The Contribution of Normal Pregnancy to Eclampsia

Eclampsia, clinically defined as unexplained seizure in a woman with preeclampsia, is a life threatening complication unique to the pregnant state. However, a subpopulation of women with seemingly uncomplicated pregnancies experience de novo seizure without preeclamptic signs or symptoms, suggesting pregnancy alone may predispose the brain to seizure. Here, we hypothesized that normal pregnancy lowers seizure threshold and investigated mechanisms by which pregnancy may affect seizure susceptibility, including neuroinflammation and plasticity of gamma-aminobutyric acid type A receptor (GABA_AR) subunit expression. Seizure threshold was determined by quantifying the amount of pentylenetetrazole (PTZ) required to elicit electrical seizure in Sprague Dawley rats that were either nonpregnant (Nonpreg, n = 7) or pregnant (Preg; d20, n = 6). Seizure-induced vasogenic edema was also measured. Further, activation of microglia, a measure of neuroinflammation (n = 6-8/group), and GABA_AR δ- and γ2-subunit protein expression in the cerebral cortex and hippocampus (n = 6/group) was determined. Seizure threshold was lower in Preg compared to Nonpreg rats (36.7±9.6 vs. 65.0±14.5 mg/kg PTZ; p<0.01) that was associated with greater vasogenic edema formation (78.55±0.11 vs. 78.04±0.19% water; p<0.05). The % of active microglia was similar between groups; however, pregnancy was associated with downregulation of cortical GABA_AR-δ and hippocampal GABA_AR-γ2 expression. Overall, pregnancy appears to be a state of increased seizure susceptibility that is not due to neuroinflammation, but rather is associated with reduced expression of GABA_AR subunits and greater edema. Understanding neurophysiological changes occurring in normal pregnancy could allow for better prevention and management of de novo seizure, including pathologic states such as eclampsia.

A novel presentation of an ocular geste antagoniste in cervical dystonia: a case report

BACKGROUND

A geste antagoniste or sensory trick is a well described phenomenon associated with primary cervical dystonia. Craniocervical tactile stimulation or stereotyped limb movements allow patients to transiently ameliorate dystonic activation of cervical musculature.

CASE REPORT

We report a patient with primary cervical dystonia who presented with a novel "ocular" geste antagoniste. Through a sensory trick of tonic left eye deviation, the patient transiently reduces cervical dystonic activity (improved range of motion and reduced dystonic tremor). Multi-channel surface electromyography and video are used to illustrate these findings.

DISCUSSION

This case presents a unique clinical observation of specific voluntary eye movements attenuating cervical dystonia. The phenomenon is phenotypically consistent with previously described limb sensorimotor tricks.

Pathology of bilateral pulvinar degeneration following long duration status epilepticus

PURPOSE

To define the neuropathological findings of pulvinar degeneration seen in long duration status epilepticus.

METHODS

We review the clinical, radiologic, neurophysiologic, investigational and neuropathological findings on a 27 year old woman who died after 162 days of prolonged refractory status epilepticus.

RESULTS

Continuous EEG monitoring confirmed recurrent uncontrolled seizure activity bilaterally and independently, most frequent in the right fronto-temporal region. Initial MRI of the brain was normal. Repeat study until on day 127 of admission showed advanced changes, with bilateral pulvinar T2/FLAIR hyperintensities. The autopsy revealed sharply defined, grey, soft, granular nodules in each medial pulvinar nucleus. Microscopically these consisted of sharply defined paucicellular areas with loss of neurons and myelin and with numerous macrophages in their centers, surrounded by reactive astrocytes with relatively spared of axons. The spinal cord at cervical and thoracic levels showed symmetric spongy vacuolation in the central part of the dorsal columns and lateral corticospinal tracts, with mild myelin loss, relatively preserved axons. The pathological lesions found in this case in thepulvinar are somewhat similar to the pathologic lesions described in Wernicke's encephalopathy. Those found in the spinal cord of our patient resemble characteristic features of B12 related subacute combined degeneration.

CONCLUSION

Characteristic pulvinar degeneration may be found as an acquired phenomenon in prolonged refractory status epilepticus. We hypothesize that the neuropathological findings result from an excessive focal metabolic demand, secondary to neuronal network over activation in the setting of prolonged, frequent bi-temporal seizures.

Low back pain associates with altered activity of the cerebral cortex prior to arm movements that require postural adjustment

OBJECTIVE

To determine whether low back pain (LBP) associates with altered postural stabilization and concomitant changes in cerebrocortical motor physiology.

METHODS

Ten participants with LBP and 10 participants without LBP performed self-initiated, voluntary arm raises. Electromyographic onset latencies of the bilateral internal oblique and erector spinae muscles were analyzed relative to that of the deltoid muscle as measures of anticipatory postural adjustments (APAs). Amplitudes of alpha event-related desynchronization (ERD) and of Bereitschaftspotentials (BP) were calculated from scalp electroencephalography as measures of cerebrocortical motor physiology.

RESULTS

The APA was first evident in the trunk muscles contralateral to the arm raise for both groups. Significant alpha ERD was evident bilaterally at the central and parietal electrodes for participants with LBP but only at the electrodes contralateral and midline to the arm raise for those without LBP. The BP amplitudes negatively correlated with APA onset latencies for participants with (but not for those without) LBP.

CONCLUSIONS

Cerebrocortical activity becomes altered prior to arm movements requiring APAs for individuals with chronic LBP.

SIGNIFICANCE

These results support a theoretical model that altered central motor neurophysiology associates with LBP, thereby implying that rehabilitation strategies should address these neuromotor impairments.

People with chronic low back pain exhibit decreased variability in the timing of their anticipatory postural adjustments

Variability in the constituents of movement is fundamental to adaptive motor performance. A sustained decrease in the variability of anticipatory postural adjustments (APAs) occurs when performing cued arm raises following acute, experimentally induced low back pain (LBP; Moseley & Hodges, 2006). This observation implies that these changes in variability may also be relevant to people with chronic LBP. To confirm that this reduced variability in the timing of APAs is also evident in people with chronic LBP, the authors examined the standard deviations of electromyographic onset latencies from the bilateral internal oblique (IO) and erector spinae muscles (in relation to deltoid muscle onset) when 10 people with chronic LBP and 10 people without LBP performed 75 trials of rapid arm raises. The participants with LBP exhibited significantly less variability of their IO muscle onset latencies, confirming that the decreased variability of postural coordination that is evident following acutely induced LBP is also evident in people with chronic LBP. Thus, people with chronic LBP may be less capable of adapting their APAs to ensure postural stability during movement.

Emerging patterns of diffusion-weighted MR imaging in Creutzfeldt-Jakob disease: case report and review of the literature

We report the use of diffusion-weighted MR imaging in the early diagnosis and monitoring of the progression of a histopathologically proved case of sporadic Creutzfeldt-Jakob disease. Ribbon-like areas of hyperintensity in the cerebral cortex on diffusion-weighted images corresponded to the localization of periodic sharp-wave complexes on the electroencephalogram.

Intraoperative monitoring of motor evoked potentials: a review of 116 cases

We reviewed the results of motor evoked potential (MEP) and somatosensory evoked potential (SEP) monitoring during 116 operations on the spine or spinal cord. We monitored MEPs by electrically stimulating the spinal cord and recording compound muscle action potentials from lower extremity muscles and monitored SEPs by stimulating posterior tibial or peroneal nerves and recording both cortical and subcortical evoked potentials. We maintained anesthesia with an N2O/O2/opioid technique supplemented with a halogenated inhalational agent and maintained partial neuromuscular blockade using a vecuronium infusion. Both MEPs and SEPs could be recorded in 99 cases (85%). Neither MEPs nor SEPs were recorded in eight patients, all of whom had preexisting severe myelopathies. Only SEPs could be recorded in two patients, and only MEPs were obtained in seven cases. Deterioration of evoked potentials occurred during nine operations (8%). In eight cases, both SEPs and MEPs deteriorated; in one case, only MEPs deteriorated. In four cases, the changes in the monitored signals led to major alterations in the surgery. We believe that optimal monitoring during spinal surgery requires recording both SEPs and MEPs. This provides independent verification of spinal cord integrity using two parallel but independent systems, and also allows detection of the occasional insults that selectively affect either motor or sensory systems.

Complications of intravenous immune globulin treatment in neurologic disease

Intravenous immune globulin (IVIg) is advocated as a safe treatment for immune-mediated neurologic disease. We reviewed the medical records of 88 patients who were given IVIg for a neurologic illness. Major complications in four patients (4.5%) included congestive heart failure in a patient with polymyositis, hypotension after a recent myocardial infarction, deep venous thrombosis in a bed-bound patient, and acute renal failure with diabetic nephropathy. Other adverse effects included vasomotor symptoms 26, headache 23, rash 5, leukopenia 4, fever 3, neutropenia 1, proteinuria (1.9 g/day) 1, viral syndrome 1, dyspnea 1, and pruritus 1. Fifty-two patients (59%) had some adverse effect of IVIg infusion, most commonly vasomotor symptoms, headaches, fever, or shortness of breath in 40 (45%), which improved with reduced infusion rate or symptomatic medications. Five (6%) had asymptomatic laboratory abnormalities and seven (8%) had other minor adverse effects. Adverse effects led to discontinuation of therapy in 16% and permanent termination of therapy in 10% of patients. There was no mortality or long-term morbidity. Although adverse effects were frequent, serious complications were rare except in patients with heart disease, renal insufficiency, and bed-bound state.

Localization of a gene for partial epilepsy to chromosome 10q

There is strong evidence for a genetic contribution to epilepsy, but it is commonly assumed that this genetic contribution is limited to 'generalized' epilepsies, and that most forms of 'partial' epilepsy are nongenetic. In a linkage analysis of a single family containing 11 affected individuals, we obtained strong evidence for localization of a gene for partial epilepsy. This susceptibility gene maps to chromosome 10q, with a maximum two-point lod score for D10S192 of 3.99 at theta = 0.0. All affected individuals share a single haplotype for seven tightly linked contiguous markers; the maximum lod score for this haplotype is 4.83 at theta = 0.0. Key recombinants place the susceptibility locus within a 10 centimorgan interval.