Full Description
The intracarotid amobarbital (or Amytal) procedure is commonly referred to as the Wada test in tribute to Juhn Wada, the physician who devised the technique and performed the fIrst basic animal research and clinical studies with this method. Wada testing has become an integral part of the pre operative evaluation for epilepsy surgery. Interestingly, however, Wada initially developed this method as a technique to assess language dominance in psychiatric patients in order that electroconvulsant therapy could be applied unilaterally to the non-dominant hemisphere. Epilepsy surgery has matured as a viable treatment for intractable seizures and is no longer confmed to a few major universities and medical institutes. Yet, as is increasingly clear by examining the surveys of approaches used by epilepsy surgery centers (e.g., Rausch, 1987; Snyder, Novelly, & Harris, 1990), there is not only great heterogeneity in the methods used during Wada testing to assess language and memory functions, but there also seems to be a lack of consensus regarding the theoretical assumptions, and perhaps, even the goals of this procedure.
Contents
1. Language.- Studies from the Montreal Neurological Institute.- Bilateral Language.- Medical College of Georgia Study.- Factors Associated with Atypical Representation.- Language Validation.- Validation of Non-Invasive Behavioral Techniques.- The Crowding Hypothesis.- Clinical Application.- 2. Memory.- Historical Background.- Original Reports of Post-Surgical Amnesia.- Rationale for Wada Memory Assessment.- General Assessment Strategies.- Memory Studies Involving Continuous Material Recognition.- Memory Studies Involving Discrete Item Presentation.- Retrograde Amnesia.- Methodologic Considerations.- Psychometric Issues.- Limitations.- Posterior Cerebral Artery Injection.- Conclusions.- 3. EEG and Neurologic Functions.- Review of Major Studies.- Neurological and EEG Effects.- Summary and Conclusions.- 4. Attention.- Arousal and Consciousness.- Hemispheric Specializations.- 5. Emotion.- Emotional Perception and Expression.- Major Empirical Investigations.- Causes of Amobarbital Emotional Reactions.- Hemispheric Specialization for Emotion.- Transcallosal Inhibition Hypothesis.- Lateralization of Autonomic Function.- Summary and Conclusions.- 6. MCG Wada Protocol.- Language Rating.- Memory Testing.- Wada Protocol Form.- References.- Senior Author Index.
