in the field of PDD and sleep.
Sleeping in a society : social aspects of sleep within colonies of honey bees (Apis mellifera)
(2010-05) Klein, Barrett Anthony; Gilbert, Lawrence E.; Mueller, Ulrich G.; Seeley, Thomas D.; Ryan, Michael J.; Abbott, John C.
Sleep is a behavioral condition fraught with mystery. Its definition—either a suite of diagnostic behavioral characters, electrophysiological signatures, or a combination of the two—varies in the literature and lacks an over-arching purpose. In spite of these vagaries, sleep supports a large and dynamic research community studying the mechanisms, ontogeny, possible functions and, to a lesser degree, its evolution across vertebrates and in a small number of invertebrates. Sleep has been described and examined in many social organisms, including eusocial honey bees (Apis mellifera), but the role of sleep within societies has rarely been addressed in non-human animals. I investigated uniquely social aspects of sleep within honey bees by asking basic questions relating to who sleeps, when and where individuals sleep, the flexibility of sleep, and why sleep is important within colonies of insects. First, I investigated caste-dependent sleep patterns in honey bees and report that younger workers (cell cleaners and nurse bees) exhibit arrhythmic and brief sleep bouts primarily while inside comb cells, while older workers (food storers and foragers) display periodic, longer sleep bouts primarily outside of cells. Next, I mapped sleep using remote thermal sensing across colonies of honey bees after introducing newly eclosed workers to experimental colonies and following them through periods of their adult lives. Bees tended to sleep outside of cells closer to the edge of the hive than when asleep inside cells or awake, and exhibited caste-dependent thermal patterns, both temporally and spatially. Wishing to test the flexibility of sleep, I trained foragers to a feeder and made a food resource available early in the morning or late in the afternoon. The bees were forced to shift their foraging schedule, which consequently also shifted their sleep schedule. Finally, I sleep-deprived a subset of foragers within a colony by employing a magnetic “insominator” to test for changes in their signaling precision. Sleep-deprived foragers exhibited reduced precision when encoding direction information to food sources in their waggle dances. These studies reveal patterns and one possible purpose of sleep in the context of a society.
Studies on particle resuspension, infant exposure, and the sleep microenvironment
(2015-08) Boor, Brandon Emil; Xu, Ying (Assistant professor); Novoselac, Atila; Corsi, Richard L; Hildebrandt Ruiz, Lea; Järnström, Helena; Howard Reed, Cynthia
Understanding the transport of particulate and gaseous indoor air pollutants from source to exposure is paramount to improve our understanding of the complexities of the built environments in which we spend the majority of our time. This dissertation offers new insights on particle resuspension from indoor surfaces, infant exposure to organic contaminants released from crib mattresses, and the dynamics of pollutant transport and human exposure while sleeping. Particle resuspension is the physical process by which settled particles detach from a surface and become airborne through application of various aerodynamic and mechanical removal forces. Resuspension is an important indoor source of coarse mode particles (> 1 µm in diameter) and can be a source mechanism for biological matter and organic contaminants that accumulate in house dust. Settled dust deposits on indoor surfaces can vary considerably in their structure and mass loading, yet little is known as to how these parameters affect resuspension. Through wind tunnel experiments, this research demonstrates that the deposit structure (monolayer or multilayer) can have a significant impact on the number of particles that aerodynamically resuspend. Furthermore, this dissertation presents the first full-scale experimental chamber study to show that human body movements in bed can resuspend settled mattress dust particles. An indoor aerosol model was utilized to provide a mechanistic understanding of the impact of movement intensity, surface vibrations, bedroom ventilation rate, and dust loading on the resuspension flux and intake fraction of resuspended particles. Infants spend most of their time sleeping and are likely to be exposed to elevated concentrations of chemicals released from their crib mattresses. Through a combination of chamber experiments and solvent extractions, this research shows that infant crib mattresses can emit a variety of volatile organic compounds (VOCs) and contain numerous chemical additives, including phthalate and alternative plasticizers, flame retardants, and unreacted isocyanates. Additionally, this study discovered that infants are exposed to approximately twice the concentrations of VOCs in their breathing zones as compared to the bulk bedroom air, due to their close proximity to the source.
The intersection of pain, fatigue, and cardiovascular risk in teens with juvenile arthritis : a biobehavioral case-control pilot study
(2021-04-06) Lewis, Kimberly Anette; Osier, Nico; Garcia, Alexandra; Tiziani, Stefano; Acton, Gayle
Teens with juvenile idiopathic arthritis (JIA) live with chronic pain and fatigue. They are at higher risk of cardiovascular morbidity and mortality than the general population. Yet there is little evidence about the metabolic processes underlying the symptoms and comorbidity. The purpose of this biobehavioral, cross-sectional pilot study is to describe the characteristics of, differences between, and relationships among groups of teens with JIA and healthy controls. The study design is guided by a synthesized model of: metabolomics theory, the Revised Child- and Family Self-Management Framework, and the Symptom Science Model. A group of n=20 controls and n=20 teens with JIA were recruited from a clinic in Austin, TX between August 2018-January 2019. Participants and their parent proxy completed a study visit with a morning, fasting blood sample collection, biometrics, and surveys. Measures include complex symptoms (pain, pain interference, fatigue), phenotypic characterization (individual characteristics, facilitators and barriers, and behaviors), and biomarkers (metabolomics signature and cardiovascular risk factors). Data were analyzed using descriptive statistics, t-tests, chi square, and Pearson’s correlations. Blood samples were processed using mass spectroscopy. Best practices for recruitment strategies for this population and study design were identified. Results indicate that the groups were equivalent in characteristics, yet they share similarities and exhibit important differences between groups. A pattern of metabolites was identified. Additional differences were found between teens with JIA in active versus inactive disease at the time of the study visit. Sixty-five metabolites were identified, 55 of which were common to both groups. Alpha-D-glucose, alpha-ketoglutaric acid, citrate, citrulline, lactate, L-histidine, L-phenylalanine, L-proline, L-serine, L-tyrosine, malate, myristic acid, N-acetyl-D-L-serine, N-acetyl-L-aspartic acid, and uracil were significantly lower in the JIA group relative to controls; Glycine and L-cysteine were significantly higher. Findings from this biobehavioral pilot study indicate 17 metabolites that were significantly different in teens with JIA relative to controls. The pathways in which these metabolites are implicated may be a source of new treatment and prevention options. Results provide initial evidence of symptom clusters or potential biomarkers. Further research is warranted to confirm these findings in a larger sample.