Late primary unilateral thalamic hemorrhage in infancy: report of two cases

Unmet needs in epileptic encephalopathy with spike-and-wave activation in sleep: A systematic review

INTRODUCTION

Developmental and/or epileptic encephalopathy with spike-and-wave activation in sleep (D/EE-SWAS), also referred to as electrical status epilepticus during sleep (ESES) or epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS or EE-CSWS), is a spectrum of rare childhood epileptic encephalopathies that can lead to long-term cognitive impairment. Despite the importance of early diagnosis and intervention for D/EE-SWAS, there is a paucity of well-controlled clinical trial data to inform treatment, and no approved treatments are available. To assess correlations between diagnosis, treatment, and outcomes in D/EE-SWAS, we carried out a systematic review of the literature.

METHODS

In August 2020, we conducted comprehensive database searches using search terms including "electrical status epilepticus," "ESES," "CSWS," and "Landau-Kleffner syndrome." Two or more independent reviewers screened titles, abstracts, and full-text articles for those that met the following criteria: prospective studies (randomized controlled trials [RCTs] or open-label trials), retrospective studies (drug evaluations or observational studies/chart reviews), and case series with ≥ 10 participants. Both interventional and non-interventional studies were included (i.e., drug intervention was not an inclusion criterion). Articles published before 2012, review articles, animal studies, and studies of surgical or dietary interventions were excluded. Standardized data extraction templates were used to capture data on study design, patient characteristics, interventions, and outcomes from each of the selected publications. Study quality was assessed using the Cochrane Risk of Bias Tool for RCTs and the Newcastle-Ottawa Scale (NOS) or the Joanna Briggs Institute (JBI) Critical Appraisal Checklist for retrospective, observational studies.

RESULTS

A total of 34 studies were included for full data extraction, most of which were uncontrolled and observational. Interpretation of study outcomes was limited by small study populations, variability in inclusion criteria, and inconsistency in methods of assessment and reporting of outcomes, which resulted in large heterogeneity in patients and their presenting symptoms. Despite these limitations, some patterns could be discerned. Several studies found that longer duration of ESES and younger age at onset were correlated with more severe language and cognitive deficits. In addition, several studies reported an association between improvement in cognitive outcomes and reduction in electroencephalogram (EEG) abnormalities and/or seizure frequency. In the 16 prospective or retrospective studies that evaluated drug treatments (e.g., antiseizure medications, corticosteroids, and high-dose diazepam), there was some improvement in EEG, seizure, and/or cognitive outcomes, although the specific outcomes and rates of improvement reported varied from study to study.

CONCLUSION

Long-term cognitive deficits remain common in D/EE-SWAS, and data gaps exist in the literature that preclude an evidence-based approach to managing this complex epilepsy indication. Early intervention with more effective medications is needed to optimize long-term outcomes. Sufficiently powered, randomized, double-blind, controlled trials with standardized methods and predefined primary and secondary outcomes are needed.

Neurocognitive Profile and 18 F-Fluorodeoxyglucose Positron Emission Tomography Brain Imaging Correlation in Children with Electrical Status Epilepticus during Sleep

Objective  Electrical status epilepticus in sleep (ESES) is defined by near-continuous epileptiform discharges during sleep along with cognitive, behavioral, and/or imaging abnormalities. We studied the neurocognitive profile and their correlation with 18 F fluorodeoxyglucose positron emission tomography (FDG PET) brain abnormalities in children with ESES. Methods  Fourteen children with ESES with normal magnetic resonance imaging (MRI) from March to December 2019 were included. The intelligence quotient (IQ) and child behavior checklist (CBCL) scores were estimated using validated scales, and FDG PET brain was done at the same point of time to look for cerebral metabolic defects which was compared with a control group. Results  Fourteen patients with a mean age of 8.2 ± 2.7 years were analyzed. The average duration of epilepsy was 6 ± 2.8 years. The mean IQ was 72.4 ± 18.2 and mean CBCL score was 37.3 ± 11.8. There was negative correlation between IQ and CBCL ( r  = -0.55, p  < 0.001). The duration of epilepsy also showed negative correlation with IQ ( r  = -4.75, p  < 0.001). FDG PET scan showed predominant thalamic hypometabolism in 12 of 14 patients (85.7%) on visual analysis with multiple other hypometabolic cortical and subcortical regions in the brain. The quantitative analysis showed significant difference in metabolism of basal ganglion when compared with control group. The total number of hypometabolic regions seen in the brain showed moderate positive correlation with CBCL score but no significant correlation with the IQ of cases. Conclusion  This study demonstrates functional impairment of cerebral cortical, basal ganglia, and thalamic hypometabolism in a cohort of ESES patients with normal structural MRI brain study. There was a moderate correlation of extent and pattern of cerebral hypometabolism with the neuropsychological status of the child and duration of epilepsy.

Electrical status epilepticus in sleep: The role of thalamus in etiopathogenesis

PURPOSE

In patients diagnosed with epilepsy, decreased ratio of N-acetyl aspartate to creatine (NAA/Cr) measured in magnetic resonance spectroscopy (MRS) has been accepted as a sign of neuronal cell loss or dysfunction. In this study, we aimed to determine whether a similar neuronal cell loss is present in a group of encephalopathy with electrical status epilepticus in sleep (ESES) patients METHODS: We performed this case-control study at a tertiary pediatric neurology center with patients with ESES. Inclusion criteria for the patient group were as follows: 1) a spike-wave index of at least 50%, 2) acquired neuropsychological regression, 3) normal cranial MRI. Eventually, a total of 21 patients with ESES and 17 control subjects were enrolled in the study. MRI of all control subjects was also within normal limits. 3D Slicer program was used for the analysis of thalamic and brain volumes. LCModel spectral fitting software was used to analyze single-voxel MRS data from the right and left thalamus of the subjects.

RESULTS

The mean age was 8.0 ± 1.88 years and 8.3 ± 1.70 years in ESES patients and the control subjects. After correcting for the main potential confounders (age and gender) with a linear regression model, NAA/Creatine ratio of the right thalamus was significantly lower in the ESES patient group compared to the healthy control group (p = 0.026). Likewise, the left thalamus NAA/Cr ratio was significantly lower in the ESES patient group than the healthy control group (p = 0.007). After correcting for age and gender, right thalamic volume was not statistically significantly smaller in ESES patients than in healthy controls (p = 0.337), but left thalamic volume was smaller in ESES patients than in healthy controls (p = 0.024).

CONCLUSION

In ESES patients, the NAA/Creatine ratio, which is an indicator of neuronal cell loss or dysfunction in the right and left thalamus, which appears regular on MRI, was found to be significantly lower than the healthy control group. This metabolic-induced thalamic dysfunction, which was reported for the first time up to date, may play a role in ESES epileptogenesis.

Reduced thalamic volume is strongly associated with electrical status epilepticus in sleep

To identify the relationship between thalamic volume and electrical status epilepticus in sleep (ESES). We analyzed subcortical gray matter volumes in patients with an ESES pattern on their electroencephalographs. All magnetic resonance imaging scans were considered within normal limits. The patients were not receiving antiepileptic drug at the time of the MRI study. High resolution T1-weighted 3-dimensional MPRAGE scans were assessed for segmentation and quantitative volumetric analysis of the brain by using the "volBrain" method. After correcting for total brain volume, volumes were compared with a group of healthy controls (HCs) and patients with benign childhood epilepsy with centrotemporal spikes (BECTS). Fifteen patients with ESES, 15 patients with BECTS, and 30 HCs were included. The median age of the patients with ESES was 8.5 (range, 5.8-13) years, 8 (range, 5-14) years for the HCs, and 7.8 (range, 4-13.5) years for the patients with BECTS. The total relative thalamic volume was significantly lower in patients with ESES than in the healthy controls (0.87 ± 0.07 vs. 0.93 ± 0.03, p = 0.002), and in patients with ESES than in those with BECTS (0.87 ± 0.07 vs. 0.93 ± 0.03, p = 0.006). There was no significant difference the HCs and patients with BECTS (0.93 ± 0.03 vs. 0.93 ± 0.03, p = 0.999). Both right and left relative thalamic volumes were lower in patients with ESES than in HCs (right thalamus: 0.43 ± 0.04 vs. 0.46 ± 0.02, p = 0.003, left thalamus: 0.44 ± 0.03 vs. 0.47 ± 0.02, p = 0.002), in patients with ESES than in patients with BECTS (right thalamus: 0.43 ± 0.04 vs. 0.46 ± 0.01, p = 0.01, left thalamus: 0.43 ± 0.04 vs. 0.47 ± 0.01, p = 0.007); however, there was no significant difference between the HCs and patients with BECTS (right thalamus: 0.46 ± 0.02 vs. 0.46 ± 0.01, p = 0.999, left thalamus: 0.47 ± 0.02 vs. 0.47 ± 0.01, p = 0.999). This study highlights the association between thalamic involvement and ESES, even when not severe enough to cause a detectable lesion on visual interpretation of MRI.

Regional White Matter Atrophy Correlates with Spike Activity in Encephalopathy Related to Status Epilepticus During Slow Sleep (ESES) After Early Thalamic Lesions

Encephalopathy related to Status Epilepticus during slow Sleep (ESES) is an age-related, epileptic syndrome, which associates cognitive/behavioral disturbances with a peculiar pattern of spike activity. One promising line of research is the study of ESES in cases of early thalamic lesions. We studied 7 ESES patients with unilateral thalamic lesions using magnetic resonance imaging to assess regional white matter (WM) and thalamic nuclei volume differences, and long-term electroencephalogram recordings to localize the epileptogenic cortex. N170 event-related potentials were used to demonstrate the dysfunctional character of the WM abnormalities. Diffusion-weighted images in a subset of 4 patients were used to parcellate the thalamus and evaluate volume asymmetries, based on cortical connectivity. Large WM regional atrophy in the hemisphere with the thalamic lesion was associated with both cortical dysfunction and epileptic activity. A correlation was demonstrated between lesions in the pulvinar and the mediodorsal thalamic nuclei and WM atrophy of the corresponding cortical projection areas. We propose that these abnormalities are due to the widespread structural disconnection produced by the thalamic lesions associated to a yet unknown age-dependent factor. Further exploration of WM regional atrophy association with the spike activity in other etiologies could lend support to the cortical disconnection role in ESES genesis.

Anatomical and physiological basis of continuous spike-wave of sleep syndrome after early thalamic lesions

OBJECTIVE

Early neonatal thalamic lesions account for about 14% of continuous spike-wave of sleep (CSWS) syndrome, representing the most common etiology in this epileptic encephalopathy in children, and promise useful insights into the pathophysiology of the disease.

METHODS

We describe nine patients with unilateral neonatal thalamic lesions which progressed to CSWS. Longitudinal whole-night and high-density electroencephalograms (EEGs) were performed, as well as detailed imaging and clinical evaluation. Visual evoked potentials were used to probe cortical excitability.

RESULTS

Thalamic volume loss ranged from 19% to 94%, predominantly on medial and dorsal nuclei and sparing the ventral thalamus. Lesions produced white matter loss and ventricle enlargement on the same hemisphere, which in four patients was associated with selective loss of thalamic-cortical fibers. Cortical thickness quantification failed to reveal hemispheric asymmetries. Impact on EEG rhythms was mild, with a volume-loss-related decrease in alpha power and preservation of sleep spindles. The sleep continuous spiking was lateralized to the hemisphere with the lesion. Visual cortex stimulation in five patients with posterior cortex spiking revealed an abnormal frequency-dependent excitability at 10-20Hz on the side of the lesion.

SIGNIFICANCE

Unilateral selective thalamic-cortical disconnection is a common feature in our patients and is associated with both a focal pattern of CSWS and a pathological type of frequency-dependent excitability (peak: 10-20Hz). We propose that this excitability represents an abnormal synaptic plasticity previously described as the augmenting response. This synaptic plasticity has been described as absent in the corticocortical interactions in healthy experimental animals, emerging after ablation of the thalamus and producing a frequency-dependent potentiation with a peak at 10-20Hz. Because this response is potentiated by sleep states of reduced brainstem activation and by appropriate stimulating rhythms, such as sleep spindles, the simultaneous occurrence of these two factors in nonrapid-eye-movement sleep is proposed as an explanation for CSWS in our patients.

Reduced thalamic volume in patients with Electrical Status Epilepticus in Sleep

PURPOSE

To test whether patients with Electrical Status Epilepticus in Sleep (ESES) and normal neuroimaging have a smaller thalamic volume than expected for age and for total brain volume.

METHODS

Case-control study comparing three groups of subjects of 4-14 years of age and normal magnetic resonance imaging: 1) ESES patients, 2) patients with refractory epilepsy control group, and 3) healthy controls. Thalamic and total brain volumes were calculated using an algorithm for automatic segmentation and parcellation of magnetic resonance imaging.

RESULTS

Eighteen ESES patients, 29 refractory epilepsy controls and 51 healthy controls were included. The median (p25-p75) age was 8.8 (7.5-10.3) years for ESES patients, 11 (7-12) years for healthy controls, and 9 (6.3-11.2) years for refractory epilepsy controls. After correcting for total brain volume and age, the left thalamus was not statistically significantly smaller in ESES patients than in healthy controls (p=0.077), in ESES patients than in refractory epilepsy controls (p=0.056); but the right thalamus was smaller in ESES patients than in healthy controls (p=0.044), and in ESES patients than in refractory epilepsy controls (p=0.033).

CONCLUSION

Patients with ESES and normal magnetic resonance imaging have smaller relative thalamic volume controlling for age and total brain volume.

Long-term follow-up of cognitive functions in patients with continuous spike-waves during sleep (CSWS)

Continuous spike-waves during sleep (CSWS) are associated with several cognitive, neurological, and psychiatric disorders, which sometimes persist after CSWS disappearance. The purpose of this retrospective study was to investigate the correlation between general (clinical and instrumental) and neuropsychological findings in CSWS, to identify variables that predispose patients to a poorer long-term neuropsychological outcome. Patients with spikes and waves during sleep with a frequency ≥25/min (spikes and waves frequency index - SWFI) were enrolled. There were patients presenting abnormal EEG activity corresponding to the classic CSWS and patients with paroxysmal abnormalities during sleep <85% with SWFI ≥25/min that was defined as excessive spike-waves during sleep (ESWS). Clinical and instrumental features and neuropsychological findings during and after the spike and wave active phase period were considered. A statistical analysis was performed utilizing the Spearman correlation test and multivariate analysis. The study included 61 patients; the mean follow-up (i.e., the period between SWFI ≥25 first recording and last observation) was 7years and 4months. The SWFI correlated inversely with full and performance IQ during CSWS/ESWS. Longer-lasting SWFI ≥25 was related to worse results in verbal IQ and performance IQ after CSWS/ESWS disappearance. Other variables may influence the neuropsychological outcome, like age at SWFI ≥25 first recording, perinatal distress, pathologic neurologic examination, and antiepileptic drug resistance. This confirms that CSWS/ESWS are a complex pathology and that many variables contribute to its outcome. The SWFI value above all during CSWS/ESWS and long-lasting SWFI ≥25 after CSWS/ESWS disappearance are the most significant indexes that appear mostly to determine cognitive evolution. This finding underscores the importance of EEG recordings during sleep in children with a developmental disorder, even if seizures are not reported, as well as the importance of using therapy with an early efficacy.

Thalamic abnormalities in children with continuous spike-wave during slow-wave sleep: An F-18-fluorodeoxyglucose positron emission tomography perspective

OBJECTIVE

Thalamic injury has been implicated in the development of continuous spike-wave during slow-wave sleep (CSWS) in children with epilepsy. We studied thalamic abnormalities in children with CSWS using F-18-fluorodeoxyglucose (FDG)-positron emission tomography (PET) imaging.

METHODS

Twenty-three patients (12 male; mean age 9 years) with CSWS and normal thalami on brain magnetic resonance imaging (MRI) underwent FDG-PET. Thalamic glucose metabolism, represented by standardized uptake value normalized to whole brain (nSUV, RT for right thalamus and LT for left thalamus), and its asymmetry--absolute asymmetry index (AAI): ¦(RT-LT)¦*100/[(RT+LT)/2]--was calculated. These values were compared with those from 10 normal healthy controls (five female; mean age 11.1 years).

RESULTS

Thalamic glucose metabolism was abnormal in 18 patients (78.3%). Thalamic nSUV was decreased (n = 6) or increased (n = 1) bilaterally in seven children without any asymmetry. Abnormal thalamic symmetry [AAI = 3.7-31.5% (0.8-3.3% in controls)] was seen in 11 children. Of these, six children had a unilateral thalamic metabolic abnormality (increased metabolism, n = 3 and decreased metabolism, n = 3), whereas 5 of 14 children had abnormal asymmetry index with bilaterally normal (n = 4) or increased (n = 1) thalamic metabolism. No clear association of thalamic metabolic abnormalities was seen with the stage of evolution of CSWS (prodromal, acute, or residual) or with the cortical FDG abnormalities.

SIGNIFICANCE

Functional thalamic abnormalities, both unilateral and bilateral, are frequently seen in patients with CSWS. FDG-PET is a sensitive and quantifiable modality to detect these changes.

Continuous Spikes and Waves during Sleep: Electroclinical Presentation and Suggestions for Management

Continuous spikes and waves during sleep (CSWS) is an epileptic encephalopathy characterized in most patients by (1) difficult to control seizures, (2) interictal epileptiform activity that becomes prominent during sleep leading to an electroencephalogram (EEG) pattern of electrical status epilepticus in sleep (ESES), and (3) neurocognitive regression. In this paper, we will summarize current epidemiological, clinical, and EEG knowledge on CSWS and will provide suggestions for treatment. CSWS typically presents with seizures around 2-4 years of age. Neurocognitive regression occurs around 5-6 years of age, and it is accompanied by subacute worsening of EEG abnormalities and seizures. At approximately 6-9 years of age, there is a gradual resolution of seizures and EEG abnormalities, but the neurocognitive deficits persist in most patients. The cause of CSWS is unknown, but early developmental lesions play a major role in approximately half of the patients, and genetic associations have recently been described. High-dose benzodiazepines and corticosteroids have been successfully used to treat clinical and electroencephalographic features. Corticosteroids are often reserved for refractory disease because of adverse events. Valproate, ethosuximide, levetiracetam, sulthiame, and lamotrigine have been also used with some success. Epilepsy surgery may be considered in a few selected patients.

Neonatal thalamic hemorrhage is strongly associated with electrical status epilepticus in slow wave sleep

PURPOSE

Thalamic hemorrhage has been associated with neonatal cerebral sinovenous thrombosis (CSVT), especially when the straight sinus is involved, and often presents with neonatal seizures. Early thalamic injury has previously been shown to predispose to epilepsy and electrical status epilepticus in slow wave sleep (ESES). The objective of this study was to assess the prevalence of sleep-induced epileptic electroencephalography (EEG) abnormalities and postneonatal epilepsy after neonatal thalamic hemorrhage associated with CSVT, in the absence of more widespread cerebral damage.

METHODS

Between 2003 and 2008 15 neonates were diagnosed with a thalamic hemorrhage due to suspected or proven CSVT. Neurodevelopment and the history of seizures were assessed at follow-up in the outpatient clinic in all 14 survivors (age 2-9 years). Whole-night or sleep-deprived EEG recordings were obtained to assess the prevalence of interictal epileptiform activity (EA) and calculate a sleep-induced spike and wave index (SWI).

KEY FINDINGS

Three children were diagnosed with classic ESES (SWI >85%). Two children had ESES spectrum disorder (SWI between 50% and 85%), and in two children significant sleep-induced epileptiform activity (SIEA) was noted (SWI between 25% and 50%). Two other children were diagnosed with focal epilepsy, in the absence of sleep-induced epileptiform EEG abnormalities. Five children (age 2-7 years) had normal EEG recordings at follow-up. Deficits in neurodevelopment were seen significantly more often in children with ESES, ESES spectrum, or SIEA.

SIGNIFICANCE

Neonates with thalamic hemorrhage associated with straight sinus thrombosis, without evidence of more widespread cerebral damage, are at high risk of developing ESES (spectrum) disorder (35%), SIEA (14%), or focal epilepsy (14%). Electrographic abnormalities may already be present prior to recognition of cognitive deficits. Early diagnosis may guide parents and caregivers, and subsequent treatment may improve neurodevelopmental outcome. Routine annual sleep EEG recordings in children with neonatal thalamic injury following CSVT may improve recognition of ESES.

Electrical status epilepticus in sleep: clinical presentation and pathophysiology

Electrical status epilepticus in sleep involves an electroencephalographic pattern where interictal epileptiform activity is potentiated in the transition from wakefulness to sleep. Near-continuous spikes and waves that occupy a significant proportion of nonrapid eye movement sleep appear as a result of sleep-potentiated epileptiform activity. This electroencephalographic pattern appears in different electroclinical syndromes that present three common characteristics with different degrees of severity: seizures, sleep-potentiated epileptiform activity, and neuropsychologic regression. Continuous spikes and waves during sleep comprise the severest epileptic encephalopathy in the electroclinical spectrum. Landau-Kleffner syndrome presents with intermediate severity. Some "benign" pediatric focal epileptic syndromes represent the mildest end of this continuum. Based on published data, we provide a framework for clinical and electrical events. The underlying mechanisms leading to sleep potentiation of epileptiform activity in electrical status epilepticus in sleep are incompletely understood. A genetic basis or acquired early developmental insult may disrupt the normal maturation of neuronal networks. These factors may dynamically alter normal processes of brain development, leading to an age-related pattern of electroclinical expression of electrical status epilepticus in sleep.

Clinical staging and electroencephalographic evolution of continuous spikes and waves during sleep

PURPOSE

Currently, in continuous spikes and waves during sleep (CSWS) there is a lack of systematic assessments of the clinically relevant stages and the evolution of the electroencephalographic features. The aim of this study is to describe the evolution over time of clinical and electroencephalographic features in CSWS.

METHODS

We enrolled patients from our video-electroencephalography (EEG) monitoring unit with CSWS and with overnight EEG studies with at least one overnight assessment per year over a minimum period of 3 years. We studied clinical presentation and electroencephalographic features. We calculated the (1) spike-wave percentage (SWP) as the percentage of 1-s bins containing at least one spike-wave complex and (2) spike frequency (SF) as the number of spikes per 100 s.

KEY FINDINGS

Nine children (six boys) met the inclusion criteria during a 15-year period. Seven (78%) had an abnormal development prior to the epilepsy onset, and in two (22%) seizures were the only presenting symptom. Median age at epilepsy onset was 2 years (range 2 days to 4 years), at neuropsychological regression 5.1 years (4-7.7 years), and at seizure freedom 8.6 years (6.5-11.4 years). Median duration and range of clinically relevant stages were as follows: dormant stage (birth-epilepsy onset median 2 years, range 2 days-4 years), prodromal stage (epilepsy onset-neuropsychological regression 3.9 years, range 0.9-7.7 years), acute stage (neuropsychological regression-seizure freedom 2.9 years, range 2.1-6.6 years), and residual stage (after seizure freedom). Seven patients (78%) had a structural lesion on neuroimaging. At last follow-up (median 11.4 years, range 7.2-20.3 years), eight patients (89%) were receiving antiepileptic treatment, and all patients had residual neurocognitive deficits. During the acute stage, SWP was <85% in 13 (42%) of 31 assessments, and after seizure freedom, 3 of 5 patients (60%) had SWP >85%. Evolution of electroencephalographic patterns included increasing-decreasing, continuously elevated, and fluctuating patterns (33.3% each). There was good correlation between SWP and SF (Spearman correlation-coefficient = 0.942; p < 0.0001). SF, which can exceed 100%, reflected changes in electroencephalography pattern in more detail than SWP, which cannot exceed 100% and therefore has a ceiling effect.

SIGNIFICANCE

Our series systematically studied the age of occurrence of the significant clinical events. These may assist in defining clinical stages, which can provide a useful framework for future clinical trials in patients with CSWS. The severity of the epileptiform discharges on EEG did not always correlate with seizure frequency and severity; epileptiform discharges could be prominent after seizure freedom and fluctuated along the course of the disease. The values of SWP and SF correlated well, but SWP based on 1-s bins has the potential disadvantage of a ceiling effect.

Early thalamic lesions in patients with sleep-potentiated epileptiform activity

OBJECTIVE

To compare the prevalence and type of early developmental lesions in patients with a clinical presentation consistent with electrical status epilepticus in sleep either with or without prominent sleep-potentiated epileptiform activity (PSPEA).

METHODS

We performed a case-control study and enrolled patients with 1) clinical features consistent with electrical status epilepticus in sleep, 2) ≥1 brain MRI scan, and 3) ≥1 overnight EEG recording. We quantified epileptiform activity using spike percentage, the percentage of 1-second bins in the EEG tracing containing at least 1 spike. PSPEA was present when spike percentage during non-REM sleep was ≥50% than spike percentage during wakefulness.

RESULTS

One hundred patients with PSPEA (cases) and 47 patients without PSPEA (controls) met the inclusion criteria during a 14-year period. Both groups were comparable in terms of clinical and epidemiologic features. Early developmental lesions were more frequent in cases (48% vs 19.2%, p = 0.002). Thalamic lesions were more frequent in cases (14% vs 2.1%, p = 0.037). The main types of early developmental lesions found in cases were vascular lesions (14%), periventricular leukomalacia (9%), and malformation of cortical development (5%). Vascular lesions were the only type of early developmental lesions that were more frequent in cases (14% vs 0%, p = 0.005).

CONCLUSIONS

Patients with PSPEA have a higher frequency of early developmental lesions and thalamic lesions than a comparable population of patients without PSPEA. Vascular lesions were the type of early developmental lesions most related to PSPEA.

Continuous spike and waves during sleep and electrical status epilepticus in sleep

Continuous spike and waves during sleep is an age-related epileptic encephalopathy that presents with neurocognitive regression, seizures, and an EEG pattern of electrical status epilepticus during sleep. Patients usually present around 5 years of age with infrequent nocturnal unilateral motor seizures that progress within 1 to 2 years to a severe epileptic encephalopathy with frequent seizures of different types, marked neurocognitive regression, and an almost continuous spike-wave EEG pattern during slow-wave sleep. The pathophysiology of continuous spike and waves during sleep is not completely understood, but the corticothalamic neuronal network involved in physiologic oscillating patterns of sleep is thought to be switched into a pathologic discharging mode. Early developmental injury and/or genetic predisposition may play a role in the potentiation of age-related hyperexcitability in the immature brain. A better understanding of the mechanisms leading to electrical status epilepticus during sleep may provide additional therapeutic targets that can improve the outcome of seizures, EEG pattern, and cognitive development in patients with continuous spike and waves during sleep.

Unilateral thalamic lesions and generalized or lateralized spike wave discharges

We report four adult patients who had thalamic lesions and lateralized or generalized spike wave discharges (SWDs). The first two patients also had cortical lesions. The role of the cortex and thalamus in the generation of SWDs is discussed. The third patient had a history of idiopathic generalized epilepsy (IGE) with intractable seizures. The last patient had partial seizures and absences. The coexistence of IGE with refractory focal epilepsy and the relation with thalamic lesions are discussed.

Thalamic lesion and epilepsy with generalized seizures, ESES and spike-wave paroxysms--report of three cases

We report three patients, who have thalamic lesion and secondary generalized epilepsy with generalized spike wave pattern. The first two patients have unilateral perinatal lesion, one with generalized tonic-clonic seizures on awakening the other with Landau-Kleffner-like syndrome. During the course of the disease both children developed electrical status epilepticus in slow wave sleep (ESES). The third patient has a dominantly unilateral thalamic tumor and epilepsy that mimics juvenile myoclonic epilepsy. All the patients have a lesion located in the inferior-medial-posterior part of the thalamus. The role of some thalamic and subthalamic nuclei in the generalized spike-wave electrical pattern patophysiology is discussed, with emphasis on the possible role of the inhibitory system from the zona incerta.

Early Thalamic Injury Associated with Epilepsy and Continuous Spike-Wave during Slow Sleep

PURPOSE

Mechanisms inducing continuous spike-wave during slow sleep (CSWS) in encephalopathy with electrical status epilepticus during sleep are still unclear. Recently, some sporadic cases with early thalamic injury associated with CSWS have been reported. The aim of the study was to investigate in a population of patients with an early thalamic injury the presence of an activation of paroxysmal activities during sleep, their characteristics, and possible relations to neuroimaging and neuropsychological features.

METHODS

Thirty-two patients with prenatal or perinatal thalamic injuries, mostly due to a vascular mechanisms, were fully examined, including neuroimaging, EEG monitoring, and cognitive follow-up.

RESULTS AND CONCLUSIONS

Twenty-nine of 32 patients showed major sleep EEG activation. Among these 29 patients, two different groups were distinguished: the first included the more or less typical CSWS (12 cases), generally with symmetry of spike and waves (SWs) and often with no spindle at all. The other cases had an usual asymmetry of SWs and presence or reduction of spindles, plus other atypical features concerning synchronism and morphology of SWs. Behavioral disorders were significantly more present in patients with a true CSWS; their improvement (and in one case of the three thoroughly followed the improvement of cognitive competence) paralleled the disappearance of CSWS. The generally predominant injury of the lateral aspect of the thalamus included reticular nucleus and ventral nuclei. An imbalance of gamma-aminobutyric acid (GABA)(B)--versus GABA(A)--mediated receptors may be evoked as a cofactor predisposing to CSWS.

Epilepsy in shunted posthemorrhagic infantile hydrocephalus owing to pre- or perinatal intra- or periventricular hemorrhage

Epilepsy is relatively common in infants with hydrocephalus. Its mechanism is controversial; in fact, studies on etiologically heterogeneous series are not able to clarify the mechanism generating epilepsy or to suggest effective prevention and treatment strategies. Our study is aimed at assessing the onset and evolution of epilepsy, as well as concurrent cognitive development of a homogeneous series of shunted posthemorrhagic hydrocephalus owing to pre- or perinatal intra- or periventricular hemorrhage. Forty patients were enrolled in the study. Twenty-six were patients with grade II-III intraventricular hemorrhage, 16 of whom had associated ischemic lesions. In the remaining 14 patients, a grade IV intra-ventricular hemorrhage was found. Epilepsy was observed in 27 patients. Aside from 10 cases with nonsyndromic forms of epilepsy, it was possible to define at least three different age-dependent epileptic syndromes: symptomatic neonatal location-related epilepsy with transient West's syndrome in infancy in 5 patients; West's syndrome in 8 patients; and continuous spike-waves during sleep in 4 patients. Epilepsy was significantly correlated with ischemic lesions only. Early thalamic injuries frequently evolved toward continuous spike-waves during sleep, indicating that patients with thalamic injury must be monitored to detect continuous spike-waves during sleep early. Cerebellar atrophy, in addition to epilepsy and other brain injuries, accounted for disorders of cognitive development.