Intrusive Traumatic Re-Experiencing Domain: Functional Connectivity Feature Classification by the ENIGMA PTSD Consortium.

Background: Intrusive traumatic re-experiencing domain (ITRED) was recently introduced as a novel perspective on posttraumatic psychopathology, proposing to focus research of posttraumatic stress disorder (PTSD) on the unique symptoms of intrusive and involuntary re-experiencing of the trauma, namely, intrusive memories, nightmares, and flashbacks. The aim of the present study was to explore ITRED from a neural network connectivity perspective. Methods: Data were collected from 9 sites taking part in the ENIGMA (Enhancing Neuro Imaging Genetics through Meta Analysis) PTSD Consortium (n= 584) and included itemized PTSD symptom scores and resting-state functional connectivity (rsFC) data. We assessed the utility of rsFC in classifying PTSD, ITRED-only (no PTSD diagnosis), and trauma-exposed (TE)-only (no PTSD or ITRED) groups using a machine learning approach, examining well-known networks implicated in PTSD. A random forest classification model was built on a training set using cross-validation, and the averaged cross-validation model performance for classification was evaluated using the area under the curve. The model was tested using a fully independent portion of the data (test dataset), and the test area under the curve was evaluated. Results: rsFC signatures differentiated TE-only participants from PTSD and ITRED-only participants at about 60% accuracy. Conversely, rsFC signatures did not differentiate PTSD from ITRED-only individuals (45% accuracy). Common features differentiating TE-only participants from PTSD and ITRED-only participants mainly involved default mode network-related pathways. Some unique features, such as connectivity within the frontoparietal network, differentiated TE-only participants from one group (PTSD or ITRED-only) but to a lesser extent from the other group. Conclusions: Neural network connectivity supports ITRED as a novel neurobiologically based approach to classifying posttrauma psychopathology.

Modulatory effects of dietary saturated fatty acids on platelet mitochondrial function following short-term exposure to ambient Particulate Matter (PM2.5).

Exposure to ambient fine particulate matter (PM2.5) was found to produce vascular injury, possibly by activating platelets within days after exposure. The aim of this study was to investigate the modulatory effects of dietary saturated fatty acids on platelet mitochondrial respiratory parameters following short-term inhalational exposure to PM2.5. A total of 22 healthy male volunteers were recruited from the Research Triangle area of North Carolina. Platelets were isolated from fresh whole blood samples and mitochondrial respiratory parameters were measured using an extracellular flux analyzer. Intake of saturated fat was averaged from multiple 24-hr dietary recalls. Daily ambient PM2.5 concentrations were obtained from ambient air quality monitoring stations. Correlation and ANOVA were used in data analyses, along with the pick-a-point method and the Johnson-Neyman technique for probing moderation. After controlling for age and omega-3 index, the intake of dietary saturated fatty acids after reaching 9.3% or higher of the total caloric intake significantly moderated the associations between PM2.5 exposure and several platelet mitochondrial respiratory parameters. In conclusion, dietary saturated fatty acids above 9.3% of total caloric intake influenced the relationship between short-term PM2.5 exposure and platelet mitochondrial respiration. Further research is needed to understand these associations and their implications for cardiovascular health.

Changes in fear-associated learning task brain activation over the COVID-19 pandemic period: a preliminary longitudinal analysis.

Background: The COVID-19 pandemic has had profound impacts on people worldwide. Previous studies have shown that fear learning, extinction, recall, and contextual information processing involve the activation of emotion and sensory brain systems, which can be modified. However, it remains unclear whether brain functions associated with these processes have been altered over the pandemic period. Methods: We compared pre- and peri-pandemic brain activation during a fear-associated learning task (FALT) using previously collected data. The participants were divided into two groups: the pandemic group (n = 16), who completed a baseline FALT before the pandemic and repeated the task during the pandemic, and the non-pandemic group (n = 77), who completed both sessions before the pandemic began. Results: Compared with the non-pandemic group, the pandemic group exhibited significant decreases in brain activation from baseline to follow-up assessments, including activation in the brainstem during early fear learning, the posterior thalamus/hippocampus during late extinction, and the occipital pole during late recall phases for contextual processing. Furthermore, activations associated with retrieving safety cues were reduced in the posterior cingulate, premotor, and calcarine cortices during the early recall phase, and activations associated with retrieving dangerous cues decreased in the occipital pole during the late recall phase. Additionally, correlations between decreased activation and elevated posttraumatic stress symptoms were observed. Conclusion: These findings suggest that activations associated with processing low arousal contextual information, safety cues, and extinguished fear cues decreased during the pandemic. These changes in brain activation may have contributed to the increase in mental health disturbances observed during this time.

Hypothalamus volume mediates the association between adverse childhood experience and PTSD development after adulthood trauma.

The hypothalamus is critical for regulation of the hypothalamic-pituitary-adrenal (HPA) axis and response to stress. Adverse childhood experience (ACE) can affect brain structure, which may contribute to development of posttraumatic stress disorder (PTSD) after subsequent adult trauma. It is unclear, however, if ACE history is particularly associated with aspects of hypothalamic structure which contribute to development of PTSD. To address this issue, the present study longitudinally assessed hypothalamic volumes and their associations with ACE and early post-trauma stress symptoms in subjects who did or did not develop PTSD during 12 months after adult trauma. 109 subjects (18-60 years, F/M = 75/34) completed the PTSD Checklist (PCL) questionnaire for post-trauma stress symptoms, the Childhood Trauma Questionnaire (CTQ) for ACE assessment, and an initial MRI brain scan for hypothalamic volume measurement, within 2 weeks after adult trauma. At post-trauma 12 months, subjects underwent a subsequent PTSD diagnosis interview using the Clinician-Administered PTSD Scale (CAPS), and a follow-up MRI scan. Left and right hypothalamus volumes at 2 weeks after adult trauma negatively correlated with CTQ scores. Right hypothalamus volume at this early time mediated an association between ACE and PTSD symptoms 12 months later. Right hypothalamus volumes also remained persistently smaller from 2 weeks to 12 months after trauma in survivors who developed PTSD. These results suggest that smaller right hypothalamus volume may be related to ACE history in ways that contribute to PTSD development after trauma in adulthood.

Association of age of adverse childhood experiences with thalamic volumes and post-traumatic stress disorder in adulthood.

Background: Adverse childhood experiences (ACEs) have been linked to brain development and mental disorders, however, the impact of the age of occurrence of ACEs on thalamic volume and post-traumatic stress disorder (PTSD) after adult trauma remains unclear. This study assessed associations between ACEs at different ages to thalamic volumes and PTSD development following acute adult trauma. Methods: Seventy-nine adult trauma survivors were recruited immediately after trauma. Within 2 weeks of the traumatic event, participants completed the PTSD Checklist (PCL) to assess PTSD symptoms, the Childhood Trauma Questionnaire (CTQ) and Childhood Age Range Stress Scale (CARSS) to evaluate ACEs and perceived stress level at preschool (<6 years old) and school (6-13 years old) ages, and structural magnetic resonance imaging (sMRI) to measure thalamic volumes. Participants were divided into three groups: those who experienced no childhood trauma or stress (non-ACEs), those who experienced childhood trauma and stress onset at preschool ages (Presch-ACEs), and those who experienced childhood trauma and stress onset at school ages (Sch-ACEs). At 3 months, participants underwent PTSD symptom evaluation using the Clinician Administered PTSD Scale (CAPS). Results: Adult trauma survivors in the Presch-ACEs group had higher CTQ and CAPS scores. In addition, survivors in the Presch-ACEs group had smaller thalamic volume compared to survivors in the non-ACEs and Sch-ACEs groups. Furthermore, smaller thalamic volume moderated a positive association between post-trauma 2-week PCL and subsequent 3-month CAPS scores. Discussion: Earlier occurrence of ACEs was associated with smaller thalamic volume, which appears to moderate a positive association between early posttraumatic stress symptom severity and PTSD development after adult trauma. This raises the possibility that early occurrence of ACEs may impact thalamic structure, specifically a reduction in thalamic volume, and that smaller thalamic volume may contribute to susceptibility to PTSD development after adult trauma.

Emotion dysregulation mediates the association between acute sleep disturbance and later posttraumatic stress symptoms in trauma exposed adults.

Background: Sleep disturbance is common within days to weeks following a traumatic event and has been associated with emotion dysregulation, a strong risk factor for PTSD development. This study aims to examine if emotion dysregulation mediates the relationship between early post-trauma sleep disturbance and subsequent PTSD symptom severity.Methods: Adult participants (n = 125) completed questionnaires regarding sleep disturbance (via Pittsburgh Sleep Quality Index Addendum; PSQI-A) and emotion dysregulation (via Difficulties in Emotion Regulation Scale; DERS) within 2 weeks after exposure to traumatic events.Results: PTSD symptom severity was assessed with PTSD Checklist for DSM-5 (PCL-5) at 3-month follow-up. There were strong correlations between PSQI-A, DERS, and PCL-5 (r ranges between .38 and .45). Mediation analysis further revealed significant indirect effects of overall emotion regulation difficulties in the relationship between sleep disturbance at 2 weeks and PTSD symptom severity at 3 months (B = .372, SE = .136, 95% CI: [.128, .655]). Importantly, limited access to emotion regulation strategies emerged as the single, significant indirect effect in this relationship (B = .465, SE = .204, 95% CI [.127, .910]) while modelling DERS subscales as multiple parallel mediators.Conclusions: Early post-trauma sleep disturbance is associated with PTSD symptoms over months, and acute emotion dysregulation explains part of this association. Those with limited emotion regulation strategies are at particular risk of developing PTSD symptoms. Early interventions focusing on the appropriate strategies for emotion regulation may be crucial for trauma-exposed individuals.

Early post-trauma sleep disturbance and emotion dysregulation associated with subsequent posttraumatic stress symptoms.Emotion dysregulation mediates associations between acute sleep disturbance and later posttraumatic stress symptoms.Limited access to effective regulatory strategies was the single, significant contributor to this mediation link.

Early self-reported post-traumatic stress symptoms after trauma exposure and associations with diagnosis of post-traumatic stress disorder at 3 months: latent profile analysis.

BACKGROUND: Trauma exposure can cause post-traumatic stress symptoms (PTSS), and persistently experiencing PTSS may lead to the development of post-traumatic stress disorder (PTSD). Research has shown that PTSS that emerged within days of trauma was a robust predictor of PTSD development. AIMS: To investigate patterns of early stress responses to trauma and their associations with development of PTSD. METHOD: We recruited 247 civilian trauma survivors from a local hospital emergency department. The PTSD Checklist for DSM-5 (PCL-5) and Acute Stress Disorder Scale (ASDS) were completed within 2 weeks after the traumatic event. Additionally, 3 months post-trauma 146 of these participants completed a PTSD diagnostic interview using the Clinician Administered PTSD Scale for DSM-5. RESULTS: We first used latent profile analysis on four symptom clusters of the PCL-5 and the dissociation symptom cluster of the ASDS and determined that a four-profile model ('severe symptoms', 'moderate symptoms', 'mild symptoms', 'minimal symptoms') was optimal based on multiple fit indices. Gender was found to be predictive of profile membership. We then found a significant association between subgroup membership and PTSD diagnosis (χ2(3) = 11.85, P < 0.01, Cramer's V = 0.263). Post hoc analysis revealed that this association was driven by participants in the 'severe symptoms' profile, who had a greater likelihood of developing PTSD. CONCLUSIONS: These findings fill the knowledge gap of identifying possible subgroups of individuals based on their PTSS severity during the early post-trauma period and investigating the relationship between subgroup membership and PTSD development, which have important implications for clinical practice.

Effects of acute pain medications on posttraumatic stress symptoms in early aftermath of trauma.

Posttraumatic stress symptoms (PTSS) develop as sequelae from traumatic injuries. Limited studies suggest that using opioids to reduce acute pain immediately after trauma may also reduce subsequent PTSS, but other pain medications rarely have been examined for preventing acute PTSS. The current study examined the effects of commonly used pain medications, opioid and nonsteroidal anti-inflammatory drugs (NSAIDs), on PTSS after acute traumatic injuries. Participants ( n = 71) were categorized into opioid or NSAID group according to their medical records and self-reported medication use. Their PTSS were assessed using posttraumatic stress disorder checklist twice within 2 weeks after trauma. Participants' pain levels reduced from pretreatment to follow-up in both groups, F (1, 55) = 6.696, P = 0.012, partial η 2 = 0.109. Interestingly, a significant interaction between time and medication group on PTSS reached statistical significance, F (1, 69) = 6.014, P = 0.017, partial η 2 = 0.080. Follow-up analyses revealed that this interaction was driven by a significant PTSS reduction only in opioid but not in NSAID group. These findings suggested that pain reduction alone is not sufficient to reduce acute PTSS in the NSAID group, highlighting the need to continue further investigations into the mechanisms by which opioids reduce PTSS in the early posttrauma period.

Longitudinal PTSD symptom trajectories: Relative contributions of state anxiety, depression, and emotion dysregulation.

BACKGROUND: Prospective research on the development and trajectory of PTSD symptoms after a traumatic event is crucial for assessment and early intervention. Further, examining predictors of PTSD pathology provides a better conceptualization of the temporal course of PTSD in trauma victims. METHODS: The present study examined PTSD symptom severity in individuals presenting to the emergency department (ED) following a traumatic event. Participants (N = 147) were assessed at four timepoints: 2-weeks, 3-months, between 6 and 9 months, and 12-months after ED admission. Growth curve modeling was conducted to examine changes in PTSD symptom severity over time. Age, sex, state anxiety, trait anxiety, emotion dysregulation, depression, and trauma type (motor vehicle accident [MVA] and assault), and PTSD diagnosis were included as covariates in the model. RESULTS: Results demonstrated that baseline PTSD symptom severity was positively associated with severity of depression and state (but not trait) anxiety, emotion dysregulation, and PTSD diagnosis. Results also revealed significant associations with PTSD symptom changes over time; greater state anxiety and depression symptoms at baseline were associated with steeper declines in PTSD symptoms over time. LIMITATIONS: Data were collected at only four timepoints over the course of 12-months. Results may be different with more measurement points over longer periods and inclusion of pre-, peri- and post-trauma risk factors. CONCLUSIONS: Results illustrate the relevance of assessing state anxiety, depression, and emotion dysregulation in following trauma victims for trauma-related psychopathology over the course of time to alleviate the negative impact of the same.

Adverse childhood experiences associate with early post-trauma thalamus and thalamic nuclei volumes and PTSD development in adulthood.

Adverse childhood experiences (ACEs) potentially contribute to posttraumatic stress disorder (PTSD) after adult trauma exposure, but underlying brain changes remain unclear. The present study tested relationships between ACEs, whole thalamus and thalamic nuclei volumes, and post-trauma stress symptoms (PTSS) after adult trauma. Trauma survivors (n = 101) completed the Childhood Trauma Questionnaire (CTQ), the PTSD checklist-special stressor version 5 (PCL), and a structural magnetic resonance imaging (sMRI) scan within post-trauma 2 weeks. At post-trauma 3 months, survivors completed a second PCL survey and a PTSD diagnosis interview using the Clinician-Administered PTSD Scale (CAPS). CTQ scores significantly positively correlated with PCL scores at post-trauma 2 weeks and 3 months (respective p's < 0.01 and < 0.001). CTQ scores significantly negatively correlated with whole thalamus and 7 thalamic nuclei volumes at post-trauma 2 weeks in the PTSD (N = 50), but not the non-PTSD (N = 51) group. Whole thalamus and 22 nuclei volumes significantly negatively correlated with PCL scores at post-trauma 3 months in the PTSD, but not the non-PTSD group. These results suggest ACEs negatively influence early post-trauma thalamic volumes which, in turn, are negatively associated with PTSS in survivors who develop PTSD.

Dispositional optimism mediates relations between childhood maltreatment and PTSD symptom severity among trauma-exposed adults.

BACKGROUND: Experiences of maltreatment in childhood, such as abuse and neglect, have been associated with poorer psychological well-being in adulthood, including elevated risk of revictimization and increased likelihood of developing posttraumatic stress disorder (PTSD) symptoms. Maltreatment has also been associated with reduced resources related to resilience, such as optimism, which may act as a protective factor for mental health. OBJECTIVES: In this study, we examined the mediating role of dispositional optimism in the relationship between childhood maltreatment and PTSD symptom severity from recent trauma in a sample of adults (n = 108) who presented to their local emergency department following trauma. METHODS: We analyzed six models to account for cumulative childhood maltreatment as well as five primary subtypes of maltreatment: emotional abuse, physical abuse, sexual abuse, emotional neglect, and physical neglect. RESULTS: Greater dispositional optimism mediated relations between total maltreatment and decreased PTSD severity (Bab = .056, SE = .029, 95 % CI [.009, .121]). Optimism also mediated relations between all maltreatment subtypes and PTSD severity, except sexual abuse. CONCLUSIONS: These results may suggest optimism and positive psychology interventions as effective techniques in reducing the likelihood of PTSD development and severity in trauma-exposed individuals.

Preliminary study examining the mediational link between mild traumatic brain injury, acute stress, and post-traumatic stress symptoms following trauma.

Background: The presence of mild traumatic brain injury (mTBI) increases post-traumatic stress disorder (PTSD) symptoms in the months following injury. However, factors that link mTBI and PTSD development are still unclear. Acute stress responses after trauma have been associated with PTSD development. mTBI may impair cognitive functions and increase anxiety immediately after trauma. Objective: This research aimed to test the possibility that mTBI increases acute stress symptoms rapidly, which in turn results in PTSD development in the subsequent months. Method: Fifty-nine patients were recruited from the emergency rooms of local hospitals. Post-mTBI, acute stress, and PTSD symptom severity were measured using the Rivermead Post-Concussion Symptoms Questionnaire (RPQ), Acute Stress Disorder Scale (ASDS), and PTSD Checklist for DSM-5 (PCL-5), respectively. Results: Moderated mediation analysis indicated that ASDS, at 2 weeks post-trauma, mediated the relationship between RPQ scores at 2 weeks and PCL-5 scores at 3 months post-trauma, only for patients who met mTBI diagnostic criteria. Conclusions: These findings present preliminary evidence suggesting that acute stress disorder symptoms may be one of the mechanisms involved in the development of PTSD among trauma survivors who have experienced mTBI, which provides a theoretical basis for early intervention of PTSD prevention after mTBI.

Antecedentes: La presencia de lesiones cerebrales traumáticas leves (mTBI, por su sigla en inglés) aumenta los síntomas del trastorno de estrés postraumático (TEPT) en los meses posteriores al daño. Sin embargo, los factores que relacionan mTBI y el desarrollo del TEPT no están claros aún. Es posible que mTBI induzca una respuesta aguda al estrés inmediatamente después del trauma, que a su vez, se asocie al desarrollo posterior de TEPT.Objetivo: Este estudio buscó probar la hipótesis de si la asociación de mediación entre mTBI, estrés agudo y severidad de los síntomas de TEPT depende del estado de mTBI.Métodos: Se reclutó a cincuenta y nueve pacientes de las salas de emergencia de hospitales locales. Se midió la severidad de los síntomas post-mTBI y de estrés agudo dentro de las 2 semanas posteriores al trauma utilizando el cuestionario de síntomas post-concusión de Rivermead (RPQ, por su sigla en inglés) y la Escala para el Trastorno de Estrés Agudo (ASDS, por su sigla en inglés), respectivamente. Se midió la severidad de los síntomas de TEPT 3 meses después del trauma utilizando la Lista de Chequeo para TEPT del DSM-5 (PCL-5, por su sigla en inglés).Resultados: Los análisis de mediación moderada indicaron que los puntajes de ASDS, a las 2 semanas post-trauma, mediaban la relación entre los puntajes de RPQ a las 2 semanas y los puntajes de la PCL-5 a los 3 meses post-trauma, sólo para pacientes que cumplían los criterios diagnósticos para mTBI.Conclusiones: Estos hallazgos presentan evidencia preliminar que sugiere que los síntomas del trastorno de estrés agudo pueden ser uno de los mecanismos involucrados en el desarrollo del TEPT entre los sobrevivientes de trauma con un diagnóstico de mTBI, lo cual provee una base teórica para la intervención temprana de TEPT después de mTBI.

A Humanities-Based Explanation for the Effects of Emotional Eating and Perceived Stress on Food Choice Motives during the COVID-19 Pandemic.

Perceived stress affects emotional eating and food choices. However, the extent to which stress associates with food choice motives is not completely understood. This study assessed whether emotional eating mediates the associations between perceived stress levels and food choice motives (i.e., health, mood, convenience, natural content, price, sensory appeal, familiarities, weight control, and ethical concerns) during the Coronavirus Disease 2019 pandemic. A total of 800 respondents were surveyed in the United States in June 2020. Their perceived stress, emotional eating, and food choice motives were assessed by the Perceived Stress Scale, Dutch Eating Behavior Questionnaire, and Food Choice Questionnaire, respectively. Moderate to high levels of perceived stress were experienced by the majority (73.6%) of respondents. Perceived stress was significantly correlated with emotional eating (r = 0.26) as well as five out of nine food choice motives: mood (r = 0.32), convenience (r = 0.28), natural content (r = -0.14), price (r = 0.27), and familiarity (r = 0.15). Emotional eating was significantly correlated with four out of nine food choice motives: mood (r = 0.27), convenience (r = 0.23), price (r = 0.16), and familiarity (r = 0.16). The mediation analyses showed that emotional eating mediates the associations between perceived stress and five food choices motives: mood, convenience, sensory appeal, price, and familiarity. Findings were interpreted using theories and concepts from the humanities, specifically, folklore studies, ritual studies, and symbolic anthropology.

Effects of an aerobic fitness test on short- and long-term memory in elementary-aged children.

Meta-analytic evidence supports that exercise has benefits for short-term memory (STM) and long-term memory (LTM). However, only three studies with children have tested the differential effects of exercise on STM and LTM. The purpose of this study was to examine the effects of an aerobic fitness test on STM and LTM and to consider the moderating effects of grade level. Children (7-13 years of age) were randomly assigned to either perform an aerobic fitness test before (exercise prior) or after (exercise post) performing the Rey Auditory Verbal Learning Test (RAVLT) to assess memory. Memory was tested again after approximately 24 hours. There were significant differences in memory performance as a function of grade with 4th and 6th graders consistently outperforming 2nd graders. For learning, Day 1 Retention, 24-hr recall, and Day 2 Retention, the exercise prior group performed better than the exercise post group. It is concluded that an aerobic fitness test performed prior to a declarative memory test benefits LTM as compared to when the aerobic fitness test is performed after the memory test.

Longitudinal change in autonomic symptoms predicts activities of daily living and depression in Parkinson's disease.

PURPOSE: The primary objective of this study was to examine the relationship of longitudinal changes in autonomic symptom burden and longitudinal changes in activities of daily living (ADLs); a secondary analysis examined the impact of depressive symptoms in this relationship. METHODS: Data were retrieved from the Parkinson's Progression Markers Initiative (PPMI), a dataset documenting the natural history of newly diagnosed Parkinson's disease (PD). The analysis focused on data from baseline, visit 6 (24 months after enrollment), and visit 12 (60 months after enrollment). The impact of longitudinal changes in autonomic symptom burden on longitudinal changes in ADLs function was examined. A secondary mediation analysis was performed to investigate whether longitudinal changes in depressive symptoms mediate the relationship between longitudinal changes in autonomic symptom burden and ADLs function. RESULTS: Changes in autonomic symptom burden, cognitive function, depressive symptoms, and motor function all correlated with ADLs. Only changes in ADLs and depression were found to be associated with changes in autonomic symptom burden. We found that longitudinal change in autonomic symptoms was a significant predictor of change in ADLs at 24 and 60 months after enrollment, with the cardiovascular subscore being a major driver of this association. Mediation analysis revealed that the association between autonomic symptoms and ADLs is partially mediated by depressive symptoms. CONCLUSIONS: Longitudinal changes in autonomic symptoms impact ADLs function in patients with early signs of PD, both directly and indirectly through their impact on depressive symptoms. Future investigation into the influence of treatment of these symptoms on outcomes in PD is warranted.

Physical activity mediates the association between striatal dopamine transporter availability and cognition in Parkinson's disease.

OBJECTIVE: Associations between cognition and nigrostriatal dopaminergic deficits in Parkinson's disease have been documented in the literature, but are incompletely understood. Here we studied the extent to which physical activity mediates the relationship between striatal dopamine transporter availability and global cognition among patients with Parkinson's disease. METHODS: Data from 174 patients from a multi-center study were analyzed using regression-based mediation analysis. Striatal dopamine transporter binding ratio (SBR), Physical Activity Scale for Elderly (PASE), and Montreal Cognitive Assessment (MoCA) were used to evaluate patients' dopamine transporter availability (DAT), physical activity, and global cognition respectively at the time of testing. Confidence intervals (CI) of 95% were established using a bootstrapping approach to test the statistical significance of the direct, indirect (i.e., mediation), and total effects of the mediation model. RESULTS: As hypothesized, the positive mediating effect of physical activity in the association between DAT and global cognition was significant, while adjusting for age (95% CI [0.0030, 0.3942]). Specifically, higher SBRs were positively associated with PASE scores, which in turn, were positively associated with MoCA scores. Secondary analyses revealed a similar positive mediation effect of physical activity for DAT in the caudate and putamen separately (95% CI [0.0377, 0.4231] and [0.0211, 1.1000], respectively). CONCLUSION: We report that the relationship of dopamine transporter availability with global cognition in Parkinson's disease is mediated by physical activity. Pending further research for specific recommendations, interventions to increase physical activity as tolerated should be considered in patients with Parkinson's disease.

The Physical Activity and Alzheimer's Disease (PAAD) Study: Cognitive outcomes.

Background: Alzheimer's disease is a progressive disease that degrades cognitive functioning and ultimately results in death. Currently, there is no cure for Alzheimer's disease and, hence, the identification of preventative strategies is important. Physical activity (PA) is a behavioral intervention that holds promise with respect to delaying the onset of Alzheimer's disease. Purpose: The purpose of this study was to explore the differential cognitive benefits achieved in response to PA as a function of a person's genetic risk for AD. Methods: Older cognitively normal adults (50-65 years) with a family history of AD (FHxAD) participated in an 8-month PA program. Cognitive performance was measured at baseline, pretest, midtest, and posttest and changes over time were assessed as a function of apolipoprotein E (APOE) status (carriers: 1-2 copies of the ɛ4 allele; noncarriers: 0 copies of the ɛ4 allele). Results: Improvements in memory were associated with PA participation irrespective of APOE ɛ4 carrier status. Conclusions: Future experimental studies are needed to confirm that PA causes improvements to cognitive performance in older cognitively normal adults with a FHxAD and that these improvements are equivalent for cognitively normal APOE ɛ4 carriers and noncarriers.

The effects of low-intensity cycling on cognitive performance following sleep deprivation.

This study examined the effect of 24h of sleep deprivation on cognitive performance and assessed the effect of acute exercise on cognitive performance following sleep deprivation. Young, active, healthy adults (n=24, 14 males) were randomized to control (age=24.7±3.7years, BMI=27.2±7.0) or exercise (age=25.3±3.3years, BMI=25.6±5.1) groups. Cognitive testing included a 5-min psychomotor vigilance task (PVT), three memory tasks with increasing cognitive load, and performance of the PVT a second time. On morning one, cognitive testing followed a typical night's sleep. Following 24-h of sustained wakefulness, cognitive testing was conducted again prior to and after the acute intervention. Participants in the exercise condition performed low-intensity cycling (∼40%HRR) for 15-min and those in the control condition sat quietly on the bike for 15-min. t-Tests revealed sleep deprivation negatively affected performance on the PVT, but did not affect memory performance. Following the acute intervention, there were no cognitive performance differences between the exercise and rested conditions. We provide support for previous literature suggesting that during simple tasks, sleep deprivation has negative effects on cognitive performance. Importantly, in contrast to previous literature which has shown multiple bouts of exercise adding to cognitive detriment when combined with sleep deprivation, our results did not reveal any further detriments to cognitive performance from a single-bout of exercise following sleep deprivation.

Motivating Mature Adults to be Physically Active.

As a population, middle-aged and older adults are not meeting national guidelines for exercise. The purpose of this study was to describe factors associated with exercise adherence in an 8-month program offered as part of a research study testing the effects of exercise on cognitive performance for persons with a family history of Alzheimer's disease (AD). After completion of the program, participants provided open-ended responses indicating their reasons for adhering to the exercise program, and they completed the Motives for Physical Activities Measure-Revised. Results indicated that adherence was tied to an interest in contributing to our understanding of AD, the opportunity to join an exercise program, perceived exercise benefits, and social support. In addition, participants reported high levels of extrinsic (fitness-related) and intrinsic (interest/enjoyment) motivation. Other possible motivating factors which emerged from day-to-day observations in the program were identified. Findings suggest directions for exercise professionals with respect to exercise adherence.