Dean Naritoku

Intravenous valproate is well tolerated in unstable patients with status epilepticus

Article abstract The authors reviewed hospital records of 13 patients with status epilepticus and hypotension who received IV valproate therapy. Most patients were elderly (74.4 ± 12.5 [SD] years) and received a loading dose of valproate of 25.1 ± 5.0 mg/kg (range 14.7 to 32.7), at a rate of 36.6 ± 25.1 mg/min (range 6.3 to 100). There were no significant changes in blood pressure, pulse, or use of vasopressors. The data suggest that valproate loading is well tolerated, even in patients with cardiovascular instability.

Prolongation of midazolam half-life after sustained infusion for status epilepticus

Article abstract Midazolam clearance was examined in two patients with medically refractory convulsive status epilepticus. One patient received a constant infusion of midazolam for 68 hours and the other patient received a constant infusion of midazolam for 148 hours. In both patients the decline in level was, overall, much slower than expected. The half-lives of the terminal phase were longer than typically published (52.9 hours in Patient 1 and 20.1 hours in Patient 2). Thus, the data suggest that midazolam exhibits use-dependent pharmacokinetic changes that may be important clinically in situations that require prolonged midazolam therapy.

Seizures, epilepsy, and functional recovery after traumatic brain injury: a reappraisal

Traumatic brain injury is an epidemic in the United States, with an estimated incidence of 2 million cases per year, of which almost 500,000 are admitted to the hospital.lZ2 In addition, the survival rates after brain injury are on the rise.3 As a result, brain injury has become an increasing problem in this country. Its major sequelae, post-traumatic epilepsy and functional disability, impose a high cost t o society and the individual survivors in terms of acute health care, rehabilitation, extended care, and anticonvulsant drug therapy. Furthermore, the resulting epilepsy and physical impairments are associated with inability to return to social isolation, and failure to resume leisure ac t iv i t ie~ .~ .~ Finally, traumatic brain injury creates a high economic burden that costs approximately

Non-linear dynamics in parkinsonism

25 billion per year,l and the long-term costs associated with this condition undoubtedly contribute to much of this expense. Previous research on traumatic brain injury has largely examined the issues of post-traumatic epilepsy and functional outcome as separate entities. However, emerging data indicate that these problems are inextricably intertwined. As we review, there are complex interactions between mechanisms of functional brain recovery and the genesis of post-traumatic epilepsy. Although the nature of brain injury influences functional outcome and the probability of epileptogenesis, an increasing body of evidence indicates the presence or absence of seizures, their temporal presentation with respect to brain injury, and that administration of anticonvulsant drugs may have profound effects on functional recovery. Because these variables may be modified by medical therapy, it is important to better understand their interactions to maximally improve the outcome in persons who sustain traumatic brain injury. Several series from civilian and military populations have identified risk factors for post-traumatic epilepsy. We recently reviewed specific risk factors c~mprehensively.~ To summarize briefly, it is clear that the greatest predictor of post-traumatic epilepsy is the severity of the injury.8-10 In cases of the most severe parenchymal injuries, the frequency of posttraumatic epilepsy approaches or exceeds 50%.11J2 Because both the worst neurologic deficits and highest frequency of post-traumatic epilepsy occur in the most severely brain-injured persons, it is not surprising that the expression of seizures has not been extensively examined as an independent factor in analyses of functional recovery.

Computed tomographic method to quantify electrode lead deformation and subdural gap after lead implantation for deep brain stimulation

Over the last 30 years, the functions (and dysfunctions) of the sensory-motor circuitry have been mostly conceptualized using linear modelizations which have resulted in two main models: the “rate hypothesis” and the “oscillatory hypothesis.” In these two models, the basal ganglia data stream is envisaged as a random temporal combination of independent simple patterns issued from its probability distribution of interval interspikes or its spectrum of frequencies respectively. More recently, non-linear analyses have been introduced in the modelization of motor circuitry activities, and they have provided evidences that complex temporal organizations exist in basal ganglia neuronal activities. Regarding movement disorders, these complex temporal organizations in the basal ganglia data stream differ between conditions (i.e., parkinsonism, dyskinesia, healthy control) and are responsive to treatments (i.e., l-DOPA, deep brain stimulation). A body of evidence has reported that basal ganglia neuronal entropy (a marker for complexity/irregularity in time series) is higher in hypokinetic state. In line with these findings, an entropy-based model has been recently formulated to introduce basal ganglia entropy as a marker for the alteration of motor processing and a factor of motor inhibition. Importantly, non-linear features have also been identified as a marker of condition and/or treatment effects in brain global signals (EEG), muscular activities (EMG), or kinetic of motor symptoms (tremor, gait) of patients with movement disorders. It is therefore warranted that the non-linear dynamics of motor circuitry will contribute to a better understanding of the neuronal dysfunctions underlying the spectrum of parkinsonian motor symptoms including tremor, rigidity, and hypokinesia.

Parkinsonian Balance Deficits Quantified Using a Game Industry Board and a Specific Battery of Four Paradigms.

BACKGROUND Deep brain stimulation is an effective treatment for movement disorders and psychiatric conditions. Intra-operative and post-operative events can result in brain tissue deformation (i.e. subdural gaps) which may cause lead deformation and its displacement from optimal target. We developed a method to quantify postoperative lead deformation and we present two DBS cases to illustrate the phenomena of lead deformation resulting from the development of subdural gaps. NEW METHOD We present a semi-automatic computational algorithm using Computed Tomography scanning with reconstruction to determine lead curvature relative to a theoretical straight lead between the skull entry site and lead tip. Subdural gap was quantified from the CT scan. RESULTS In 2 patients who had leads implanted, analysis of CT scans was completed within 5 min each. The maximum deviation of the observed lead from the theoretical linear path was 1.1 and 2.6 mm, and the subdural gap was 5.5 and 9.6 mL, respectively. COMPARISON WITH EXISTING METHOD(S) This is the first method allowing a comprehensive characterization of the lead deformation in situ. CONCLUSIONS The computational algorithms provide a simple, semiautomatic method to characterize in situ lead curvature related to brain tissue deformation after lead placement.

Using a Virtual Training Program to Train Community Neurologist on EEG Reading Skills

This study describes a cost-effective screening protocol for parkinsonism based on combined objective and subjective monitoring of balance function. Objective evaluation of balance function was performed using a game industry balance board and an automated analyses of the dynamic of the center of pressure in time, frequency, and non-linear domains collected during short series of stand up tests with different modalities and severity of sensorial deprivation. The subjective measurement of balance function was performed using the Dizziness Handicap Inventory questionnaire. Principal component analyses on both objective and subjective measurements of balance function allowed to obtained a specificity and selectivity for parkinsonian patients (vs. healthy subjects) of 0.67 and 0.71 respectively. The findings are discussed regarding the relevance of cost-effective balance-based screening system as strategy to meet the needs of broader and earlier screening for parkinsonism in communities with limited access to healthcare.

Long-Term Tolerability and Safety of Lamotrigine Extended-Release: Pooled Analysis of Three Clinical Trials

Background: EEG training requires iterative exposure of different patterns with continuous feedback from the instructor. This training is traditionally acquired through a traditional fellowship program, but only 28% of neurologists in training plan to do a fellowship in EEG. Purpose: The purpose of this study was to determine the value of online EEG training to improve EEG knowledge among general neurologists. Methods: The participants were general neurologists invited through bulk e-mail and paid a fee to enroll in the virtual EEG program. A 40-question pretest exam was performed before training. The training included 4 online learning units about basic EEG principles and 40 online clinical EEG tutorials. In addition there were weekly live teleconferences for Q&A sessions. At the end of the program, the participants were asked to complete a posttest exam. Results: Fifteen of 20 participants successfully completed the program and took both the pre- and posttest exams. All the subjects scored significantly higher in the posttest compared to their baseline score. The average score in the pretest evaluation was 61.7% and the posttest average was 87.8% (p = .0002, two-tailed). Conclusions: Virtual EEG training can improve EEG knowledge among community neurologists.