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Dizziness and balance difficulties are not uncommon in children, with prevalence estimates in the general population ranging from 5%-18%, although the precise prevalence of those caused by vestibular dysfunction is not known. Whilst healthcare professionals are aware that vestibular dysfunction may lead to poor balance and delayed gross motor development in young children, little is known generally about the longer-term consequences of vestibular dysfunction in this group. This thesis sought to identify the existing evidence in the literature regarding the impact of vestibular dysfunction in children and young people (CYP), to identify the evidence gaps, and to add to the existing knowledge base by reporting on the author's own original research study regarding chronic symptoms and health-related quality of life in this group. The thesis includes a scoping review of the literature performed to identify and summarize evidence from studies investigating the impact of vestibular dysfunction in CYP (e.g. ongoing symptoms, balance function, motor development and health-related quality of life). Databases and other sources were searched methodically and 33 studies met the criteria for inclusion in the review. The review confirmed that there is some evidence about the physical effects of vestibular dysfunction in children, but that this evidence is limited by methodological and design quality issues and the heterogeneous nature of the studies. There is a paucity of evidence about the interaction between vestibular and cognitive function, and the impact on psychological wellbeing and quality of life in CYP with vestibular dysfunction, The empirical research paper, presented in a journal paper format, reports on the author's own observational cohort study of CYP with vestibular dysfunction. For this study, 49 CYP with vestibular dysfunction and 44 of their parents/carers completed a survey which included the Paediatric Vestibular Symptom Questionnaire (pVSQ), the Paediatric Quality of Life Inventory (PedsQL) and an open question asking for comments about vestibular dysfunction affects their/their child's life. The findings indicate that chronic vestibular symptoms are ongoing in many CYP with vestibular dysfunction even years after the onset of vestibular dysfunction: the majority of CYP (76%) in this study and most of the parents and carers (81%) reported the presence of significant levels of vestibular symptoms (the mean duration since onset of was 7.9 years), with females reporting more severe symptoms than males. Vestibular dysfunction was associated with impaired health-related quality of life (HRQoL): 61% of the children and young people in this study, and 57% of their parent/carers reported significantly impaired HRQoL in all domains compared to healthy norms. Linear regression modelling confirmed that high levels of vestibular symptoms are the main predictor of poor HRQoL with congenital vestibular dysfunction, and bilateral or central vestibular dysfunction also being additional risk factors for reduced HRQoL. Thematic analysis of the qualitative data collected explored study participants' perceptions of the consequences of vestibular dysfunction. Overarching themes identified were ongoing 'Symptoms' and 'Falls & Imbalance', which affected activities such as 'School', 'Exercise', 'Everyday activity', and had an impact on 'Emotions'. The final chapter of the thesis provides a critical review of the process and findings of the scoping review and research study, and the implications of the findings for clinical practice and future research. There is also a reflective account of the author's experience conducting the research as part of the Higher Specialist Scientist Training programme (HSST), and how this has contributed to personal and professional development.

The current thesis has been prepared in journal format and it reports a systematic literature review, an empirical research study, and a paper on relevant critical reflections. Based on a hybrid cognitive and metacognitive model for social anxiety disorder and on a metacognitive approach to emotional difficulties, the main aim of the thesis was to investigate the potential contributions of metacognitive beliefs to social anxiety over and above that of cognitive beliefs. To this effect, the systematic literature review investigated the nature and strength of the associations between social anxiety and two types of beliefs: cognitive beliefs, referred to as social beliefs, (i.e., conditional and unconditional self-beliefs, and high standards) and metacognitive beliefs (i.e., beliefs about thoughts and thinking processes). Cross-sectional, longitudinal and experimental studies were included, and correlation and regression coefficients, as well as results from group comparisons were extracted. Twenty three papers were reviewed using narrative synthesis. The results showed a robust positive association between social beliefs and social anxiety and suggested a possible mediation effect of cognitive processes. Metacognitive beliefs were also positively associated with social anxiety both directly and indirectly, through cognitive processes. The empirical study expanded on these results by investigating the potential prospective associations between metacognitive beliefs and social anxiety. A sample of 156 university students and staff completed a battery of questionnaires twice, two months apart. Regression analyses showed that irrespective of social beliefs, metacognitive beliefs about the uncontrollability and dangerousness of thoughts were individual positive predictors of and explained additional variance in social anxiety two months later. This effect was partly mediated by self-focused attention. Social beliefs did not show a prospective individual contribution to social anxiety. Following the above, the critical reflections paper focused on the process of conducting these studies. The adopted epistemological stance is discussed and the process of decision making during the various stages of research is expounded. The strengths and limitations, the findings in the context of wider research, and the implications for clinical practice and future research are discussed.

Obesity is one of the most serious public health challenges of the 21st century, associated with a range of adverse physical, psychological, social and economic consequences. The aetiology of obesity is complex; however, the psychological factors associated with overweight and obesity remain poorly understood. The first paper critically appraises evidence for three of the most developed psychological theories of obesity. Based on these findings, literature from the fields of emotion regulation and attachment are reviewed, and a novel developmental theory of obesity based on an integration of these theoretical constructs is proposed. Recommendations for future research based on a theoretical framework of emotion regulation are made, and implications for clinical practice including a focus on enhancing caregiver sensitivity are highlighted. The second paper explores the applicability of an established cognitive model of Bulimia Nervosa (BN) and binge eating to an overweight and obese sample. Findings support the relevance of cognitive aspects of the model in an overweight and obese sample, and highlight the potential role of early attachment relationships in the formation of cognitions that make an individual vulnerable to overweight and obesity in later life. Theoretical and clinical implications based on the established cognitive model are considered. Limitations include reliance on self-report and the correlational nature of analyses used. Recommendations for future research with larger, more representative samples to address these limitations are made. Overall, this dissertation makes a unique contribution to the psychological understanding of overweight and obesity, which has the potential to enhance treatment outcomes and suggests useful avenues for further research.

Aims: Recently, empirical literature exploring cognitive characteristics of intimate partner violence offenders has received considerable attention with both theory and practice historically focusing on victims of the abuse. Qualitative exploration has proposed implicit theories (ITs), that is distinct sets of schemas that offenders hold in relation to themselves, the world and others. In relation to cognition in intimate partner violence offenders, this thesis had two aims: to systematically analyse qualitative literature exploring cognition in intimate partner violence offenders and to implement interpretative phenomenological analysis to explore cognition in intimate partner violence sex offenders. Methods: Aims are addressed separately in two journal articles. A systematic review of qualitative literature exploring cognition in intimate partner violence offenders is presented in journal article 1. Journal article 2 utilises interpretative phenomenological analysis to explore cognition in 11 intimate partner sex offenders. Results: In relation to journal article 1, systematic searches of bibliographic databases in addition to hand-searches of various articles in the domain of intimate partner violence were conducted to identify eight empirical papers qualitatively exploring cognition in intimate partner violence offenders. Synthesis of the papers resulted in 10 themes being extrapolated thought to be representative of cognition in intimate partner violence males: “violence is normal”; “policing partner”; “women are provoking” “need for control”; “grievance/revenge”; “external factors responsible”; “rejection/abandonment”; “minimisation/denial”; “entitlement” and “remorse”. Journal article two utilised interpretative phenomenological analysis of 11 transcripts of IPV offenders. This revealed five superordinate and 14 subthemes which are proposed as implicit theories present in this specific offender group. These are: “violence is acceptable”; “grievance/revenge”; “dangerous world”; “need for control”; “real man”; “entitlement/women are objects”; “male sex drive/policing partner”; “women are provoking”; “rejection/abandonment”; “women are supportive”; “uncontrollability”; “nature of harm”; “the new me” and “I‟m not like them”. Conclusions: Cognitions identified from the systematic review are discussed in addition to limitations of the synthesis and clinical and empirical utility. The implicit theories identified in journal article 2 are discussed in relation to other offending behaviour groups in addition to their clinical implications in the development of effective interventions and risk assessment tools.

Introduction: Schizotypy is a personality trait that shares some of the characteristics of clinical disorders such as schizophrenia. Similarities are found in expression of psychotic-like experiences and presence of attenuated negative signs. Furthermore, schizotypal samples are associated with impairments in cognitive tasks, albeit in a less comprised form. For these reasons and others, schizotypy is considered a part of the extended-phenotype of schizophrenia and as such can be utilised as an analogue sample without some of theconfounds associated with illness. Objective: The aim of the PhD is to examine the relationship of schizotypal features and brain function and structure in a sample of adolescents and young adults (age 16-25 years). This will attempt to provide further evidence for the placement of schizotypy on the continuum, along with insights into pathophysiological mechanisms involved in schizophrenia and related disorders. Methods: The study involved three main phases: recruitment via an online survey, further neuropsychological testing and brain imaging on selected high schizotypes and controls. The thesis comprises 5 papers/experiments. Paper 1 utilises confirmatory factor analysis (CFA) to examine the factorial structure of the schizotypal personality questionnaire (SPQ) in a community sample aged 16-25 years. It also examined the effects of demographics on schizotypal levels. Paper 2 examined the association between schizotypy and measures of sustained attention and spatial working memory both in a total sample, and in samples split by age and by sex. Paper 3 further examined the association between schizotypy and cognition laboratory tests of attention, executive function and verbal learning/memory. Paper 4 tested the same participants on measures of functional brain asymmetry. Paper 5 used diffusion tensor imaging (DTI) to examine white matter structures in a sample of high schizotypes and controls. Results: Paper 1 confirmed that the SPQ is most appropriately modelled by a four-factor structure in an adolescent and young adult sample. Demographic effects on SPQ subscales scores mirrored those seen in clinical samples. Paper 2 found that where small associations between schizotypy and sustained attention/spatial working memory function occurred, these were in relation to either age of sex. Paper 3 demonstrated an association between increased schizotypal features and a slight reduction in performance on verbal learning/memory, but no association with tasks of executive function or attention. In Paper 4, schizotypy was associated with a left-hemifield bias on a computerised line bisection task. Paper 5 found that a group of high schizotypes had an increase in tract coherence in the uncinate fasciculus compared to controls. Furthermore, increasing subclinical hallucinatory experiences were associated with increased tract coherence in the right hemisphere arcuate fasciculus. Conclusions: Schizotypy was associated with changes in brain function and structure similar to that demonstrated in more serious mental illness, although to a lesser degree. The current studies suggested that schizotypy is associated with relatively intact prefrontal function, but slight performance bias on measures of medial temporal lobe function. There was also evidence for structural brain changes in schizotypes, with these being indicative of either a protective factor, or a marker of a pathological process. Correlations between hallucinatory experiences and white matter tracts between language regions support theories implicating hyperconnectivity and presentation of symptoms in clinical groups. The functional and structural data collected from this study suggests that the ‘schizotypal’ brain may represent an ‘early’ stage of pathology, but which is likely to be compensated enough such that transition to serious mental illness is unlikely. Further studies could examine similarities and differences between the schizotypal profile and clinical conditions, which would provide further insights into aetiological mechanisms in schizophrenia/psychosis.

In this thesis, I explore the ongoing development of symbol use in three domains: pretend play, speech and gestures. In chapter 1, the specific behavioural manifestations of symbol use in these domains are identified and previous literature that has explored the cognitive underpinnings of these abilities is discussed, with a particular focus on children's social cognition. In chapter 2, I review previous research that has sought pairwise relations between these abilities and the theoretical perspectives that have been utilised to explain these relations. In chapter 3, I introduce the four pertinent research questions that emerged from the previous review of the current literature, and provide an overview as to the methods adopted to address these issues. Chapters 4 to 6 constitute three papers designed to explore and evaluate children's symbol production in a sample of preschool children in pretend play speech and gestures. For the first paper, 38-40 month old children were given a battery of standardised measures to assess their symbolic capacities while controlling for non-verbal abilities. These data were analysed for concurrent relations between symbolic capacities. The second paper extends these concurrent relations longitudinally, by giving the children the same battery of measures six and twelve months after initial testing. Correlational and multiple regression analyses were used to assess the potential predictive relations between these measures, and whether there is a changing relation between these symbolic domains over developmental time. The third paper investigates children's iconic gesture production in further detail, by evaluating whether children aged 44-46 months incorporate the iconic gestures they observe an adult perform into their own descriptions of a novel object.Taken together, the results indicate a changing relation between the three symbolic measures of interest during the preschool years. The present findings suggest that both pretend play and gesture production are mediated by speech, but in different ways. It was also found that children appear to incorporate the gestures they observe into their own descriptions of objects but this uptake is dependent on the properties of the gesture itself. In the final chapter, these findings are discussed in relation to previous theoretical notions that place pretend play, speech and gestures as manifestations of an underlying symbolic system. I also discuss the enduring relation between these three abilities and how the pattern of predictive relations found in the present thesis can be explained. Furthermore, I discuss the ontogenesis of symbolic gesture production in children, specifically how children may use the gestures of others as a guide to their own gesture production. Finally I outline some limitations of the present research, and indicate potential avenues for future study.

Thesis Abstract An Investigation of Cognitive Deficits Related to Surgery for Glioblastoma using a Computerised Assessment Tool - Rohitashwa Sinha Glioblastoma, the most aggressive type of primary brain cancer, causes abysmal survival rates and high risks of cognitive deficit to its sufferers. These deficits are due to both its being diffusely infiltrative and its radical treatments such as brain surgery and radiotherapy. Currently the course of cognitive deficits from before to after surgery has not been reliably researched. Studies report high rates of drop-out due to burdensome 'pen-and-paper' based assessments conducted by neuropsychologists, a lack of these resources entirely or the data collection being focused on the period around radiotherapy or less aggressive tumours instead. As a result, patients still undergo resection surgery for glioblastoma without a reliable evidence base for making their treatment decisions, without any assessment for their cognitive deficit burden and without any targeted interventions to protect their cognitive function. In this doctoral research, I have set up a prospective study to assess cognitive function before and after resection surgery, but before radiotherapy and with particular focus on participants with glioblastoma who have been underserved by current infrastructure and research focus. The methodology involves using a computerised testing battery called 'OCS-Bridge', which has broadened the access to such cognitive assessments. Participant retention has been higher than in the literature. This may be due in part to the efficiency of the format as well as the study design for data collection, where assessment timepoints were advised by patients and carers rather than clinicians. Using a variety of analysis techniques, this thesis progresses through a systematic review confirming the lack of reliable consensus in this area and a format comparison study to support the use of OCS-Bridge by comparison to conventional testing. Next, machine learning and Kaplan-Meier analyses are used to show cognitive deficits as predictors of clinical outcomes including overall survival. The longitudinal analyses of the high peri-operative odds of cognitive deficits until radiotherapy follows. Finally, a tract based spatial statistics study using diffusion tensor MRI brain scans demonstrates that a common anatomical mechanism exists, affecting the same right hemisphere white matter tracts underlying social cognition deficits in participants with glioblastoma as is seen in traumatic brain injury and neurodegenerative disease contexts. 3 By contributing new knowledge, research methodology, immediately translational implications for clinical practice and by linking the mechanisms of cognitive deficits between glioblastoma and other neurological diseases, the results herein have already secured further research funding. This future work will build on the understanding of cognitive deficits presented here and to trial a targeted rehabilitation intervention to help people with glioblastoma and their families.

Cognitive abilities vary widely across the animal kingdom, and multiple hypotheses have been formulated to explain why. The Relationship Intelligence Hypothesis (RIH) posits that maintaining and managing high quality pair-bonds is a key driver of cognitive evolution. The RIH was first proposed more than a decade ago, and while its introductory paper has been widely cited, little work has been done to interrogate the RIH's central predictions. In this thesis, I critically evaluate the RIH. First, in Chapters 2 - 4, I test central predictions of the RIH within one wild study system, the jackdaw (Corvus monedula). Specifically, I test whether (i) pairs have fully aligned fitness interests (Chapter 2); (ii) pairs use consolation as a mechanism through which to manage and maintain their bond (Chapter 3); (iii) pair-bond strength (1) varies between pairs, (2) is consistent within pairs, (3) positively correlates with socio-cognitive performance, and (4) positively correlates with reproductive success (Chapter 4). Finally, I test whether a commonly used method in the study of cognitive evolution - the comparative study of brain size - is methodologically robust (Chapter 5). I find that jackdaw partners do not always have fully aligned fitness interests, and that they do not use consolation to manage and maintain their pair-bond. However, pair-bond strength does vary between pairs, is consistent within pairs and is positively correlated with a measure of socio-cognitive performance, partner responsiveness. While I did not find a link between pair-bond strength and reproductive success, partners with stronger bonds were better able to adjust hatching synchrony to environmental conditions. Finally, I demonstrate that comparative studies of brain size are not methodologically robust. In Chapter 6, I integrate my findings with contemporary empirical and theoretical evidence in order to critically evaluate the RIH. I end by proposing future directions for the study of cognitive evolution.

Most of the research on treatment approaches for acute ischemic stroke have focused on the effect of thrombolysis (IVT) and thrombectomy (EVT) on survival and functional outcomes. Little is known about the cognitive outcomes after IVT and EVT following acute ischemic stroke. The objective of this systematic review was to determine the differential cognitive and functional outcomes following thrombolysis or thrombectomy after mild to severe ischemic stroke in adults. Data was sourced using seven online databases. The SITS Registry was also searched as well as the grey literature in the form of Open Grey and Google Scholar. Initially, 1,040 articles were identified from 2000-2020. After screening full text papers, a total of 7 articles were eligible for data synthesis. Cognitive impairment on the Montreal Cognitive Assessment (MoCA) at 90 days post stroke was evident in patients who received either IVT or EVT. On tasks of executive function in particular the Trail Making Test, impaired performance was observed for EVT at 90 days and 365 days post stroke and IVT at 180 days post-stroke. A higher percentage of patients treated with EVT achieved functional independence on activities of daily living on the Barthel Index (BI) at 90 days and 2190 days post stroke, compared to those treated with IVT.  The current empirical study examined predictors of post-acute memory impairment and the relative contributions of alcohol (intoxication at time of injury and history of problematic alcohol use) on memory during the post- acute recovery stage after Traumatic Brain Injury (TBI). Case files from 303 individuals admitted to inpatient neuro-rehabilitation after single incident TBI were reviewed. Approximately 40% had a documented history of problematic alcohol use and around one third were intoxicated at time of injury. Using hierarchical regression analyses, older age and history of problematic alcohol use significantly predicted poorer performance on measures of immediate memory and global memory. Having a high skilled occupation significantly predicted better performance on the immediate and delayed memory index on the RBANS. Both history of problematic alcohol use and intoxication at time injury provided a significant and unique contribution to the prediction of global memory performance on the RBMT in the post-acute recovery stage after TBI (F (9,167) = 6.24, p < .001), albeit accounting for a small variance. Being intoxicated at time of injury resulted in more intact global memory in this mild to severe TBI sample. Clinical implications and limitations are discussed.