Merosin-negative congenital muscular dystrophy,occipital epilepsy with periodic spasms and focal cortical dysplasia. Report of three Italian cases in two families

We report clinical, EEG and neuroimaging findings of three patients in two Italian families with merosin-negative congenital muscular dystrophy (CMD), drug-resistant occipital epilepsy, diffuse persistent cerebral white matter changes and focal cortical dysplasia. Clinical and epilepsy histories, EEG and neuroimaging findings were very similar in all patients. Seizures started in childhood and mainly consisted of periodic spasms, a particular type of partial seizure characterized by clusters of epileptic spasms. The motor expression of the spasms was very mild so that they had been frequently missed or misinterpreted as non-convulsive generalized absence seizures. Interictal EEG showed occipital spike-waves and bilateral synchronous slow spike-wave discharges. Ictal EEG showed prolonged periodic sequences of slow waves with associated fast rhythm complexes, characteristic of periodic spasms. Two patients had normal intelligence, one patient presented moderate mental retardation. Focal cortical dysplasia in the posterior areas of the brain, in addition to marked diffuse white matter alterations, was detected in the magnetic resonance images of all patients. Findings in these patients indicate that in merosin-negative CMD brain involvement can include cortical dysplasia, in addition to white matter changes. In such cases the brain damage can lead to a childhood-onset localization-related symptomatic occipital epilepsy. Epileptic seizures and cortical dysplasia can be, however, difficult to detect in CMD. The clinical semiology of epileptic seizures may in fact be modified because of muscular weakness. This implies that epilepsy may be misdiagnosed or even missed and EEG-polymyographic recordings may be necessary to identify it. Similarly, cortical dysplasia may be very localized and visible by neuroimaging only if it is carefully investigated on the basis of epileptological and EEG-polymyographic findings.     

Temporal lobe microdysgenesis in epilepsy versus control brains

Histopathologic evaluation of brain tissue derived from surgically treated patients with medically refractory temporal lobe epilepsy (TLE) frequently reveals structural brain lesions in the surgical specimen. While several of the most commonly encountered lesions such as low-grade neoplasms or vascular malformations are well established as structural substrates of epilepsy, the significance of subtle microscopic characteristics has remained controversial. Within the spectrum a broad range of microscopic features has previously been reported as "mild cortical dysplasia," "focal cortical dysplasia," or "microdysgenesis," including cortical laminar disorganization, columnar arrangement of cortical neurons, marked clustering of neurons throughout cortical layers II-VI, increased numbers of molecular layer neurons, marked perivascular clustering of oligodendroglia in the white matter, single heterotopic neurons in the deep white matter, glioneuronal hamartia, giant neurons, and balloon cell change. In this paper we report the frequency of these features in temporal lobe tissue of 47 surgically treated TLE-patients vs 29 normal autopsy controls. While most of them were found in both cases and controls, clustering of neurons throughout cortical layers II-VI, perivascular clustering of oligodendroglia in the white matter, increased single heterotopic white matter neurons, and glioneuronal hamartias predominated in tissue from patients with epilepsy (p < 0.05). A count of more than 10 white matter neurons/HPF was associated with a worse postoperative outcome (p < 0.05). These data suggest that certain microscopic characteristics are associated with the epileptic process, while others appear as normal variants.     

Occipital encephalocele and epilepsy]

We report the incidence of epilepsy in 7 patients with occipital encephalocele (meningocele: 6 cases, meningoencephalocystocele: 1 case). Two cases had epilepsy and a case without the history of epileptic seizure had an epileptic pattern on the EEG. All these 3 cases had cortical dysplasia(CD) such as schizencephaly and subcortical gray matter, and two of them were associated with mental retardation. The location of the prominent CD was correlated with the EEG abnormalities and clinical epileptic pattern in each case. Associated hydrocephalus and placement of VP shunt had no significant influence on the occurrence of the epilepsy. Thus, complicated CD is thought to be epileptogenic in patients with occipital encephalocele.     

Generalized cortical dysplasia. Clinical and pathologic aspects

Three children with profound mental retardation and intractable seizures died at ages 10 months, 3 years, and 7 years, respectively. Complete examination of their brains showed generalized cortical dysplasia, without any major malformation of the external gyral pattern. The neuropathologic features of cortical dysplasia include abnormally thickened cortex with indistinct demarcation of the gray-white matter junction. In many areas, the cortex contained increased numbers of large neurons with disordered cortical lamination. Heterotopic neurons were scattered throughout the white matter with decreased myelination of the underlying white matter. To our knowledge, these cases represent the first fully detailed neuropathologic study of diffuse cortical dysplasia--a newly recognized entity of abnormal neuronal migration.     

New Syndrome With the Sakoda Complex, Bilateral Anophthalmia, and Cortical Dysgenesis

An 8-year-old Japanese boy had Sakoda complex (basal encephalomeningocele, agenesis of the corpus callosum, and cleft lip and/or palate) associated with bilateral anophthalmia, dysgenesis of the cerebral cortex, severe mental retardation, and intractable epilepsy as core symptoms and hemiparesis, microcephalus, short stature, and hemivertebra. Tada and Nakamura described the first case of the Sakoda complex associated with bilateral anophthalmia, cortical dysgenesis, neonatal-onset seizures, and severe mental retardation. Fourteen patients with the Sakoda complex with or without ocular dysplasia were reviewed. It is proposed that these cases belong to a clinical entity that is distinguishable from the remaining 12 patients because of bilateral anophthalmia, cortical dysgenesis, and its resulting severe mental retardation and intractable epilepsy. There is a possibility that these two cases are one severe end of certain spectrum disorders in which certain common gene(s) might be implicated.     

EPILEPSY AND FOCAL GYRAL ANOMALIES DETECTED BY MRI: ELECTROCLINICO-MORPHOLOGICAL CORRELATIONS AND FOLLOW-UP

The authors studied 10 patients (mean age 15 years 6 months) with localized developmental gyral disorder detected by MRI. There were two groups of major malformations. Seven patients (group 1) had unilateral 'macrogyric-like' insulo-opercular changes, one of whom died early in life and had extensive microgyria. The six others had mental retardation and epilepsy, three of whom had focal neurological signs. Age at onset of epilepsy varied greatly. Clinical and EEG data suggested a wider cerebral involvement than recognized on MRI. The remaining three patients (group 2) had abnormal gyri of variable topography and extension, with bulging grey matter and ventricular deformity. One had mental retardation, another had neurological signs. All had intractable complex partial seizures and focal EEG anomalies correlating with the MRI lesion site, pointing to a well-defined epileptogenic zone. No clinical or EEG evidence of significant malformation in the remaining brain tissue was observed. Ablative surgery was beneficial for one patient; focal cortical dysplasia was the pathological substrate.     

Structural MRI biomarkers of shared pathogenesis in autism spectrum disorder and epilepsy

Etiological factors that contribute to a high comorbidity between autism spectrum disorder (ASD) and epilepsy are the subject of much debate. Does epilepsy cause ASD or are there common underlying brain abnormalities that increase the risk of developing both disorders? This review summarizes evidence from quantitative MRI studies to suggest that abnormalities of brain structure are not necessarily the consequence of ASD and epilepsy but are antecedent to disease expression. Abnormal gray and white matter volumes are present prior to onset of ASD and evident at the time of onset in pediatric epilepsy. Aberrant brain growth trajectories are also common in both disorders, as evidenced by blunted gray matter maturation and white matter maturation. Although the etiological factors that explain these abnormalities are unclear, high heritability estimates for gray matter volume and white matter microstructure demonstrate that genetic factors assert a strong influence on brain structure. In addition, histopathological studies of ASD and epilepsy brain tissue reveal elevated rates of malformations of cortical development (MCDs), such as focal cortical dysplasia and heterotopias, which supports disruption of neuronal migration as a contributing factor. Although MCDs are not always visible on MRI with conventional radiological analysis, quantitative MRI detection methods show high sensitivity to subtle malformations in epilepsy and can be potentially applied to MCD detection in ASD. Such an approach is critical for establishing quantitative neuroanatomic endophenotypes that can be used in genetic research. In the context of emerging drug treatments for seizures and autism symptoms, such as rapamycin and rapalogs, in vivo neuroimaging markers of subtle structural brain abnormalities could improve sample stratification in human clinical trials and potentially extend the range of patients that might benefit from treatment.This article is part of a Special Issue entitled “Autism and Epilepsy”.     

Double Inversion Recovery Magnetic Resonance Imaging in Identifying Focal Cortical Dysplasia

BackgroundFocal cortical dysplasia is commonly recognized in pediatric epilepsy surgery. Despite characteristic radiographic features, focal cortical dysplasia can be subtle on magnetic resonance imaging. Double inversion recovery acquisition suppresses the white matter signal, which may enhance visualization of abnormal features at the gray–white matter interface. We assessed the ability of double inversion recovery to distinguish focal cortical dysplasia from periventricular nodular heterotopia and normal brain.MethodsPatients with focal cortical dysplasia were identified from our patient database, as was a control group comprising patients with periventricular nodular heterotopia and healthy persons. A senior neuroradiologist reviewed all clinical images and classified them as patients with focal cortical dysplasia (n = 16) or control subjects (periventricular nodular heterotopia, n = 13; normal, n = 20). Four neuroradiologists reviewed the de-identified and randomized double inversion recovery and magnetization prepared rapid acquired gradient echoes (MPRAGE) sequences for each person and scored them as normal, focal cortical dysplasia, or periventricular nodular heterotopia.ResultsAmong individual reviewers, double inversion recovery showed sensitivity from 50% to 88% and specificity from 67% to 91% in detecting focal cortical dysplasia. The sensitivity was notably higher in reviewers with more clinical experience with the technique. Consensus agreement among the three most experienced reviewers gave a sensitivity of 88% (95% confidence interval [CI], 72% to 97%) and specificity of 88% (95% CI, 62% to 98%) for double inversion recovery and sensitivity of 44% (95% CI, 20% to 70%) and specificity of 100% (95% CI, 89% to 100%) for MPRAGE.ConclusionsDouble inversion recovery is sensitive for detection of focal cortical dysplasia with experienced users, particularly when there is consensus agreement. The use of two clinically available magnetic resonance imaging acquisitions—double inversion recovery and another sequence with high specificity such as MPRAGE—would be complementary in the evaluation of lesional epilepsy.     

The clinical spectrum of focal cortical dysplasia and epilepsy

Focal cortical dysplasia is an important pathologic substrate in patients with epilepsy, but its clinical spectrum has not yet been completely defined. We retrospectively studied 30 epilepsy surgery patients with focal abnormalities of neuronal migration as the only histopathologic finding in resected tissue. Patients comprised two clinical groups. Seventeen patients with extratemporal epilepsy had early (median age, 7.0 years) extratemporal resection or hemispherectomy for severe epilepsy (47% of patients with > 10 partial seizures a day) that began in infancy or early childhood (median age, 1.0 year), usually in the setting of mental retardation or developmental delay (59% of patients), and often with magnetic resonance imaging (MRI) evidence of focal neuronal migration abnormality (44% of patients). In contrast, 13 patients with temporal lobe epilepsy were significantly older at age of seizure onset (median, 8.0 years; p = 0.001) and surgery (median, 22.0 years; p = 0.001), with less severe epilepsy (no patients with an average of > 10 seizures a day; p = 0.004), and without mental retardation or MRI evidence of neuronal migration abnormality (p = 0.001). In both groups, positron emission tomography (PET) was more sensitive than MRI and showed focal hypometabolism in seven patients with normal MRI. Seizure-free outcome tended to be more common after temporal lobectomy (77%) than after extratemporal resection or hemispherectomy (53%). Pathologic abnormalities were more severe in patients with extratemporal epilepsy than in patients with temporal lobe epilepsy. The clinical spectrum of focal cortical dysplasia included not only infants and children with severe extratemporal epilepsy and mental retardation, but also older patients with temporal lobe epilepsy and at least boderline IQ. Preoperative diagnosis may be difficult in cases with less severe pathologic abnormality, but high-resolution MRI and PET can increase the yield.     

Fiber tractography assessment in double cortex syndrome

Introduction  

Subcortical band heterotopia (SBH) or double cortex syndrome is a malformation of cortical development that may be related to intractable epilepsy and severe mental retardation or to mild epilepsy and slight mental delay or normal cognitive functions. Several studies have been performed using neuroradiological or neurophysiological techniques, like SPECT, PET, MRS, fMRI, and MEG, in attempt to better characterize this neuronal migration disorder. Recently, also diffusion tensor imaging (DTI) and fiber tracking (FT) have been used to investigate on white matter anomalies in SBH, adding more information about such gray matter anomaly.     

Cortical dysplasia with angiodysgenesis and chronic inflammation in multifocal partial epilepsy

A 25-year-old man with a long history of temporal lobe epilepsy developed right occipital lobe seizures and a progressive right homonymous hemianopia. MRI showed diffuse enhancement of the left temporoparieto-occipital white matter and cortical thickening of the left medial temporal lobe. The resected temporal lobe revealed cortical dysplasia and angiodysplasia with foci of more recent ischemic necrosis and chronic inflammation as an explanation for the clinical deterioration.     

Epilepsy surgery in children with focal cortical dysplasia (FCD): results of long-term seizure outcome

The purpose of this study was to assess the effect of epilepsy surgery on seizure outcome in children and adolescents under 18 years with intractable epilepsy due to focal cortical dysplasia. We analysed clinical data, such as age at seizure onset, epilepsy course, localisation of focus from presurgical evaluation, MRI, tissue pathology and seizure outcome in 68 patients 6 months to 9 years after epilepsy surgery. Seizure outcome was classified according to the Engel classification. Mean age at seizure onset was 7 months, ranging from the first days of life to 7 years. All patients had medically intractable epilepsy. Localisation of the lesion was predominantly extratemporal: posterior (uni- or multilobar) 43 %, frontal without central region 26 %, multilobar involving central area 19 % and temporal in 12 %. MRI signs typically seen in cortical dysplasia (FCD) such as localised blurring of gray-white matter junction was found in 68 %, dysgyria in 62 %, thickening of the cortical ribbon in 46 % and T2 signal elongation of the subcortical white matter in 40 % of the patients' MRI. Age at surgery ranged from 5 months to 16 years; 14 patients were under 2 years when operated on. In 34 patients (6 patients under 3 years) subdural grid electrode evaluation was performed prior to surgery. Pathology revealed focal cortical dysplasia without balloon cells (type I) in 60 %, FCD of the balloon cell subtype (type II) in 40 % of the specimens. Postoperative complications were subdural hygroma in 5 and an increased motor deficit in 2 patients. Up to two years after epilepsy surgery 50 % of the children were seizure free (Engel class I), 10 % Engel class II, 33 % Engel class III and 7 % unchanged (Engel class IV). Long-term seizure outcome (> 3 years post surgery) in 32 patients showed similar results (class I 50 %, class II 19 %, class III 28 %, class IV 3 %). Complete resection of the dysplastic lesion was significantly correlated with favorable seizure outcome, whereas seizure outcome was not significantly different in patients with mild (type I) or balloon cell (type II) FCD. Children operated after 6 years of age had no better outcome than children operated in infancy or at preschool age. Epilepsy surgery resulted in good (class I and II) seizure control in 60 % of children with intractable epilepsy due to focal cortical dysplasia.     

Altered layer-specific gene expression in cortical samples from patients with temporal lobe epilepsy

Purpose: Neuropathologic investigations frequently reveal the presence of architectural cortical dysplasia in patients with temporal lobe epilepsy (TLE), sometimes as an isolated finding but more commonly associated with hippocampal sclerosis (HS) and white matter abnormalities. The histologic pattern and the developmental origin of these alterations are not clear, and their diagnostic criteria are poorly defined. The aim of this study was to investigate the expression patterns of layer‐specific genes in cortical specimens from patients with TLE presenting different subtypes of cortical malformations in order to elucidate the disorganization of the laminar architecture of such epileptogenic abnormalities and provide evidence to enable a more objective neuropathologic diagnosis. Methods: We analyzed the expression patterns of CUX2, RORBETA, ER81, NURR1, and CTGF genes, respectively specific markers of layers II–III, IV, V, VI, and VIb, in surgical samples by means of in situ hybridization and compared them with those observed in control cortices. The pathologic samples included typical architectural dysplasia (group 1); temporal lobe sclerosis, a variant of architectural dysplasia (group 2); and white matter heterotopic neuronal aggregates, namely small lentiform nodules (group 3). These abnormalities may have been associated or not with HS. Key Findings: All of the genes had a laminar expression pattern in normal cortices, whereas groups 1 and 2 showed alterations mainly involving layers V and VI, and highlighted by the altered distribution of ER81‐ and NURR1‐positive cells. The expression of ER81 and NURR1 genes was different among the groups, and atypical coexpression of NURR1 and CUX2 mRNA was detected in the neurons making up the small lentiform nodules. Significance: These findings indicate that defects in cortical organization involving the deeper cortical neurons may be a common etiopathogenic mechanism in group 1 and 2 cortical dysplasia, whether isolated or associated with HS, and that developmental disorders may also be present in the white matter (group 3). They also provide evidence that the layer‐specific genes can be usefully used to investigate the neuropathology of human cortical dysplasia.     

Cortical dysplasia in temporal lobe epilepsy: magnetic resonance imaging correlations

Cortical dysplasia has been documented in histological specimens surgically removed for treatment of refractory temporal lobe epilepsy. We studied 10 patients with cortical dysplasia and complex partial seizures who underwent temporal lobectomy. Magnetic resonance imaging revealed abnormalities in 5 of the patients who had microscopically detectable major abnormalities. Magnetic resonance imaging revealed an abnormal cortical-white matter architectonic pattern in 2 patients with moderate cortical dysplasia. In the remaining 3 patients, magnetic resonance imaging findings were unremarkable. These observations suggest that magnetic resonance imaging is sensitive in the detection of certain dysplastic lesions in temporal lobe epilepsy. Preoperative identification of these abnormalities by magnetic resonance imaging may permit early and optimal surgical treatment in patients with refractory epilepsy.     

A case in the spectrum of the oculo-encephalo-hepato-renal syndrome

An 18-year-old male is presented with unprecedented central nervous system findings (cerebral dysplasia and sacral meningocele) possibly in the spectrum of the oculo-encephalo-hepato-renal syndrome. He had severe mental retardation, triplegia, epilepsy, retinitis pigmentosa, and chronic renal failure. Magnetic resonance imaging demonstrated cerebral dysplasia (left dominant abnormal gyri, hypoplastic white matter, basal ganglia, and thalamus, and absence of the septum pellucidum) and the hypoplastic cerebellum and brainstem. A sacral meningocele was observed first at 16 years of age. His renal function gradually worsened after 11 years of age. His liver function was normal. The previously reported 72 cases with the oculo-encephalo-hepato-renal syndrome are reviewed.     

An autopsy case of bathtub drowning in epilepsy

We report an autopsy case of bathtub drowning in epilepsy. A 26-year-old female with mental retardation had been treated for refractory epilepsy. Her younger sister found her floating supine in the bathtub 45 min after starting bathing. Neuropathological examination revealed cerebral cortical dysplasia in the precentral gyrus of the left hemisphere, which had not been detected by MRI, suggesting the etiology of epilepsy. In bathtub submersion injury of an unidentified cause, neuropathological examination should be performed to reveal any lesion underlying epileptic seizures. Additionally, we present statistics on bathtub submersion injury in children aged 5 years or older in Japan based upon nationwide survey data obtained in 1991. Forty-seven percent of them had associated epilepsy or convulsive attacks and 71% died. It is necessary for epileptic patients and their families to understand that the risk of bathtub drowning can be minimized if proper precautions are taken.     

Enhanced visualization of blurred gray-white matter junctions in focal cortical dysplasia by voxel-based 3D MRI analysis

PURPOSE: Focal cortical dysplasia (FCD), a frequent cause of partial epilepsy, is often associated with blurring of the gray-white matter junction in magnetic resonance images (MRI). To improve the recognition and delineation of FCD we developed a novel voxel-based image post-processing method for enhanced visualization of blurred gray-white matter junctions. METHODS: Using standard algorithms of statistical parametric mapping software (SPM99) a T1-weighted MRI volume data set is normalized and segmented. The distribution of gray and white matter is analyzed on a voxelwise basis and compared with a normal database. Based on this analysis, a three-dimensional feature map is created which highlights brain areas with blurred gray-white matter transition. This method was applied to the MRI data of 25 epilepsy patients with histologically proven FCD. RESULTS: In 18/25 patients the new feature maps clearly showed that the dysplastic lesions were accompanied by blurring of the gray-white matter junction. Combined with a formerly published method of voxel-based 3D MRI analysis, 21/25 FCD lesions were shown to be associated with either blurring or abnormal extension of gray matter beyond the normal cortical ribbon, including four cases with lesions not or incompletely recognized on conventional MRI. CONCLUSIONS: The MRI post-processing presented here improves the visualization of FCD and may increase the diagnostic yield of MRI. Thereby, it provides a valuable additional diagnostic tool in the presurgical evaluation of epilepsy patients.     

Cognitive abilities in children with congenital muscular dystrophy: correlation with brain MRI and merosin status.

The aim of the study was to evaluate whether children with merosin-positive or merosin-deficient congenital muscular dystrophy (CMD) show any cognitive impairment and whether this is related to brain abnormalities on magnetic resonance imaging (MRI). Twenty-two patients (age range: 5.8-15.3 years) were assessed by the Wechsler Intelligence Scales. Twelve were merosin-positive and ten merosin-deficient. One child had severe mental retardation and could not be tested. The full scale IQ in the remaining 21 ranged from 51 to 134, the verbal IQ ranged from 78 to 136 and the performance from 51 to 136. Of the twelve children with normal merosin one had a mild delay (IQ < 75) and two were borderline (IQ 75-95). Of the ten children with merosin-deficiency, one showed severe mental retardation and could not be tested, one showed a mild delay and two had borderline results. While the children with merosin deficiency with the typical diffuse white matter changes on MRI had normal scores, the children who in addition had cerebellar hypoplasia had lower performance IQ. The child with cortical dysplasia had severe mental retardation. Our results suggest that the spectrum of cognitive abilities in CMD is very wide even within genetically homogeneous conditions.     

Voxel-based 3D MRI analysis helps to detect subtle forms of subcortical band heterotopia

PURPOSE: To evaluate the potential diagnostic value of a novel magnetic resonance image (MRI) postprocessing technique in subtle forms of subcortical band heterotopia (SBH). The method was introduced to improve the visualization of blurred gray-white matter junctions associated with focal cortical dysplasia but was found to be applicable also to SBH. METHODS: In the voxel-based MRI analysis presented here, T1-weighted MRI volume data sets are normalized and segmented using standard algorithms of SPM5. The distribution of gray and white matter is analyzed on a voxelwise basis and compared with a normal database of 150 controls. Based on this analysis, a three-dimensional feature map is created that highlights brain areas if their signal intensities fall within the range between normal gray and white matter and differ from the normal database in this respect. The method was applied to the MRI data of 378 patients with focal epilepsy in three different epilepsy centers. RESULTS: SBH was diagnosed in seven patients with five of them showing subtle forms of SBH that had gone unrecognized in conventional visual analysis of MRI and were only detected by MRI postprocessing. In contrast to distinct double cortex syndrome, these patients had partial double cortex with SBH mostly confined to posterior brain regions. CONCLUSIONS: The results of this study suggest that a considerable part of cases with SBH might remain unrecognized by conventional MRI. Voxel-based MRI analysis may help to identify subtle forms and appears to be a valuable additional diagnostic tool in the evaluation of patients with cryptogenic epilepsy.     

Microdysgenesis in mesial temporal lobe epilepsy: a clinicopathological study

The interrelationship of mesial temporal lobe epilepsy (MTLE), hippocampal sclerosis, and febrile convulsions still remains an enigma. Additional microscopical cortical dysplasia or microdysgenesis has been suggested as pre-existent susceptibility factor rendering the affected brain vulnerable to the development of MTLE after initial precipitating injuries such as febrile convulsions. Twenty-four MTLE cases with histopathologically definite hippocampal sclerosis were examined for clearly defined features of microdysgenesis and further signs of neocortical dysplasia. Although unequivocal signs of dysplasia were absent, 29.2% of cases showed cortical neuronal clustering, 25.0% showed perivascular clustering, and 20.8% showed increased white matter neurons. The features of microdysgenesis studied here were not linked with each other and were not related to initial precipitating injuries, positive family history, or any other clinical parameter. Their suggested fundamental role as dysplastic factor within development of hippocampal sclerosis and MTLE is not confirmed.