PubMed · 9855562
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R W Beck. 1998. Vigabatrin-associated retinal cone system dysfunction.. https://doi.org/10.1212/wnl.51.6.1778-c
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Epilepsy is the most common serious neurological disorder and is one of the world's most prevalent noncommunicable diseases. As the understanding of its physical and social burden has increased it has moved higher up the world health agenda. Over four-fifths of the 50 million people with epilepsy are thought to be in developing countries; much of this condition results from preventable causes. Around 90% of people with epilepsy in developing countries are not receiving appropriate treatment. Consequently, people with epilepsy continue to be stigmatized and have a lower quality of life than people with other chronic illnesses. However, bridging the treatment gap and reducing the burden of epilepsy is not straightforward and faces many constraints. Cultural attitudes, a lack of prioritization, poor health system infrastructure, and inadequate supplies of antiepileptic drugs all conspire to hinder appropriate treatment. Nevertheless, there have been successful attempts to provide treatment, which have shown the importance of community-based approaches and also indicate that provision for sustained intervention over the long term is necessary in any treatment programme. Approaches being adopted in the demonstration projects of the Global Campaign Against Epilepsy--implemented by the International League Against Epilepsy, the International Bureau for Epilepsy, and the World Health Organization--may provide further advances. Much remains to be done but it is hoped that current efforts will lead to better treatment of people with epilepsy in developing countries.
Selection criteria are specified in clinical trials to define the study population from which the sample will be obtained. It is common for one of these criteria to be based on historical or baseline measurements of the clinical sign or symptom that will serve as the response variable in the trial. The effect of such selection criteria has been studied extensively for normally distributed responses, but less is known about the situation in which the response is a count or a possibly recurrent event. In this paper we examine the bias and relative efficiency of some common methods of analysis for count data in the presence of selection criteria. The investigation is carried out using asymptotic theory pertaining to misspecified models and by simulation. Applications involving data from an epilepsy trial and a study of transient myocardial ischaemia illustrate the effect of ignoring the selection mechanism.