Characteristics of visual evoked potentials related to the electro-clinical expression of reflex seizures in photosensitive patients with idiopathic occipital lobe epilepsy

Seizures provoked by visual stimuli may be induced by abnormal responses to light (photosensitivity) and structured patterns (patternsensitivity). In this study, we analysed visual evoked potentials (VEPs) in three different samples: i) 38 photosensitive patients (21 males, 17 females; mean age 10.0 ± 2.9 years) with idiopathic occipital lobe epilepsy and reflex seizures (RS); ii) 13 non-photosensitive patients (6 males, 7 females; mean age 11.7 ± 5.3) with idiopathic occipital lobe epilepsy; 20 healthy controls (12 males, 8 females; mean age 10.0 ± 3.4). After written informed consent, all subjects underwent a standard procedure of visual stimulation with intermittent light and pattern stimulation, under digital video-EEG recording. The EEG signal was processed off-line by averaging analysis for each stimulus to obtain the corresponding VEP. Comparisons among groups showed no significant differences for P100 latency. Higher P100 amplitude as well as higher after-discharge (AD) were found in photosensitive patients with RS. Thirty-seven of these patients had one or more RS during the procedure of stimulation for a total of 66 episodes. Significant increases of P100 amplitude and higher values of AD amplitude were found in relation to the occurrence of photoparoxysmal response (PPR) and/or seizures during full-field pattern stimulation. The increase in amplitude of the AD was higher when PPR was associated with seizures. The high amplitude of early VEP components confirms the abnormal hyperexcitability in the cortex of photosensitive patients with occipital lobe epilepsy. Moreover, the AD amplitude appears to be related to electro-clinical expression, being greater when PPR evolves into clinically evident seizures

Cortical Evoked Potentials in Children of Diabetic Mothers

Type 1 diabetic mothers' infants show a delay of visual evoked potential (VEP) significantly related to some parameters of poor metabolic control during pregnancy. In the present paper we analyzed the characteristics of VEPs and somatosensory evoked potentials (SEPs) recorded in 16 three-year-old type 1 diabetic mothers' children (DMC). Compared with controls (23 nondiabetic mothers' healthy matched children), DMC showed significantly delayed mean latency of VEP (P2) and SEP (P22). In 3 cases (19%), we found pathological responses (+3 SD from the mean value of controls) of VEPs and SEPs. At the age of 3 years, the offspring of type 1 diabetic mothers showed delay of cortical evoked responses in both visual and somatosensory systems

Can patients with epilepsy become bone marrow donors? A case report of allogeneic hematopoietic stem transplantation from child with seizures

Hematopoietic stem cell (HSC) transplantation is an important treatment option for malignant and non-malignant hematopoietic disorder in adults and children. For long time epilepsy was temporary exclusion condition to voluntary donation, and donors had to be medication or seizure free. It is still unclear if people with history of epilepsy are indeed potential eligible donors, even if a significant increased risk of adverse events in these donors has not been demonstrated. We studied a 10-year-old boy with symptomatic focal epilepsy who was the only available donor for his monozycote twin, suffering from acute lymphoblastic leukemia. A total of 3.39 x 108/kg HSCs were collected and reinfused to the leukemic brother after conditioning treatment. At the end of follow-up, our epilepsy patient had no consequences and his brother is in complete remission of the disease at 3 years from the transplant procedure. Our observation confirms that a patient with epilepsy can be a donor, without consequences for himself and for the recipient

A novel developmental encephalopathy with epilepsy and hyperkinetic movement disorders associated with a deletion of the sodium channel gene cluster on chromosome 2q24.3

We reported a 21 months-old boy with a complex epilepsy phenotype, developmental delay, and hyperkinetic movement disorders, associated with a deletion of the whole sodium channel gene cluster. Whether this unusual phenotype results from leading to haploinsufficiency of either SCN1A or SCN2A, or the combination of both, remains subject of speculation. However, nobody of the numerous reported patients with truncating mutations in SCN1A has ever manifested such a clinical phenotyp

A Multicentre Database for Normative Brainstem Auditory Evoked Potentials (BAEPs) in Children: Methodology for Data Collection and Evaluation

The influence of physiological and methodological factors on recordings of brainstem auditory evoked potentials (BAEPs) is greater in children than in adults. To collect and evaluate BAEP data in normal children, and measure intra- and inter-laboratory variability. Seven hundred and fifty unselected BAEP recordings were collected and evaluated from children ranging from neonates to 14-year-olds by eight laboratories in Italy. In newborns, three laboratories showed satisfactory concordance; wave I was more broadly distributed than wave V and IPL I-V. The evaluation of pooled BAEP data from the older children showed that laboratories with age-matched data gave overlapping results; those with unmatched-age data differed significantly. The sound intensities of the laboratories did not significantly affect absolute BAEP latencies or IPLs. Females had shorter latencies than males; the difference was not significant. A single exponential regression model was an adequate but not the best predictor of normal data. The pooled data were consistent with the physiological maturation of the brainstem acoustic pathway. The BAEPs was reliably normalised using the natural logarithm of age. The differences between Centres were related to sample size, measurement accuracy, and inclusion and selection criteria. The creation of multicentre common database from an unmatched data collection is feasible and reliable enough for clinical diagnosis and multicentre clinical research

Nondestructive imaging of atomically thin nanostructures buried in silicon

It is now possible to create atomically thin regions of dopant atoms in silicon patterned with lateral dimensions ranging from the atomic scale (angstroms) to micrometers. These structures are building blocks of quantum devices for physics research and they are likely also to serve as key components of devices for next-generation classical and quantum information processing. Until now, the characteristics of buried dopant nanostructures could only be inferred from destructive techniques and/or the performance of the final electronic device; this severely limits engineering and manufacture of real-world devices based on atomic-scale lithography. Here, we use scanning microwave microscopy (SMM) to image and electronically characterize three-dimensional phosphorus nanostructures fabricated via scanning tunneling microscope–based lithography. The SMM measurements, which are completely nondestructive and sensitive to as few as 1900 to 4200 densely packed P atoms 4 to 15 nm below a silicon surface, yield electrical and geometric properties in agreement with those obtained from electrical transport and secondary ion mass spectroscopy for unpatterned phosphorus δ layers containing ~1013 P atoms. The imaging resolution was 37 ± 1 nm in lateral and 4 ± 1 nm in vertical directions, both values depending on SMM tip size and depth of dopant layers. In addition, finite element modeling indicates that resolution can be substantially improved using further optimized tips and microwave gradient detection. Our results on three-dimensional dopant structures reveal reduced carrier mobility for shallow dopant layers and suggest that SMM could aid the development of fabrication processes for surface code quantum computers.ISSN:2375-254

L'impiego dei potenziali evocati nella sclerosi tuberosa

Evoked potentials (EP) allow the assessment of the functional integrity and degree of maturation of the main pathways of sensory afference (visual, acoustic and somaesthetic). For this reason, EP can be used in the study of patients with tuberous sclerosis. In clinical practice, EP serve to give information for early diagnosis and a better prognostic assessment of the individual patient. A recent analysis of visual evoked potentials (VEP) and brain stem acoustic evoked potentiials (BAEP) in children with tuberous sclerosis disclosed an increased average latency of some components of both VEP (component IV or P2) and BAEP (V wave and I-V interpeak). Impaired responses were present in 80% of VEP and 85% of BAEP. In addition, impaired BAEP were also present in patients without subtentorial structural abnormalities. EP serve as a useful instrument for early diagnosis of tuberous sclerosis. Given the anatomofunctional differences of the systems stimulated and the preferential location of lesions in certain areas, the various different EP have varying degrees of sensitivity in disclosing abnormalities: visual and brain stem acoustic EP are more sensitive than somatosensory EP