Lori A. Schuh

A direct brain interface based on event-related potentials

Cross-correlation between a trigger-averaged event-related potential (ERP) template and continuous electrocorticogram was used to detect movement-related ERPs. The accuracy of ERP detection for the five best subjects (of 17 studied), had hit percentages >90% and false positive percentages <10%. These cases were considered appropriate for operation of a direct brain interface.

Identification of electrocorticogram patterns as the basis for a direct brain interface.

This study reports on the first step in the development of a direct brain interface based on the identification of event-related potentials (ERPs) from an electrocorticogram obtained from the surface of the cortex. Ten epilepsy surgery patients, undergoing monitoring with subdural electrode strips and grid arrays, participated in this study. Electrocorticograms were continuously recorded while subjects performed multiple repetitions for each of several motor actions. ERP templates were identified from action-triggered electrocorticogram averages using an amplitude criterion. At least one ERP template was identified for all 10 subjects and in 56% of all electrode-recording sets resulting from a subject performing an action. These results were obtained with electrodes placed solely for clinical purposes and not for research needs. Eighty-two percent of the identified ERPs began before the trigger, indicating the presence of premovement ERP components. The regions yielding the highest probability of valid ERP identification were the sensorimotor cortex (precentral and postcentral gyri) and anterior frontal lobe, although a number were recorded from other areas as well. The recording locations for multiple ERPs arising from the performance of a specific action were usually found on close-by electrodes. ERPs associated with different actions were occasionally identified from the same recording site but often had noticeably different characteristics. The results of this study support the use of ERPs recorded from the cortical surface as a basis for a direct brain interface.

Suppression of dyskinesias in advanced Parkinson's disease. II: Increasing daily clozapine doses suppress dyskinesias and improve parkinsonism symptoms

We gave increasing daily doses of clozapine to six patients with advanced Parkinsons disease (PD) and levodopa-induced dyskinesias. Clozapine reduced the daily dyskinesia time five-fold, increased “on” time eightfold, and doubled the serum [DOPA] producing half-maximal dyskinesia. Parkinsonism scores after overnight DOPA withdrawal improved with increasing daily clozapine intake, and there was no clozapine dose-related shift in levodopa dose response for relief of parkinsonism. Patients experienced sedation, sialorrhea, and orthostatic hypotension. Clozapine appears to be an effective agent for suppression of levodopa-induced dyskinesias in PD.

Suppression of dyskinesias in advanced Parkinson's disease: I. Continuous intravenous levodopa shifts dose response for production of dyskinesias but not for relief of parkinsonism in patients with advanced Parkinson's disease

We characterized the clinical dose-response curves for relief of parkinsonism and production of dyskinesias as a function of plasma levodopa and 3-O-methyldopa levels in six patients with advanced Parkinsons disease (PD) and fluctuating responses to oral levodopa/carbidopa. Dose response to ramped intravenous levodopa infusion was measured after overnight drug withdrawal on two occasions: first after chronic, intermittent oral levodopa/carbidopa, and second after 3 to 5 days of continuous intravenous levodopa. Continuous intravenous levodopa shifted the dyskinesia dose-response curve to the right, reduced maximum dyskinesia activity, but did not significantly alter dose response for relief of parkinsonism. Improvement in dyskinesia was apparent by the second day of continuous levodopa, during which ratios of plasma dopa/3-O-methyldopa remained constant. Our results support the hypothesis that relief of parkinsonism and production of dyskinesia by levodopa occur by separate mechanisms.

Indications and outcome of ictal recording with intracerebral and subdural electrodes in refractory complex partial seizures

Intracranial electrophysiologic recording has often been used to localize ictal onset zones in presurgical evaluation of refractory complex partial seizures. Specific indications for intracranial ictal monitoring have not been analyzed in detail, however. The authors designed this study to test the utility of intracranial monitoring in specific indications and considered six specific indications for intracranial monitoring. They compared prospectively determined indications and outcomes of chronic intracerebral and subdural electrophysiologic recording in 50 consecutive patients whose ictal onset zones had been inadequately localized with interictal and ictal EEG using extracranial electrodes, magnetic resonance imaging, interictal[18F]fluorodeoxyglucose positron emission tomography, and neuropsychological testing. In 47 patients ictal onset zones were localized with intracranial recordings, leading to resections in 38 patients. Each indication for intracranial monitoring selected a group in which the majority went on to have efficacious epilepsy surgery (5-year follow-up). Definitive diagnosis of bilateral independent ictal onset zones in temporal lobe epilepsy required intracranial ictal EEG. Intracranial EEG localization supported efficacious resection in most patients, despite contradictory or nonlocalizing extracranial ictal EEG and neuroimaging abnormalities. Critical analysis of these specific indications for intracranial monitoring may be useful in multicenter evaluation of these techniques.

Value of Inpatient Diagnostic CCTV-EEG Monitoring in the Elderly

Summary: Purpose: To examine the outcome of inpatient diagnostic closed circuit TV‐EEG (CCTV‐EEG) monitoring in a consecutive series of elderly patients admitted to an adult epilepsy‐monitoring unit (EMU) over a continuous 6‐year period.

Education Research: Neurology residency training in the new millennium

Objective: To survey adult neurology program directors (ANPD) to identify their most pressing needs at a time of dramatic change in neurology resident education. Methods: All US ANPD were surveyed in 2007 using an instrument adjusted from a 1999 survey instrument. The goal was to characterize current program content, the institution and evaluation of the core competencies, program director characteristics, program director support, the institution of work duty hour requirements, resident support, and the curriculum needs of program directors and programs. Results: A response rate of 82.9% was obtained. There is a significant disconnect between administration time spent by ANPD and departmental/institutional support of this, with ANPD spending approximately 35% of a 50-hour week on administration with only 16.7% salary support. Rearrangement of rotations or services has been the most common mode for ANPD to deal with work duty hour requirements, with few programs employing mid level providers. Most ANPD do not feel work duty hour reform has improved resident education. More residents are entering fellowships following graduation than documented in the past. Curriculum deficiencies still exist for ANPD to meet all Neurology Program Requirements, especially for nontraditional neurology topics outside the conventional bounds of clinical neurology (e.g., practice management). Nearly one quarter of neurology residency programs do not have a meeting or book fund for every resident in the program. Conclusions: Adult neurology program directors (ANPDs) face multiple important financial and organizational hurdles. At a time of increasing complexity in medical education, ANPDs need more institutional support.

Initiation of an effective neurology resident ethics curriculum.

The authors’ neurology residency program used a case-based curriculum developed by the American Academy of Neurology’s Ethics, Law and Humanities Committee to provide a resident education course in ethics. A pretest and post-test were developed and administered. A survey was completed at the end of the course to evaluate resident satisfaction. Post-test scores improved an average of 19% and this increase was significant (p < 0.0004). Residents found the course useful for their education and the time commitment acceptable.

Invited article: Neurology education research.

Background: There is a need to rigorously study the neurologic education of medical students, neurology residents, and neurologists to determine the effectiveness of our educational efforts. Methods: We review the status of neurologic education research as it pertains to the groups of interest. Results: We identify opportunities and impediments for education research. The introduction of the Accreditation Council for Graduate Medical Education core competencies, the Accreditation Council of Continuing Medical Education requirement to link continuing medical education to improved physician behavior and patient care, and the American Board of Medical Specialties/American Board of Psychiatry and Neurology–mandated maintenance of certification program represent research opportunities. Challenges include numerous methodologic issues such as definition of the theoretical framework of the study, adequate sample size ascertainment, and securing research funding. Conclusions: State-of-the-art education research will require multidisciplinary research teams and innovative funding strategies. The central goal of all concerned should be defining educational efforts that improve patient outcomes. GLOSSARY: AAN = American Academy of Neurology; ABPN = American Board of Psychiatry and Neurology; ACCME = Accreditation Council of Continuing Medical Education; ACGME = Accreditation Council for Graduate Medical Education; CME = continuing medical education; ERWG = Education Research Work Group; MOC = Maintenance of Certification; PI = Principal Investigator; RITE = Resident Inservice Training Examination.

Electrocorticogram as the basis for a direct brain interface: Opportunities for improved detection accuracy

A direct brain interface (DBI) based on the detection of event-related potentials (ERPs) in human electrocorticogram (ECoG) is under development. Accurate detection has been demonstrated with this approach (near 100% on a few channels) using a single-channel cross-correlation template matching (CCTM) method. Several opportunities for improved detection accuracy have been identified. Detection using a multiple-channel CCTM method and a variety of detection methods that take advantage of the simultaneous occurrence of ERPs and event-related desynchronization/synchronization (ERD/ERS) have been demonstrated to offer potential for improved detection accuracy.