Is Speech Arrest during Wada Testing a Valid Method for Determining Hemispheric Representation of Language?

Background and objective: The intracarotid amobarbital procedure, or Wada test, is the method of choice to determine hemispheric representation of language, and is routinely used in the presurgical evaluation for intractable epilepsy. Some investigators perform comprehensive language assessments, but others base language lateralization solely on speech arrest. This study sought to determine whether speech arrest alone during Wada testing provides valid data regarding language lateralization. Methods: The subjects (previously reported) were 21 patients evaluated for intractable epilepsy, who underwent language lateralization by Wada testing and functional MRI (FMRI). For each patient, language representation was determined by calculating: (1) a Wada laterality index based exclusively on speech arrest; (2) a Wada laterality index based on comprehensive language assessment; and (3) an FMRI laterality quotient. Correlation coefficients and categorical classifications were analyzed. Results: There was no significant correlation between the Wada laterality quotient derived from duration of speech arrest and either the comprehensive Wada language laterality score (r= .35,p= .12) or FMRI language laterality score (r= .32,p= .16). Categorical classification as left, right or bilateral language also showed marked discordance between speech arrest and the other two methods. Conclusion: Duration of speech arrest during Wada testing is not a valid measure of language dominance.     

Functional neuroimaging in neurology and psychiatry

How can functional neuroimaging be applied to clinical neurology and psychiatry? This article reviews selected contributions of functional neuroimaging to the clinical neurosciences. We review selected technical aspects of positron emission tomography, single photon emission tomography, and functional magnetic resonance imaging with a focus on the relative strengths and weaknesses of these techniques. Consumers of functional neuroimaging research are encouraged to consider the limitations of imaging techniques and theoretical pitfalls of cognitive task design when interpreting results of functional imaging studies. Then, we selectively review the contributions of functional neuroimaging to neurology and psychiatry, including the areas of epilepsy, stroke, chronic pain, schizophrenia, depression, and obsessive-compulsive disorder. Future directions of functional neuroimaging research are offered, with the emphasis that the best conclusions are informed by a convergence of research from functional neuroimaging, neurophysiological, and lesion studies.     

Functional Magnetic Resonance Imaging of Language in Epilepsy

Functional magnetic resonance imaging (fMRI) has revolutionized our understanding of functional networks and cerebral organization in both normal and pathological brains. In the present review, we describe the use of fMRI for mapping language in epilepsy patients prior to surgical intervention including a discussion of methodological issues and task design, comparisons between fMRI and the intracarotid sodium amobarbital test, fMRI studies of language reorganization, and the use of fMRI laterality indexes to predict outcome after anterior temporal lobectomy.     

Hypothesis testing in patients with chronic progressive multiple sclerosis

Patients with chronic progressive MS (N = 38) were compared with an age and education matched medical control group (N = 19) on a visual discrimination task designed to evaluate hypothesis testing and focusing behavior. Thirty-three MS patients (85%) and all control patients were able to formulate and use hypotheses, but MS patients were less likely to employ strategies leading to a correct solution. Furthermore, MS patients were more likely to perseverate with one strategy despite negative verbal feedback. Five MS patients were unable to formulate hypotheses. These findings suggest that MS patients have impaired cognitive functioning in addition to previously reported problems with memory.     

生活医学化与健康恐慌的关系及其反思*--论Michael Fitzpatrick《健康的暴政：医生及生活方式的控制》

迈克尔·菲茨帕特里克的《健康的暴政：医生及生活方式的控制》一书,以健康干预为主线,以健康政治化、生活医学化、疾病道德化为主题,论述了生活医学化的不同方面和形成过程,并力图揭示医学化背后隐含着的医学对社会的干预和控制。其中作者关于生活医学化和健康恐慌的一些哲学思考,尤其是生活医学化与健康恐慌的内涵及特点、生活医学化与健康恐慌的关系以及对生活医学化的审视与反思,在一定程度上蕴涵着对当今社会发展的启示。     

Situation awareness as a function of frame of reference, computer-graphics eyepoint elevation, and geometric field of view

The purpose of this study was to determine how 3 variables for the design of a "heads-down" spatial display--the frame of reference (pilot's eye vs. God's eye), geometric field of view, and elevation of the computer graphics eyepoint--influenced situation awareness. Thirteen flight-naive subjects each flew a simulated F-16 over a computer-generated flight environment to lock onto and intercept a series of sequentially appearing targets. The flight scene consisted of both an "out-the-window" view and a computer-generated heads-down spatial display showing an airplane symbol superimposed on a perspective view of the flight environment. During the interactive phase of the experiment, root mean square flight-path error, target lock-on time, and target acquisition time were measured. After the interactive phase of the study was completed, subjects were required to mark the location of the targets from memory on a computer-generated top-down view of the flight scene in an attempt to reconstruct the spatial mental model which subjects formed of the flight environment. The results for the interactive phase of the study indicated that performance was superior using the pilot's-eye display. However, for the spatial reconstruction task, performance was better using the God's-eye display. It was also shown that the ability to maintain the optimal flight-path using the more top-down view of the scene (600 eyepoint) was superior to the 300 eyepoint elevation. Implications of the results for the design of spatial instruments are discussed.