Diagnostic utility of invasive EEG for epilepsy surgery: Indications,modalities, and techniques

Many patients with medically refractory epilepsy now undergo successful surgery based on noninvasive diagnostic information, but intracranial electroencephalography (IEEG) continues to be used as increasingly complex cases are considered surgical candidates. The indications for IEEG and the modalities employed vary across epilepsy surgical centers; each modality has its advantages and limitations. IEEG can be performed in the same intraoperative setting, that is, intraoperative electrocorticography, or through an independent implantation procedure with chronic extraoperative recordings; the latter are not only resource intensive but also carry risk. A lack of understanding of IEEG limitations predisposes to data misinterpretation that can lead to denying surgery when indicated or, worse yet, incorrect resection with adverse outcomes. Given the lack of class 1 or 2 evidence on IEEG, a consensus‐based expert recommendation on the diagnostic utility of IEEG is presented, with emphasis on the application of various modalities in specific substrates or locations, taking into account their relative efficacy, safety, ease, and incremental cost‐benefit. These recommendations aim to curtail outlying indications that risk the over‐ or underutilization of IEEG, while retaining substantial flexibility in keeping with most standard practices at epilepsy centers and addressing some of the needs of resource‐poor regions around the world.     

Methodological and statistical considerations in measuring alcohol treatment effects

This article addresses the design and selection of outcome methods for treatment research from a statistical perspective. Two of the major statistical and methodological issues relevant to the selection of dependent variable(s) are statistical power and social utility. Power is the paramount issue in research design. Power can be improved by measures and methods tailored to the predicted effects of treatment. These effects should vary from treatment to treatment, suggesting that no single outcome measure is suitable for all purposes. In estimating power, researchers should also consider the time-varying nature of most types of treatment effects. Given these considerations, timeline procedures have advantages because they allow the derivation of measures linked to specific treatment components. They also permit the study of time-varying effects of variables such as life stress. An analysis on the relationship between drinking and self-reported stress is presented as an illustration of how advanced statistical methods, in conjunction with carefully gathered data, can provide process data on how treatment can affect individual responses to stressors or other events. From a social utility perspective, however, having research focus on narrower and narrower slices of behavior in the search for power raises questions about the value of this research to clients and society. For dealing with this dilemma, it will be necessary to build a series of studies linking improvement in specific aspects of short-term outcome to longer term outcome and ultimately benefit to society.     

A comprehensive study of psychometric properties of the Edmonton Symptom Assessment System (ESAS) in Spanish advanced cancer patients

Background

The Edmonton Symptom Assessment System (ESAS) is developed for daily symptom assessment. Validation studies tested a variety of languages and patients. The purpose was to carry out a comprehensive examination of the psychometric properties of the ESAS through validation of the version in Spanish advanced cancer patients.

Method

A reverse translation method was used to translate the ESAS. Previous studies find appropriate Spanish terms to explore, with verbal scales, fatigue, depression and anxiety. Psychometric aspects evaluated were reliability, validity, responsiveness and utility.

Results

171 advanced cancer patients participated. Internal consistency with Cronbach’s Alpha was 0.75. In test-retest (0-6 h), Spearma’s correlation was between 0.65 and 0.94. Factor analysis found 3 central domains: ‘soft’ and ‘hard physical’ and ‘emotional’. Concurrent validity with the Rotterdam Symptom Check List (RSCL) found good correlation in physical symptoms (Kappa until 0.66) but weak correlation in emotional symptoms (Kappa 0.35). Discriminant validity (Spearman) found significant differences (p < 0.001) classifying by Karnofsky. ESAS discriminate between inpatients and outpatients (Mann-Whitney, p < 0.001). Responsiveness was tested with ESAS at 0-48 h (Wilcoxon test, p < 0.05). Average time to complete the instrument was 5.5 min.

Conclusion

ESAS is a valid, reliable, responsive and feasible instrument with adequate psychometric properties when tested on Spanish advanced cancer patients.     

Priorities and Prospect Theory

Whose preferences are to be used for cost-effectiveness analysis? It has been recommended that community preferences for health states are the most appropriate ones for use in a reference case analysis. However, critics maintain that persons are not able properly to judge a health state if they have not experienced the condition themselves. This problem is analyzed here in the framework of Prospect Theory. It can be argued that the differing reference points of patients and the general public are responsible for deviating results. In addition, we argue that risk attitudes with respect to health-related quality of life are an indicator of reference points. If patients and the general public refer to the same reference point, i.e., they have the same risk attitude, the hypothesis is that deviations no longer significantly differ. Evaluations of the health condition of tinnitus by 210 patients and 210 unaffected persons were compared. The Time Tradeoff and Standard Gamble methods were applied to elicit preferences. Risk attitude was measured with the question of whether participants would undergo a treatment that could either improve or worsen their health condition, both with an equal chance (five possible answers between “in no case” and “in any case”). Affected persons indicated significantly higher values for tinnitus-related quality of life according to the Standard Gamble method. The difference between Time Tradeoff values was less dramatic but still significant. In addition, nonaffected persons are more risk-averse than affected persons. However, differences in evaluations are not significant considering single risk groups (e.g., those who answered “in no case”). Prospect Theory is a reasonable framework for considering the question of whose preferences count. If this result can be generalized for other diseases as well, it allows the mathematical combination of “objective” evaluations by the general public with the illness experience of patients. These evaluations should be weighted with patients' risk attitudes, i.e., community preferences can be used if they are corrected for risk attitudes.     

Health related utility measurement in rheumatology: an introduction

Utility measures of health-related quality of life are preference values that patients attach to their overall health status. In clinical trials, utility measures summarize both positive and negative effects of an intervention into one single value between 0 (equal to death) and 1 (equal to perfect health). These measures allow for comparison of patient outcomes of different diseases and allow for comparison between various health care interventions. There are two different approaches to utility measurement. The first is to classify patients into categories based on their responses to a number of questions about their functional status, as for instance the Quality of Well-Being questionnaire. The second approach is to ask patients to assign a single rating to their overall health by means of rating scale, standard gamble, time trade-off, or willingness to pay. The Quality Adjusted Life Year (QALY) as outcome measure includes both effects in terms of quality and quantity of life. Utilities are used as weights to adjust life years for the quality of life in order to calculate QALYs. Both QALYs and utilities are useful in decision-making regarding appropriate procedures for groups of patients.     

深圳市职工卫生服务利用分析

采用分层整群随机抽样的方法对深圳市职工卫生服务现状进行了调查分析,结果显示:职工两周就诊率,年平均住院率均高于1993年全国服务总调查大城市水平,与7国12地区平均水平接近。影响职工就诊的主要因素有性别、年龄、职工的文化程度、月平均收入以及是否参加了医疗保险。     

The cost–utility of lumbar disc herniation surgery

The cost and utility of surgery for a herniated lumbar disc has not been determined simultaneously in a single cohort. The aim of this study is to perform a cost–utility analysis of surgical and nonsurgical treatment of patients with lumbar disc herniation. Ninety-two individuals in a cohort of 1,146 Swedish subjects underwent lumbar disc herniation surgery during a 2-year study. Each person operated on was individually matched with one treated conservatively. The effects and costs of the treatments were determined individually. By estimating quality of life before and after the treatment, the number of quality adjusted life years (QALY) gained with and without surgery was calculated. The medical costs were much higher for surgical treatment; however, the total costs, including disability costs, were lower among those treated surgically. Surgery meant fewer recurrences and less permanent disability benefits. The gain in QALY was ten times higher among those operated. Lower total costs and better utility resulted in a better cost utility for surgical treatment. Surgery for lumbar disc herniation was cost-effective. The total costs for surgery were lower due to lower recurrence rates and fewer disability benefits, and surgery improved quality of life much more than nonsurgical treatments.