Artefact detection and removal algorithms for EEG diagnostic systems

The electroencephalogram (EEG) is a medical technology that is used in the monitoring of the brain and in the diagnosis of many neurological illnesses. Although coarse in its precision, the EEG is a non-invasive tool that requires minimal set-up times, and is suitably unobtrusive and mobile to allow continuous monitoring of the patient, either in clinical or domestic environments. Consequently, the EEG is the current tool-of-choice with which to continuously monitor the brain where temporal resolution, ease-of- use and mobility are important. Traditionally, EEG data are examined by a trained clinician who identifies neurological events of interest. However, recent advances in signal processing and machine learning techniques have allowed the automated detection of neurological events for many medical applications. In doing so, the burden of work on the clinician has been significantly reduced, improving the response time to illness, and allowing the relevant medical treatment to be administered within minutes rather than hours. However, as typical EEG signals are of the order of microvolts (μV ), contamination by signals arising from sources other than the brain is frequent. These extra-cerebral sources, known as artefacts, can significantly distort the EEG signal, making its interpretation difficult, and can dramatically disimprove automatic neurological event detection classification performance. This thesis therefore, contributes to the further improvement of auto- mated neurological event detection systems, by identifying some of the major obstacles in deploying these EEG systems in ambulatory and clinical environments so that the EEG technologies can emerge from the laboratory towards real-world settings, where they can have a real-impact on the lives of patients. In this context, the thesis tackles three major problems in EEG monitoring, namely: (i) the problem of head-movement artefacts in ambulatory EEG, (ii) the high numbers of false detections in state-of-the-art, automated, epileptiform activity detection systems and (iii) false detections in state-of-the-art, automated neonatal seizure detection systems. To accomplish this, the thesis employs a wide range of statistical, signal processing and machine learning techniques drawn from mathematics, engineering and computer science. The first body of work outlined in this thesis proposes a system to automatically detect head-movement artefacts in ambulatory EEG and utilises supervised machine learning classifiers to do so. The resulting head-movement artefact detection system is the first of its kind and offers accurate detection of head-movement artefacts in ambulatory EEG. Subsequently, addtional physiological signals, in the form of gyroscopes, are used to detect head-movements and in doing so, bring additional information to the head- movement artefact detection task. A framework for combining EEG and gyroscope signals is then developed, offering improved head-movement arte- fact detection. The artefact detection methods developed for ambulatory EEG are subsequently adapted for use in an automated epileptiform activity detection system. Information from support vector machines classifiers used to detect epileptiform activity is fused with information from artefact-specific detection classifiers in order to significantly reduce the number of false detections in the epileptiform activity detection system. By this means, epileptiform activity detection which compares favourably with other state-of-the-art systems is achieved. Finally, the problem of false detections in automated neonatal seizure detection is approached in an alternative manner; blind source separation techniques, complimented with information from additional physiological signals are used to remove respiration artefact from the EEG. In utilising these methods, some encouraging advances have been made in detecting and removing respiration artefacts from the neonatal EEG, and in doing so, the performance of the underlying diagnostic technology is improved, bringing its deployment in the real-world, clinical domain one step closer.

Home, family and society: women of the Irish landed class, 1860-1914. A Munster case study

The thesis analyses the roles and experiences of female members of the Irish landed class (wives, sisters and daughters of gentry and aristocratic landlords with estates over 1,000 acres) using primary personal material generated by twelve sample families over an important period of decline for the class, and growing rights for women. Notably, it analyses the experiences of relatively unknown married and unmarried women, something previously untried in Irish historiography. It demonstrates that women’s roles were more significant than has been assumed in the existing literature, and leads to a more rounded understanding of the entire class. Four chapters focus on themes which emerge from the sources used and which deal with their roles both inside and outside the home. These chapters argue that: Married and unmarried women were more closely bound to the priorities of their class than their sex, and prioritised male-centred values of family and estate. Male and female duties on the property overlapped, as marriage relationships were more equal than the legislation of the time would suggest. London was the cultural centre for this class. Due to close familial links with Britain (60% of sample daughters married English men) their self-perception was British or English, as well as Irish. With the self-confidence of their class, these women enjoyed cultural and political activities and movements outside the home (sport, travel, fashion, art, writing, philanthropy, (anti-)suffrage, and politics). Far from being pawns in arranged marriages, women were deeply conscious of their marriage decisions and chose socially, financially and personally compatible husbands; they also looked for sexual satisfaction. Childbirth sometimes caused lasting health problems, but pregnancy did not confine wealthy women to an invalid state. In opposition to the stereotypical distant aristocratic mother, these women breastfed their children, and were involved mothers. However, motherhood was not permitted to impinge on the more pressing role of wife

Immune and stress factors in the pathophysiology of the mdx mouse model of Duchenne Muscular Dystrophy

Duchenne Muscular Dystrophy (DMD) is a fatal multi-system neuromuscular disease caused by loss of dystrophin. The loss of dystrophin from membranes of contractile muscle cells and the dysregulation of the DAPC, induces chronic inflammation due to tissue necrosis and eventual replacement with collagen which weakens muscular force and strength. Dystrophin deficiency may cause under-diagnosed features of DMD include mood disorders such as depression and anxiety and dysfunction of the gastrointestinal tract. The first study in the thesis examined mood in the dystrophin-deficient mdx mouse model of DMD and examined the effects of the tri-cyclic antidepressant, amitriptyline on behaviours. Amitriptyline had anti-depressant and anxiolytic effects in the mdx mice possibly through effects on stress factors such as corticotrophin-releasing factor (CRF). This antidepressant also reduced skeletal muscle inflammation and caused a reduction in circulating interleukin (IL)-6 levels. In the second and third studies, we specifically blocked IL-6 signalling and used Urocortin 2, CRFR2 agonist to investigate their potential as therapeutic targets in mdx mice pathophysiology. Isometric and isotonic contractile properties of the diaphragm, were compared in mdx mice treated with anti IL-6 receptor antibodies (anti IL-6R) and/or Urocortin 2. Deficits in force production, work and power detected in mdx mice were improved with treatment. In study three I investigated contractile properties in gastrointestinal smooth muscle. As compared to wild type mice, mdx mice had slower faecal transit times, shorter colons with thickened muscle layers and increased contractile activity in response to recombinant IL-6. Blocking IL-6 signalling resulted in an increase in colon length, normalised faecal output times and a reduction in IL-6-evoked contractile activity. The findings from these studies indicate that for both diaphragm and gastrointestinal function in a dystrophin-deficient model, targeting of IL-6 and CRFR2 signalling has beneficial therapeutic effects.

The ‘Celtic’ dimension of pre-first World War religious discourse in Britain: Wellesley Tudor Pole and the Glastonbury phenomenon

This article will explore the contribution made to the construction of discourse around religion outside of mainstream Christianity, at the turn of the twentieth century in Britain, by a Celticist movement as represented by Wellesley Tudor Pole (d.1968) and his connection to the Glastonbury phenomenon. I will detail the interconnectedness of individuals and movements occupying this discursive space and their interest in efforts to verify the authenticity of an artefact which Tudor Pole claimed was once in the possession of Jesus. Engagement with Tudor Pole’s quest to prove the provenance of the artefact, and his contention that a pre-Christian culture had existed in Ireland which had extended itself to Glastonbury and Iona creating the foundation for an authentic Western mystical tradition, is presented as one facet of a broader, contemporary discourse on alternative ideas and philosophies. In conclusion, I will juxtapose Tudor Pole’s fascination with Celtic origins and the approach of leading figures in the ‘Celtic Revival’ in Ireland, suggesting intersections and alterity in the construction of their worldview. The paper forms part of a chapter in a thesis under-preparation which examines the construction of discourse on religion outside of mainstream Christianity at the turn of the twentieth century, and in particular the role played by visiting religious reformers from Asia. The aim is to recover the (mostly forgotten) history of these engagements.