Nick Medford - Academia.edu (original) (raw)

Papers by Nick Medford

Oxford Textbook of Neuropsychiatry

Malnutrition is a hugely extensive global health issue, with an estimated 800 million affected wo... more Malnutrition is a hugely extensive global health issue, with an estimated 800 million affected worldwide and almost 2 billion when those with specific nutritional deficiencies are taken into account. This chapter discusses the link between nutritional deficiency and neuropsychiatric disorder. In some cases, this can take the form of a clear cause and effect such as the prevalence of Wernicke’s encephalopathy in those with thiamine deficiency. However, it is important to develop means to determine the relationship between malnutrition and neuropsychiatric disorders in general. It focuses firstly on malnutrition, exploring the cognitive and central nervous system changes in those who would be found malnourished by the Waterlow criteria, before moving on to specific deficiencies and their associated neuropsychiatric presentations, such as B6 (pyridoxine) and epilepsy, or iron and neurodevelopmental disorders such as autism and attention-deficit/hyperactivity disorder.

Auerbach Publication, CRC Press (Taylor + Francis Group), 2015

Biological Psychiatry, 2004

The International Journal of Neuropsychopharmacology, 2004

Journal of Cognitive Neuroscience, 2000

The Lancet Psychiatry, 2020

Background Dissociative seizures are paroxysmal events resembling epilepsy or syncope with charac... more Background Dissociative seizures are paroxysmal events resembling epilepsy or syncope with characteristic features that allow them to be distinguished from other medical conditions. We aimed to compare the effectiveness of cognitive behavioural therapy (CBT) plus standardised medical care with standardised medical care alone for the reduction of dissociative seizure frequency. Methods In this pragmatic, parallel-arm, multicentre randomised controlled trial, we initially recruited participants at 27 neurology or epilepsy services in England, Scotland, and Wales. Adults (≥18 years) who had dissociative seizures in the previous 8 weeks and no epileptic seizures in the previous 12 months were subsequently randomly assigned (1:1) from 17 liaison or neuropsychiatry services following psychiatric assessment, to receive standardised medical care or CBT plus standardised medical care, using a web-based system. Randomisation was stratified by neuropsychiatry or liaison psychiatry recruitment site. The trial manager, chief investigator, all treating clinicians, and patients were aware of treatment allocation, but outcome data collectors and trial statisticians were unaware of treatment allocation. Patients were followed up 6 months and 12 months after randomisation. The primary outcome was monthly dissociative seizure frequency (ie, frequency in the previous 4 weeks) assessed at 12 months. Secondary outcomes assessed at 12 months were: seizure severity (intensity) and bothersomeness; longest period of seizure freedom in the previous 6 months; complete seizure freedom in the previous 3 months; a greater than 50% reduction in seizure frequency relative to baseline; changes in dissociative seizures (rated by others); health-related quality of life; psychosocial functioning; psychiatric symptoms, psychological distress, and somatic symptom burden; and clinical impression of improvement and satisfaction. p values and statistical significance for outcomes were reported without correction for multiple comparisons as per our protocol. Primary and secondary outcomes were assessed in the intention-to-treat population with multiple imputation for missing observations. This trial is registered with the International Standard Randomised Controlled Trial registry, ISRCTN05681227, and ClinicalTrials.gov, NCT02325544.

Cognitive neuropsychiatry, 2018

Metacognition, or "thinking about thinking", is a higher-order thought process that all... more Metacognition, or "thinking about thinking", is a higher-order thought process that allows for the evaluation of perceptual processes for accuracy. Metacognitive accuracy is associated with the grey matter volume (GMV) in the prefrontal cortex (PFC), an area also impacted in schizophrenia. The present study set out to investigate whether deficits in metacognitive accuracy are present in the early stages of psychosis. Metacognitive accuracy in first-episode psychosis (FEP) was assessed on a perceptual decision-making task and their performance compared to matched healthy control participants (N = 18). A novel signal detection theory approach was used to model metacognitive sensitivity independently from objective perceptual performance. A voxel-based morphometry investigation was also conducted on GMV. We found that the FEP group demonstrated significantly worse metacognitive accuracy compared to controls (p = .039). Importantly, GMV deficits were also observed in the super...

Emotion Review, 2012

Depersonalization disorder (DPD) is a psychiatric condition in which there is a pervasive change ... more Depersonalization disorder (DPD) is a psychiatric condition in which there is a pervasive change in the quality of subjective experience, in the absence of psychosis. The core complaint is a persistent and disturbing feeling that experience of oneself and the world has become empty, lifeless, and not fully real. A greatly reduced emotional responsivity, or “de-affectualization,” is frequently described. This article examines the phenomenology and neurobiology of DPD with a particular emphasis on the emotional aspects. It is argued that the study of DPD may provide valuable insights into the relationship between emotion, experience, and identity.

Biological psychiatry, Jan 17, 2017

Structural abnormalities across multiple white matter tracts are recognized in people with early ... more Structural abnormalities across multiple white matter tracts are recognized in people with early psychosis, consistent with dysconnectivity as a neuropathological account of symptom expression. We applied advanced neuroimaging techniques to characterize microstructural white matter abnormalities for a deeper understanding of the developmental etiology of psychosis. Thirty-five first-episode psychosis patients, and 19 healthy controls, participated in a quantitative neuroimaging study using neurite orientation dispersion and density imaging, a multishell diffusion-weighted magnetic resonance imaging technique that distinguishes white matter fiber arrangement and geometry from changes in neurite density. Fractional anisotropy (FA) and mean diffusivity images were also derived. Tract-based spatial statistics compared white matter structure between patients and control subjects and tested associations with age, symptom severity, and medication. Patients with first-episode psychosis had ...

Trials, Jun 6, 2017

Dissociative seizures (DSs), also called psychogenic non-epileptic seizures, are a distressing an... more Dissociative seizures (DSs), also called psychogenic non-epileptic seizures, are a distressing and disabling problem for many patients in neurological settings with high and often unnecessary economic costs. The COgnitive behavioural therapy versus standardised medical care for adults with Dissociative non-Epileptic Seizures (CODES) trial is an evaluation of a specifically tailored psychological intervention with the aims of reducing seizure frequency and severity and improving psychological well-being in adults with DS. The aim of this paper is to report in detail the quantitative and economic analysis plan for the CODES trial, as agreed by the trial steering committee. The CODES trial is a multicentre, pragmatic, parallel group, randomised controlled trial performed to evaluate the clinical effectiveness and cost-effectiveness of 13 sessions of cognitive behavioural therapy (CBT) plus standardised medical care (SMC) compared with SMC alone for adult outpatients with DS. The object...

Frontiers in Psychology, 2016

This paper presents functional MRI work on emotional processing in depersonalization disorder (DP... more This paper presents functional MRI work on emotional processing in depersonalization disorder (DPD). This relatively neglected disorder is hallmarked by a disturbing change in the quality of first-person experience, almost invariably encompassing a diminished sense of self and an alteration in emotional experience such that the sufferer feels less emotionally reactive, with emotions experienced as decreased or "damped down," so that emotional life seems to lack spontaneity and subjective validity. Here we explored responses to emotive visual stimuli to examine the functional neuroanatomy of emotional processing in DPD before and after pharmacological treatment. We also employed concurrent skin conductance measurement as an index of autonomic arousal. In common with previous studies we demonstrated that in DPD, there is attenuated psychophysiological response to emotional material, reflected in altered patterns of (i) regional brain response, (ii) autonomic responses. By scanning participants before and after treatment we were able to build on previous findings by examining the changes in functional MRI response in patients whose symptoms had improved at time 2. The attenuation of emotional experience was associated with reduced activity of the insula, whereas clinical improvement in DPD symptoms was associated with increased insula activity. The insula is known to be implicated in interoceptive awareness and the generation of feeling states. In addition an area of right ventrolateral prefrontal cortex emerged as particularly implicated in what may be "top-down" inhibition of emotional responses. The relevance of these findings to the wider study of emotion, self-related processes, and interoception is discussed.

Clinical Psychology Forum

This thematic evaluation suggests a new neuropsychiatry and psychology service has ameliorated so... more This thematic evaluation suggests a new neuropsychiatry and psychology service has ameliorated some previously reported difficulties associated with a national shortage of such localised provision, particularly for people with medically unexplained symptoms (MUS). However, vast unmet need remains. Service-specific recommendations may be generalised to inform the development of other services in line with current health policy.

Frontiers in psychology, 2015

The control of physiological arousal can assist in the regulation of emotional state. A subset co... more The control of physiological arousal can assist in the regulation of emotional state. A subset cortical and subcortical brain regions are implicated in autonomic control of bodily arousal during emotional behaviors. Here, we combined human functional neuroimaging with autonomic monitoring to identify neural mechanisms that support the volitional regulation of heart rate, a process that may be assisted by visual feedback. During functional magnetic resonance imaging (fMRI), 15 healthy adults performed an experimental task in which they were prompted voluntarily to increase or decrease cardiovascular arousal (heart rate) during true, false, or absent visual feedback. Participants achieved appropriate changes in heart rate, without significant modulation of respiratory rate, and were overall not influenced by the presence of visual feedback. Increased activity in right amygdala, striatum and brainstem occurred when participants attempted to increase heart rate. In contrast, activation ...

International Journal of Interactive Worlds, 2013

Although improvements in basic computer graphics rendering hardware and lighting algorithms have ... more Although improvements in basic computer graphics rendering hardware and lighting algorithms have produced some remarkable results, it is still computationally demanding to render a highly realistic Virtual Environment (VE) in real-time. This paper presents a real-time synthetic lighting system incorporating sophisticated global illumination algorithms aiming to induce similar subjective lighting impressions as in the real world. The lighting system proposed is designed to render an interactive VE on an fMRI display, enabling the conduct of formal neuroscientific experiments, investigating the effects of visual fidelity as well as varied lighting configurations on feelings of presence, 'reality' and comfort. Ultimately, the goal is to use this system to explore the effect of lighting variations (daylight vs forms of artificial light) on subjective impressions of a group of patients suffering from the 'depersonalization' syndrome. The system was developed in close collaboration with the Brighton and Sussex Medical School in the UK. It was a challenge to develop an interactive lighting system to be utilized for fMRI experimentation due to infrastructural and technical demands. Such demands were based on acquiring user input when immersed in the constrained environment of an fMRI scanner while the system reacts to it in real-time. fMRI experiments usually employ simple display material, for example using photographs, video clips or simple computerized stimuli. Employing VEs in fMRI has the advantage that it is possible to involve participants in interactive animated environments which more realistically reflect social and emotional situations.

2011 Third International Conference on Games and Virtual Worlds for Serious Applications, 2011

... Page 3. obedience but a range of moral dillemas, an area of research that it is not otherwise... more ... Page 3. obedience but a range of moral dillemas, an area of research that it is not otherwise open to experimental study for ethical reasons, through the employment of VEs. ... Quantifying Fidelity for Virtual Environment Simulations Employing Memory Schema Assumptions. ...

Psychiatry Research - Neuroimaging, 2001

Psychiatry Research: Neuroimaging, 2014

(2014) Grey-matter texture abnormalities and reduced hippocampal volume are distinguishing featur... more (2014) Grey-matter texture abnormalities and reduced hippocampal volume are distinguishing features of schizophrenia. Psychiatry Research: Neuroimaging, 223 (3). pp. 179-186.