The relationship between PTSD, hypervigilance and disordered sleep

Disordered sleep in PTSD constitutes a major component of the presenting symptomatology. However, the literature on PTSD and sleep is characterized by discrepancies across studies, especially due to the fact that some use objective and some use subjective measures of sleep quality. As a result, disordered sleep and its underlying mechanism have been ambiguously characterized in PTSD. Our research focused on the link between PTSD and disordered sleep, using both objective and subjective measures of sleep quality. Specifically, we investigated hypervigilance (one of the three symptom clusters in the PTSD diagnosis) as an underlying mechanism of this link. We also investigated whether hypervigilance affects dream content and themes in individuals with PTSD

The functional neurophysiological sequelae associated with high frequency dream recallers

Background: Dreaming is a universal experience, yet there is considerable inter-individual variability with regard to dream recall frequency (DRF). Research on DRF has been prolific leading to the development of various models delineating possible processes involved in dream recall. One such model is the 'arousal-retrieval' model positing that intra-sleep wakefulness is required for dream traces to be encoded into long-term storage, essentially proposing increased DRF as a product of a better memory for dreams. Results from recent studies support this model by demonstrating longer periods of intra-sleep wakefulness in high frequency recallers (HFRs) compared to low frequency recallers (LFRs). Furthermore, results showed heightened brain reactivity, as well as increased regional cerebral blood flow in areas in the brain associated with dream production. These results are indicative of the existence of a functional neurophysiological trait innate to HRs, while also supporting the premise that apart from a better memory for dreams, HRs also may produce more dreams. Awakenings from rapid eye movement (REM) sleep yield the highest dream recall rates, rendering REM sleep as a reasonable starting point for studying rates of dream production. Furthermore, increased dream production during REM sleep might also affect related processes, for example, leading to enhanced overnight emotional memory consolidation and emotion regulation. Hypotheses: The current study investigated the functional neurophysiological sequelae associated with HFRs in a design where HFRs are compared to LFRs. Hypotheses include: (1) HFRs will score significantly higher on certain personality dimensions; (2) HFRs will experience significantly more awakenings, as well as longer periods of intra-sleep wakefulness; (3) HFRs will have significantly higher rates of dream production as measured by the frequency of eye movements (REM density) during REM sleep; and (4) increased dream production during REM sleep will lead to enhanced overnight emotional memory consolidation and emotion regulation in HFRs. Methods: The study consisted of two groups of healthy young adults: high frequency recallers (n = 19) and low frequency recallers (n = 17) who underwent polysomnographic recordings on two non-consecutive nights. Memory tasks and affective questionnaires were completed before and after a night of sleep. Results: (1) HFRs scored significantly higher on the 'agreeableness' personality dimension and on the Boundary Questionnaire; (2) HFRs experienced significantly more awakenings, especially from stage 2 non-rem (NREM) sleep, as well as significantly longer periods of intra-sleep wakefulness; (3) no significant between-group differences with regard to REM density, nor (4) overnight emotional memory consolidation and emotion regulation were found. Conclusion: Results support, firstly, the proposition that certain personality traits, differences in sleep architecture, and increased DRF are an expression of a functional neurophysiological arrangement innate to HFRs. Secondly, the findings suggest that NREM sleep, as opposed to REM sleep, is important in relation to DRF in this specific population. This is the first study to not only replicate existing findings, but to also contribute to the extant literature by illuminating additional characteristics and features associated with HFRs

A randomized-controlled study of a modified technique to reduce extracardiac activity in myocardial perfusion imaging

INTRODUCTION : Various techniques have been used in an attempt to reduce interfering extracardiac activity in myocardial perfusion imaging with inconsistent results. The aim of this study was to investigate the effect of a combined intervention on the frequency and intensity of interfering extracardiac activity. METHODS : Patients (n=230) routinely referred for a 2-day stress-rest myocardial perfusion examination were assigned randomly to one of two groups. Group A (n=114) received a single intervention (diluted lemon juice) before stress imaging and a combined intervention (diluted lemon juice and soda water) before rest imaging. Interventions were reversed for group B (n=116). Three interpreters, blinded to the intervention, assessed early and delayed planar images from 195 patients in terms of the frequency and the intensity of interfering extracardiac activity. RESULTS : The myocardial to extracardiac (MYO : EXC) ratio between groups for the rest studies was marginally not significant (P=0.060 and 0.059), showing an increase in ratio when the combined intervention was administered. There were significant differences (P≤0.001) in the frequency, intensity, and MYO : EXC ratio between the early and the delayed studies. CONCLUSION : Combining interventions that stimulate radiopharmaceutical hepatic excretion and utilize the volume effect is advantageous in myocardial perfusion imaging, with delayed imaging being advocated as a complementary intervention.http://journals.lww.com/nuclearmedicinecomm2018-01-31hb2017Nuclear MedicineRadiograph

The South African 24-hour movement guidelines for birth to 5 years: An integration of physical activity, sitting behavior, screen time, and sleep

Background: In December 2018, the South African 24-hour movement guidelines for birth to 5 years were released. This article describes the process used to develop these guidelines. Methods: The Grading of Recommendations Assessment, Development, and Evaluation-ADOLOPMENT approach was followed, with some pragmatic adaptions, using the Australian guidelines for the early years as a starting point. A consensus panel, including stakeholders in early childhood development and academics, was formed to assist with the development process. Results: At a face-to-face meeting of the panel, global and local literatures were considered. Following this meeting, a first draft of the guidelines (including a preamble) was formulated. Further reviews of these drafts by the panel were done via e-mail, and a working draft was sent out for stakeholder consultation. The guidelines and preamble were amended based on stakeholder input, and an infographic was designed. Practical tips documents were also developed for caregivers of birth to 5-year-olds and early childhood development practitioners. The guidelines (and accompanying documents) were released at a launch event and disseminated through various media channels. Conclusions: These are the first movement guidelines for South African and the first such guidelines for this age group from a low- and middle-income country