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Surgery of children with frontal lobe lesional epilepsy: neuropsychological study

AIM OF THE STUDY was to provide new data about the evolution of neuropsychological findings in patients with lesional frontal lobe epilepsy (FLE) operated on with lesion excision. PATIENTS AND METHODS Twelve patients with lesional FLE underwent full clinical examination including neurological, neuropsychological and developmental assessments, high-resolution magnetic resonance imaging (MRI), ictal and interictal prolonged EEG monitoring and evaluation of seizure semeiology before and after surgery. The mean follow-up duration was 2 years and 10 months (range=14 months-7 years). Another group of lesional temporal lobe epilepsy, matched for the age at surgery and side of surgery, was likewise studied in order to compare neuropsychological patterns and to try to find out specific features in frontal lobe epilepsy evolution. RESULTS All patients resulted seizure free at outcome except one belonging to Engels class II. Before surgery general intelligence was similar in FLE as well as in TLE group. Executive functions and motor coordination were frequently affected in FLE whereas patients with TLE often presented with deficits in naming, visual memory and visuo-spatial attention. After surgery there was a frequent decline of IQ in FLE group together with a slight deterioration, especially of executive functions in some patients. An improvement of behaviour was often observed in both groups. CONCLUSIONS As already reported in literature, neuropsychological pre-surgical data confirms the involvement of attention and executive functions in lesional FLE. No significant neuropsychological improvement was produced by surgery that determined in some cases a slight decline of general intelligence and specific frontal abilities. Yet, generally behaviour improved and seizures were controlled.

Cognitive decline in Dravet syndrome: is there a cerebellar role?

PURPOSE The aim of the study was to perform a detailed assessment of cognitive abilities and behaviour in a series of epileptic patients with Dravet syndrome (DS) in order to establish a possible cerebellar-like pattern. METHODS Nine children with DS without major behavioural disturbances and with cognitive abilities compatible with the assessment of specific cognitive skills (IQ>45) were enrolled in the study, in parallel with another group of nine epileptic patients (cryptogenic or symptomatic with minor brain injuries) consecutively admitted into the hospital matched for chronological age and IQ. All cases underwent neurological examination, long term EEG monitoring, neuroimaging and genetic analysis as well as a neuropsychological assessment including specific cognitive skills. RESULTS On neurological examination 8 of the 9 DS patients had cerebellar signs, which were mild in six and more severe in the other two cases. DS patients had a constant discrepancy between verbal and performance items scales (verbal better than visual-spatial) that was not found in the control group. As to specific cognitive competence, the DS patients differ from the control group in the pattern of cognitive defects involving four main areas of cognitive abilities (a) expressive language with relatively spared comprehension, (b) visual-spatial organization, (c) executive function defects, (d) behavioural disorders. CUNCLUSIONS The pattern of cognitive difficulties found in DS patients is consistent with what is reported in literature as cerebellar cognitive syndrome and may account for a possible cerebellar origin (at least as co-factor) of the cognitive decline observed in DS patients, as suggested by other clinical and experimental studies.

Early onset myoclonic epilepsy and 15q26 microdeletion: observation of the first case.

The authors report the study of a 30‐month‐old girl with refractory myoclonic epilepsy associated with mental retardation, growth delay, peculiar facial appearance, and minor physical anomalies. Extensive genetic studies were performed, including an array‐based comparative genomic hybridization (array‐CGH) that showed a cryptic interstitial deletion of 15q (5 Mb) affecting the 15q26.1–26.2 region. Partial deletions of the long arm of chromosome 15, including the 15q26 region, were observed in syndromic associations that typically include congenital diaphragmatic hernia, but neurologic features were poorly described and epileptic seizures were never reported. Our findings suggest that genes for seizures could be included in the 15q26.1q26.2 deletion interval.

Novel de novo heterozygous loss-of-function variants in MED13L and further delineation of the MED13L haploinsufficiency syndrome

MED13L haploinsufficiency has recently been described as responsible for syndromic intellectual disability. We planned a search for causative gene variants in seven subjects with intellectual disability and overlapping dysmorphic facial features such as bulbous nasal tip, short mouth and straight eyebrows. We found two de novo frameshift variants in MED13L, consisting in single-nucleotide deletion (c.3765delC) and duplication (c.607dupT). A de novo nonsense variant (c.4420A>T) in MED13L was detected in a further subject in the course of routine whole-exome sequencing. By analyzing the clinical data of our patients along with those recently described in the literature, we confirm that there is a common, recognizable phenotype associated with MED13L haploinsufficiency, which includes intellectual disability and a distinctive facial appearance. Congenital heart diseases are found in some subjects with various degree of severity. Our observation of cleft palate, ataxia, epilepsy and childhood leukemia observed in single cases broadens the known clinical spectrum. Haploinsufficiency for MED13L should be considered in the differential diagnosis of the 1p36 microdeletion syndrome, due to overlapping dysmorphic facial features in some patients. The introduction of massive parallel-sequencing techniques into clinical practice is expected to allow for detection of other causative point variants in MED13L. Analysis of genomic data in connection with deep clinical evaluation of patients could elucidate genetic heterogeneity of the MED13L haploinsufficiency phenotype.

Unusual 4p16.3 deletions suggest an additional chromosome region for the Wolf-Hirschhorn syndrome-associated seizures disorder

Seizure disorder is one of the most relevant clinical manifestations in Wolf‐Hirschhorn syndrome (WHS) and it acts as independent prognostic factor for the severity of intellectual disability (ID). LETM1, encoding a mitochondrial protein playing a role in K+/H+ exchange and in Ca2+ homeostasis, is currently considered the major candidate gene. However, whether haploinsufficiency limited to LETM1 is enough to cause epilepsy is still unclear. The main purpose of the present research is to define the 4p chromosome regions where genes for seizures reside.

Clinical and genetic factors predicting Dravet syndrome in infants with SCN1A mutations

Objective: To explore the prognostic value of initial clinical and mutational findings in infants with SCN1A mutations. Methods: Combining sex, age/fever at first seizure, family history of epilepsy, EEG, and mutation type, we analyzed the accuracy of significant associations in predicting Dravet syndrome vs milder outcomes in 182 mutation carriers ascertained after seizure onset. To assess the diagnostic accuracy of all parameters, we calculated sensitivity, specificity, receiver operating characteristic (ROC) curves, diagnostic odds ratios, and positive and negative predictive values and the accuracy of combined information. We also included in the study demographic and mutational data of the healthy relatives of mutation carrier patients. Results: Ninety-seven individuals (48.5%) had Dravet syndrome, 49 (23.8%) had generalized/genetic epilepsy with febrile seizures plus, 30 (14.8%) had febrile seizures, 6 (3.5%) had focal epilepsy, and 18 (8.9%) were healthy relatives. The association study indicated that age at first seizure and frameshift mutations were associated with Dravet syndrome. The risk of Dravet syndrome was 85% in the 0- to 6-month group, 51% in the 6- to 12-month range, and 0% after the 12th month. ROC analysis identified onset within the sixth month as the diagnostic cutoff for progression to Dravet syndrome (sensitivity = 83.3%, specificity = 76.6%). Conclusions: In individuals with SCN1A mutations, age at seizure onset appears to predict outcome better than mutation type. Because outcome is not predetermined by genetic factors only, early recognition and treatment that mitigates prolonged/repeated seizures in the first year of life might also limit the progression to epileptic encephalopathy.

Sleep-potentiated epileptiform activity in early thalamic injuries: Study in a large series (60 cases).

OBJECTIVE The study aims at a better definition of continuous spike-waves during sleep (CSWS) with an early thalamic lesion, focusing on various grades of sleep-potentiated epileptiform activity (SPEA). Their possible relationship with different clinical features was studied to try to define prognostic factors of the epileptic disorder, especially relating to behavior/cognitive outcome, in order to improve prevention and treatment strategies. METHODS Sixty patients with early thalamic injury were followed since the first registration of SPEA with serial neurological, long term EEG monitoring and neuropsychological examinations, as well as neuroimaging and a detailed clinical history. They were classified in three different groups according to the sleep spike-waves (SW) quantification: electrical status epilepticus during sleep (ESES), more than 85% of slow sleep; overactivation between 50% and 85% and simple activation between 10 and 50%). Results were then examined also with a statistical analysis. RESULTS In our series of CSWS occurring in early brain injured children with unilateral thalamic involvement there is a common neuropathologic origin but with various grades of SPEA severity. Statistical analysis showed that patients evolving toward ESES presented more commonly the involvement of the mediodorsal part of thalamus nuclei and a bilateral cortico-subcortical brain injury, epilepsy was more severe with a delayed onset; moreover, in the acute stage .ESES patients presented the worst behavior/cognitive performances. As to cognitive and behavior outcome, longer SPEA duration as well as bilateral brain injury and cognitive/behavior impairment in acute phase appear linked to a poor outcome; some particular neuropathology (ischemic stroke and haemorrhagic infarction) as well as hydrocephalus shunting are associated with behavior disorders. CONCLUSIONS Discrete features seem to support different underlying mechanisms in ESES patients in comparison with less severe SPEA; they represent negative prognostic factors. Longer SPEA duration as well as bilateral brain injury and cognitive/behavior impairment in acute phase seem predictive of a worse cognitive/behavior outcome.

A prospective longitudinal study on visuo-cognitive development in Dravet syndrome: Is there a "dorsal stream vulnerability"?

A group of five DS patients whose first development was already reported were longitudinally followed up till the scholar age. Beside the general and epileptic clinical evolution, visual and cognitive functions were investigated in order to define their trajectory and possibly provide information about mechanisms of cognitive decline as well as to improve prognosis and tertiary prevention. Neuropsychological assessment was performed with a test battery investigating the development of visual function that progressively integrates into extrastriate components and higher cognitive skills (global form and motion coherence, stereopsis, crowding cards, ABCDEFV battery, general intelligence and specific cognitive tests). Main results showed a fall in visuo-motor items including global motion coherence and specific cognitive skills, presenting a continuity of the visual function deterioration extended from basic abilities to visuo-motor dorsal pathway skills. Moreover, a case whose previous visual and cognitive functions had been in the normal range began showing a visual deterioration with increasing age, followed by the cognitive decline; that prevents from excluding in early ages a poor development in presence of a normal visual function. A dorsal stream vulnerability seems thus shown in this sample of DS patients, like in other genetic syndromes (Williams, Prader Willi. fragile-X), providing new information about mechanisms underlying cognitive decline and suggesting a possible strategy to improve their neuropsychological outcome. Larger cohorts may confirm whether these findings are part of a specific pattern of DS neuropsychological phenotype.

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.

The forward parachute reaction and independent walking in infants with brain lesions

Aim  The aim of this study was to assess the onset of forward parachute reaction (FPR) in infants with brain lesions and its correlation with age of walking.