The role of posttraumatic stress disorder in explaining the psychosocial outcome of subarachnoid haemorrhage patients and their informal carers in both the short- and long-term

Surviving subarachnoid haemorrhage (SAH) patients' experience significantly reduced health-related quality of life (HRQoL) in both the short- and long-term, as well as mysterious symptoms of fatigue and sleep dysfunction. Patients’ family members and friends - who often act as their informal carers - can also experience psychosocial disability. The cause for these poor outcomes remains unknown. Traditional explanations focusing on the neurological sequelae associated with SAH or the characteristics of the illness are not satisfactory; nor are attempts to explain family members' difficulties on the basis of carer burden. The hypothesis which is tested in this thesis is that post-traumatic stress disorder (PTSD) may be abnormally high in both the SAH patient and 'significant other' (SO) population and that this may explain their outcomes. SAH patients are known to be at risk of suffering from PTSD, but it is unknown if this explains their outcome. In terms of patients' SOs, they are known to experience psychiatric symptoms and I suggest these could be caused by their development of PTSD, but this has never been examined. In Part One (Chapter 2-5), I focus on patients' outcomes. Before examining my PTSD hypothesis, I present a meta-analysis (Chapter 2) I conducted of studies which have tried to explain patients' outcome using neurological factors. I conducted the meta-analysis as a tendency for prior studies to be underpowered and use unreliable statistics could have meant that the actual importance of traditional factors was obscured. The results of my meta-analysis however did not support this possibility and instead showed traditional neurological variables did not explain patients' outcome. With this in mind, I then present a longitudinal study (Chapter 5) in which I examined one of the largest prospective series of SAH patients to establish PTS D's explanative importance. Using regression analyses, this study showed PTSD was the best predictor for patients' mental HRQoL - the domain most persistently impaired. It also helped predict patients' physical HRQoL. Moreover, PTSD was linked to sleep problems and may therefore cause fatigue. Crucially, to establish the cause of PTSD, logistic regression was performed. This showed that maladaptive stress coping strategies were the best predictor for PTSD development. In Part Two of the thesis (Chapter 6), I present my longitudinal study of one of the largest prospective samples of SOs. All SOs were assessed with a diagnostic PTSD measure and coping skills were assessed. An elevated incidence of PTSD was found in both the short- and long-term. Although SOs' PTSD did not impinge on the recovery of the SAH patients being cared for, given that it is important to ensure SOs continue caring, regression results are presented which show the cause of SOs' PTSD was (at least in the short- term) due to the use of maladaptive coping strategies. The overarching conclusion is that the elevated incidence of PTSD in SAH patients and SOs helps explain why they experience psychosocial disability. In the final part of the thesis (Chapter 8) the clinical and theoretical implications of this conclusion are considered, such as that teaching patients and their SOs more effective coping skills might prevent PTSD and psychosocial disability

On the energy-momentum of light : an all optical view of the Abraham-Minkowski controversy

The energy-momentum of light in a medium is known to have two conflicting descriptions, due to Abraham and Minkowski. In non-linear electrodynamics, a strong field can cause the vacuum to behave analogously to a dielectric material. We investigate the Abraham-Minkowski controversy in this context, and show that for non-linear electrodynamics in vacuum, the Minkowski description is the most natural

Should we stop saying "epileptic"? A comparison of the effect of the terms "epileptic" and "person with epilepsy"

AbstractObjectiveThe advantages and disadvantages of using “epileptic” as a noun to describe someone with epilepsy have long been debated. Recent high-profile recommendations have stated that the term should not be used, including in English, as it perpetuates stigma. This decision was largely informed by a Brazilian Global Campaign Against Epilepsy study that reported experimental evidence indicating that, with students, the label evokes more negative attitudes than “person with epilepsy”. The generalizability of this effect to different countries/cultures, and thus the justification for the recommendations, has never been tested.MethodsWe replicated the Brazilian study in the UK, in English, while also addressing methodological limitations. It was powered to detect the effects reported by the Brazilian study, with 234 students completing a survey regarding epilepsy attitudes. Half were randomized to Group 1 and half to Group 2. In Group 1, patients were referred to as “people/person with epilepsy” within the attitudinal measures, while in Group 2 they were referred to as “epileptic/s”. Measures included translations of the questions used in the Brazilian study and the Attitudes and Beliefs about Living with Epilepsy scale. Participants' epilepsy familiarity and knowledge were also assessed.ResultsThe two groups were comparable in characteristics. A comparison of their responses to the attitude measures revealed no statistically significant or meaningful differences.ConclusionsIn this English replication, the word “epileptic” did not provoke more negative attitudes. This suggests that the effect reported by the Brazilian study might be culturally dependent. Methodological limitations to that study might also be relevant. Our results have implications for the global debate about how negative attitudes towards epilepsy might be addressed. Simply not saying “epileptic” may not promote the positive attitudes towards epilepsy that had been expected. To know how to best refer to those with epilepsy, evidence on the preferences of those actually living with epilepsy is needed

On the energy-momentum tensor of light in strong fields : an all optical view of the Abraham-Minkowski controversy

The Abraham-Minkowski controversy is the debate surrounding the "correct" form of the energy-momentum tensor of light in a medium. Over a century of theoretical and experimental studies have consistently produced conflicting results, with no consensus being found on how best to describe the influence of a material on the propagation of light. It has been argued that the total energy-momentum tensor for each of the theories, which includes both wave and material components, are equal. The difficulty in separating the full energy-momentum tensor is generally attributed to the fact that one cannot obtain the energy-momentum tensor of the medium for real materials. Non-linear electrodynamics provides an opportunity to approach the debate from an all optical set up, where the role of the medium is replaced by the vacuum under the influence of a strong background field. We derive, from first principles, the general form of the energy-momentum tensor in such theories, and use our results to shed some light on this long standing issue

Electron beam cooling in intense focussed laser pulses

In the coming years, a new generation of high-power laser facilities (such as the Extreme Light Infrastructure) will become operational, for which it is important to understand how the interaction with intense laser pulses affects the bulk properties of relativistic electron bunches. At such high field intensities, we expect both radiation reaction and quantum effects to have a dominant role to play in determining the dynamics. The reduction in relative energy spread (beam cooling) at the expense of mean beam energy predicted by classical theories of radiation reaction has been shown to occur equally in the longitudinal and transverse directions, whereas this symmetry is broken when the theory is extended to approximate certain quantum effects. The reduction in longitudinal cooling suggests that the effects of radiation reaction could be better observed in measurements of the transverse distribution, which for real-world laser pulses motivates the investigation of the angular dependence of the interaction. Using a stochastic single-photon emission model with a (Gaussian beam) focussed pulse, we find strong angular dependence of the stochastic heating

Common aquatic pollutants modify hemocyte immune responses in Biomphalaria glabrata.

Funding The studentship supporting this research was awarded by the UK Natural Environment Research Council (NERC). Acknowledgments We are grateful to Dr. David Rollinson (Natural History Museum) for providing B. glabrata snails and to Drs. Nuha Mansour and Quentin Bickle (London School of Hygiene and Tropical Medicine) for providing parasite material. We thank the UK Natural Environment Research Council (NERC) for funding.Peer reviewedPublisher PD