Very fast capillary electrophoresis with electrochemical detection for high-throughput analysis using short, vertically aligned capillaries.

A method for conducting fast and efficient capillary electrophoresis (CE) based on short separation capillaries in vertical alignment was developed. The strategy enables for high-throughput analysis from small sample vials (low microliter to nanoliter range). The system consists of a lab-made miniaturized autosampling unit and an amperometric end-column detection (AD) cell. The device enables a throughput of up to 200 separations per hour. CE-AD separations of a dye model system in capillaries of only 4 to 7.5 cm length with inner diameters (ID) of 10 or 15 µm were carried out under conditions of very high electric field strengths (up to 3.0 kV/cm) with high separation efficiency (half peak widths below 0.2 s) in less than 3.5 s migration time. A non-aqueous background electrolyte, consisting of 10 mM ammonium acetate and 1 M acetic acid in acetonitrile, was used. The practical suitability of the system was evaluated by applying it to the determination of dyes in overhead projector pens.

Long-term cognitive and behavioural follow-up in three patients with eye closure-triggered paroxysmal activity.

PURPOSE: To study clinical, EEG, neuropsychological and behavioural evolution of three patients presenting with epileptic activity triggered by eye closure (EC) over a mean 10-year follow-up period. METHODS: All patients were studied at the time of the first observation (T0) and after a long follow-up period (T1). At both T0 and T1, each patient underwent: 1) traditional and specific activation techniques during prolonged video-EEG monitoring to detect possible inducing factors; 2) neuropsychological evaluations during video-EEG monitoring either with eyes closed or eyes open to detect any transient cognitive impairment (TCI); 3) detailed neuropsychological assessment without simultaneous EEG recording, to detect any stable cognitive impairment (SCI). RESULTS: EEG recordings showed transient, generalized paroxysms in one case and a continuous epileptic activity triggered by eye closure in the other two cases, at both T0 and T1. In all patients, no particular epileptiform discharge-induced factors were identified except for eye blinking (spontaneous, voluntary or induced by corneal reflex). The results of neuropsychological assessment while eyes were closed as compared to performances with eyes open, showed no significant differences at T0 or at T1 in two cases, thus possibly indicating the absence of TCI. Wechsler Intelligence Scales showed a decrease in performance at T1 in the two patients with eye closure-induced, continuous epileptiform activity. Detailed neuropsychological assessment without EEG recordings demonstrated an impairment of facial recognition ability in all three patients at T1. CONCLUSIONS: The lack of any differences between the results of neuropsychological tests performed with eyes open and eyes closed in two patients might suggest that not all eye-closure-triggered paroxysms are associated with TCI. On the other hand, our data highlight that EC-triggered, EEG epileptic discharges can produce long-lasting neuropsychological and behavioural effects, and also indicate that EEG discharges recurring over time might exert a disruptive effect on cognitive functions. Our three patients showed extreme variability across the neuropsychological tasks except for a facial recognition deficit that was evident in all cases, thus suggesting a possible dysfunction of temporo-occipital brain structures and/or of the fusiform face area as recently demonstrated by combined fMRI/EEG studies in patients with fixation-off sensitivity.

Inter-rater reliability of the EEG reading in patients with childhood idiopathic epilepsy.

The level of agreement in the interpretation of EEG records by different experienced readers working in three child neurology tertiary centers has been evaluated. EEG recordings randomly chosen from patients with idiopathic epilepsy were included. Optimal or suboptimal agreement was found for presence of ictal and interictal discharges. Contrary to ictal discharges, the distribution and location of interictal discharges was not unanimously interpreted and agreement was unsatisfactory when assessing the background activity.

Study of attentional processes in children with idiopathic epilepsy by Conners' Continuous Performance Test.

Before starting antiepilepsy therapy (T1) and after 1 year (T2), 19 children (7 female) affected by focal or generalized idiopathic epilepsy were considered with the aim of studying attention performance. All of the children received a neurological examination and clinical interview, electroencephalography (EEG) in wakefulness or sleep, and a standardized computerized measure of attention (Conners' Continuous Performance Test). At T1, 21% of the patients showed a specific attention disorder, and their percentage rose to 42% after 1 year, despite complete control of seizures. The prognosis was strongly correlated with (1) the presence of active seizures for a period of over 6 months, (2) the persistence of specific interictal abnormalities on an electroencephalogram at T2, and (3) the presence of emotional and behavioral disorders at the diagnosis of epilepsy. Our results confirm that attention disorders are frequent in children with idiopathic epilepsy. The Conners' Continuous Performance Test has proven useful both for diagnosis and follow-up over time.

Neuropsychological and behavioural aspects in children and adolescents with idiopathic epilepsy at diagnosis and after 12 months of treatment.

PURPOSE: To study neuropsychological functions in children with idiopathic epilepsy at onset of treatment and after 1 year of therapy and to identify factors associated with cognitive impairment. METHODS: 43 Subjects aged 5.2-16.9 years with newly diagnosed idiopathic epilepsy were enrolled and started treatment with valproate or carbamazepine. At admission and after 12 months, all patients underwent clinical examinations, the Child Behavioural Checklist, EEG and a neuropsychological test battery. The results of each test were correlated to demographic, clinical, electrophysiological and therapeutic variables. RESULTS: Except for attention, all neuropsychological functions were normal at admission and after 12 months. An improvement with time was noted for memory (p<0.05) and logical-executive functions (p<0.01). Attentive deficit was worse at 12 months (53.5% vs. 32.6%). Low socio-economic level and emotional and behavioural disturbances were the only factors negatively correlated to intelligence, memory and attention. Compared to valproate, carbamazepine was most commonly implicated. DISCUSSION: Idiopathic epilepsy can affect attention, even before starting treatment. Emotional and behavioural difficulties and a low socio-economical status are associated with cognitive impairment.

Relationship between migraine and epilepsy in pediatric age.

OBJECTIVE: Many studies have supported the hypothesis of alteration of cortical hyperexcitability as a possible pathological mechanism underlying the onset of migraine and epileptic attacks. Different biochemical pathways involving cellular structures may increase or decrease the excitability of neuronal membranes. The aim of this study was to identify a possible link between migraine and epilepsy from a clinical and neurophysiologic point of view. METHODS: One-hundred thirty-seven children and adolescents consecutively diagnosed for tension-type headache and idiopathic migraine with and without aura were studied. Anamnestic, clinical, and instrumental data were collected by a neurological examination, a specific questionnaire, and awake electroencephalogram (EEG) registrations. EEG features of nonheadache and nonseizures control group were compared. RESULTS: Fourteen cases (10.2%) had a positive history for seizures with fever, isolated seizures, or epilepsy. Distribution differed according to headache diagnosis; migraine with aura (MWA) was largely prevalent. Specific electroencephalographic abnormalities were present in 11.7% of the sample, with a significant different distribution across the groups of children with headache and the control group: specific interictal abnormalities were found in 10 of 23 (43.5%) children with MWA. Two factors, seizures and specific interictal electroencephalographic abnormalities, showed a different distribution in patients with MWA compared to other classes of headache and control group (P < or = .01). CONCLUSION: The present study supports the hypothesis of a possible clinical continuum between some types of MWA and epileptic syndromes as entities due to altered neuronal excitability with similar genetic substrates.

Functional analysis of novel KCNQ2 and KCNQ3 gene variants found in a large pedigree with benign familial neonatal convulsions (BFNC).

Benign familial neonatal convulsion (BFNC) is a rare autosomal dominant disorder caused by mutations in KCNQ2 and KCNQ3, two genes encoding for potassium channel subunits. A large family with nine members affected by BFNC is described in the present study. All affected members of this family carry a novel deletion/insertion mutation in the KCNQ2 gene (c.761_770del10insA), which determines a premature truncation of the protein. In addition, in the family of the proposita's father, a novel sequence variant (c.2687A>G) in KCNQ3 leading to the p.N821S amino acid change was detected. When heterologously expressed in Chinese hamster ovary cells, KCNQ2 subunits carrying the mutation failed to form functional potassium channels in homomeric configuration and did not affect channels formed by KCNQ2 and/or KCNQ3 subunits. On the other hand, homomeric and heteromeric potassium channels formed by KCNQ3 subunits carrying the p.N821S variant were indistinguishable from those formed by wild-type KCNQ3 subunits. Finally, the current density of the cells mimicking the double heterozygotic condition for both KCNQ2 and KCNQ3 alleles of the proband was decreased by approximately 25% when compared to cells expressing only wild-type alleles. Collectively, these results suggest that, in the family investigated, the KCNQ2 mutation is responsible for the BFNC phenotype, possibly because of haplo-insufficiency, whereas the KCNQ3 variant is functionally silent, a result compatible with its lack of segregation with the BFNC phenotype.