The prognosis and development of new outcome measures for the assessment of treatment effects in the chronic condition of epilepsy
Epilepsy is a common condition whose overall prognosis is good. However for those patients with drug-resistant seizures it is a chronic, disabling condition with serious physical risks, social restrictions and psychological consequences which impair well-being and quality of life. In a minority of these patients surgery may be curative but this does not guarantee satisfactory psychosocial adjustment. Furthermore the majority of patients are dependent on the development of new drugs. Whilst these often reduce seizure frequency they rarely produce a sustained remission. Thus there is a need for the development of more sensitive methods of assessing the efficacy of treatment of chronic epilepsy. The aim of this research was the development of measures of seizure severity and health-related quality of life (HRQL) and to examine their potential as outcome measures for epilepsy. This thesis contains nine chapters which are summarised below. CHAPTER 1 reviews the prognosis of epilepsy and the factors which influence this. Emphasis is placed on the prognostic relevance of accepted syndromic and aetiological classification. CHAPTER 2 describes the physical, social and psychological complications of the chronic condition. This approach is relevant to the measurement of health-related quality of life (HRQL). CHAPTER 3 investigates the assessment of treatment effects in epilepsy emphasizing the insensitivity of simple seizure counts and examines the possibility of measuring seizure severity and HRQL. CHAPTER 4 briefly describes the process of measurement and discusses the essential properties of scales designed to measure subjective phenomena. The development, reliability and validity of patient-based measures of seizure severity and HRQL are described in CHAPTERS 5 to 6respectively. CHAPTER 7 considers the interaction between physical and psychological components of life quality using multivariate methods, while CHAPTER 8 examines the sensitivity of the scales in the context of a placebo-controlled trial of a novel anti-epileptic drug, lamotrigine. I have tried to address deficiencies of this work in the appropriate chapters while CHAPTER 9 concentrates on conclusions and further developments of this instrument.