Pretreatment neuropsychological deficits in children with brain tumors

Treatment of childhood brain cancer has been associated with long-term cognitive morbidity in children. In the present study, the cognitive status of children with brain tumors was examined prior to any treatment to single out the role of tumor and tumor-related factors in cognitive deficits. Eighty-three children with newly diagnosed brain tumors (mean age, 8.6 years; range, 7 months to 16.6 years; median, 9.4 years) completed an extensive battery of age-related tests to assess cognitive function before any therapeutic intervention. Magnetic resonance imaging (MRI) was used to determine tumor site and volume and tumor-related factors. Performance under test was compared with symptom duration, neurological status, epilepsy, and MRI. Cognitive difficulties are detected at diagnosis in as many as 50% of patients for some cognitive domains; 6% of patients present with true-diagnosed mental retardation. The location of the tumor is the principal determinant of cognitive deficits, with major impairment in children with cortical tumors. Symptom duration and the presence of epilepsy are significantly associated with neuropsychological disabilities, while neuroradiological tumor-related variables do not correlate clearly with neurocognitive performance. The knowledge of the pre-existing cognitive deficits is critical to evaluate the results of treatment, providing a baseline for assessing the true impact of therapy in determining cognitive decline. In addition, the study suggests that some clinical variables require careful monitoring, because they could be specifically implicated in the neuropsychological outcome; the efforts to reduce the impact of these factors could ameliorate long-term prognosis.

Epilepsy surgery of posterior quadrant dysplasia in the first year of life: experience of a single centre with long term follow-up

Posterior quadrant dysplasia (PQD) is a rare variant of cortical dysplasia involving the posterior regions of a single hemisphere. It is always associated with early onset, refractory epilepsy often characterized by a "catastrophic" evolution. The experience on its surgical management during the first year of life is limited to sporadic, isolated cases. Between 2002 and 2005, four children less than one-year-old and affected by drug-resistant epilepsy associated with PQD were admitted to our Institution and underwent surgical treatment. One patient remained seizure-free during all the follow-up (Engel I). The remaining three children showed a recurrence of the seizures, requiring subsequent surgical procedures in two cases. In one case (Engel II), the seizure control has been obtained thanks to pharmacological treatment. The other two patients respectively had only a partial (Engel III) and a less relevant reduction of the number of seizures (Engel IV). Both the epileptic and the neuropsychological outcome of our series were significantly influenced by persistent contralateral interictal anomalies rather than by the timing of the surgical procedure. Unpredictable results should be expected in this kind of patients if there is the detection of contralateral independent epileptiform activities on the EEG at diagnosis. Parents and relatives should be aware of the results' variability, even though a reduction of seizures may be expected, enabling an easier handling of the child's condition.

Protocadherin 19 mutations in girls with infantile-onset epilepsy

OBJECTIVE

To explore the causative role of PCDH19 gene (Xq22) in female patients with epilepsy.

METHODS

We studied a cohort of 117 female patients with febrile seizures (FS) and a wide spectrum of epilepsy phenotypes including focal and generalized forms with either sporadic or familial distribution.

RESULTS

PCDH19 screening showed point mutations in 13 probands (11%). Mean age at seizure onset was 8.5 months; 8 patients (62%) presented with FS, 4 (33%) with cluster of focal seizures, and 1 with de novo status epilepticus (SE). Subsequent seizure types included afebrile tonic-clonic, febrile, and afebrile SE, absences, myoclonic, and focal seizures. Seven patients (54%) had a clinical diagnosis consistent with Dravet syndrome (DS); 6 (46%) had focal epilepsy. In most patients, seizures were particularly frequent at onset, manifesting in clusters and becoming less frequent with age. Mental retardation was present in 11 patients, ranging from mild (7; 64%) to moderate (1; 9%) to severe (3; 27%). Five patients (38%) had autistic features in association to mental retardation. Mutations were missense (6), truncating (2), frameshift (3), and splicing (2). Eleven were new mutations. Mutations were inherited in 3 probands (25%): 2 from apparently unaffected fathers and 1 from a mother who had had generalized epilepsy.

CONCLUSIONS

PCDH19 is emerging as a major gene for infantile-onset familial or sporadic epilepsy in female patients with or without mental retardation. In our cohort, epileptic encephalopathy with DS-like features and focal epilepsy of variable severity were the associated phenotypes and were equally represented.

[Algorithm for assessment of exposure to asbestos]

There is no universally approved method in the scientific literature to identify subjects exposed to asbestos and divide them in classes according to intensity of exposure. The aim of our work is to study and develope an algorithm based on the findings of occupational anamnestical information provided by a large group of workers. The algorithm allows to discriminate, in a probabilistic way, the risk of exposure by the attribution of a code for each worker (ELSA Code--work estimated exposure to asbestos). The ELSA code has been obtained through a synthesis of information that the international scientific literature identifies as the most predictive for the onset of asbestos-related abnormalities. Four dimensions are analyzed and described: 1) present and/or past occupation; 2) type of materials and equipment used in performing working activity; 3) environment where these activities are carried out; 4) period of time when activities are performed. Although it is possible to have informations in a subjective manner, the decisional procedure is objective and is based on the systematic evaluation of asbestos exposure. From the combination of the four identified dimensions it is possible to have 108 ELSA codes divided in three typological profiles of estimated risk of exposure. The application of the algorithm offers some advantages compared to other methods used for identifying individuals exposed to asbestos: 1) it can be computed both in case of present and past exposure to asbestos; 2) the classification of workers exposed to asbestos using ELSA code is more detailed than the one we have obtained with Job Exposure Matrix (JEM) because the ELSA Code takes in account other indicators of risk besides those considered in the JEM. This algorithm was developed for a project sponsored by the Italian Armed Forces and is also adaptable to other work conditions for in which it could be necessary to assess risk for asbestos exposure.

Early development of epileptic infants with pre- or perinatal brain injuries: role of the epileptic disorder

To try to understand the causative role of epilepsy PER SE in the developmental deterioration of brain injured infants, twenty-eight infants affected with early acquired, pre- and perinatal brain injuries were enrolled and divided into three groups, a) those with West syndrome, b) those with other non-West epilepsies, and c) those without epilepsy. Developmental monitoring consisted of a full clinical assessment, including examination of visual function, Griffiths developmental scales, standard EEG, long-term monitoring when necessary, and MRI, from the seizure onset or the first observation to the end of follow-up. Patients with epilepsy showed at study onset abnormal clinical features (neurological and developmental) distinct from those of non-epileptic patients, partially due to the varying severity of their brain injuries. A definite differentiation between groups was observed in the clinical evolution that showed among the epileptic patients, mostly in West syndrome, a significant deterioration. Moreover, impaired visual function at seizure onset was possibly associated with a bad developmental evolution. A developmental deterioration, mostly in West syndrome, accounts for a causative role of the epileptic disorder PER SE, but in few cases it was also observed in infants with only a brain injury, suggesting other aetiopathogenic mechanisms. The predictive value of early visual function seems to be confirmed.

Early hemispherectomy in catastrophic epilepsy

The authors report their experience about a neuro-cognitive and epileptic long-term follow-up of children with catastrophic epilepsy treated with hemispherectomy in the first 5 years of life. Nineteen children with resistant epilepsy that significantly interfered with their neuro-cognitive development underwent hemispherectomy within 5 years of life (mean: 2 years, 3 months; range: 5 months to 5 years). All patients were assessed before surgery and after, at least at the end of the follow-up (mean: 6 years and 6 months; range: 2-11 years and 2 months) with a full clinical examination including motor ability and functional status evaluation as well as behaviour observation, neuroimaging and an ictal/interictal prolonged scalp video-EEG. A seizure-free outcome was obtained in 73.7% of patients. Gross motility generally improved and cognitive competence did not worsen, with an evident progress in two cases. Consistently with previous reports, evolution was worse in cortical dysplasia than in progressive or acquired vascular cerebropathies. The excellent epileptic outcome and the lack of developmental deterioration in comparison with other more aged series seem to suggest a possible better evolution in earlier surgery treatment. To confirm this suggestion, however, further experience with larger series is needed.

Temporal decorrelation of collective oscillations in neural networks with local inhibition and long-range excitation

We consider two neuronal networks coupled by long-range excitatory interactions. Oscillations in the gamma frequency band are generated within each network by local inhibition. When long-range excitation is weak, these oscillations phase lock with a phase shift dependent on the strength of local inhibition. Increasing the strength of long-range excitation induces a transition to chaos via period doubling or quasiperiodic scenarios. In the chaotic regime, oscillatory activity undergoes fast temporal decorrelation. The generality of these dynamical properties is assessed in firing-rate models as well as in large networks of conductance-based neurons.

Seizure semiology of lesional frontal lobe epilepsies in children

The aim of the study was to analyse the semiology of seizures in children with frontal lobe epilepsy (FLE) and to compare them with other paediatric cohorts described in the literature as well as with adult counterparts. We analysed 174 registered seizures of 18 cases under 12 years with lesional epilepsy whose frontal origin was defined by the concordance of neuroimaging and ictal electrographic findings, and confirmed by surgery in the six cases operated on. Seizures were generally short, with a high daily frequency and usually related to sleep. The most characteristic semiological pattern consisted of complex motor seizures, particularly hypermotor. Often seizures corresponded to a mixture of different semiological patterns (tonic, gelastic, automotor, hypermotor, versive) presenting in the same seizure, often as a unique type in the same patient. With regard to several aspects the semiology of FLE in our cohort looks like that reported in adult series, in particular as to the frequency of complex motor seizures. However, our cohort was also characterised by a more protean array of seizure semiology, stressing the occurrence of seizures typically present in adults (versive and complex motor) and of some seizure patterns more characteristic in children such as epileptic spasms; moreover, the rare occurrence of secondarily generalised tonic clonic seizures (SGTCS) was confirmed.