INTRODUCTION The electroencephalography (EEG), since its inception in the 1930s, has become one of the most used investigative tools in psychiatry. Its uses include exclusion of seizure disorders and encephalopathic conditions. In psychiatry distinguishing between a primary psychiatric disorder and psychiatric manifestations of an underlying medical condition is of vital importance. This determines which course of management the psychiatrist should follow, and most importantly, determines the prognosis. However, EEG studies done in psychiatry have yielded unfavourable results. The yield of positive (abnormal) EEG results is very low. Despite this, it is still widely requested by most psychiatrists. There is a dearth of literature assessing the usefulness of EEG in psychiatry in our South African setting. The current study looked at which users are referred for EEG and the outcomes thereof. METHODS The study was conducted at Sterkfontein psychiatric hospital. A retrospective review of clinical records, and EEG reports, of inpatients 18yrs and older that underwent EEG between January 2008 to June 2009 was done. A data sheet was used as a recording tool. Data was analysed using the Statistica 9.0 system. RESULTS The total sample was 85. Seventy four (87%) records were normal, 7(8,2%) were abnormal, 2(2,4%) were inconclusive and two EEG reports were unavailable. Only one user’s diagnosis changed based on abnormal EEG results. There was no statistically significant correlation between abnormal EEG results and demographic variables, symptoms, admission diagnosis and medications. CONCLUSION The positive yield of EEG results remains very low in psychiatry. EEG results do not appear to influence the treating psychiatrist’s decision regarding management.

Thesis (M Med (Psychiatry))--University of Limpopo (Medunsa Campus), 2010. / The yield of EEG amongst psychiatric patients has been reported to be low and the value of EEG in the practice of psychiatry is questionable.EEG is used as part of a diagnostic work up for patients with psychiatric disorders .Often the reason given for its use is to exclude epilepsy as a cause of psychiatric symptoms. Epilepsy is primarily a clinical diagnosis, but the EEG may provide strong support by the findings of inter – ictal Epileptogenic discharge METHOD: All the adult EEGs requested at Dr George Mukhari psychiatric hospital, over a 36 month period ,were reviewed to describe the outcome of the requested EEG reports .The study is a simple retrospective analysis of 111 consecutive EEG requested to the department of Neurology at DGMH from psychiatric unit at DGMH. Subjects were both inpatients and outpatients .All the EEG was reported by a qualified Neurologist. Data were extracted from the EEG request form and the patients’ clinical files, which reported on the clinical reason for the EEG test, nature of psychiatric diagnosis of patients, the psychiatric treatment received prior to the EEG test and the nature of the EEG results RESULTS There were 111 EEG reports analysed, and 69 EEG reports for males and 42 EEG reports for females. The reason for EEG request was dominated mainly by exclusion of epilepsy. Majority of the patients were diagnosed with a psychotic disorder , followed second by a mood disorder , all of which was attributed to GMC (epilepsy).About 62.73% of patients were on a combination of treatment of antipsychotic drug and anticonvulsants, whilst 34.55% were on antipsychotic monotherapy prior to the EEG test. Further analysis of the requested EEG form was carried out in whom the test was to determine whether or not the patients were suffering from epilepsy.EEG abnormalities were identified amongst 24% of the patients. About 11,7% of patients presented with non specific EEG results .Out of a total number of 111 patients whom an EEG test was requested and epilepsy was highly suspected from clinical presentation, only 14 patients (12.6%),presented with epileptiform discharge on their EEG results. However majority of the patients (76%) demonstrated normal EEG pattern, which doesn’t exclude a diagnosis of epilepsy. CONCLUSION The yield of EEG in psychiatry is low. To diagnose epilepsy as a cause of psychiatric presentation, clinicians should continue to rely on the clinical history of attacks and not the EEG .In the practice of psychiatry it is not recommended to routinely order an EEG to exclude a diagnosis of epilepsy, more so to confirm a psychiatric diagnosis.The presence of a psychiatric symptoms in patients who presents with epilepsy, is rarely associated with meaningful EEG changes

No description available.

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 94-96).

Thesis (M.S.)--Wisconsin. / Includes bibliographical references (leaves 64-65).

The past decade has witnessed an intense interest in the influence of drugs and metabolic substances upon EEG "activation" and arousal mechanisms, mediated by the reticular activating system of the brain stem. Numerous pharmacological agents produce variations of the electrical activity of the brain. Analysis of their effects has suggested that the reticular activating system is an area wherein numerous drugs may act, and point to its multineuronal, polysynaptic character as playing a major role in central drug action. A technique has been developed which lends itself well to the study of the direct actions of drugs upon the various components of the reticular activating system of the brain stem. The experimental analysis of EEG "activation" requires the presence of a well deactivated background pattern. Observations made in the cat demonstrate that partial trigeminalectomy, cervical dorsalectomy and low cervical transection produce a preparation in which the resting EEG regularly manifests maximal deactivation. A permanent catheter inserted through the right subclavian artery and into the innominate artery so that its tip is positioned at the origin of the two carotids, has furnished a means for simultaneous bilateral distribution of injected drugs to the brain without embarrassing flow in the carotid arteries. The advantages of this technique include (a) an intact brain stem, (b) the maintenance of adequate spontaneous respiratory and circulatory states, and (c) the ability to perform various operative procedures without the necessity for extraneous pharmacological agents (anaesthetics, muscle relaxants), which may themselves have complicating effects on the EEG. In this preparation adrenergic and cholinergic agents as well as histamine and serotonin all produced prompt, short-lasting and reproducible EEG "activation" in low doses following direct intra-innominate administration. In "equi-activating" doses, isoproterenol is the most potent EEG activating catechol adrenergic amine and norepinephrine the least potent, with epinephrine occupying an intermediate position. Amphetamine and eserine both produce long-lasting EEG "activation", with amphetamine having a much shorter latency than eserine. Clear differentiation between the EEG effects resulting from direct drug-induced influences and those which may occur over reflex pathways has been demonstrated in preparations with bilateral carotid sinus denervation. Complete temporal independence is shown between the onset and termination of the actions of "activating" agents introduced directly by intra-innominate administration and the vascular effects of these agents as reflected in blood pressure alterations. Partial destruction in the tegmentum rostral to ponto-mesencephalic junction produces an increase in threshold for adrenergic EEG activation. Unilateral lesions which destroy most or all of the mesencephalic-tegmentum abolish adrenergic-induced activation in the ipsi-lateral cortex but do not affect cholinergic activation. Results obtained with various synaptic blocking agents have suggested the possible existence in the brain of three types of receptors capable of converging on the final pathway for EEG "activation"; one responsive to cholinergic compounds and blocked by atropine; one responsive to serotonin and blocked only by chlorpromazine and atropine; and one responsive to histamine and the short-acting adrenergic amines and blocked by phenoxybenzamine as well as chlorpromazine and atropine. The responses of the adrenoceptive components in the reticular activating system of the brain stem are not identical with those of any other known adrenergic receptors. This observation emphasizes the difficulty in attempts to classify receptors into a few clearly defined and discrete categories. / Medicine, Faculty of / Anesthesiology, Pharmacology and Therapeutics, Department of / Graduate

Issued also as thesis, Leyden.

Issued also as thesis, Leyden.

This report is about a project where electroencephalography (EEG) wasused to control a two player game. The signals from the EEG-electrodeswere amplified, filtered and processed. Then the signals from the playerswere compared and an algorithm decided what would happen in the gamedepending on which signal was largest. The controls and the gaming mechanismworked as intended, however it was not possible to gather a signal fromthe brain with the method used in this project. So ultimately the goal wasnot reached. / electroencephalography, EEG

This study uses statistical techniques to determine anesthetic depths of three females undergoing total abdominal hysterectomies. Spectral analysis of the electronencephalogram is employed to define changes in brain wave activity under different levels of anesthesia after administration of diazepam and isoflurane. The multivariate statistical technique of discriminant function analysis is used to determine which frequencies, or linear combinations of frequencies, yield the most information for classification of the electronencephalogram samples into one of the three anesthetic depths (mild sedation, moderate anesthesia, and anesthetic sleep). Spectral analysis of the electronencephalogram showed similar results for all three patients after administration of diazepam (mild sedation), but widely varying results among patients during anesthesia using isoflurane. The combination of spectral analysis and discriminant function analysis showed reliable discrimination among the three anesthetic depths. The ability to discriminate was significantly improved when only two anesthetic depths were used.