Coupling of fMRI and NIRS measurements in the study of negative BOLD response to intermittent photic stimulation

Functional Magnetic Resonance Imaging (fMRI) in combination with Near Infrared Spectroscopy (NIRS) is finding widespread use in the analysis of brain function. While most of the studies deal with the detection of positive responses, here we focus on negative responses to visual stimulation. In a group fMRI study on Intermittent Photic Stimulation (IPS) we detected a sustained Negative BOLD Response (NBR) in the extrastriate visual cortex. To confirm and better characterize NBR, we repeated the same protocol during NIRS recordings. In this paper we show fMRI results and demonstrate the NBR on the basis of NIRS findings.

Efficacy and tolerability of eperisone in patients with spastic palsy: a cross-over, placebo-controlled dose-ranging trial

BACKGROUND AND OBJECTIVES

Central muscle relaxants are a clinical option in patients with spastic palsy. Eperisone is a central muscle relaxant used in several conditions, but its therapeutic potential in spastic palsy needs to be verified. This dose-ranging trial compares two doses of eperisone in patients with spastic palsy associated to cerebral or spinal diseases.

PATIENTS AND METHODS

In this randomized, placebo-controlled, double-blind, three-way cross-over study, patients (18-75 years) with spastic palsy received eperisone 150 mg/day, eperisone 300 mg/day, or placebo for 8 weeks. Treatment periods lasted for 14 days. Objective clinical parameters (intensity of spasticity and physiological reflexes) and functional parameters (walking capability, capability to climb stairs, rigidity) were measured. Tolerability was also evaluated.

RESULTS

Eighteen patients were enrolled. The reduction in the intensity of spasticity versus the beginning of each treatment cycle was significant with eperisone 300 mg/day (p = 0.004). Similar findings were observed in the evaluation of patellar reflex (p = 0.01), while the other reflexes were not significantly different. Walking capability was significantly improved with eperisone 300 mg/day (p < 0.05). No significant differences were observed in the capability to climb stairs and in rigidity. A trend towards a reduction in pain was noted with eperisone 300 mg/day versus placebo. The incidence of adverse events was similar in all groups.

DISCUSSION

Eperisone 300 mg/day might be an effective and well-tolerated treatment for spastic palsy. Larger studies are required to further characterize the efficacy of eperisone in this therapeutic area.

Efficacy and tolerability of eperisone and baclofen in spastic palsy: a double-blind randomized trial

INTRODUCTION

Few trials have compared different central muscle relaxants in the treatment of spastic palsy. This head-to-head phase 3 trial compares oral eperisone, a central muscle relaxant with a promising activity in spasticity therapy, and oral baclofen.

METHODS

Patients (>18 years) with moderate to severe spastic palsy were eligible in this double-blind, randomized study; they received eperisone 300 mg/ day or baclofen 60 mg/day for 6 weeks. The efficacy evaluations included: functional analysis (Pedersen's scale, muscular tone, joint range of motion, 10-meter walking time); physiological and pathological reflexes; and electromyography (Hmax/Mmax amplitude ratio and the Wartenberg test). Physicians and patients globally assessed treatment efficacy.

RESULTS

Both eperisone (n=40) and baclofen (n=40) significantly improved functionality of lower limbs versus baseline (eperisone: -9.1%, P<0.01; baclofen: -8.3%, P<0.05), but only eperisone improved this parameter in the upper limbs (-7.8%, P<0.01 vs. -6.3%, P=NS). Both drugs reduced muscular tone from week 2. Only eperisone improved the joint range of motion (-32.5%, P<0.01 vs. -14.6%, P=NS). Both treatments reduced the 10-meter walking time (eperisone: -20.2%, P<0.01; baclofen: -24.0%, P<0.01); this effect was evident at week 2 with eperisone only. Both drugs improved reflexes. Eperisone and baclofen decreased the Hmax/Mmax amplitude ratio (eperisone: -30.0%, baclofen: -18.6%; P<0.01 for both). Eperisone increased the number of leg oscillations at the Wartenberg test (P<0.05) while baclofen increased the velocity of leg falling (P<0.01). For tolerability, no differences were observed between eperisone and baclofen in any parameters. Eperisone was judged as "good" by a higher number of physicians and patients than baclofen. Eighteen adverse events, most of mild intensity, were reported with eperisone and 27 with baclofen.

CONCLUSION

Eperisone 300 mg/day and baclofen 60 mg/day, administered orally, are effective and well-tolerated drugs in the treatment of spastic palsy. However, eperisone might be associated with some additional clinical benefits when compared with baclofen.

On the Classification of Experimental Data Modeled Via a Stochastic Leaky Integrate and Fire Model Through Boundary Values

We present a computational algorithm aimed to classify single unit spike trains on the basis of observed interspikes intervals (ISI). The neuronal activity is modeled with a stochastic leaky integrate and fire model and the inverse first passage time method is extended to the Ornstein-Uhlenbeck (OU) process. Differences between spike trains are detected in terms of the boundary shape. The proposed classification method is applied to the analysis of multiple single units recorded simultaneously in the thalamus and in the cerebral cortex of unanesthetized rats during spontaneous activity. We show the existence of at least three different firing patterns that could not be classified using the usual statistical indices.

Inductive current density perturbations to probe electron internal transport barriers in tokamaks

Improved electron energy confinement in tokamak plasmas, related to internal transport barriers, has been linked to nonmonotonic current density profiles. This is difficult to prove experimentally since usually the current profiles evolve continuously and current injection generally requires significant input power. New experiments are presented, in which the inductive current is used to generate positive and negative current density perturbations in the plasma center, with negligible input power. These results demonstrate unambiguously for the first time that the electron confinement can be modified significantly solely by perturbing the current density profile.

Sensorimotor cortex excitability in Unverricht–Lundborg disease and Lafora body disease

Objective: To investigate whether Unverricht–Lundborg disease (ULD) and Lafora body disease (LBD) can be differentiated on the basis of their neurophysiologic profiles.

Methods: Somatosensory evoked potentials (SSEPs), long-loop reflexes (LLRs), and the influence of conditioning nerve stimulation on the motor potentials evoked by transcranial stimulation in 8 patients with LBD and 10 patients with ULD were investigated.

Results: Both groups showed sensorimotor cortex hyperexcitability, but their electrophysiologic profiles were different. Enlarged P25 to N33 SSEP components and enhanced LLRs were common in the ULD patients, whereas medium-latency “giant” SSEP components and less consistently enhanced LLRs were more frequently found in the patients with LBD. Cortical relay time was extremely brief in ULD but varied in LBD. Conditioning somatosensory stimuli differently affected motor cortex excitability, leading to early facilitation in ULD and delayed and prolonged facilitation in LBD.

Conclusions: Patients with Unverricht–Lundborg disease (ULD) and Lafora body disease (LBD) have different electrophysiologic profiles. The ULD findings point to an aberrant subcortical or cortical loop (possibly short-cutting the somatosensory cortex) that is involved in generating the prominent action myoclonus characterizing the disorder. The LBD findings highlight sustained hyperexcitability of the sensorimotor cortex in response to afferent stimuli, which fit with a more severe impairment of inhibitory mechanisms.

A novel mutation in KCNQ2 associated with BFNC, drug resistant epilepsy, and mental retardation

BACKGROUND

Benign familial neonatal convulsion (BFNC) is a rare autosomal dominant disorder caused by mutations in two genes, KCNQ2 and KCNQ3, encoding for potassium channel subunits underlying the M-current. This current limits neuronal hyperexcitability by causing spike-frequency adaptation.

METHODS

The authors describe a BFNC family with four affected members: two of them exhibit BFNC only while the other two, in addition to BFNC, present either with a severe epileptic encephalopathy or with focal seizures and mental retardation.

RESULTS

All affected members of this family carry a novel missense mutation in the KCNQ2 gene (K526N), disrupting the tri-dimensional conformation of a C-terminal region of the channel subunit involved in accessory protein binding. When heterologously expressed in CHO cells, potassium channels containing mutant subunits in homomeric or heteromeric configuration with wild-type KCNQ2 and KCNQ3 subunits exhibit an altered voltage-dependence of activation, without changes in intracellular trafficking and plasma membrane expression.

CONCLUSION

The KCNQ2 K526N mutation may affect M-channel function by disrupting the complex biochemical signaling involving KCNQ2 C-terminus. Genetic rather than acquired factors may be involved in the pathophysiology of the phenotypic variability of the neurologic symptoms associated with BFNC in the described family.

Retrospective diagnosis of congenital cytomegalovirus infection and cortical maldevelopment

Congenital cytomegalovirus (CMV) infection can cause malformations of cortical development (MCD). It is difficult to establish CMV as a cause of MCD several months postpartum. This can now be done by detection of CMV DNA in dried blood spots (DBS test) on Guthrie cards. The authors used DBS tests to assess 10 patients with MCD of unknown cause. Four of the 10 patients were positive for CMV.

Unilateral periventricular nodular heterotopia associated with diffuse areas of cerebral functional abnormalities

A 17-year-old boy with polymorphic simple and complex partial seizures is described. Magnetic resonance imaging revealed a unilateral periventricular nodular heterotopia near the occipital ventricular right horn. Interictal and ictal electroencephalographic recordings showed bilateral specific epileptiform anomalies in the occipital region and asynchronous slow waves in frontal areas. Single photon emission computed tomography documented a reduction in regional cerebral blood flow in an area of the left occipital cortex and a symmetric increase in tracer uptake in the frontal lobes. The neuropsychologic assessment revealed a dysfunction of the frontal associative areas. Data collected led the authors to suspect a more diffuse cortical dysfunction than the nodular heterotopia revealed on magnetic resonance imaging.

Familial perisylvian polymicrogyria: a new familial syndrome of cortical maldevelopment

Two familial X-linked dominant syndromes of cortical maldevelopment have recently been described: double cortex/lissencephaly syndrome and bilateral periventricular nodular heterotopia. We report on 12 kindreds with familial perisylvian polymicrogyria (FPP) presenting at 10 centers, examine the clinical presentation in these familial cases, and propose a possible mode of inheritance. The clinical and radiological pattern was variable among the 42 patients, with clinical differences among the families and even within members of the same family. Pseudobulbar signs, cognitive deficits, epilepsy, and perisylvian abnormalities on imaging studies were not found in all patients. When present, they displayed a spectrum of severity. The only clear correlation in this study was between bilateral imaging findings and abnormal tongue movements and/or pronounced dysarthria. Most of the families provided evidence suggestive of, or compatible with, X-linked transmission. On the other hand, the pedigrees of 2 families ruled out X-linked inheritance. The most likely mode of inheritance for these 2 families was autosomal dominant with decreased penetrance; however, autosomal recessive inheritance with pseudodominance could not be ruled out in 1 family. We conclude that FPP appears to be genetically heterogeneous. However, most of the families probably represent a third previously undescribed X-linked syndrome of cortical maldevelopment.

Bilateral perisylvian polymicrogyria in three generations

A family is described in which bilateral perisylvian polymicrogyria was present in 6 members of 3 consecutive generations. Typical anatomic and clinical findings of the syndrome, with a mild phenotype, were present in the 5 affected women from all 3 generations. More severe impairment was observed in the only affected male individual, a boy, in the third generation. Analysis of the pedigree and severity of the phenotype in the affected boy are consistent with transmission of an X-linked dominant trait, although other patterns of inheritance cannot be ruled out with certainty.

Diazepam binding inhibitor (DBI) in the plasma of pediatric and adult epileptic patients

The polypeptide diazepam binding inhibitor (DBI) displays epileptogenic activity by binding to benzodiazepine receptors. We analyzed DBI concentrations in the plasma of pediatric and adult epileptic patients, as a possible peripheral marker in epilepsy. DBI plasma concentrations are significantly higher (+ 62%, P < 0.001) in adult patients and slightly but significantly higher (+15%, P < 0.01) in pediatric patients, compared to age-related controls. Strikingly, plasma DBI is much higher (+81%, P < 0.001) in generalized epilepsy in adults and in drug-resistant pediatric and adult patients. Based on these findings, plasma DBI may be considered as a peripheral biological marker of epilepsy and, in association with lymphocyte benzodiazepine receptor density, of anticonvulsant drug responsiveness.

Lung cancer mortality among female mine workers exposed to silica

A mortality cohort study (1951-1988) was conducted on 526 female workers in two lead and zinc mines in southwestern Sardinia (Italy), 310 of whom had been exposed to silica. Women exposed to silica showed a nonsignificant 38% increase in the standardized mortality ratio (SMR) for nonmalignant respiratory diseases, which was highest and statistically significant among women at the mine with the highest exposure to silica (SMR = 217; 95% confidence interval [CI] = 104, 400; based on 10 observed and 4.6 expected deaths). Five deaths from lung cancer also occurred among those exposed to silica (SMR = 283; 95% CI = 91,660), but the excess was not related to the level or duration of exposure. No information was available concerning lifestyle risk factors in this cohort. However, smoking was quite rare among Sardinian women at the time cohort members worked, so it may be presumed that very few of them were smokers.

Double cortex syndrome: electroclinical study of three cases

We describe three female patients (aged 10, 11 and 21 years) with a Magnetic Resonance appearance of band heterotopia, a diffuse neuronal migration disorder, also known as double cortex syndrome. The clinical picture was characterized by the association of epilepsy and mental retardation in all three cases, as has been previously described in patients with double cortex syndrome. The epileptic syndrome (Lennox-Gastaut syndrome in one case, and symptomatic partial epilepsy in the other two), the response to medical treatment, and the severity of mental retardation were markedly different in the three patients. No clear-cut relationship was found between the clinical picture and the severity of the neuronal migration disorder, as revealed by magnetic resonance imaging. In the three cases, EEG shares some common features: multifocal epileptic activity with frequent bilateral diffusion, and high-amplitude anterior fast activity, intermingled in two patients with bursts of repetitive spikes.

Hypersomnia in dystrophia myotonica: a neurophysiological and immunogenetic study

Ten patients with dystrophia myotonica (8 adults and 2 prepubertal children), from three unrelated families, were investigated for diurnal sleepiness, using a sleep questionnaire and multiple sleep latency test (MSLT). Immunogenetic study was also carried out to assess the involvement of HLA region genes in modulating susceptibility to excessive diurnal sleepiness (EDS). EDS was reported by 5 patients and confirmed in each case by MSLT. In the whole patients group, mean daytime sleep latency was significantly shorter than in healthy controls matched for age and sex. At clinical or neurophysiological evaluation, EDS did not show the features associated with the narcoleptic type. In only one case hypersomnolence could be explained by underlying sleep-disordered breathing. HLA patterns were different from those frequently observed in the narcoleptic or non-narcoleptic types of hypersomnia. In patients with EDS, the frequency of the DQW1 and particularly of the DRW6-DQW1 haplotype appeared to be over-represented.

Differential effects of valproic acid and enzyme-inducing anticonvulsants on nimodipine pharmacokinetics in epileptic patients

1. The single dose pharmacokinetics of orally administered nimodipine (60 mg) were investigated in normal subjects and in two groups of epileptic patients receiving chronic treatment with hepatic microsomal enzyme-inducing anticonvulsants (carbamazepine, phenobarbitone or phenytoin) and sodium valproate, respectively. 2. Compared with the values found in the control group, mean areas under the plasma nimodipine concentration curve were lowered by about seven-fold (P less than 0.01) in patients taking enzyme-inducing anticonvulsants and increased by about 50% (P less than 0.05) in patients taking sodium valproate. 3. Nimodipine half-lives were shorter in enzyme-induced patients than in controls (3.9 +/- 2.0 h vs 9.1 +/- 3.4 h, means +/- s.d., P less than 0.01), but this difference could be artifactual since in the patients drug concentrations declined rapidly below the limit of assay, thus preventing identification of a possible slower terminal phase. In valproate-treated patients, half-lives (8.2 +/- 1.8 h) were similar to those found in controls.

Daytime sleepiness in healthy university students: a multiparametric study

A multiparametric investigation of daytime sleepiness was performed in 18 healthy young university students. After undergoing a standard polysomnographic recording at home the night before, all subjects were evaluated by Multiple sleep latency test (MSLT) at 10.00, 12.00, 14.00, 16.00, 18.00. Subjective sleepiness (by using Visual Analogue Rating Scale) and performance tasks (Cancellation Test, Digit Symbol Substitution, Choice Reaction Time, Critical Flicker Fusion Threshold) were also assessed at the same times. Mean daily sleep latency was found to be about 10 minutes, with several individual values in the borderline range (greater than 5 less than 10 minutes). Subjects did not rate themselves as excessively sleepy and there was no correlation between subjective and objective estimates of sleepiness. No consistent correlation was found between subjective-objective sleepiness and results of performance tests. Anxiety trait (Spielberg State Anxiety Trait) did not correlate with sleepiness, but higher anxiety scores were significantly associated with poor performance. These results confirm the occurrence of fairly marked objective drowsiness in healthy young subjects which, however, was not associated with subjective sleepiness and did not adversely affect performance on a variety of tests of CNS function.

Comparative pharmacokinetics and pharmacodynamics of eterobarbital and phenobarbital in normal volunteers

The comparative pharmacokinetics and pharmacodynamics of single oral doses of eterobarbital (N,N'-dimethoxymethylphenobarbital, DMMP, 400 mg) and phenobarbital (200 mg) were evaluated in a double-blind study in 8 normal volunteers. Following administration of DMMP, no unchanged drug could be detected in serum. The active monomethoxymethyl metabolite (MMP) appeared rapidly in the circulation but its concentration remained generally low and declined below the limit of detection (0.5 micrograms/ml) usually before 9.5 h. Serum levels of DMMP-derived PB increased slowly and reached a peak between 24 and 48 h in most cases. One subject showed an atypical pharmacokinetic profile, characterized by relatively high levels of MMP and a delayed appearance of low levels of PB. After administration of PB, serum drug levels peaked within 1.5 h and remained, at all sampling times, higher than those observed after intake of DMMP. Compared with DMMP, PB induced greater sedative effects as assessed by visual analogue rating scale, critical flicker fusion frequency and multiple sleep latency tests.

Nocturnal sleep and oxygen balance in Duchenne muscular dystrophy. A clinical and polygraphic 2-year follow-up study

A long-term, clinical and polygraphic investigation of nocturnal sleep was performed in nine non-ambulatory Duchenne muscular dystrophy patients (mean age 16.2 years, range 10-20) with normal daytime blood gas tensions. The data show that nocturnal sleep has some adverse influence on oxygen balance in these patients as suggested by the occurrence of arterial oxyhaemoglobin desaturation occurring mainly during REM stages. This adverse effect tended to worsen significantly within a 2-year period in the absence of any sleep-related symptoms. A significant correlation between the degree of oxygen imbalance during sleep and the degree of restrictive thoracic syndrome during wakefulness was shown.

Sleep patterns in patients with late onset partial epilepsy receiving chronic carbamazepine (CBZ) therapy

A night-time polygraphic sleep recording was performed in 14 patients with late onset partial epilepsy receiving chronic carbamazepine monotherapy. All patients had unstable nocturnal sleep patterns as indicated by significantly altered sleep continuity parameters compared with normal controls. Patients with poor seizure control tended to show greater alterations of sleep stability compared to patients in complete clinical remission but the difference failed to reach statistical significance. Epileptic patients also showed less REM sleep and longer REM latencies compared with normal controls, the most altered REM values being observed in patients with poor seizure control. These data confirm that polygraphic sleep alterations are seen in patients with symptomatic focal epilepsy and indicate that these abnormalities occur irrespective of seizure recurrence.

Time-dependent pharmacodynamic effects of phenobarbital in humans

The relationship between the serum concentration of phenobarbital and its pharmacodynamic effects was assessed in a double-blind controlled study in eight normal volunteers who were given single oral doses of phenobarbital (200 mg) and placebo according to a randomized cross-over design. Compared with the placebo session, phenobarbital was found to induced CNS-depressing effects as assessed by visual analogue rating scales (VARS) and critical flicker fusion tests (CFF), whereas no significant effects were detected on choice reaction times, tappings, and digit symbol substitutions. There was a clear-cut dissociation between the time course of serum phenobarbital levels, which remained at a plateau throughout most of the period of observation (up to 72 h) and its subjective (VARS) and objective (CFF) effects, which could be documented only for up to 9 h after administration. These data suggest that pharmacodynamic tolerance develops rapidly even after a single oral dose of the drug. Multiple Sleep Latency Tests (MSLTs) were also performed in the same subjects and showed that phenobarbital increases diurnal drowsiness and attenuates the circadian variation in drowsy state that is seen under control conditions. MLSTs appeared to be superior to other tests in documenting the sedative effects of the barbiturate.

[In vitro sensitivity of 39 strains of Pseudomonas aeruginosa isolated from urine culture of hospitalized patients]

Research was conducted in 39 cases of urinary infections caused by Pseudomonas Aeruginosa in patients in various hospital wards. The aim was to assess the onset of such opportunistic infections in the hospital environment as reported earlier by other authors. A comparison was then made between the most commonly used antibacterial drugs used to combat such infections assessing their percentage efficacy on the basis of the germs' resistance to the drug.